This is less useful than most people expected. Redwood has been struggling because the expected battery turnover is not occurring. EV batteries are lasting a long time, so they stay in the car are and not being recycled or reused in any quantity yet.
If EV batteries last 20+ years in EV's, it'll be > 2040 before there are significant numbers of EV batteries available to recycle or reuse.
A lot of the early EV battery life projections were based on Nissan Leaf Gen 1. Which had a horrendous battery pack that combined poor choice of chemistry, aggressive usage and a complete lack of active cooling.
When EVs with good battery pack engineering started hitting the streets, they outperformed those early projections by a lot. And by now, it's getting clear that battery pack isn't as much of a concern - with some of the better designs, like in early Teslas, losing about 5-15% of their capacity over a decade of use.
Don't forget that the original Leaf pack was only 24 kWh. So if you assume a ~1000 full-equivalent-charge-cycles lifespan, then the large Gen2 62 kWh pack will live 2.5 times longer than an original 24 kWh pack. If you average 3.5 miles/kWh, the 24 kWh battery will be expected to last somewhere around 84,000 miles. While the 62 kWh pack will last for 217,000 miles.
The vast majority of EV owners will spend $0 to replace their batteries since the batteries last longer than the rest of the car does.
Edit: part of that is that a Prius with 250,000 miles needing its second battery replacement is still a valuable car with a reasonable expectation of a lot more miles. OTOH a Tesla at 250,000 miles needing its first battery replacement...
Similarly Chrysler hybrid owners spend less money on battery replacements than Toyota hybrid owners. Not a compliment, it means they're scrapping their cars earlier.
My 2015 Model as’ battery went the day the warranty ended and so they gave me a trash refurbished one “half price” for $8k
This low maintenance cost thing is BS once something actually goes wrong. And it’s awfully frustrating / sus when it happens the moment the warranty ends
My 2017’s HV fuse went just days before the warranty ended. They tried to charge me $330 for that planned part.
LFP does have a lot more cycles in them by the nature of the chemistry. However EV grade NMC aren’t terrible either.
Depth of discharge and charge rate affect LFP specifically in such a way that if you keep them a good margin above cutoff voltage, relatively cool (60C and under, and do 1C and lower charging you can get 10,000 cycles per their data sheets. The same sheets will also list lower cycle counts for harder use that lines up with the standards used for earlier cells. Basically I think we’ll find a lot of gently to moderately used hardware will last a long time.
Whatever a believable use case looks like will probably end up on those data sheets and it wouldn’t surprise me if we see 15,000 and 20,000 cycles advertised for cells intended in low charge and discharge use cases (probably not cars but maybe home energy storage).
My Taycan has an ongoing battery issue relating to LG Pouch cells but its construction rather than composition that is the culprit. The same compositions from LG in prismatic and cylindrical models, the only models they sell now, so far haven’t been a mess for car makers.
I am a bit more concerned about batteries now as opposed to an year ago.
We had this article from Elektrek [1] about battery issues in South Korea. When I asked my local electric maintenance shop [2, sorry for the FB link], they said they have started seeing the same issue in Model 3s and Ys in Canada as well. (They also said that it is too early to tell how common it would become)
This may bode well for recycling since the issues is an unbalance, not the whole pack failing.
Tesla made powerwalls a product for a reason. They were supposed to come from outdated Tesla cars, but that never materialized. If it is materializing now, they already know what they are going to do.
I can respect that. For what it is worth, I validated with a well-trusted local shop that works on EVs (and works with Tesla) that said the issue is starting to pop up. Moreover, it's the government of Korea that is making this claim as well.
(I also find it difficult to separate noise from signal about Tesla. However, I don't consider them innocent victims; besides the elephant in the room, they literally eliminated their PR department)
Bad reasons to hate something are bad press for Tesla, and how many people are going to read past a headline that confirms their bias? This isn't limited to Tesla, mind you,
and is a broader statement on clickbait, and the state of the Internet and media and society today. Of course, anybody on Tesla's side knows to take Electrek and the rest of the Inernet’s coverage with a grain of salt, but with rabid fanboys on both sides, it's hard to know how large a grain of salt, and when.
Electrek's Fred has a ton of Tesla referral credits. Tesla owes him 2 Roadster's and has reneged. After Tesla screwed him, Fred's coverage turned from glowing to negative.
LiPo batteries were quiet expensive when it was initially released. NiMH was really the only option in town.
And with a lower energy density battery that's also heavier, adding a cooling system would have also added a bunch of weight to the already heavy car with a barely usable range of 100 miles.
Gen 2, however, had no excuses. They had every opportunity to add active cooling and they still decided to go with just air cooling.
Every generation of the production Nissan Leaf has used lithium batteries. AFAIK no modern (~post-2000) mass-produced (>10k units sold) EV has ever used NiMH or lead-acid batteries.
Edit: Checking Wikipedia to verify my information, I found out that Nissan actually sold a lithium-battery EV in 1997 to comply with the same 90s CARB zero-emissions vehicle mandate that gave us the GM EV-1: https://en.wikipedia.org/wiki/Nissan_R%27nessa#Nissan_Altra
EVs no, but I think some Toyota hybrids (which are of course not even PHEVs) still use NiMH. Toyota tends to be very tight-lipped about their batteries and their sizes (or rather, lack thereof).
Tends to be tight lipped??? It is in the catalog[1]! It is more that American consumers aren't tech obsessed than Toyota being reluctant to share.
Even just looking at online media reports[2][3] clearly sourced from some exact same press event, it is obvious that US English equivalents are much lighter in content than Japanese versions. They're putting the information out, no one's reading it. It's just been the types of information that didn't drive clicks. Language barrier would have effects on it too, that Toyota is a Japanese company and US is an export market, but it's fundamentally the same phenomenon as citizen facing government reports that never gets read and often imagined as being "hidden and withheld from public eyes", just a communication issue.
I was looking up this year's Corolla a while ago and likewise there was minimal info that I could see about the battery capacity, which I think I figured out was about 3kWh.
Leaf Gen 1 didn't have NiMH. It had a lithium-based battery chemistry, but some bastard offshoot of it. One that really didn't fare well under high current draw, or deep discharge, or high temperatures, or being looked at wrong.
On the used market you'll find absolutely cooked (literally) Leafs whose first life was in Arizona and barely have enough range to back out of the driveway.
Is there any value in fixing the battery on these? IE: Do the other components last long enough to be worth the cost?
It seems like procuring the battery is not as expensive as the Tesla battery (I see someone who did it themselves for $6k on Youtube with the battery from a wrecked leaf). In comparison, the cost I see for my Model 3 is about ~$18k CAD.
Getting a car up and running for $8k might be worth it if it is otherwise dependable, but I've only heard unfortunate stories about the first gen Leaf.
Is it worth spending money on a car that old? You are putting more than the car is worth into fixing it and you won't get that back if you sell. You also have no idea when/if something else will go. thew worst case is the day after you fix it someone hits you and the repairs will be $30,000 - what it cost new and there are still a lot of worn out parts: insurance will give you $4000 and tell you to eat the loss.
30k is the real cost to repair some accident damage to a leaf - think bent frame. this could happen anytime. Nobody would pay that price to the whole car ends up in a junk yard.
> Gen 2, however, had no excuses. They had every opportunity to add active cooling and they still decided to go with just air cooling.
The Lizard pack in the later Nissan Leafs has held up surprisingly well. I have a 2015 that still gets 75 miles of range. I'm sure they thought it wasn't necessary and they probably had the actuarial numbers to justify it.
It didn't just had horrendous service life, it was designed for some set years of life to be regularly replaced and repurposed for battery storages. Nissan had business schemes outlined for that with Leaf packs.
I think Tesla deserves credit for rethinking hat model into chassis-life battery packs and surpluses rather than recovered cells for grid storages.
Especially considering that, resales of Gen1 Leafs milked for EVs and renewables incentives is like destination fees atrocious. You can find fairly zero-milage ones with a functional 100-yard battery pack on sale for couple hundred dollars in some places. Even crashed wrecks of a Tesla cost magnitudes more.
A car chassis is essentially immortal: 30, 40 or even 100+ years. Modern steal is franky amazing compared to cars of the past. Tesla batteries are nowhere near chassis life numbers.
I was stuck in traffic behind an 87 caddy yesterday. It was not a collector car. That chassis is still on the road, seemed to be taking kids to school.
I find this somewhat amusing, because the black PR of the fossil-fuel industry would have us believe that EV batteries basically have a 2-year lifespan, cost lots of CO2 to produce, instantly become toxic waste after those 2 years, are non-recyclable, and overall as a result EVs emit more CO2 than gasoline-burning cars. We are being told that EVs have a larger CO2 footprint than gasoline-burners.
Then Redwood shows up with a perfect way to utilize all those discarded batteries without even opening them up, and… that toxic industrial junk isn't even there?
That's part of it. Yet there is a growing gwh of EV batteries that gets retired on a yearly basis. Which is what Redwood has been tapping into. There is also a certain amount of cells that don't make it past the quality gates in the factory that get recycled via them.
Also people forget how quickly EVs have grown. The Tesla Model 3 came out in 2017; that's eight years ago. That was pretty much the first mass market EV that got produced by the hundreds of thousands per year. It had eight years of battery warranty. Most EVs you see on the road were produced after 2017 and typically come with similar warranty. The simple reality is that the vast majority of EV batteries ever produced is still under it's factory warranty and nowhere near its warranty life time. The amount of gwh of battery that becomes available for companies like Redwood is fairly predictable as it is tied to the production volume 8-15 years ago.
Redwood is basically tapping into the growing number of cars that get scrapped early because of accidents or other failures. That's a smallish percentage of overall vehicles produced but at the rate EVs started getting produced around eight years ago, it's starting to add up to a few gwh of battery per year. It's not a lot yet but it's not that unpredictable. And it's not nothing. If you manufacturer new batteries at 80$/kwh, producing 1 gwh new would cost about 80M$. So giving batteries a second life has quite a bit of economic value. The issue for Redwood is probably more that competition for these batteries is quite fierce. There is a lot of valuable stuff you can do with these things and lots of companies eagerly looking to pick up second hand EVs for their batteries.
"It’s the largest microgrid in North America and it’s the largest second-energy storage site in the world. So that’s like you said at the top, it’s a 12-megawatt AC, 63-megawatt-hour grid supporting about 2 or 3 megawatts of data centers and run by solar. So all the energy comes from another 12 megawatts of solar."
Sure, so while not supplying power to a city, they are proving this is viable. Just because it's not "turn off the coal plants now" moment doesn't mean this isn't a very good direction. Everyone has to start and grow. I don't understand the whole shit on something because it's not an immediate solve. If these guys waited until 2040 to start the business, well, that'd just be dumb. It essentially sounds like capacity will just continue to increase year over year, maybe around 2040 there will be a huge spike. Doesn't seem like anything is wrong here.
> Redwood has been struggling because the expected battery turnover is not occurring
Redwood pitched recycling. But its principal business was primary production. (Processed black mass is analogous to lithium ore.) They're struggling because demand for American-made batteries remains low.
I've been intrigued by used solar panels for sale, seems like you can get an amazing price for ones that are only lightly degraded. Is there a downside, or do you just mean that it isn't popular currently?
In addition to my sibling comment: The cost of the panels is a rather small fraction of the total cost of a typical installation. Most of that cost ist labor, some regulatory requirements and the inverter. Whether you pay a factor of 2 for the panels or not typically doesn't matter. In other words: Reusing used panels will only ever be able to safe you a minuscule amount.
The low cost of the modules themselves has led to the suggestion of cost optimized DC-coupled PV systems being used to directly drive resistive heaters. The cost per unit of thermal energy in a cost optimized system moderate scale system (> residential, < utility scale) may be in the range of $3-5/GJ, very competitive with natural gas. Low cost maximum power point trackers would be useful; inverters would not be needed.
Low cost modules allow one to do away with things like optimally tilted modules and single axis tracking. The modules can also be tightly packed, reducing mounting and wiring costs.
What's the proposed system design? For example, in January, I get about 9 hours of sunlight and have an average daily high of 25 F. I'm gonna need to store heat somehow or another.
The place I saw this most clearly described was in Standard Thermal's concept, which will store the heat in huge piles of dirt heated to 600 C. The thermal time constant of such piles can be many years.
If we assume the delta of 550 degrees (600 down to 50), you'll need: 7.913×10^10 J / (550K * 1000Jkg^-1K^-1) = 143,872,727 kg of material in your pile. This is a ridiculously stupid number. And I don't see any obvious mistakes?
I use units(1), which also helps me avoid dimensional errors (dividing when I should have multiplied, etc.):
You have: 7.913e10 J / 550K / (1J/g/K)
You want: kg
* 143872.73
/ 6.9505876e-06
maxerickson says, "Still big number," and 144 tonnes would typically be an unwieldy quantity of material if you had to buy it. But Standard Thermal's intention is not to buy dirt, just pile up already-on-site dirt with a bulldozer or excavator. If we assume 1.3 tonnes/m³, that's 110m³, or, in medieval units, 144 cubic yards. https://www.eaglepowerandequipment.com/blog/2022/03/how-much... tells us:
> An excavator could be used to dig anywhere from 350 to 1,000 cubic yards per day, depending on a number of factors including bucket capacity, type of ground, operator skill and efficiency level, and more. (...)
> One of the biggest factors that impact how much an excavator can dig in one day is the unit’s bucket size, which typically ranges from 0.5 to 1.5 cubic yards of bucket capacity. Most common regular-size excavators have a 1 cubic yard bucket capacity, and mini excavators are closer to the 0.5 cubic yard capacity.
So, with this number, we're talking about a few hours of work for a "mini excavator". https://www.bigrentz.com/rental-locations/pennsylvania/pitts... tells us that a "4,000 lb. mini excavator" rents for US$197 per day. So the expense of moving the dirt is not really significant, compared to other household projects such as replacing the roof, insulating the walls, or repainting the exterior.
Standard Thermal mentions that they are in effect firing the clay in the ground, that they've had significant trouble with resistance-heater reliability, and that their objective is to power steam-turbine power stations with the stored heat. These three facts lead me to believe that they're targeting a temperature closer to 1000° than to 600°.
600 C is about what a coal fired power plant would use. And 600 C is around the maximum that you want if you're using cheap steel for the pipes. Much beyond that and creep becomes a problem. So I don't think 1000 C is their target.
Hmm! Interesting! I would have thought that 600° would be close to the minimum for producing supercritical steam, so any energy stored up to 600° would be "overhead" that couldn't be effectively recovered—only the heating above that. And I assumed they would have to use cheap ceramic for the pipes, because oxidation is usually a problem for cheap steel even below 600°.
Oh, apparently because of "dramatic improvements in power plant performance":
> Starting with the
traditional 2400 psi / 1000 F (165 bar / 538 C)
single-reheat cycle, dramatic improvements in
power plant performance can be achieved by
raising inlet steam conditions to levels up to
4500 psi/310 bar and temperatures to levels in
excess of 1112 F/600 C. It has become industry
practice to refer to such steam conditions, and
in fact any supercritical conditions where the
throttle and/or reheat steam temperatures
exceed 1050 F/566 C, as “ultrasupercritical”.
Anyway, those are the plants that Standard Thermal wants to sell their product/service to. And once the hot dirt falls below 600°, it can no longer heat the water to 600°. So I think they have to be aiming far above that temperature, which is also why heating element reliability is a challenge and why the clays in the soil are firing (a phenomenon which only happens at 600° for the lowest-firing terra-cotta clays, more typically requiring 1000°–1400°).
Here's an article giving the state of such plants in the US in 2011. Since then I imagine some of the smaller/older plants have been retired. There is no new coal capacity coming online in the US.
Sounds like it was 80% subcritical at the time. I hadn't realized. It sounds like even "regular supercritical steam" is at like 580°, though. Maybe dirt at only 600° could still provide a substantial fraction of its stored energy to subcritical steam circuits, if they're much colder than that?
I think "storage at 600 C" could provide most of its heat output at close to 600 C. It's not like the entire thermal store is tapped at the same time.
Imagine a pile with long pipes through it. Cool fluid is introduced at one end; the steam is gradually heated as it travels down the pipes, emerging as hot steam at the end. If needed, gang two of these together with the second pile acting to top off the temperature from the first one (or more than two).
So, during discharge, a wave of cold sweeps down the pile(s), while the pile near the outlet end stays pretty hot. Only when most of the piles are discharged does the temperature decline.
The Standard Thermal approach is described as heating the piles with embedded resistive heaters, but it could also use an external heater that sends in steam in the opposite direction from when it discharges. This would turn the system into a giant counterflow heat exchanger. Counterflow heat exchangers are known for their high performance, enabling almost all the delta-T between two fluid streams to be interchanged.
Hmm, you're right that a counterflow heat exchanger could indeed provide 600° output by cooling a hot dirt pile most of which is well below 600°. I hadn't thought of that, even though I knew it in other contexts. I mistakenly thought that only the heat over the output temperature would be available.
The only drawback is that, when you're heating the pile, most of the time you are only heating part of it (the cold part), so your heating elements need to have a significantly higher power capacity, assuming you're heating the pile with embedded resistors as described, rather than with a heat transfer fluid as you suggest.
I don't think you want the heat transfer fluid in the dirt pile to be steam; that would involve making the pipes through the hot dirt resistant to both pressure and steam corrosion, which would make them expensive. It also means you'd have a high-pressure steam leak deep inside the dirt pile when they did fail, which would probably cause damage to other pipes and to resistors and a significant uncontrolled heat transfer from the zone of the leak to other parts of the dirt pile. I think you want a more relaxing atmospheric-pressure heat transfer fluid that allows you to use cheap pipes, or even no pipes. Air, for example. Solar salt can reach those temperatures, and it has a much larger heat capacity, but it's fairly corrosive.
For a seasonal thermal store, also, we're talking about astoundingly low power densities, so low-density heat transfer fluids like air should be fine. If we're cooling the hot dirt from 600° down to 100° over a 3-month low-sun season, and the dirt is 1J/g/K, we're only extracting 63 watts per tonne, which at 1.3 tonnes of dirt per cubic meter is 80 watts per cubic meter. My human body is largely air-cooled and generates about 800 watts per tonne in normal operation, even without forced air.
I don't think it's necessary for the pipes in the piles to be operating at the pressure of the steam in the turbines. There could be an intermediate heat exchanger to transfer heat from the low density steam (or air) in the pipes to the high pressure steam in the turbine loop.
Yes, that is what I meant to propose, but when you have that additional heat exchanger, why would you use steam rather than air (or some other fluid like helium or argon) in the low-pressure pipes?
The surface will always be only slightly hot. Heat will be stored inside, insulated by overlying dirt. Dirt isn't the best insulator by thickness, but it's a very good insulator by $.
I haven't seen pfdietz's proposed system design, but a so-called "sand battery," consisting of a box of sand with a heating element running through it, should work fine. You can PWM the heating element with a power MOSFET to keep it from overheating; you can measure its temperature with its own resistance, but also want additional thermocouple probes for the sand and to measure the surface of the box. A fan can blow air over or through the sand to control the output power within limits.
I'll work out some rough figures.
Let's say your house is pretty big and badly insulated, so we want an average of 5000 watts of heating around the clock with a time constant on the order of 10 hours, and we don't want our heating element to go over 700°. (Honest-to-God degrees, not those pathetic little Fahrenheit ones.) That way we don't have to deal with the ridiculous engineering issues Standard Thermal is battling. There's a thermal gradient through the sand down to room temperature (20°) at the surface. Suppose the sand is in the form of a flat slab with the heating element just heating the center of it, which is kind of a worst case for amount of sand needed but is clearly feasible. Then, when the element is running at a 100% duty cycle, the average sand temperature is 360°. Let's say we need to store about 40 hours of our 5000W. Quartz (cheap construction sand) is 0.73J/g/K, so our 720MJ at ΔT averaging 340K is 2900kg, a bit over a cubic meter of sand. This costs about US$100 depending mostly on delivery costs.
The time constant is mostly determined by the thickness of the sand (relative to its thermal diffusivity), although you can vary it with the fan. The heating element needs to be closely enough spaced that it can heat up the sand in the few hours that it's powered. In practice I am guessing that this will be about 100mm, so 1.5 cubic meters of sand can be in a box that's 200mm × 2.7m × 2.7m. You can probably build the box mostly out of 15m² of ceramic tiles, deducting their thermal mass from the sand required. In theory thin drywall should be fine instead of ceramic if your fan never breaks, but a fan failure could let the surface get hot enough to damage drywall. Or portland cement, although lime or calcium aluminate cement should be fine. You can use the cement to support the ceramic tiles on an angle iron frame and grout between them if necessary.
7.5m² of central plane with wires 100mm apart requires roughly 27 2.7m wires, 75m, probably dozens of broken hair dryers if you want to recycle nichrome, though I suspect that at 700° you could just use baling wire, especially if you mix in a little charcoal with the sand to maintain a reducing atmosphere in the sand pore spaces. (But then if it gets wet you could get carbon monoxide until you dry it out.) We're going to be dumping the whole 720MJ thermal charge in in under 9 hours, say 5 hours when the sunshine is at its peak, so we're talking about maybe 40kW peak power here. This is 533 watts per meter of wire, which is an extremely reasonable number for a wire heating element, even a fairly fine wire in air without forced-air cooling.
If we believe https://www.nature.com/articles/s41598-025-93054-w/tables/1 the thermal conductivity of dry sand ranges from 0.18 W/m/K to 0.34 W/m/K. So if we have a linear thermal gradient from our peak design temperature of 700° to 20° over 100mm, which is 6800K/m, we should get a heat flux of 1200–2300W/m² over our 15m² of ceramic tiles, so at least 18kW, which is more than we need, but only about 3×, so 200mm thickness is in the ballpark even without air blowing through the sand itself. (As the core temperature falls, the heat gradient also falls, and so does the heat flux. 720MJ/18kW I think gives us our time constant, and that works out to 11 hours, but it isn't exactly an exponential decay.) Maybe 350mm would be better, with corresponding increases in heating-element spacing and decreases in wire length and box surface area and footprint.
To limit heat loss when the fan is off, instead of a single humongous wall, you can split the beast into 3–6 parallel walls with a little airspace between them, so they're radiating their heat at each other instead of you, and cement some aluminum foil on the outside surfaces to reduce infrared emissivity. The amount of air the fan blows between the walls can then regulate the heat output over at least an order of magnitude. (In the summer you'll probably want to leave the heating element off.)
The sand, baling wire, aluminum foil, lime cement, angle irons, charcoal, thermocouples, power MOSFETs, microcontroller, fans, and ceramic tiles all together might work out to US$500. But the 40kW of solar panels required are about US$4000 wholesale, before you screw them to your siding or whatever. At US prices they'd apparently be US$10k.
720MJ is 200kWh in cursed units, so this is about US$2.50/kWh. Batteries are about US$80/kWh on the Shanghai Metals Market.
Sand batteries have a much higher cost per unit of energy storage capacity, so they are in more direct competition with batteries for shorter term storage. It's hard to compete with a storage material you just dig out of a local hole. The economics pushes toward crude and very cheap.
Having said that: a good design for sand batteries would use insulated silos, pushing/dropping sand into a fluidized bed heat exchanger where some heat transfer gas is intimately mixed with it. This is the NREL concept that Babcock and Wilcox was (still is?) exploring for grid storage, with a round trip efficiency back to electricity of 54% (estimated) using a gas turbine. Having a separate heat exchanger means the silos don't have to be plumbed for the heat exchange fluid or have to contain its pressure.
Getting the sand back to the top (where it will be heated and dropping into silos) is a problem that could be solved with Olds Elevators, which were only recently invented (amazingly).
(I completed my parent comment since you wrote your response, which may make it confusing to read your response; sorry about that.)
I agree that local dirt is much cheaper than trucked-in construction sand, but I think my design sketch above shows that a "sand battery" whose only moving parts are fans will be about 30× cheaper than a real battery at household scale, even though the sand is still most of the estimated cost. A "sand battery" designed to power a steam turbine is a much more difficult problem to solve, but in this case the stated problem is just that it's 24°F (-3°) outside, so I think much cheaper solutions are fine, with no pressure vessels, stainless steel, insulated silos, sand conveyors, or heat transfer fluids other than garden-variety air.
Do you have a good handle on the pressure (and therefore power) requirements for getting air to flow upward through sand? I feel like you ought to be able to get a pretty decent amount of thermal power out of half a tonne of sand with a really minimal amount of pumping, but that's only a gut feeling. Definitely as you go to graded-granulometry gravel the required head drops off to almost nothing.
Thanks for the link to the Olds device! That's utterly astounding. Archimedes could have used it for raising sand, although making a sturdy enough tube out of wood might have been a bit of a chore.
A thing I forgot to calculate: with 75m of wire dissipating 533 watts per meter, how thick should the wire be? Suppose we divide it into three 25m circuits so that we still have most of our heat if a wire burns out, and suppose we're using 48Vdc. So E²/R = 13.3kW, R = E²/13.3kW = 0.173Ω, and each of those elements is carrying an astonishing 277 amps. So we want 7 milliohms per meter. It turns out that that's about 12-gauge copper wire, nominally 5 milliohms per meter. 2 millimeters across. A higher-resistivity metal like iron or nichrome would have to be even thicker.
Better idea: put 9 2.7-meter wires in parallel on each of the three circuits, so each wire can have 9×0.173Ω = 1.56 Ω = 0.58Ω/m. That's 32-gauge copper magnet wire, 0.2mm diameter, 0.54Ω/m; or its thicker equivalent in other metals. Iron's resistivity is 5.7 times copper's, so you need a 5.7 times thicker wire: 0.5mm, 24-gauge. Nichrome is 11 times the resistivity of iron, so you'd need 1.6-mm-diameter nichrome.
I don't know, I think the copper would probably melt faster than the sand could conduct the heat away from it, and the nichrome would definitely be fine, but too expensive. But you can extrapolate from this how to solve the problem: by shortening the distance along the heating wires to low-resistance busbars (possibly made of rebar or leftover angle iron) and thus increasing the number of parallel paths, you allow the use of higher-resistance-per-unit-length and thus cheaper and more workable heating elements; the limit of this lightweighting is that the wires' surface area in contact with the sand must cool them enough to prevent melting. By this method you can use a small amount of a conductor of any resistivity at all, limited mainly by the temperature.
All these metals are fine at 700°, or for that matter 1000°. Copper will have less of a tendency to oxidize than iron, which would require a reducing atmosphere, and nichrome will oxidize but remain protected by its oxidation. (A reducing atmosphere will destroy nichrome.) But, at a lower temperature still, like 600°, you could use 10μm thick household aluminum foil, which is much easier to work with than any kind of 20μm wire, but has a similar ratio of surface area to volume. It has 54% more resistivity than copper, so a 10μm × 1mm strip is 2.7 ohms per meter. Our previous objective of 0.58Ω/m is a 4.6mm-wide-strip, which transfers heat to the sand along its 9.2mm perimeter, like a 10-gauge wire. 75m × 4.6mm is the size of about 5 or 6 pages of A4 paper cut into strips.
Austin Vernon claims they have a very cheap resistor material for Standard Thermal but hasn't said what it is. I look forward to hearing that detail when it leaks out. A good chunk of their work while in stealth was on the resistors, I understand.
I think I've shown above that you can make the resistor material itself almost arbitrarily cheap, calculating for example how you can get 40 kilowatts out of 9.3 grams of aluminum foil, and showing that with more busbars you can use even less resistor material than that. Aluminum itself wouldn't work for Standard Thermal's target temperatures, but you can make an arbitrarily thin foil out of any metal, supporting it as a thin film on an insulating ceramic such as porcelain if necessary. Copper, gold, silver, mild steel, nickel, nichrome, other stainless, titanium, platinum, and platinum/iridium, could all be made to work, and in no case would the material cost be significant. Metal film resistors supported on ceramic are being used to convert electrical energy into heat in probably every electronic device in your house.
And the old standby for resistive heating of giant piles of dirt, for example to bake it into carborundum, isn't a metal at all—it's plain old carbon, which you can if necessary bake in situ. Carborundum itself can also work, though it's not malleable, and controlling its resistivity can be tricky.
MIG welding wire is an interesting possibility.
The main potential obstacle, I think, is the manufacturing cost, and as sandy234590 was saying, potentially durability in use. Vernon said resistor durability had been one of their major problems; I'd think that sand would impose less stress on the resistors than generic dirt, but, with quartz in particular, you could greatly reduce the risk by not crossing the quartz dunting temperature at 573°: https://digitalfire.com/glossary/quartz+inversion That obviously isn't an option for Standard Thermal, but it would be completely viable for household climate control, just requiring somewhat more sand.
Sandy points out, implicitly, that mild steel such as the baling wire I suggested typically does not last long at high temperatures. But that's because it oxidizes. The same vulnerability is present in most metals, though not silver, gold, platinum, and platinum/iridium alloys, and only to a limited extent for nickel, nichrome, and other stainlesses. That oxidation can only happen in an oxidizing atmosphere; the thin iron ballast wires in Nernst lamps last indefinitely because they're sealed in a reducing (hydrogen) atmosphere. As I said, I think you can maintain a reducing atmosphere in the sand pore space by just including a little charcoal, which will scavenge any oxygen that gets close to the heating elements when they're hot, and may even be able to reduce any oxide that does form, at the cost of carbon monoxide emission.
If the atmosphere inside the sand is oxidizing, you'd probably want to either use something that won't be damaged by oxidization, such as gold or nichrome, or use a very thick heating element such as carbon so that it will have an adequate service life despite the oxidation. Most stainless steels will start to oxidize at a few hundred degrees, even though they're fine at room temperature.
(The main heating element in Nernst lamps, cubic zirconia, was also immune to oxidation, but it had some other drawbacks; for example, it needed to be preheated into its conductive range with a platinum preheat wire, and its rather aggressive negative temperature coefficient of resistance made it prone to thermal runaway when operated on a constant-voltage source—thus the iron ballast wire.)
I would instead say that, familiar with many designs from millennia of history of using thermal mass for indoor climate control, I outlined a design of an electric night storage heater that is especially cheap and convenient. Or an "electric day storage heater", I guess, since the day is when it stores heat.
I've heard of farmers doing this, well I think they actually had an inverter. But limits on how much they could dump into the grid, meant that they had lots of surplus electricity and installing resistive heating was very cheap.
Even if they don't have surplus electricity all the time.
Is it worth using heat pumps in this setup (in addition to resistive elements)? I understand they can't reach the absolute temperature of resistive heating, but from an efficiency POV for the first few tens of degrees they are much more efficient.
Depends - the problem with heat pumps is when you need them the most they don't work. If it never gets below -10c (exact temperature needs more study, could be as low as -25) where you live they are fine - but that implies you live in an area where you don't get many cold days and so the expense isn't worth it (it also implies you live where it gets hot in sumner so you want ac anyway and the marginal additional cost makes it worth it again). If you live in an area where it gets colder you need additonal backup heat that can cover those really cold days and so you may as well run that system only.
I think unless you're in an area dominated by cooling needs, an optimally sized heat pump system will not cover 100% of heating needs. It would make sense to make it smaller and use a backup resistive heater for rare very cold events.
cooling is more important but not by much. however the real problem is temperature delta: 100f-70f is 30 degrees, 70f-10f is 60 degrees. If you size a system for cooling it can't make up.
of course things arenot actually linear on temperature but as a rough estimate it gets the point across.
Efficiency allows you to use less solar panels, but more solar panels are cheaper than a heat pump. I think the ratio is about 5:1 at this point and widening.
To be concrete, I'm told that recently in the US a certain 34000btu/hour (10kW) output heat pump consuming up to 14A at 220V at the compressor (3kW) cost US$2700 installed, which is 27¢ per peak watt of output. But https://www.solarserver.de/photovoltaik-preis-pv-modul-preis... gives a price of €0.055 per peak watt (US$0.065/Wp) for low-cost solar panels. So the heat pump costs, in some sense, 4.2 times as much as the solar panels.
But the heat pump doesn't save you 10kW over resistive heating when it's running full-tilt. It saves you 10-3 = 7kW. So it costs 39¢ per watt of saved energy, which is 6 times as much as the solar panels.
In some simplified theoretical sense, if you decide you need another 10kW of heating for your house, you could spend US$2700 on this heat pump, and also buy 3000 Wp of solar panels to power it, costing US$194, for a total cost of US$2894. Or you could buy 10000 Wp of solar panels, costing US$645, and a resistive wire, costing US$10, for a total cost of US$655. US$655 is almost five times cheaper than US$2894. (4.4 times cheaper.)
There are a lot of factors that this simplified cost estimate overlooks; for example:
• Maybe you need to run the heater 16 hours a day but you only get sunlight 7 hours a day, either because it's winter in Norway, or because there are tall pine trees that shade your property most of the day, and you can't put the panels up on the trees. So maybe in some sense one watt of peak heater output is worth 2.3 watts of peak solar panel output. Or maybe it's the other way around, where your house only needs active heating during a few hours at night, so one watt of peak heater output is only worth 0.43 watts of peak solar panel output.
• The prices are in different countries. Solar panels are more expensive in the US, even wholesale.
• US$2700 is the retail price of the heat pump, including installation and warranty, and 6.5¢/Wp is the wholesale price of low-cost solar panels with no warranty ("Minderleistungs-Solarmodule, B-Ware, Insolvenzware, Gebrauchtmodule, PV-Module mit eingeschränkter oder ohne Garantie, die in der Regel auch keine Bankability besitzen.") Even in Europe the retail price of solar panels is three or four times this.
• Driving a resistive heating element from solar panels is considerably easier than driving a heat pump from solar panels; adapting a heating element to run on lower voltage is just a matter of connecting more wires to the middle of it, while adapting a heat pump to run on lower voltage may involve redesigning the whole power supply board or even rewinding the motor. Which is in a hermetically sealed refrigerant circuit, by the way, which you'd have to reseal. In practice, you'd just buy an inverter, but a 3000-watt inverter is expensive.
• As you said, for sensible-heat thermal storage, the heat pump craps out at about 50° or 60°, while any garden-variety resistive heating element (plus a lot of crappy improvised ones) will be just fine at 600° or 700°. That means you need ten times as much thermal mass for the same amount of storage. Sand is dirt cheap, but once you get into the tens of tonnes, even dirt isn't really cheap.
Despite such complications, I still think that pair of numbers is a useful summary of the situation: the heat pump costs 39¢ per watt saved, while the solar panel costs 6.5¢ per watt produced.
IDK sounds like you got ripped off. I diy'd and panels were cheap of course, but fittings were perhaps 3-5x cheaper. Inverter is typically same as your panels (hybrid, grid-tied are quite a bit cheaper).
For all of your context/reference, if you buy whole pallets from a central European port warehouse, glass-glass modules run around $0.11/Wp plus shipping.
Unless you're just bolting them to the floor or to an uninsulated wall, mounting will (sadly) run you a sizable fraction of that cost in the best case.
Maybe, but these aren’t fittings, they’re ground mounts with large screws that screw into the ground to hold the entire array down, including under high wind (and have to come with PE stamped system-level engineering drawings talking about things like rated wind load of the whole array to pass building inspections).
But yeah, at the end of the day, just bent bars of aluminum with ground screws and bolts to hold the corners of the panels, versus the technological marvels of the solar panels they hold.
These days it’s a stack of microinverters. Which are not cheaper but do improve array efficiency outside of idea conditions. But that’s another up front cost.
I think they were referring to the fact that the chief reason there is not large-scale PV panel recycling is that very few panels have ever been retired. It turns out that short of physical destruction by hail etc a PV panel does not degrade beyond economic usefulness simply by being out in the sun. In fact some panels actually get more powerful. The surprising-to-some conclusion of NREL's PV Lifetime Project is that the economic lifetime of a PV panel is basically forever.
How much of a difference does it actually make in terms of the all-inclusive price of installation (e.g. panels, inverters, mounting hardware, and labor)?
(Asking because I genuinely don't know, not because I have a specific answer in mind.)
Labor is by far the top cost. But I'm intrigued by the economics of a small setups paired with like a <5kwh battery. And for something like that where you literally just throw 4-6 panels out, you can just brute force by buying more panels instead of optimizing angles. Basically a slightly beefier version of a European balcony setup
Used panels are cheap because of where we are in the improvement curve. Let's say you're a large business with a factory rooftop full of 100W panels that was installed installed 10 years ago. Today, you can upgrade that rooftop to 300W panels without any additional footprint and often for less than the original deployment cost (adjusted for inflation).
Those old panels have to go somewhere and still have at least 2/3 of their life left. Probably more because we're finding out that well-made panels do not degrade as quickly as previously thought.
The used panel market (in the US anyway) might dry up soon if the tariffs stay in place, as that will make a lot of customers reluctant to upgrade due to greatly increased costs. But I guess we'll see. I've been wrong before.
Still have mine. Battery capacity is around 80% of the new capacity. I'm not planning on switching anytime soon as it's got plenty of range still. I'll probably swap the pack out when it hits 70% in the next 2 or 3 years.
I'm not even sure how to calculate our deg! Same, 2018 3 long range. I think they advertised it as 305mi but some time later increased the capacity of the car to 315mi; I max charged it to 314 once but never quite saw that 315. I think we're around 273 as max now so 89.5% of the original quoted life, 87% of the "updated" life. Car has 115k miles, ~ 185,000km.
That is quite high mileage. I'm certain someone smarter and less lazy than me can calculate the amount of expected cycles that the battery would have seen.
Do you leave it fully charged for long periods of time, or do you discharge it down to empty or nearly empty quite regularly?
Top it how cheap batteries have gotten it makes little sense to remanufacture unless you are extremely dedicated DIYer, live somewhere with very cheap labour or it's done in massive scale to achieve economies of scale.
In NZ you can get 60KWh used Tesla battery for 6-10k NZD, then spend another 1-2k for additional gear + labour to hack it (overall $116-200/KWh) or 15KWh for 3.5k ($233/KWh) with warranty and safety guarantees.
The typical EV industry trade show has a small handful of cars and a vast amount of tangential businesses including many finance options, a vast amount of home charger gizmos, fast charging gizmos, electricity suppliers and the companies promising grid-scale storage, either from actively used cars or recycled EV batteries. There is a vast constellation of this stuff, with specialist insurance companies that nobody really asked for outnumbering the car brands or even e-bike brands present.
In time there will be consolidation. This constellation of EV startup bottom-feeders will be decimated along with the 'excuses' to not make money.
I don't think the problem is that EV batteries are lasting longer, it is just that the EV market from before the Model 3 came along is miniscule. Hence not many second hand batteries to recycle.
As for EV batteries and their availability, when was the last time you saw an OG Tesla Model S with the fake grill? Those cars used to be everywhere, but where are they now? The German EVs that came out to compete, for example, Taycan and eTron, those things are not going to last the distance since the repairs cost a fortune and the parts supply is limited.
All considered, there will come a time before 2040+ when there are large quantities of these electric car batteries to upcycle, by which time the EV business will be consolidated with only a few players.
If there was money in recycling cars then every auto manufacturer would be in on it.
There is one constant to all these conversations and that is Silicon Valley tech dudes are grossly misinformed about the lifecycle of things. Solar panels don't wear out, batteries don't wear out as fast as they used to. This is evidenced both by undertaking weird dead-end startup ideas, and being susceptible to propaganda about the supposed downsides of solar energy and batteries.
"most people" even now are just parroting dumb FUD they read on facebook.
You really shouldn't give any weight to the opinions of laypeople on topics that are as heavily propagandized and politically charged as renewable energy.
there is an ubiquitous failure of Panasonic-created cells for Tesla. I made a research on forums, because I wanted one, and investigated why there is such a price drop. Cars getting close to the age of 8 years immediately drop on price to even 10k usd. It's because if you get your battery replaced on warranty - you won. Otherwise it often deteriorates suddenly.
Prius Plugin 2015 (last year of that model) - full charge/discharge at least 3-4 times a week, currently still a bit more than 80% of capacity (granted the battery seems somewhat overbuilt, yet it is normally does 10-15C which is much tougher mode than in a pure EV where 2-3C is usually enough and only high-end Teslas and the likes would do 5-6C). There has been large continuous improvement in lithium batteries over the last couple decades.
From my model airplane experience, I believe it's "capacity per hour". So, a 1Ah battery discharged at 1c would mean 1 amp; discharged at 10c would be 10 amps. The higher the C, the harder the batteries are being used.
1 C current fully discharges battery in 1 hour. Thus 4KWh battery running 60 KW engine means 15C current, and it would discharge the battery in 4 minutes (in a very simplified linear model).
There's currently no technological path for fusion to be cheaper than fission. It would require a technological breakthrough that we have not yet imagined.
And already, solar plus storage is cheaper than new nuclear. And solar and storage are getting cheaper at a tremendous rate.
It's hard to imagine a scenario where fusion could ever catch up to solar and storage technology. It may be useful in places with poor solar resources, like fission is now, but that's a very very long time from now.
The low energy future that was envisioned is not happening.
The AI arms race, which has become an actual arms race in the war in Ukraine, needs endless energy all times a day.
China is already winning the AI cold war because it adds more capacity to its grid a year than Germany has in a century.
If we keep going with agrarian methods of energy production don't be surprised that we suffer the same fate as the agrarian societies of the 19th century. Any country that doesn't have the capability to train and build drones on mass won't be a country for long.
You have that exactly backwards: solar + storage is what will give us energy abundance at less money than we could ever imagine from nuclear fission or fusion.
China is winning the AI Cold war because it's adding solar, storage, and wind at orders of magnitude more than nuclear.
I'm not sure who's doing your supposed "envisioning" but there is no vision for cheap abundant energy from fusion. Solar and storage deliver it today, fusion only delivers it in sci fi books.
Nuclear is 20th century technology that does not fit with a highly automated future. With high levels of automation, construction is super expensive. You want to spend your expensive construction labor on building factories, not individual power generation sites.
Building factories for solar and storage lets them scale to a degree that nuclear could never scale. Nuclear has basically no way of catching up.
China has been building out nuclear capacity at 5% a year for 25 years.
Solar and wind capacity had shot through the roof in the last five years because they can't sell hardware to the west any more.
The other big item is hydro power, which China has a ton of untapped potential for. Unfortunately for the West every good river has already been damed so we can't follow them there.
> Solar and wind capacity had shot through the roof in the last five years because they can't sell hardware to the west any more.
"can't sell hardware??" hah! I've never heard that weird made-up justification, where did you pick it up from?
China installed 277GW of solar in 2024, capacity factor corrected that's 55.4 GW of solar power. That's equivalent to the entire amount of nuclear that China has ever built. One year versus all time. And then in the first half of 2025, China installed another 212GW of solar. In six months.
Nuclear is a footnote compared to the planned deployment of solar and wind and storage in China.
Anybody who's serious about energy is deploying massive amounts of solar, storage, and some wind. Some people that are slow to adapt are still building gas or coal, but these will be stranded assets far before their end of life. Nuclear fusion and fission are meme technologies, unable to compete with the scale and scope that batteries and solar deliver every day. This mismatch grows by the month.
> China installed 277GW of solar in 2024, capacity factor corrected that's 55.4 GW of solar power.
The problem is not just the mean capacity factor, but the capacity factor in _winter_. It's terrible for China, less than 15%. And more importantly, you can have _weeks_ with essentially zero solar power when you need it most.
This is not an issue in China as they overprovision demand by 50 percent. Their grid can run off baseload generation alone in their 2060 plan.
Trying to explain that a grid build by electrical engineers, rather than financial engineers, has resilience build in to people whose whole idea about electricity generation is greenwashed bullshit from McKinsey and Co is at best a waste of time and at worst an excellent way to raise one's blood pressure.
55.4 GW per 277 GW is an (annual) capacity factor of 20%, so the response here is "yes, and?"
> And more importantly, you can have _weeks_ with essentially zero solar power when you need it most.
Half the country is a mid-latitude desert. What makes you think the whole country has "weeks" with zero solar? And it does have to be the whole country in this case, because one thing a centrally planned economy can do well is joining up the infrastructure, which in this case means "actually make the power grid the USA and the EU keep wringing their hands over".
> Half the country is a mid-latitude desert. What makes you think the whole country has "weeks" with zero solar?
The "whole country" is irrelevant. You can't transmit arbitrary amounts of power across the large geographic areas, most of energy has to be generated in a reasonably close proximity.
> And it does have to be the whole country in this case, because one thing a centrally planned economy can do well is joining up the infrastructure
Transmission lines are expensive, regardless of your ideology.
> The "whole country" is irrelevant. You can't transmit arbitrary amounts of power across the large geographic areas, most of energy has to be generated in a reasonably close proximity.
Only technically correct because you said "arbitrary": it's well within China's manufacturing capabilities to make a grid that can transmit 3 TW over 40,000 km, with a conductor cross section so thick it only has 1 Ω resistance.
As in: all the world's current electricity demand, the long way around the planet.
I have, in fact, done the maths on this.
> Transmission lines are expensive, regardless of your ideology.
"Expensive" but not "prohibitively expensive".
All infra is "expensive". Nations have a lot of money.
> Only technically correct because you said "arbitrary": it's well within China's manufacturing capabilities to make a grid that can transmit 3 TW over 40,000 km, with a conductor cross section so thick it only has 1 Ω resistance.
And it'll turn out to cost more than building a nuke in each backyard.
> Solar and wind capacity had shot through the roof in the last five years because they can't sell hardware to the west any more.
They can't sell as much as they would like, specifically to the USA, due to tariffs/trade war, but there's a much bigger world out there than just the US, and the overall exports are up over the last five years: https://www.canarymedia.com/articles/solar/chart-chinas-sola...
There's a Chinese-made Balkonkraftwerk sitting a few meters away from me on my patio, it cost €350, of which €50 was delivery and another €50 was the mounting posts, the remaining €250 got me 800 W of both panel and inverter.
> Unfortunately for the West every good river has already been damed so we can't follow them there.
> Unfortunately for the West every good river has already been damed so we can't follow them there.
You don't need a river for hydro power storage. All you need are two reservoirs with a height difference between them. Typically one of the two reservoirs is preexisting and the second is constructed. ANU identified ~1 million potential sites.
I blame these for the unquestioned belief that fusion is desirable. It's a trope because it enables stories to be told, and because readers became used to seeing, not because science fiction has a good track record on such things.
The fact that the volumetric power density of ARC is 40x worse than a PWR (and ITER, 400x worse!) should tell one that DT fusion at least is unlikely to be cheap.
With continued progress down the experience curve, PV will reach the point where resistive heat is cheaper than burning natural gas at the Henry Hub price (which doesn't include the cost of getting gas through pipelines and distribution to customers.) And remember cheap natural gas was what destroyed the last nuclear renaissance in the US.
> It would require a technological breakthrough that we have not yet imagined.
Maybe, but not necessarily. The necessary breakthrough might have been high-temperature superconducting magnets, in which case not only has it been imagined, but it has already occurred, and we're just waiting for the engineering atop that breakthrough to progress enough to demonstrate a working prototype (the magnets have been demonstrated but a complete reactor using them hasn't yet).
Or it might be that the attempts at building such a prototype don't pan out, and some other breakthrough is indeed needed. It'll probably be a couple of years until we know for sure, but at this point I don't think there's enough data to say one way or the other.
> And already, solar plus storage is cheaper than new nuclear.
It depends how much storage you mean. If you're only worried about sub-24h load-shifting (like, enough to handle a day/night cycle on a sunny day), this is certainly true. If you care about having enough to cover for extended bad weather, or worse yet, for seasonal load-shifting (banking power in the summer to cover the winter), the economics of solar plus storage remain abysmal: the additional batteries you need cost just as much as the ones you needed for daily coverage, but get cycled way less and so are much harder to pay for. If the plan is to use solar and storage for _all generation_, though, that's the number that matters. Comparing LCoE of solar plus daily storage with the LCoE of fixed-firm or on-demand generation is apples-and-oranges.
I think solar plus storage absolutely has the potential to get there, but that too will likely require fundamental breakthroughs (probably in the form of much cheaper storage: perhaps something like Form Energy's iron-air batteries).
One can discuss base load and season shifting all day long. But ultimately fusion will fail for two simple reasons; time and money.
If we started building a fusion commercial scale plant today (ie started by planning, permits, environmental assessments, public consultation, inevitable lawsuits, never mind actual construction and provisioning) it'd come online in what? 10 years? 15 years? 20 years?
Want to deploy more batteries? It can be online in months. And needs no more construction than a warehouse.
Financially fusion requires hundreds of billions, committed now, with revenue (not returns) projected at 10 years away (which will slide.) Whereas solar + storage (lots and lots of storage) requires anything from thousands to billions depending on how much you want to spend. We can start tomorrow, it'll be online in less than 2 years (probably a lot less) and since running costs are basically 0, immediate revenue means immediate returns.
Of course I'm not even allowing for fusion being "10 years" from "ready". It's been 10 years from ready for 50 years. By the time it is ready, much less the time before it comes online, it'll be redundant. And no one will be putting up the cash to build one.
High temperature superconducting magnets are not a panacea for the problems with DT fusion. Those issues follow from limits on power/area at the first wall, and the needed thickness of the first wall; these ensure DT reactors will have low volumetric power density, regardless of the confinement scheme used.
With HTSC magnets, a tokamak much smaller than ITER could be built, but ITER is so horrifically bad that one can be much better than it and still be impractical.
And these are not new issues, they've been known for more than 40 years, but never addressed. From the 1983 Led
> But even though radiation damage rates and heat transfer requirements are much more severe in a fusion reactor, the power density is only one-tenth as large. This is a strong indication that fusion would be substantially more expensive than fission because, to put it simply, greater effort would be required to produce less power.
In terms of cost of materials to build a reactor, sure, that seems right. But most of the cost of fission is dealing with its regulatory burden, and fusion seems on track to largely avoid the worst of that. It seems conceivable that it ends up being cheaper for entirely political/bureaucratic reasons.
Relaxed regulatory burden doesn't seem to be making fission competitive in China; renewables are greatly overwhelming it now, particularly solar.
We might ask why regulations are so putatively damaging to nuclear, when they aren't to civil aviation. One possibility is that aircraft are simply easier to retrofit when design flaws are found. If there's a problem with welding in a nuclear plant (for example) it's extremely difficult to repair. Witness the fiasco of Flamanville 3 in France, the EPR plant that went many times over budget.
What would this imply for fusion? Nothing good. A fusion reactor is very complex, and any design flaw in the hot part will be extremely difficult to fix, as no hands on access will be allowed after the thing has started operation, due to induced radioactivity. This includes design or manufacturing flaws that cause mere operations problems, like leaks in cooling channels, not just flaws that might present public safety risks (if any could exist.) The operator will view a smaller problem that renders their plant unusable nearly as bad as a larger problem that also threatens the public.
I was struck by a recent analysis of deterioration of the tritium breeding blanket that just went ahead and assumed there were no initial cracks in the welded structure more than a certain very small size. Guaranteeing quality of all the welds in a very large complex fusion reactor, an order of magnitude or more larger than a fission reactor of the same power output, sounds like a recipe for extreme cost.
Regulation is not a problem, and even the construction costs are not terrible. We can take the Rooppur NPP as a base, it produces reliable energy at 6-7 cents per kWh. The reason for cost overruns is simply because NPPs are one-off products, the Western countries don't have a pipeline for NPP production.
If I understand correctly, the cost/year of an engineer in India is maybe 1/3rd that in the US, and for general labor the disparity is even larger. So it shouldn't be too surprising NPP construction in India is cheaper than in the US. India doesn't have a large NPP pipeline, they just have cheaper labor.
Yes, but solar power panels are also mostly produced in China, where engineers still get less than 1/3 of the US/Europe salary.
European power plants will be more expensive, but even with the LCOE of 12 (twice that of Rooppur) it's still going to be way cheaper than storage for areas that get cold weather (Midwest, Germany, most of China).
Anything south of California? Yeah, just get solar+wind, no need to bother with nuclear.
As we pointed out, PV is still trouncing nuclear in China. So if the difference is smaller there, it's still in favor of solar.
Storage is another matter here, but even there costs for batteries have simply collapsed. Understand that massive storage is needed even in a nuclear-powered economy. If all the 283 million cars and trucks in the US were replaced with 70 kWh BEVs, the storage would be enough to power the US grid (at its current average consumption) for 40 hours. That's a lot of batteries. So the demand is there to continue to drive them down their experience curves. In China, they're already around $50/kWh for installed grid storage systems (not just cell price).
The final storage problem, the only reed that nuclear can be clinging to at this point, is long term/seasonal storage. That's needed either to smooth wind variability (~ week scale) or to move solar from summer to winter (~6 months). There are at least two different ways this could be solved: hydrogen and heat. As mentioned elsewhere in these threads, the latter is very promising, with capex as little as $1/kWh of storage capacity and a RTE of about 40%. Should that work out anywhere close to that nuclear would be in a hopeless position anywhere in the world, even at very high latitudes.
> As we pointed out, PV is still trouncing nuclear in China. So if the difference is smaller there, it's still in favor of solar.
Sure. Solar is easy to scale when you don't care about reliability, nobody is arguing with that. But it's another issue entirely when you need a stable grid.
I'm not aware of any countries (even tropical ones) that managed anything close to 100% renewables with solar. E.g. Hawaii has to pay for extremely expensive diesel generation even though they have plenty of solar potential.
And nuclear is scalable if you force other sources off the grid in favor of nuclear (and force customers to not use renewables "behind the meter").
In a fair grid, solar and wind get built out, and the residual demand has no baseload component. Unless nuclear is given the right to force other sources off the grid it becomes inappropriate.
In Texas now there is no chance of new nuclear construction. ERCOT is a competitive market and new nuclear simply doesn't make sense.
First, coal has a much larger share of its cost as variable cost which is avoided if you don't run the plant. 40% for coal, only 10% for nuclear. This makes integrated a coal fired plant into a renewable grid easier than a nuclear plant. China is increasingly doing this with its coal plants.
Second, coal is much more forgiving of maintenance sloppiness, and even in the event of catastrophic malfunction the plant remains repairable.
Nuclear has been available in its current (and no longer competitive) state longer than solar/wind have been in their current economic state, so if you look at historical data you might conclude nuclear is better. But that's backward looking and says little about what's better in the future.
You are aware that a nuclear plant tripping offline was part of the cause of ERCOT's last winter cold problem?
The nuclear power plant wear-and-tear is roughly proportional to the number of hours it runs at full power. By not running the plant, you can extend its service life (probably to more than 100 years, with periodic annealing). The main limiting factor is the reactor vessel, its steel walls can only tolerate so much neutron bombardment before becoming too brittle for service.
Nuclear power plants have similar behavior to coal plants in another regard, they take approximately the same time to ramp up/down.
> You are aware that a nuclear plant tripping offline was part of the cause of ERCOT's last winter cold problem?
They just need to build more of them. Problem solved.
Anyway, nuclear power plants went from 0% to 70% generation in France within 20 years in 70-s. We don't see anything like this happening with solar, even in smaller island countries. Solar is successful only when it's backed by fossil fuels and government subsidies to keep that fossil fuel generation running.
Sure, you can save some maintenance cost by operating at low capacity factor. But this is a minor part of the cost of nuclear energy, so you don't save much. Nuclear simply isn't constituted to be useful as a dispatchable source.
The technical ability to ramp up/down is beside the point; it's the financial ability to do so that matters.
What nuclear did in France half a century ago is irrelevant. What matters is if nuclear makes sense today. It doesn't, even if it could be done.
Nuclear can be made flexible, that's my point. It works best as a constant baseload, but it's mostly because the current plants were not designed for dispatchable use (except for some plants in France).
Nuclear plants do not degrade at a constant rate, regardless of their power. By idling the plant, you extend its service life, essentially amortizing the capital cost over a longer period of time. And the capital cost is the main driver in the cost of the nuclear power, as you're pointing out yourself.
You ignore the counterargument I already gave you to what you're saying there.
Nuclear can be made technically flexible. It can't be made economically flexible. The large fixed costs prevent the technical ability you are describing there from being useful. It's pyrrhic engineering, straining to achieve an outcome that's useless. Even France depends largely on the rest of Europe to deal with variations in demand rather than spooling their power plants up and down.
> The reason for cost overruns is simply because NPPs are one-off products
But there's no fundamental reason they _have_ to be one-off products. They just historically have been for at least partly regulatorily motivated reasons: because each reactor's approval process starts afresh (or rather, did until quite-recent NRC reforms), there's little advantage in reuse, and because many compliance costs are both high and fixed, there's an incentive to build fewer huge reactors rather than more small ones, which makes factory construction difficult to achieve and economies of scale hard to realize.
Regulatory costs and waste disposal are not significance cost centers for nuclear, at least as far as I can tell from any cost breakdowns.
One doesn't need super high quality welding and concrete pours becuase of regulations as much as the basic desire to have a properly engineered solution that lasts long enough to avoid costly repairs.
Take for example this recent analysis on how to make the AP1000 competitive:
There are no regulatory changes proposed because nobody has thought of a way that regulations are the cost drivers. Yet there's still a path to competitive energy costs by focusing hard on construction costs.
Similarly, reactors under completely different regimes such as the EPR are still facing exactly the same construction cost overruns as in the rest of the developed world.
If regulations are a cost driver, let's hear how to change them in a way that drives down build cost, and by how much. Let's say we get rid of ALARA and jack up acceptable radiation levels to the earliest ones established. What would that do the cost? I have a feeling not much at all, but would like to see a serious proposal.
One approach would be to reduce the size of the containment building by greatly reducing the volume of steam it must hold. This would be done by attaching Filtered Containment Venting Systems (FCVS) that strip most of the radioactive elements from the vented steam in case of a large accident.
The containment building is a significant cost driver, costing about as much as the nuclear island inside of it.
If such a system had been attached to the reactors that melted down at Fukushima exposure could have been reduced by maybe two orders of magnitude. And if the worst case exposure is that low, perhaps much more frequent meltdowns could be tolerated, allowing relaxation of paperwork requirements elsewhere.
Oh for sure, I'm not claiming that CFS (or Tokamak Energy or Type One or whoever else) will for sure succeed, or if they do, that they've already solved all the problems that will need solving to do so. My only assertion/prediction is that I think if they end up succeeding, when future historians look back and write the history of this energy revolution or whatnot, HTSC magnets will turn out to have been the key breakthrough that made it possible.
> If the plan is to use solar and storage for _all generation_, though, that's the number that matters.
And that's the problem with these Internet discussions: that's almost never the plan, but commenters trying to make solar look bad assume it is (to your credit, you made it explicit; many commenters treat it as an unspoken assumption).
In real life, solar and batteries is almost always combined with other forms of generation (and other forms of storage like pumped hydro), in large part due to being added to an already existing large-scale grid. The numbers that matter are for a combination of existing generation (thermal power plants, large-scale hydro, etc) with solar plus storage. Adding batteries for just a few hours of solar power is enough to mitigate the most negative consequences of adding solar to the mix (non-peaking thermal power plants do not like being cycled too fast, but solar has a fast reduction of generation when the sun goes down; batteries can smooth that curve by releasing power they stored during the mid-day peak).
In the end we're still making steam and running a turbine. Just the steam turbine part of the power plant has a hard time competing with solar in sunny locations.
Fission is expensive for regulation reasons more than technological reasons, so if fusion doesn't face the same barriers then it could be cheaper than fission.
But I agree that it doesn't look like fusion is going to be cheap any time soon.
Fission is also expensive for several mundane reasons, like the fact that massive steam turbines are expensive, and because any large construction project in the West is expensive. Neither fusion nor regulatory reform are going to solve those.
The steam generator that the fusion generator connects to might be more expensive than solar at this point. That would be even if fusion cost nothing and had infinite amounts of fuel, there would be no customers for its energy on a sunny afternoon.
Having worked extensively with battery systems, I think the grid storage potential of second-life EV batteries is more complex than it appears. We found that typical EV batteries retain 70-80% capacity after 8-10 years of vehicle use, but the real challenge is standardization and integration. Different manufacturers use vastly different battery management systems (BMS) and cell configurations - a Tesla pack is fundamentally different from a Nissan Leaf pack.
The economics are interesting though. New grid storage batteries cost around $200-300/kWh, while second-life EV batteries can be acquired for $50-100/kWh. However, you need to factor in significant integration costs (~$50-75/kWh) to build compatible BMS systems and thermal management. We also found cycle life degrades about 20% faster in repurposed packs compared to new ones, likely due to accumulated stress patterns from automotive use.
Has anyone here successfully integrated mixed second-life batteries at scale? I'm particularly curious about how you handled thermal management across different pack designs while maintaining safe operating parameters.
> New grid storage batteries cost around $200-300/kWh
That doesn't sound right. You can already get high-quality, prismatic LFP cells for ~50 US$/kWh [1] from European distributors at low-volumes, so bulk from China should be even cheaper. And there's no way that balancing and BMS cost an additional 150-250 US$/kWh at scale, not even a tenth of that.
We don't have a lot of car makers and we do not have a huge amount of EV models.
Either you are doing this on small scale, than you can select one or two specific EV models and use these batterie packs or you do it in big scale, than you can also easily adapt the most x batterie packs and only use these across your system.
If you go down to the cell level, its more effort true but then you probably only handel cell types of a handfull of manufacturer again.
You can't really mix different types of cells together in the same pack. Even cells with the same manufacturer and chemistry can be problematic to mix if they are at different wear levels (or even from different batches from the same factory).
This is only practical if you reuse the whole pack, or at least the modules. And for that to work well you also need a lot of complex software to keep the packs working well with each other (like balancing power levels between the packs).
BMS software is no joke, it is already hard and complex enough when using brand new battery packs and cells of the same chemistry and manufacturer and wear level. Any kind of mixing massively increases the complexity and safety concerns.
> Having worked extensively with battery systems, I think the grid storage potential of second-life EV batteries is more complex than it appears.
Complex, by t very much doable. Toyota implemented such a system with enough packs to power a Mazda factory [1]
> However, you need to factor in significant integration costs (~$50-75/kWh) to build compatible BMS systems and thermal management.
Shouldn't this be a once-off cost per battery-pack version? Or was this your armortized cost for your deployment capacity. If you've written the BMS for a 2019 Model 3 Panasonic battey pack once, won't you reuse it for all the subsequent battery packs of the same model/SKU?
> Shouldn't this be a once-off cost per battery-pack version?
A BMS isn't just software. It requires a µC, voltage and temperature sensors for cell monitoring, and power electronics for cell balancing. However, those are all comparatively cheap, especially at scale, and the quoted cost of 50–75 US$/kWh looks ridiculously overpriced to me.
I expect EV batteries to have all those components preinstalled already, and naively thought the grid-integration involves reverse engineering the battery's protocol, and perhaps bypassing/replacing a µC or 3.
> the real challenge is standardization and integration. Different manufacturers use vastly different battery management systems (BMS) and cell configurations - a Tesla pack is fundamentally different from a Nissan Leaf pack.
Isn't that exactly what the article is about? Have you actually read the article?
Personally speaking, having just bought an Ioniq 5 and installing solar at home what I see as the near future improvement is adding V2L functionality, which I can hook up to the generator input of my solar inverter, essentially adding another 60kWh buffer to my grid storage.
Considering how expensive residential batteries are and how quickly EVs depreciate, I think soon it'll be cheaper to get a used EV as a cheap source of cells that accidentally happens to be able to drive itself around.
Imo V2G, and V2H is unnecessary and add too much complication, I think for the future, solar inverters already have the necessary hardware and certifications to be able to take power and safely connect to the grid - something that requires different hardware and standards compliance in basically every country (yes even within the EU).
Residential batteries are not that expensive anymore, at least not all of them.
That's a misconception I also held until a few years ago ;-)
My first 14.3 kWh pack cost about 2800$ DDP from China, delivered 03/2023. For that one I did calculate how long it took for amortization, which I projected at about 5 years.
The second, identical pack was delivered 08/2024 and cost 2000$ DDP. Since we got an EV that's drawing about 14kWh per day, I didn't bother doing the math and just ordered it.
These are 280Ah 16S 51.6V packs, based on the EVE LF280K. In an enclosure, with a BMS (Seplos, 200A) and a dedicated balancer. They are good for 6000 cycles at 140A or less [each]. Mind these were both part of small bulk orders - I think each time we ordered 6 to 8 of these, which reduced shipping costs.
Unfortunately, almost all three-phase [1] on-grid inverters that are on the market, especially hybrid inverters, only support batteries with much higher voltages, like 150 V or even more.
[1] Three-phase wiring in homes seems to be very rare in the US, but is extremely common in Europe.
That looks quite a bit cheaper than the pricing I'm used to seeing, like less than half - not saying they're bad, but probably there's a DIY and risk factor involved compared to buying a more established brand like BYD or Huawei.
I'm just pointing out this is way lower than typical pricing
Maybe, but I think the premium charged by the main manufacturer's is unjustifiably high. Those battery boxes are relatively dumb: besides the cells, they just need some voltage and temperature sensors for monitoring, some power electronics for balancing, a microprocessor, and an enclosure with connectors. Unlike a grid-tied inverter, this is a really simple system, and there's no way a 500–700% price premium over the cells is reasonable.
My new batteries were about 250EUR/kWh - my 10KWh unit cost 2500 EUR - scaling it up to a decent used 5 year old EV price - you can have one for 15k with 60+ kWh batteries, so I'd say it's at a very similar price.
I would take that further and say that residential solar without batteries has been proven to be a bad solution. Solar with batteries allows utilities and consumers to schedule when power can be sent to the grid. California utilities consider solar without batteries a PITA, and incentive structures have changed to reflect that shift in policy.
> Imo V2G, and V2H is unnecessary and add too much complication
I believe that's more a function of auto makers (and charger cos) not trying to do much about it (and grid cos not caring), than a technical issue. The benefits (especially if V2G) are quite significant.
I doubt any car owner will say no to earning revenue from something that costs them almost nothing. The problem is more of "how do we get there at scale". (Disclaimer, I studied this topic in my thesis.)
EVs are probably not going to depreciate as much in the future. The depreciation mostly happened because new electric cars have become cheaper.
As an example, let's say a 2 year old car is only worth 80% of an identical brand new car. The old car was bought for $50k at new, leading to a expected depreciated value of $40k. But since manufacturing has become more efficient a brand new car of the same model can be had for the same $40k. Nobody would be willing to buy the 2 year old car at the same price. You'd probably have to charge only $32k [0]. But then it looks to you as if it has depreciated 36%.
The question is how much new electric cars will fall in price in the future. And if they continue to fall, at some point the dollar value of the depreciation will be too small to care about.[1]
0: $32k = 0.8 * $40k
1: E.g. if a new car is $10k, $3600 in depreciation over two years is annoying, but not a big deal.
In the US, V2L limits your ability to output power from the car to about 1500 W. It's not going to power your house as more than a stopgap, even if you do have supplementary house batteries. V2H/V2G justify their complexity by solving that problem, along with all the ancillary grid benefits.
Not sure if that's the case - however doing V2L requires the manufacturer to add an inverter to the car, and making that powerful probably adds extra cost most customers wouldn't pay. TI just looked it up and my Ioniq can only do about 2kW sustained - but since this charges the house battery, that's enough - idle load is just a couple hundred watts.
You pointed out a significant limitation of my current setup - right now there are 2 plugs - one for discharging the car through a proprietary manufacturer's V2L adapter, and one for charging.
I'm planning to make a 'box' that can switch between the 2 functionalities on the same cable.
The whole setup is a bit clunky as it is right, now, but I'm kinda more surprised that it works at all, and how well the fundamentals work.
This whole thing was more of an experiment in 'no way you can do this' to actually doing it, but I think this is HUGE, and will transform the way people think about electric cars.
If you have solar panels or time-of-use electrical rates, you charge the car when power is cheap/free, and spend stored power when the grid costs are high. During a protracted outage, maybe you drive the car to a fast charger.
A typical house averages less than 1500W. And most of the higher usage overlaps the sun being out. So if you have supplemental house batteries to handle bursts then 1500W of V2L can go a very long way.
the average hides a lot of information. the largest peak load is often an electric stove, which is regularly greater than 1,500 kW.
Also, this idea that higher usage overlap with the sun being out is laughably wrong. Solar noon is between 11 AM and 2 PM. Very few people are home at that time. There is a reason that peak grid demand in almost every country is in the early evening.
> the largest peak load is often an electric stove, which is regularly greater than 1,500 kW.
Does that change anything about what I said? This is specifically about "if you do have supplementary house batteries".
> Also, this idea that higher usage overlap with the sun being out is laughably wrong.
The reason we have the duck curve is that insolation and demand largely overlap (especially when we're talking about the worst case part of the summer), but then for part of the evening they really don't overlap.
The peak use is evening, but there's a significant ramp up when the sun rises and the whole day is much higher than night. https://ars.els-cdn.com/content/image/1-s2.0-S03062619173137... (This isn't the US but finding household graphs in particular is annoying, and most of the US has more summer heat than denmark)
Anyway evening is one of those bursts where you use the supplementary battery to handle the rest of the load. Even 10% of the car's capacity, 6kWh, could cover almost all use above 1500W.
Everything you describe is true only in some places, likely California. In much of the rest of the world, electricity demand peaks in the evening, when the sun is low in the sky and continues well into the evening, when the sun isn’t out. Notice how even the Wikipedia page about the duck curve lists mainly California. Even in Australia and the UK, daylight hours and electricity demand mostly do not overlap.
1. It does. The only issue is that the car can only output about 2kW sustained (this is a model limitation). That's fine since I have batteries in the house.
2. Tbh not super familiar with V2G/V2H, other than it being super expensive for both the wall box and the car (only high end models tend to support it)/
3. No idea, but it's not a high end feature, I wouldn't count on any inverter to just have it, but if you're looking to buy one that does, I don't think you'll be breaking the bank.
Imo the future is for solar inverters to offer a dedicated DC car charger port, as once again all the hardware is already in there.
Thanks for the answers. I used to work for a EV smart charging company (Kaluza) that ran a V2G trial. V2G was financial success for the users, but I always thought the wall box was a potential blocker. I don't think the 2kW output is a big issue as the customer could still reduce there load when required, but the elimination of a wall box makes onboarding much easier.
As long as the inverter can also provide charging this definitely has some potential.
> Can "second life" EV batteries work as grid-scale energy storage?
Yes
is it profitable? probably not.
Looking at the price for brid battery storage, and its dropping precipitously. The cost isn't as much in the batteries them selves, it packaging, placing and then controlling them.
For example if you want to have a 200Mwhr 100Mw storage site, you'll need to place it, join it to the grid, all doable. Then you need the switch gear to make it work as you want it to.
For day ahead, 30 minute trading, thats fairly simple.
For grid stabilisation, thats a bit harder, you need to be able to lead/match/lag the grid frequency by n degrees instantaneously. which is trivial at a few kw, much harder at 100Mw
Germany alone had to pay 2 billion in dispatch measures to energy providers. And in the last 6 month we had news about a HUGE request of companies wanting to build grid stabilisation and grid market battery systems in a range of over 100GwH.
Also we do have industries which would be able to save a ton of money if the invest in smaller but similiar systems today already due to energy prices.
And in germany for example, we do have a lot of wind energy in the north but not enough live transit capacity to get it into the south. In this scenario the market would again stabilize the grid by charging at night from cheap / free wind energy production in north and transfering it to the south and then using it at day.
I think car cells will be much more useful if they are packaged as replacement batteries for all the various battery powered tools, ebikes, etc.
There's a consumer profit margin to absorb the repackaging and teardown.
Maybe for home grid batteries they'll work too. Again, a consumer margin.
Sodium Ion and other grid-specific storage will simply be too cheap for secondhand EV batteries to compete. And the retiring cells won't be any better in density and will be less safe than the higher density sodium ion and LFP that is hitting the market.
I've spoken to people about starting a Tesla EV battery replacement business here. Battery replacement on a Tesla is a pretty simple process that can be done by one person in about 4 hours.
The problem is that it's still really hard to get your hands on salvage Tesla batteries. Enthusiasts and hackers snatch them up quickly and the used price is not very competitive with a new EV replacement from Tesla.
>So top of the list for us, of course, designing this thing is safety.
Funny issue I learned after talking to a founder at a similar company: although the battery packs were certified safe for cars (passing crash tests, wild heat differences from AK to AZ, people sitting on top of the battery packs in the car)
... the founder had issues re-certifying the batteries for safe use in a static location for grid storage.
The certification process treated his company like the batteries were made from scratch even though they used the same BMS/coolant lines/etc. already proven and tested.
It's clear you still need strong safety regulations and practices in the rare case there's an event, but the founder noted the grid storage industry regulations were adding redundant safety testing and slowing down adoption. The founder also added it's difficult to compete on cost even with effectively free used EV batteries in this startup space of grid storage against the low cost of Chinese made grid-specific batteries due to the added testing + custom hardware + space constraints and other items. (Caveat: I didn't fact check any of their statements)
only if industry and government grow some gonads and fully standardise the cells, and hardware
for battery packs to allow for quick and easy dissasembly, testing, repair, and reuse, for off grid, and secondary mobile use, as industry will never trust used components for primary aplications,
it is impossible to overstate how allergic industry is to this.....
second
sodium is comming NOW!, and it is cheaper and safer.
successfull?, maybe, we will see if fires, insurance, and end of life disposal costs leave any roe, plus there are no large scale used car battery grid storage plants, just green washing for data centers, where they are most definitly worried about fires, given the huge spacing between units,
green washing/cred,scamenomics,, but most certainly, not grid scale
Not second life, but first life. All EVs and charging stations should be reversible. In a world where fossil fuels cost their true value (~10x as much) and people still drive this would be a necessity for electricity generation
Without being a battery chemistry expert, why do these battery packs become not useful for an EV yet could still be useful for energy storage. They keep saying that 80% of life becomes unusable for EV, but that's still a lot of life. Is it that grid energy is more of a constant drain while the EV is lots of hard pulls (for lack of better wording)? In an EV, the battery cannot provide the higher volts being requested within rating, but a grid is never demanding peak performance?
It's not just about capacity (80% is still a lot), it's that degraded batteries lose their ability to deliver high current under load—so acceleration suffers and voltage sags under hard pulls. For grid storage, you're doing slow, steady charge/discharge cycles over hours, so the same battery that can't handle aggressive driving anymore works perfectly fine. Plus, grid storage has virtually unlimited space and no range anxiety, so if you need 25% more packs to hit your capacity target, you just stack them in a warehouse where real estate is cheap.
Also, batteries will degrade faster over time when they start to degrade, because they need more frequent charging. Their internal resistance increase and that promotes heat buildup during fast charging/discharging, another thing that promotes degradation. Slow charge/discharge cycles also help with heat management.
They claim to have taken the Moss Landing fire into account with how they are placing their batteries. We won't know if they've really solved the problem or not until their first battery pack experiences a runaway thermal event.
Space and weight are serious constraints in the car space, but not such a big deal on the side of a house. That’s how they retain their usefulness.
80% could indeed be plenty of usable life for your EV use cases, but it strongly depends on usage patterns. More degradation means more trips to the charger on a road trip. It means trips that you’d regularly make just charging at home at the end of day now require you to plug in at the destination too. It means more range anxiety as a whole.
The load in an EV is very different than in storage. Basically the charge and discharge rate is what deteriorates the battery. EVs need a lot of power delivered quickly in bursts when you accelerate (tens/hundreds of kw). And then fast charging when the driver is in a hurry also puts a lot of stress on the battery. With storage solutions, the power requirements are much less intense. These high bursts of energy would actually blow the fuse in your house. They are simply not needed. And there is no need for fast charging them either. Instead they get charged over many hours when there is cheap power available.
Companies like Redwood are good at assessing the state of the battery and then managing it such that it is run optimally. Usually, it's just a few cells that are no longer working; the rest of the pack is still be fine. So that just means the max output of the pack drops a bit. But that's still more than fine for storage if all you need is a few kw of output.
Running the battery optimally also extends the useful life of the remaining cells.
Seems like the market is going the hybrid route. It's kind of easy to see why, best of both worlds. Some BYD hybrids have crazy ranges like 1500 km on a tank of gas. The more practical car is winning. They put in a much small battery in these for fast charge, and the daily commute range. And you have gas, for longer trips. Maybe smaller batteries would be better for grid-scale storage too. If they're lighter and easier to handle.
I don't have first-hand experience, but these guys have an EV repair shop for a while and do also hybrids, their articles always offer lots of insight.
Short run down:
- micro/mild hybrids are useless: batteries too small, engines too small to be the sole source of power, so contribution to emission reduction is very small, batteries tend to fail early because they're very small
- full hybrids have bigger batteries and engines large enough to run pure EV, but you still rely on ICE engine for everything, so there's no ability to charge at home or save on gas
- plug-in hybrids are full hybrids, but you can charge them externally; according to many studies the estimated emissions are much higher than declared, because people simply don't charge them at home and run on ICE the whole time
In all these types of hybrids the batteries are smaller than pure EVs, so they cycle faster and degrade faster. You're carrying two drivetrains all the time with added weight, one of which has plenty of maintenance items. So they're not drop-in replacements.
From what I've seen from EVClinic above, many manufacturers use custom pouch cells, not cylindrical modules like the more advanced pure EVs, so you can't repair an individual failed cell. That means full pack replacement. For many manufacturers you can't order replacement parts of the electric drivetrain, and if you do, they cost a huge chunk of the car.
So all in all if everything's well, you're good. If something goes wrong, be prepared to spend the same as you would spend for a battery replacement of a pure EV, or even more.
No, hybrid is just a temporary solution until the charging infrastructure becomes good enough. And depending where you live, it's already there.
Hybrid is the worse of both worlds in a way. You have a combustion engine to maintain, that is useless when using electricity. You have a heavy battery useless when using your combustion engine.
You don't get all the benefits of electric, and you don't get all the benefits of ICE.
Exactly this. Here in Denmark, 48k plug-in hybrids were sold in 2020, falling to 4k in 2025. The same numbers for fully electric cars were 38k in 2020 and 144k in 2025. Once the public charging infrastructure was here, the change was dramatic. I bought my first electric car this year and I haven't had trouble finding a public AC charger when I needed to, which is often since I live in a condo.
It's possible it might actually be more reliable long term, once the technology matures. For example, in cold weather the gas engine might heat the battery for better battery performance, maybe even extend its life if it prevents it from being drawn down too much. The gas engine, would also likely last longer since its not used for daily commutes.
"In many PHEV systems, there are different modes:
Electric mode (EV mode): The vehicle runs purely on the electric motor(s) and battery until the battery depletes to some extent.
Hybrid/Parallel mode: Both the petrol engine and electric motor(s) work together to drive the wheels, especially under high load, higher speeds or when battery is low.
Ithy
Series mode (in some designs): The petrol engine acts only as a generator to charge the battery or power the electric motor(s), and the wheels are driven by the electric motor(s).
For the BYD Leopard 5 (and many BYD PHEVs) the petrol engine can drive the wheels (i.e., it is not purely a generator). It is part of the drive system, especially when high power or long range is needed.
At the same time, it likely can assist with charging the battery or maintaining battery state of charge (SOC) when needed (for example, to keep the battery at some reserve level or in “save” mode). User-reports show that the petrol engine will kick in to support the electric system, charge the battery, or assist the drive under certain conditions" -
It's not like reliable gas cars ever had substantial maintenance problem in the gas part. So removing the gas part didn't do much in practice.
People do/did have frustrations with gas car mannerisms and mental approachability, like, everything was written in a mix of translated foreign language documents and borderline insane gearhead languages. That lead them to imagine that removing the gas part would drastically change the industry, in their favor.
But, in the end, gas cars are good with regular maintenance for something like 100k miles over 8 years, so, I wouldn't know what consumer product were more reliable than a gas car in the first place.
And this is what I'm referring to by approachability issues. Even HNers can't correctly enumerate maintenance items for a car.
If I said iPads are better than laptops because there's no need to regularly replace soft drive Window and repaste NPUs every 2000 hours, everyone knows what kind of person I would be. Yet, that just casually happen all the time when it comes to EVs.
Not that I'm aware of. I've heard that many hybrids actually require less maintenance - for instance, the car can use electric power for hard acceleration instead of stressing the engine, so oil tends to last longer, and regenerative braking causes the friction brakes to wear out more slowly.
Eh, my PHEV has a 2 year oil change interval, which is longer than my ICE only cars. You should probably bring in your EV every 2 years to get things looked at too.
The engine in a hybrid should live an easier life compared to an ICE. No extended idle, mostly running in the power band, etc. There are lots of different ways to setup the hybrid system, but typically, rather than a small stater motor, you have a larger motor/generator that also starts the engine; it's less likely to get worn out, because it's built for continuous use.
In my PHEV, it has a 'toyota synergy' style 'e-CVT' which eliminates gear selection and should be very low maintenance (although mine had to be replaced under a service bulletin due to bearing failure because of manufacturing error) again nicer than an ICE. But some hybrids have a more traditional transmission.
Certainly, you can do ICE only or EV only, but there's a lot of room to use the ICE for things it's good for, and the EV for things it's good for, and blend where there's overlap.
Ford Escape? I have a friend that needed the transmission on his 2023 PHEV replaced under warranty... no service bulletin, but mechanics caught a manufacturing error at a regular service. Hopeful my hybrid Maverick doesn't have similar problems.
2014? Ford C-MAX energi TSB 16-0105 [1] (although there's a similar TSB 22-2396 [2] with a wider range)
I'd just say, if it starts making bearing noises (loudest around 15mph), check in and get yelly. Cause apparently they keep screwing them up. HF35 is designed and built by Ford for Ford, so they really should have everything they need to do it right. sigh
I saw a picture somewhere where they had an extra hole carved through the casing from this, worked fine until it breached and the fluid came out, then it died pretty quick.
That two year oil change cycle is the minumum required to not void the warranty.
It shouldn’t be taken as the optimal interval to maximise engine life.
Of course, modern fully synthetic engine oils are longer lasting, and I believe the newer Toyotas, at least the hybrids anyway, have electric oil pumps, and use very thin engine oil to make sure the engine is well lubricated at startup.
In an ice storm and cold cloudy snap that sweeps the country, NO lithium batteries will save the grid. I'm weary of this tunnel vision of the absurd. The only 'storage' that works is to pump water uphill with 'surplus' energy, and there is not and never will be a surplus. And these evaporartion tanks are on a scale that ecologists have to remember countless horror stories (eg., Glenn Canyon Dam). And of course there's always "mfft!" (another scheme with no numbers behind it so it's credible because I'm talking about it).
The last time there was anything rational on the table was Perry under the Trump administration's 30-day rule proposal ( https://www.nucnet.org/news/nuclear-is-vital-to-us-national-... ). It gave a hard industry incentive to any energy supplier who can have 30 days' fuel on site. This means nuclear and coal. This was no gimmick, it was the first time anyone faced reality about National Security as related to Energy for the grid and survival. And now AI datacenter yadda yadda, we're also talking about the luxury of keeping schools heated in Winter. Adverse weather even for a week is grid down game over for wind and solar. Proven natural gas are ~300 years, joy! As soon as they get around to sending pregnant whales across the ocean (losing ~20% of the gas-energy in cooling) it may even last 50 years! Before we have to go to endless war again.
You are just not able to comprehend basic writing styles.
The author is a journalist and not the expert he is interviewing thats the first thing. So why would you even evaluate the journalists 'expertise' if you get the answers from the experts.
And secondly what he probalby meant was that what if this company can 'push out' all active lifecycle before they recycle them.
> Journalists write for an audiance which normally gets it.
That's a bullshit justification. "It's factually wrong, but that's okay, the true audience knows what the author means anyway." Then why write it at all? It makes no sense. Stop making up excuses for clueless journalists.
We don't need ev batteries for this. We just need cheap enough LifePo4 so we're not burning more shit down. Prismatics from China are a start, Salt batteries showing some promise next.
Betteridge's law of headlines finally fails? TL;DR: Yes, but you can also make it 'not work' if you choose to politicize the tech solution to the energy problem.
This is less useful than most people expected. Redwood has been struggling because the expected battery turnover is not occurring. EV batteries are lasting a long time, so they stay in the car are and not being recycled or reused in any quantity yet.
If EV batteries last 20+ years in EV's, it'll be > 2040 before there are significant numbers of EV batteries available to recycle or reuse.
https://www.geotab.com/blog/ev-battery-health/
A lot of the early EV battery life projections were based on Nissan Leaf Gen 1. Which had a horrendous battery pack that combined poor choice of chemistry, aggressive usage and a complete lack of active cooling.
When EVs with good battery pack engineering started hitting the streets, they outperformed those early projections by a lot. And by now, it's getting clear that battery pack isn't as much of a concern - with some of the better designs, like in early Teslas, losing about 5-15% of their capacity over a decade of use.
Don't forget that the original Leaf pack was only 24 kWh. So if you assume a ~1000 full-equivalent-charge-cycles lifespan, then the large Gen2 62 kWh pack will live 2.5 times longer than an original 24 kWh pack. If you average 3.5 miles/kWh, the 24 kWh battery will be expected to last somewhere around 84,000 miles. While the 62 kWh pack will last for 217,000 miles.
https://coolienergy.com/lfp-vs-nmc-batteries-the-science-beh...
This is a big reason why hybrid's are generally a bad idea. Their batteries wear out a lot quicker than the batteries on EV's.
The batteries in a hybrid are much smaller (~1.3 kWh for a Prius), and so cost much less to replace.
The vast majority of EV owners will spend $0 to replace their batteries since the batteries last longer than the rest of the car does.
Edit: part of that is that a Prius with 250,000 miles needing its second battery replacement is still a valuable car with a reasonable expectation of a lot more miles. OTOH a Tesla at 250,000 miles needing its first battery replacement...
Similarly Chrysler hybrid owners spend less money on battery replacements than Toyota hybrid owners. Not a compliment, it means they're scrapping their cars earlier.
My 2015 Model as’ battery went the day the warranty ended and so they gave me a trash refurbished one “half price” for $8k
This low maintenance cost thing is BS once something actually goes wrong. And it’s awfully frustrating / sus when it happens the moment the warranty ends
My 2017’s HV fuse went just days before the warranty ended. They tried to charge me $330 for that planned part.
These things aren’t cheap.
Why would you only assume 1000 cycles? Is the chemistry that bad? The LFP battery on my balcony is rated for 5000 cycles iirc.
LFP does have a lot more cycles in them by the nature of the chemistry. However EV grade NMC aren’t terrible either.
Depth of discharge and charge rate affect LFP specifically in such a way that if you keep them a good margin above cutoff voltage, relatively cool (60C and under, and do 1C and lower charging you can get 10,000 cycles per their data sheets. The same sheets will also list lower cycle counts for harder use that lines up with the standards used for earlier cells. Basically I think we’ll find a lot of gently to moderately used hardware will last a long time.
Whatever a believable use case looks like will probably end up on those data sheets and it wouldn’t surprise me if we see 15,000 and 20,000 cycles advertised for cells intended in low charge and discharge use cases (probably not cars but maybe home energy storage).
My Taycan has an ongoing battery issue relating to LG Pouch cells but its construction rather than composition that is the culprit. The same compositions from LG in prismatic and cylindrical models, the only models they sell now, so far haven’t been a mess for car makers.
We did 12.000 km in our id.4 last year.
I suspect it'll die due to rust. But yes, might take a while. Even in Denmark where we salt the roads in a winter.
I am a bit more concerned about batteries now as opposed to an year ago.
We had this article from Elektrek [1] about battery issues in South Korea. When I asked my local electric maintenance shop [2, sorry for the FB link], they said they have started seeing the same issue in Model 3s and Ys in Canada as well. (They also said that it is too early to tell how common it would become)
This may bode well for recycling since the issues is an unbalance, not the whole pack failing.
[1] https://electrek.co/2025/10/14/tesla-is-at-risk-of-lossing-s...
[2] https://www.facebook.com/groups/albertaEV/posts/248558844207...
Idk, not really worried about that. There are shops that are able to swap out a faulty module, and the cost is not too horrible:
https://www.reddit.com/r/electricvehicles/comments/1e3onbp/c...
Tesla made powerwalls a product for a reason. They were supposed to come from outdated Tesla cars, but that never materialized. If it is materializing now, they already know what they are going to do.
I would be more concerned if the source were anyone but Electrek~. Their vendetta against Tesla has forfeited all their credibility on Tesla news.
"many of these vehicles are now out of warranty, as they sometimes exceed the maximum mileage"
They have good numbers for the number of affected vehicles, but the best they can do for out-of-warranty stats is "many" and "sometimes". Convenient.
~To be fair this applies to a lot of popular tech sites I used to respect. Dunking on Tesla is its own industry these days, it seems.
I can respect that. For what it is worth, I validated with a well-trusted local shop that works on EVs (and works with Tesla) that said the issue is starting to pop up. Moreover, it's the government of Korea that is making this claim as well.
(I also find it difficult to separate noise from signal about Tesla. However, I don't consider them innocent victims; besides the elephant in the room, they literally eliminated their PR department)
>Dunking on Tesla is its own industry these days, it seems.
Are you suggesting Tesla is criticized without good reason?
Idk enough but I assume there are good reasons, however when a website is biased and finds even bad reasons to hate that's still a problem right?
Bad reasons to hate something are bad press for Tesla, and how many people are going to read past a headline that confirms their bias? This isn't limited to Tesla, mind you, and is a broader statement on clickbait, and the state of the Internet and media and society today. Of course, anybody on Tesla's side knows to take Electrek and the rest of the Inernet’s coverage with a grain of salt, but with rabid fanboys on both sides, it's hard to know how large a grain of salt, and when.
What are the bad reasons that bias electrek’s coverage?
Electrek's Fred has a ton of Tesla referral credits. Tesla owes him 2 Roadster's and has reneged. After Tesla screwed him, Fred's coverage turned from glowing to negative.
It seems a lot more biased against what Elons spent the last 2 years doing. If we can call that bias.
extremist "journalists" and/or undisclosed sponsorship? Contrast their Tesla coverage with their almost giddy stories on anything China related.
I'll defend the leaf a little.
LiPo batteries were quiet expensive when it was initially released. NiMH was really the only option in town.
And with a lower energy density battery that's also heavier, adding a cooling system would have also added a bunch of weight to the already heavy car with a barely usable range of 100 miles.
Gen 2, however, had no excuses. They had every opportunity to add active cooling and they still decided to go with just air cooling.
Every generation of the production Nissan Leaf has used lithium batteries. AFAIK no modern (~post-2000) mass-produced (>10k units sold) EV has ever used NiMH or lead-acid batteries.
Edit: Checking Wikipedia to verify my information, I found out that Nissan actually sold a lithium-battery EV in 1997 to comply with the same 90s CARB zero-emissions vehicle mandate that gave us the GM EV-1: https://en.wikipedia.org/wiki/Nissan_R%27nessa#Nissan_Altra
EVs no, but I think some Toyota hybrids (which are of course not even PHEVs) still use NiMH. Toyota tends to be very tight-lipped about their batteries and their sizes (or rather, lack thereof).
Tends to be tight lipped??? It is in the catalog[1]! It is more that American consumers aren't tech obsessed than Toyota being reluctant to share.
Even just looking at online media reports[2][3] clearly sourced from some exact same press event, it is obvious that US English equivalents are much lighter in content than Japanese versions. They're putting the information out, no one's reading it. It's just been the types of information that didn't drive clicks. Language barrier would have effects on it too, that Toyota is a Japanese company and US is an export market, but it's fundamentally the same phenomenon as citizen facing government reports that never gets read and often imagined as being "hidden and withheld from public eyes", just a communication issue.
1: https://www.toyota.com/priuspluginhybrid/features/mpg_other_...
2: https://www.motortrend.com/news/toyota-aqua-prius-c-hybrid-b...
3: https://car.watch.impress.co.jp/docs/news/1339263.html
It's nice to get a reminder about this problem once in a while, I've fallen into the trap myself at times.
Interestingly they don't tell you anything (unless I missed it) about the battery for the non-plugin hybrids, eg. the Corolla Cross: https://www.toyota.com/corollacross/features/mpg_other_price...
I was looking up this year's Corolla a while ago and likewise there was minimal info that I could see about the battery capacity, which I think I figured out was about 3kWh.
Despite your ??? and ! the only article you posted that's about hybrids (and not PHEVs) mentions nothing about battery capacity.
> Battery capacity (kWh) 13.6
It's under Weights/Capacities but you have to expand the section yourself, no way to link directly to it.
The page you are referring to is literally titled "Plug-In Hybrid Specifications"
/out
Sorry, I just saw you objected to the lack of information for battery capacity, not the type of hybrid or chemistry.
Early Hybrids used NiMH because Chevron was holding on to a lot of the patents around using Lithium Ion for the purpose IIRC.
Leaf Gen 1 didn't have NiMH. It had a lithium-based battery chemistry, but some bastard offshoot of it. One that really didn't fare well under high current draw, or deep discharge, or high temperatures, or being looked at wrong.
1st gen was LMO
On the used market you'll find absolutely cooked (literally) Leafs whose first life was in Arizona and barely have enough range to back out of the driveway.
I have a gen 1 leaf with a remaining range of about 500 yards if you drive gently...
I use it in my driveway to make it look to thieves like someone is home (round me, houses with no car get broken into).
Sounds like an old Roomba I used to have that could clean for about 2 minutes before it ran out of juice.
Is there any value in fixing the battery on these? IE: Do the other components last long enough to be worth the cost?
It seems like procuring the battery is not as expensive as the Tesla battery (I see someone who did it themselves for $6k on Youtube with the battery from a wrecked leaf). In comparison, the cost I see for my Model 3 is about ~$18k CAD.
Getting a car up and running for $8k might be worth it if it is otherwise dependable, but I've only heard unfortunate stories about the first gen Leaf.
Is it worth spending money on a car that old? You are putting more than the car is worth into fixing it and you won't get that back if you sell. You also have no idea when/if something else will go. thew worst case is the day after you fix it someone hits you and the repairs will be $30,000 - what it cost new and there are still a lot of worn out parts: insurance will give you $4000 and tell you to eat the loss.
30000? What? Leaf packs are swap able between years… here in bc 2k and you have a newer pack in
30k is the real cost to repair some accident damage to a leaf - think bent frame. this could happen anytime. Nobody would pay that price to the whole car ends up in a junk yard.
NiMH was used in Priuses for a very long time, and these seem to have lasted for ages.
> Gen 2, however, had no excuses. They had every opportunity to add active cooling and they still decided to go with just air cooling.
The Lizard pack in the later Nissan Leafs has held up surprisingly well. I have a 2015 that still gets 75 miles of range. I'm sure they thought it wasn't necessary and they probably had the actuarial numbers to justify it.
It didn't just had horrendous service life, it was designed for some set years of life to be regularly replaced and repurposed for battery storages. Nissan had business schemes outlined for that with Leaf packs.
I think Tesla deserves credit for rethinking hat model into chassis-life battery packs and surpluses rather than recovered cells for grid storages.
Especially considering that, resales of Gen1 Leafs milked for EVs and renewables incentives is like destination fees atrocious. You can find fairly zero-milage ones with a functional 100-yard battery pack on sale for couple hundred dollars in some places. Even crashed wrecks of a Tesla cost magnitudes more.
A car chassis is essentially immortal: 30, 40 or even 100+ years. Modern steal is franky amazing compared to cars of the past. Tesla batteries are nowhere near chassis life numbers.
I was stuck in traffic behind an 87 caddy yesterday. It was not a collector car. That chassis is still on the road, seemed to be taking kids to school.
I see you don't live in Michigan... my 22 year old car has growing rust holes in front of the rear wheels.
That's amazing good news for the environment, thank you I hadn't heard this.
> the expected battery turnover is not occurring
I find this somewhat amusing, because the black PR of the fossil-fuel industry would have us believe that EV batteries basically have a 2-year lifespan, cost lots of CO2 to produce, instantly become toxic waste after those 2 years, are non-recyclable, and overall as a result EVs emit more CO2 than gasoline-burning cars. We are being told that EVs have a larger CO2 footprint than gasoline-burners.
Then Redwood shows up with a perfect way to utilize all those discarded batteries without even opening them up, and… that toxic industrial junk isn't even there?
That's part of it. Yet there is a growing gwh of EV batteries that gets retired on a yearly basis. Which is what Redwood has been tapping into. There is also a certain amount of cells that don't make it past the quality gates in the factory that get recycled via them.
Also people forget how quickly EVs have grown. The Tesla Model 3 came out in 2017; that's eight years ago. That was pretty much the first mass market EV that got produced by the hundreds of thousands per year. It had eight years of battery warranty. Most EVs you see on the road were produced after 2017 and typically come with similar warranty. The simple reality is that the vast majority of EV batteries ever produced is still under it's factory warranty and nowhere near its warranty life time. The amount of gwh of battery that becomes available for companies like Redwood is fairly predictable as it is tied to the production volume 8-15 years ago.
Redwood is basically tapping into the growing number of cars that get scrapped early because of accidents or other failures. That's a smallish percentage of overall vehicles produced but at the rate EVs started getting produced around eight years ago, it's starting to add up to a few gwh of battery per year. It's not a lot yet but it's not that unpredictable. And it's not nothing. If you manufacturer new batteries at 80$/kwh, producing 1 gwh new would cost about 80M$. So giving batteries a second life has quite a bit of economic value. The issue for Redwood is probably more that competition for these batteries is quite fierce. There is a lot of valuable stuff you can do with these things and lots of companies eagerly looking to pick up second hand EVs for their batteries.
From TFA:
David Roberts
When did automotive batteries become the majority of your input by volume?
Colin Campbell
That is a good question.
David Roberts
Was it recent or was that early on?
Colin Campbell
I would say the transition to EV batteries dominating what we received, it’s been in the last year or 18 months.
David Roberts
So the front edge of a very large wave of batteries has begun to arrive?
Colin Campbell
Yeah, the wave is out there, it’s coming. The waters have finally started to arrive at the beach here.
He's just talking his book. Their deployment this year was 1/4000th share of the BESS market.
Battery Energy Storage System for anyone else like me that has no knowledge of this world and their acronyms.
Reading between the lines of the corporate speak will validate my point. Redwood was founded in 2017.
"It’s the largest microgrid in North America and it’s the largest second-energy storage site in the world. So that’s like you said at the top, it’s a 12-megawatt AC, 63-megawatt-hour grid supporting about 2 or 3 megawatts of data centers and run by solar. So all the energy comes from another 12 megawatts of solar."
Sure, so while not supplying power to a city, they are proving this is viable. Just because it's not "turn off the coal plants now" moment doesn't mean this isn't a very good direction. Everyone has to start and grow. I don't understand the whole shit on something because it's not an immediate solve. If these guys waited until 2040 to start the business, well, that'd just be dumb. It essentially sounds like capacity will just continue to increase year over year, maybe around 2040 there will be a huge spike. Doesn't seem like anything is wrong here.
> Redwood has been struggling because the expected battery turnover is not occurring
Redwood pitched recycling. But its principal business was primary production. (Processed black mass is analogous to lithium ore.) They're struggling because demand for American-made batteries remains low.
So, basically the same reason recycling of PV modules hasn't taken off.
I've been intrigued by used solar panels for sale, seems like you can get an amazing price for ones that are only lightly degraded. Is there a downside, or do you just mean that it isn't popular currently?
In addition to my sibling comment: The cost of the panels is a rather small fraction of the total cost of a typical installation. Most of that cost ist labor, some regulatory requirements and the inverter. Whether you pay a factor of 2 for the panels or not typically doesn't matter. In other words: Reusing used panels will only ever be able to safe you a minuscule amount.
The low cost of the modules themselves has led to the suggestion of cost optimized DC-coupled PV systems being used to directly drive resistive heaters. The cost per unit of thermal energy in a cost optimized system moderate scale system (> residential, < utility scale) may be in the range of $3-5/GJ, very competitive with natural gas. Low cost maximum power point trackers would be useful; inverters would not be needed.
Low cost modules allow one to do away with things like optimally tilted modules and single axis tracking. The modules can also be tightly packed, reducing mounting and wiring costs.
What's the proposed system design? For example, in January, I get about 9 hours of sunlight and have an average daily high of 25 F. I'm gonna need to store heat somehow or another.
The place I saw this most clearly described was in Standard Thermal's concept, which will store the heat in huge piles of dirt heated to 600 C. The thermal time constant of such piles can be many years.
https://www.orcasciences.com/articles/standard-thermal-copy
https://austinvernon.substack.com/p/building-ultra-cheap-ene...
https://news.ycombinator.com/item?id=45012942
I ran the numbers on that, and it just doesn't work. Stone has rather lousy specific heat capacity (less than 1kJ/kg/K, compared to 4.2kJ for water).
A typical house in Midwest needs around 22,000kWh (7.913×10^10 J) over the winter (75 million BTU - https://www.eia.gov/todayinenergy/detail.php?id=57321 ).
If we assume the delta of 550 degrees (600 down to 50), you'll need: 7.913×10^10 J / (550K * 1000Jkg^-1K^-1) = 143,872,727 kg of material in your pile. This is a ridiculously stupid number. And I don't see any obvious mistakes?
Your decimal point slipped three places in that last calculation; the result is too high by a factor of 1000.
A more worthy criticism is that the pile for just a single house is too small and would cool off too quickly.
I don't believe it did? Delta of 550 degrees Kelvin multiplied by 1000J per kg per Kelvin.
7.913e10 / ( 5.5e2 * 1.0e3 ) = 1.438e5, not 1.438e8
When doing calculations like this I just fire up a lisp and enter the thing to be calculated as lisp form.
I use units(1), which also helps me avoid dimensional errors (dividing when I should have multiplied, etc.):
maxerickson says, "Still big number," and 144 tonnes would typically be an unwieldy quantity of material if you had to buy it. But Standard Thermal's intention is not to buy dirt, just pile up already-on-site dirt with a bulldozer or excavator. If we assume 1.3 tonnes/m³, that's 110m³, or, in medieval units, 144 cubic yards. https://www.eaglepowerandequipment.com/blog/2022/03/how-much... tells us:> An excavator could be used to dig anywhere from 350 to 1,000 cubic yards per day, depending on a number of factors including bucket capacity, type of ground, operator skill and efficiency level, and more. (...)
> One of the biggest factors that impact how much an excavator can dig in one day is the unit’s bucket size, which typically ranges from 0.5 to 1.5 cubic yards of bucket capacity. Most common regular-size excavators have a 1 cubic yard bucket capacity, and mini excavators are closer to the 0.5 cubic yard capacity.
So, with this number, we're talking about a few hours of work for a "mini excavator". https://www.bigrentz.com/rental-locations/pennsylvania/pitts... tells us that a "4,000 lb. mini excavator" rents for US$197 per day. So the expense of moving the dirt is not really significant, compared to other household projects such as replacing the roof, insulating the walls, or repainting the exterior.
Standard Thermal mentions that they are in effect firing the clay in the ground, that they've had significant trouble with resistance-heater reliability, and that their objective is to power steam-turbine power stations with the stored heat. These three facts lead me to believe that they're targeting a temperature closer to 1000° than to 600°.
600 C is about what a coal fired power plant would use. And 600 C is around the maximum that you want if you're using cheap steel for the pipes. Much beyond that and creep becomes a problem. So I don't think 1000 C is their target.
Hmm! Interesting! I would have thought that 600° would be close to the minimum for producing supercritical steam, so any energy stored up to 600° would be "overhead" that couldn't be effectively recovered—only the heating above that. And I assumed they would have to use cheap ceramic for the pipes, because oxidation is usually a problem for cheap steel even below 600°.
The critical temperature of water is 374 C.
You're right; I wonder why they operate supercritical steam turbines at 600° instead? https://direns.minesparis.psl.eu/Sites/Thopt/en/co/cycles-su... https://www.mdpi.com/2673-7264/5/1/1 https://www.modernpowersystems.com/analysis/is-700-c-steam-t...
Oh, apparently because of "dramatic improvements in power plant performance":
> Starting with the traditional 2400 psi / 1000 F (165 bar / 538 C) single-reheat cycle, dramatic improvements in power plant performance can be achieved by raising inlet steam conditions to levels up to 4500 psi/310 bar and temperatures to levels in excess of 1112 F/600 C. It has become industry practice to refer to such steam conditions, and in fact any supercritical conditions where the throttle and/or reheat steam temperatures exceed 1050 F/566 C, as “ultrasupercritical”.
https://www.gevernova.com/content/dam/gepower-new/global/en_...
Anyway, those are the plants that Standard Thermal wants to sell their product/service to. And once the hot dirt falls below 600°, it can no longer heat the water to 600°. So I think they have to be aiming far above that temperature, which is also why heating element reliability is a challenge and why the clays in the soil are firing (a phenomenon which only happens at 600° for the lowest-firing terra-cotta clays, more typically requiring 1000°–1400°).
Most coal plants in the US aren't ultrasupercritical. The first one only went operational in 2013, in Arkansas (the John W. Turk, Jr. Power Plant).
Oh, really? What temperatures do US power plants operate their steam at?
Here's an article giving the state of such plants in the US in 2011. Since then I imagine some of the smaller/older plants have been retired. There is no new coal capacity coming online in the US.
https://www.powermag.com/coal-fired-generation-cost-and-perf...
Sounds like it was 80% subcritical at the time. I hadn't realized. It sounds like even "regular supercritical steam" is at like 580°, though. Maybe dirt at only 600° could still provide a substantial fraction of its stored energy to subcritical steam circuits, if they're much colder than that?
I think "storage at 600 C" could provide most of its heat output at close to 600 C. It's not like the entire thermal store is tapped at the same time.
Imagine a pile with long pipes through it. Cool fluid is introduced at one end; the steam is gradually heated as it travels down the pipes, emerging as hot steam at the end. If needed, gang two of these together with the second pile acting to top off the temperature from the first one (or more than two).
So, during discharge, a wave of cold sweeps down the pile(s), while the pile near the outlet end stays pretty hot. Only when most of the piles are discharged does the temperature decline.
The Standard Thermal approach is described as heating the piles with embedded resistive heaters, but it could also use an external heater that sends in steam in the opposite direction from when it discharges. This would turn the system into a giant counterflow heat exchanger. Counterflow heat exchangers are known for their high performance, enabling almost all the delta-T between two fluid streams to be interchanged.
Hmm, you're right that a counterflow heat exchanger could indeed provide 600° output by cooling a hot dirt pile most of which is well below 600°. I hadn't thought of that, even though I knew it in other contexts. I mistakenly thought that only the heat over the output temperature would be available.
The only drawback is that, when you're heating the pile, most of the time you are only heating part of it (the cold part), so your heating elements need to have a significantly higher power capacity, assuming you're heating the pile with embedded resistors as described, rather than with a heat transfer fluid as you suggest.
I don't think you want the heat transfer fluid in the dirt pile to be steam; that would involve making the pipes through the hot dirt resistant to both pressure and steam corrosion, which would make them expensive. It also means you'd have a high-pressure steam leak deep inside the dirt pile when they did fail, which would probably cause damage to other pipes and to resistors and a significant uncontrolled heat transfer from the zone of the leak to other parts of the dirt pile. I think you want a more relaxing atmospheric-pressure heat transfer fluid that allows you to use cheap pipes, or even no pipes. Air, for example. Solar salt can reach those temperatures, and it has a much larger heat capacity, but it's fairly corrosive.
For a seasonal thermal store, also, we're talking about astoundingly low power densities, so low-density heat transfer fluids like air should be fine. If we're cooling the hot dirt from 600° down to 100° over a 3-month low-sun season, and the dirt is 1J/g/K, we're only extracting 63 watts per tonne, which at 1.3 tonnes of dirt per cubic meter is 80 watts per cubic meter. My human body is largely air-cooled and generates about 800 watts per tonne in normal operation, even without forced air.
I don't think it's necessary for the pipes in the piles to be operating at the pressure of the steam in the turbines. There could be an intermediate heat exchanger to transfer heat from the low density steam (or air) in the pipes to the high pressure steam in the turbine loop.
Yes, that is what I meant to propose, but when you have that additional heat exchanger, why would you use steam rather than air (or some other fluid like helium or argon) in the low-pressure pipes?
You have 8*10^10 in the numerator and 5*10^5 in the denominator, so the result should be roughly 8/5*10^5.
Still big number.
I'm going to want that pile hot enough to kill all the bugs and pets that want to get near it.
The surface will always be only slightly hot. Heat will be stored inside, insulated by overlying dirt. Dirt isn't the best insulator by thickness, but it's a very good insulator by $.
I haven't seen pfdietz's proposed system design, but a so-called "sand battery," consisting of a box of sand with a heating element running through it, should work fine. You can PWM the heating element with a power MOSFET to keep it from overheating; you can measure its temperature with its own resistance, but also want additional thermocouple probes for the sand and to measure the surface of the box. A fan can blow air over or through the sand to control the output power within limits.
I'll work out some rough figures.
Let's say your house is pretty big and badly insulated, so we want an average of 5000 watts of heating around the clock with a time constant on the order of 10 hours, and we don't want our heating element to go over 700°. (Honest-to-God degrees, not those pathetic little Fahrenheit ones.) That way we don't have to deal with the ridiculous engineering issues Standard Thermal is battling. There's a thermal gradient through the sand down to room temperature (20°) at the surface. Suppose the sand is in the form of a flat slab with the heating element just heating the center of it, which is kind of a worst case for amount of sand needed but is clearly feasible. Then, when the element is running at a 100% duty cycle, the average sand temperature is 360°. Let's say we need to store about 40 hours of our 5000W. Quartz (cheap construction sand) is 0.73J/g/K, so our 720MJ at ΔT averaging 340K is 2900kg, a bit over a cubic meter of sand. This costs about US$100 depending mostly on delivery costs.
The time constant is mostly determined by the thickness of the sand (relative to its thermal diffusivity), although you can vary it with the fan. The heating element needs to be closely enough spaced that it can heat up the sand in the few hours that it's powered. In practice I am guessing that this will be about 100mm, so 1.5 cubic meters of sand can be in a box that's 200mm × 2.7m × 2.7m. You can probably build the box mostly out of 15m² of ceramic tiles, deducting their thermal mass from the sand required. In theory thin drywall should be fine instead of ceramic if your fan never breaks, but a fan failure could let the surface get hot enough to damage drywall. Or portland cement, although lime or calcium aluminate cement should be fine. You can use the cement to support the ceramic tiles on an angle iron frame and grout between them if necessary.
7.5m² of central plane with wires 100mm apart requires roughly 27 2.7m wires, 75m, probably dozens of broken hair dryers if you want to recycle nichrome, though I suspect that at 700° you could just use baling wire, especially if you mix in a little charcoal with the sand to maintain a reducing atmosphere in the sand pore spaces. (But then if it gets wet you could get carbon monoxide until you dry it out.) We're going to be dumping the whole 720MJ thermal charge in in under 9 hours, say 5 hours when the sunshine is at its peak, so we're talking about maybe 40kW peak power here. This is 533 watts per meter of wire, which is an extremely reasonable number for a wire heating element, even a fairly fine wire in air without forced-air cooling.
If we believe https://www.nature.com/articles/s41598-025-93054-w/tables/1 the thermal conductivity of dry sand ranges from 0.18 W/m/K to 0.34 W/m/K. So if we have a linear thermal gradient from our peak design temperature of 700° to 20° over 100mm, which is 6800K/m, we should get a heat flux of 1200–2300W/m² over our 15m² of ceramic tiles, so at least 18kW, which is more than we need, but only about 3×, so 200mm thickness is in the ballpark even without air blowing through the sand itself. (As the core temperature falls, the heat gradient also falls, and so does the heat flux. 720MJ/18kW I think gives us our time constant, and that works out to 11 hours, but it isn't exactly an exponential decay.) Maybe 350mm would be better, with corresponding increases in heating-element spacing and decreases in wire length and box surface area and footprint.
To limit heat loss when the fan is off, instead of a single humongous wall, you can split the beast into 3–6 parallel walls with a little airspace between them, so they're radiating their heat at each other instead of you, and cement some aluminum foil on the outside surfaces to reduce infrared emissivity. The amount of air the fan blows between the walls can then regulate the heat output over at least an order of magnitude. (In the summer you'll probably want to leave the heating element off.)
The sand, baling wire, aluminum foil, lime cement, angle irons, charcoal, thermocouples, power MOSFETs, microcontroller, fans, and ceramic tiles all together might work out to US$500. But the 40kW of solar panels required are about US$4000 wholesale, before you screw them to your siding or whatever. At US prices they'd apparently be US$10k.
720MJ is 200kWh in cursed units, so this is about US$2.50/kWh. Batteries are about US$80/kWh on the Shanghai Metals Market.
What do you think?
Sand batteries have a much higher cost per unit of energy storage capacity, so they are in more direct competition with batteries for shorter term storage. It's hard to compete with a storage material you just dig out of a local hole. The economics pushes toward crude and very cheap.
Having said that: a good design for sand batteries would use insulated silos, pushing/dropping sand into a fluidized bed heat exchanger where some heat transfer gas is intimately mixed with it. This is the NREL concept that Babcock and Wilcox was (still is?) exploring for grid storage, with a round trip efficiency back to electricity of 54% (estimated) using a gas turbine. Having a separate heat exchanger means the silos don't have to be plumbed for the heat exchange fluid or have to contain its pressure.
Getting the sand back to the top (where it will be heated and dropping into silos) is a problem that could be solved with Olds Elevators, which were only recently invented (amazingly).
https://www.youtube.com/watch?v=-fu03F-Iah8
(I completed my parent comment since you wrote your response, which may make it confusing to read your response; sorry about that.)
I agree that local dirt is much cheaper than trucked-in construction sand, but I think my design sketch above shows that a "sand battery" whose only moving parts are fans will be about 30× cheaper than a real battery at household scale, even though the sand is still most of the estimated cost. A "sand battery" designed to power a steam turbine is a much more difficult problem to solve, but in this case the stated problem is just that it's 24°F (-3°) outside, so I think much cheaper solutions are fine, with no pressure vessels, stainless steel, insulated silos, sand conveyors, or heat transfer fluids other than garden-variety air.
Do you have a good handle on the pressure (and therefore power) requirements for getting air to flow upward through sand? I feel like you ought to be able to get a pretty decent amount of thermal power out of half a tonne of sand with a really minimal amount of pumping, but that's only a gut feeling. Definitely as you go to graded-granulometry gravel the required head drops off to almost nothing.
Thanks for the link to the Olds device! That's utterly astounding. Archimedes could have used it for raising sand, although making a sturdy enough tube out of wood might have been a bit of a chore.
A thing I forgot to calculate: with 75m of wire dissipating 533 watts per meter, how thick should the wire be? Suppose we divide it into three 25m circuits so that we still have most of our heat if a wire burns out, and suppose we're using 48Vdc. So E²/R = 13.3kW, R = E²/13.3kW = 0.173Ω, and each of those elements is carrying an astonishing 277 amps. So we want 7 milliohms per meter. It turns out that that's about 12-gauge copper wire, nominally 5 milliohms per meter. 2 millimeters across. A higher-resistivity metal like iron or nichrome would have to be even thicker.
Better idea: put 9 2.7-meter wires in parallel on each of the three circuits, so each wire can have 9×0.173Ω = 1.56 Ω = 0.58Ω/m. That's 32-gauge copper magnet wire, 0.2mm diameter, 0.54Ω/m; or its thicker equivalent in other metals. Iron's resistivity is 5.7 times copper's, so you need a 5.7 times thicker wire: 0.5mm, 24-gauge. Nichrome is 11 times the resistivity of iron, so you'd need 1.6-mm-diameter nichrome.
I don't know, I think the copper would probably melt faster than the sand could conduct the heat away from it, and the nichrome would definitely be fine, but too expensive. But you can extrapolate from this how to solve the problem: by shortening the distance along the heating wires to low-resistance busbars (possibly made of rebar or leftover angle iron) and thus increasing the number of parallel paths, you allow the use of higher-resistance-per-unit-length and thus cheaper and more workable heating elements; the limit of this lightweighting is that the wires' surface area in contact with the sand must cool them enough to prevent melting. By this method you can use a small amount of a conductor of any resistivity at all, limited mainly by the temperature.
All these metals are fine at 700°, or for that matter 1000°. Copper will have less of a tendency to oxidize than iron, which would require a reducing atmosphere, and nichrome will oxidize but remain protected by its oxidation. (A reducing atmosphere will destroy nichrome.) But, at a lower temperature still, like 600°, you could use 10μm thick household aluminum foil, which is much easier to work with than any kind of 20μm wire, but has a similar ratio of surface area to volume. It has 54% more resistivity than copper, so a 10μm × 1mm strip is 2.7 ohms per meter. Our previous objective of 0.58Ω/m is a 4.6mm-wide-strip, which transfers heat to the sand along its 9.2mm perimeter, like a 10-gauge wire. 75m × 4.6mm is the size of about 5 or 6 pages of A4 paper cut into strips.
Maybe stainless steel for the heating elements and busbars?
Cheaper than nichrome and copper. I feel like mild steel would not last long in practice.
Copper plated MIG welding wire might be good enough?
Probably want to think about thermal expansion also, especially configured as "walls", and with skins considerably colder than cores.
Austin Vernon claims they have a very cheap resistor material for Standard Thermal but hasn't said what it is. I look forward to hearing that detail when it leaks out. A good chunk of their work while in stealth was on the resistors, I understand.
I think I've shown above that you can make the resistor material itself almost arbitrarily cheap, calculating for example how you can get 40 kilowatts out of 9.3 grams of aluminum foil, and showing that with more busbars you can use even less resistor material than that. Aluminum itself wouldn't work for Standard Thermal's target temperatures, but you can make an arbitrarily thin foil out of any metal, supporting it as a thin film on an insulating ceramic such as porcelain if necessary. Copper, gold, silver, mild steel, nickel, nichrome, other stainless, titanium, platinum, and platinum/iridium, could all be made to work, and in no case would the material cost be significant. Metal film resistors supported on ceramic are being used to convert electrical energy into heat in probably every electronic device in your house.
And the old standby for resistive heating of giant piles of dirt, for example to bake it into carborundum, isn't a metal at all—it's plain old carbon, which you can if necessary bake in situ. Carborundum itself can also work, though it's not malleable, and controlling its resistivity can be tricky.
MIG welding wire is an interesting possibility.
The main potential obstacle, I think, is the manufacturing cost, and as sandy234590 was saying, potentially durability in use. Vernon said resistor durability had been one of their major problems; I'd think that sand would impose less stress on the resistors than generic dirt, but, with quartz in particular, you could greatly reduce the risk by not crossing the quartz dunting temperature at 573°: https://digitalfire.com/glossary/quartz+inversion That obviously isn't an option for Standard Thermal, but it would be completely viable for household climate control, just requiring somewhat more sand.
Sandy points out, implicitly, that mild steel such as the baling wire I suggested typically does not last long at high temperatures. But that's because it oxidizes. The same vulnerability is present in most metals, though not silver, gold, platinum, and platinum/iridium alloys, and only to a limited extent for nickel, nichrome, and other stainlesses. That oxidation can only happen in an oxidizing atmosphere; the thin iron ballast wires in Nernst lamps last indefinitely because they're sealed in a reducing (hydrogen) atmosphere. As I said, I think you can maintain a reducing atmosphere in the sand pore space by just including a little charcoal, which will scavenge any oxygen that gets close to the heating elements when they're hot, and may even be able to reduce any oxide that does form, at the cost of carbon monoxide emission.
If the atmosphere inside the sand is oxidizing, you'd probably want to either use something that won't be damaged by oxidization, such as gold or nichrome, or use a very thick heating element such as carbon so that it will have an adequate service life despite the oxidation. Most stainless steels will start to oxidize at a few hundred degrees, even though they're fine at room temperature.
(The main heating element in Nernst lamps, cubic zirconia, was also immune to oxidation, but it had some other drawbacks; for example, it needed to be preheated into its conductive range with a platinum preheat wire, and its rather aggressive negative temperature coefficient of resistance made it prone to thermal runaway when operated on a constant-voltage source—thus the iron ballast wire.)
Did you just reinvent electric night storage heaters?
I would instead say that, familiar with many designs from millennia of history of using thermal mass for indoor climate control, I outlined a design of an electric night storage heater that is especially cheap and convenient. Or an "electric day storage heater", I guess, since the day is when it stores heat.
I've heard of farmers doing this, well I think they actually had an inverter. But limits on how much they could dump into the grid, meant that they had lots of surplus electricity and installing resistive heating was very cheap.
Even if they don't have surplus electricity all the time.
Agriculture is one of the target markets for Standard Thermal. For example, grain drying is a large consumer of propane, which is expensive.
Is it worth using heat pumps in this setup (in addition to resistive elements)? I understand they can't reach the absolute temperature of resistive heating, but from an efficiency POV for the first few tens of degrees they are much more efficient.
Depends - the problem with heat pumps is when you need them the most they don't work. If it never gets below -10c (exact temperature needs more study, could be as low as -25) where you live they are fine - but that implies you live in an area where you don't get many cold days and so the expense isn't worth it (it also implies you live where it gets hot in sumner so you want ac anyway and the marginal additional cost makes it worth it again). If you live in an area where it gets colder you need additonal backup heat that can cover those really cold days and so you may as well run that system only.
I think unless you're in an area dominated by cooling needs, an optimally sized heat pump system will not cover 100% of heating needs. It would make sense to make it smaller and use a backup resistive heater for rare very cold events.
cooling is more important but not by much. however the real problem is temperature delta: 100f-70f is 30 degrees, 70f-10f is 60 degrees. If you size a system for cooling it can't make up.
of course things arenot actually linear on temperature but as a rough estimate it gets the point across.
Efficiency allows you to use less solar panels, but more solar panels are cheaper than a heat pump. I think the ratio is about 5:1 at this point and widening.
To be concrete, I'm told that recently in the US a certain 34000btu/hour (10kW) output heat pump consuming up to 14A at 220V at the compressor (3kW) cost US$2700 installed, which is 27¢ per peak watt of output. But https://www.solarserver.de/photovoltaik-preis-pv-modul-preis... gives a price of €0.055 per peak watt (US$0.065/Wp) for low-cost solar panels. So the heat pump costs, in some sense, 4.2 times as much as the solar panels.
But the heat pump doesn't save you 10kW over resistive heating when it's running full-tilt. It saves you 10-3 = 7kW. So it costs 39¢ per watt of saved energy, which is 6 times as much as the solar panels.
In some simplified theoretical sense, if you decide you need another 10kW of heating for your house, you could spend US$2700 on this heat pump, and also buy 3000 Wp of solar panels to power it, costing US$194, for a total cost of US$2894. Or you could buy 10000 Wp of solar panels, costing US$645, and a resistive wire, costing US$10, for a total cost of US$655. US$655 is almost five times cheaper than US$2894. (4.4 times cheaper.)
There are a lot of factors that this simplified cost estimate overlooks; for example:
• Maybe you need to run the heater 16 hours a day but you only get sunlight 7 hours a day, either because it's winter in Norway, or because there are tall pine trees that shade your property most of the day, and you can't put the panels up on the trees. So maybe in some sense one watt of peak heater output is worth 2.3 watts of peak solar panel output. Or maybe it's the other way around, where your house only needs active heating during a few hours at night, so one watt of peak heater output is only worth 0.43 watts of peak solar panel output.
• The prices are in different countries. Solar panels are more expensive in the US, even wholesale.
• US$2700 is the retail price of the heat pump, including installation and warranty, and 6.5¢/Wp is the wholesale price of low-cost solar panels with no warranty ("Minderleistungs-Solarmodule, B-Ware, Insolvenzware, Gebrauchtmodule, PV-Module mit eingeschränkter oder ohne Garantie, die in der Regel auch keine Bankability besitzen.") Even in Europe the retail price of solar panels is three or four times this.
• Driving a resistive heating element from solar panels is considerably easier than driving a heat pump from solar panels; adapting a heating element to run on lower voltage is just a matter of connecting more wires to the middle of it, while adapting a heat pump to run on lower voltage may involve redesigning the whole power supply board or even rewinding the motor. Which is in a hermetically sealed refrigerant circuit, by the way, which you'd have to reseal. In practice, you'd just buy an inverter, but a 3000-watt inverter is expensive.
• As you said, for sensible-heat thermal storage, the heat pump craps out at about 50° or 60°, while any garden-variety resistive heating element (plus a lot of crappy improvised ones) will be just fine at 600° or 700°. That means you need ten times as much thermal mass for the same amount of storage. Sand is dirt cheap, but once you get into the tens of tonnes, even dirt isn't really cheap.
Despite such complications, I still think that pair of numbers is a useful summary of the situation: the heat pump costs 39¢ per watt saved, while the solar panel costs 6.5¢ per watt produced.
Yeah, we paid more for the little bits of metal that held up the panels than for the panels themselves (aluminum, but still).
IDK sounds like you got ripped off. I diy'd and panels were cheap of course, but fittings were perhaps 3-5x cheaper. Inverter is typically same as your panels (hybrid, grid-tied are quite a bit cheaper).
For all of your context/reference, if you buy whole pallets from a central European port warehouse, glass-glass modules run around $0.11/Wp plus shipping.
Unless you're just bolting them to the floor or to an uninsulated wall, mounting will (sadly) run you a sizable fraction of that cost in the best case.
Maybe, but these aren’t fittings, they’re ground mounts with large screws that screw into the ground to hold the entire array down, including under high wind (and have to come with PE stamped system-level engineering drawings talking about things like rated wind load of the whole array to pass building inspections).
But yeah, at the end of the day, just bent bars of aluminum with ground screws and bolts to hold the corners of the panels, versus the technological marvels of the solar panels they hold.
These days it’s a stack of microinverters. Which are not cheaper but do improve array efficiency outside of idea conditions. But that’s another up front cost.
They are still pretty unpopular. Solves niche problem (small roof, shade) for a quite a bit more money.
I think they were referring to the fact that the chief reason there is not large-scale PV panel recycling is that very few panels have ever been retired. It turns out that short of physical destruction by hail etc a PV panel does not degrade beyond economic usefulness simply by being out in the sun. In fact some panels actually get more powerful. The surprising-to-some conclusion of NREL's PV Lifetime Project is that the economic lifetime of a PV panel is basically forever.
How much of a difference does it actually make in terms of the all-inclusive price of installation (e.g. panels, inverters, mounting hardware, and labor)?
(Asking because I genuinely don't know, not because I have a specific answer in mind.)
Labor is by far the top cost. But I'm intrigued by the economics of a small setups paired with like a <5kwh battery. And for something like that where you literally just throw 4-6 panels out, you can just brute force by buying more panels instead of optimizing angles. Basically a slightly beefier version of a European balcony setup
Find an installer who will warranty work using third party let alone used solar panels and then we can talk.
Used panels are cheap because of where we are in the improvement curve. Let's say you're a large business with a factory rooftop full of 100W panels that was installed installed 10 years ago. Today, you can upgrade that rooftop to 300W panels without any additional footprint and often for less than the original deployment cost (adjusted for inflation).
Those old panels have to go somewhere and still have at least 2/3 of their life left. Probably more because we're finding out that well-made panels do not degrade as quickly as previously thought.
The used panel market (in the US anyway) might dry up soon if the tariffs stay in place, as that will make a lot of customers reluctant to upgrade due to greatly increased costs. But I guess we'll see. I've been wrong before.
We are only 5-6 years into the car ev market. Tesla model 3 started being sold in 2018 in meaningful numbers
Still have mine. Battery capacity is around 80% of the new capacity. I'm not planning on switching anytime soon as it's got plenty of range still. I'll probably swap the pack out when it hits 70% in the next 2 or 3 years.
It probably will take a lot longer than that to hit 70%. Degradation on Tesla batteries slows down considerably after it hits 85%.
there are exceptions, though.
Your 2018 tesla has a battery SOH of 80%?
How many km's on the clock, and how often do you fast charge if you dont mind me asking?
To me that SOH stat sounds really bad!
270,000 km. And fast charging about 3 times a year.
If I were to guess, the main factor harming the battery is my garage gets pretty hot in the summer (37 or 38C)
I'm not even sure how to calculate our deg! Same, 2018 3 long range. I think they advertised it as 305mi but some time later increased the capacity of the car to 315mi; I max charged it to 314 once but never quite saw that 315. I think we're around 273 as max now so 89.5% of the original quoted life, 87% of the "updated" life. Car has 115k miles, ~ 185,000km.
There was about 2 years of rapid drop off that I experienced and I don't exactly know why.
That is quite high mileage. I'm certain someone smarter and less lazy than me can calculate the amount of expected cycles that the battery would have seen.
Do you leave it fully charged for long periods of time, or do you discharge it down to empty or nearly empty quite regularly?
I charge it to 70% and leave it there most of the time.
I don't often fully discharge, that's bad for the lipos. I usually keep a 40-70 range SOC.
I agree, reads like carefully crafted FUD.
What possible motivation would I have to spread FUD about my own car?
To me this is perfectly reasonable degradation after 7 years of ownership with the number of miles I have.
There is also just an element of luck that's involved. Batteries degrade at different rates and there's not really any accounting for it.
Top it how cheap batteries have gotten it makes little sense to remanufacture unless you are extremely dedicated DIYer, live somewhere with very cheap labour or it's done in massive scale to achieve economies of scale.
In NZ you can get 60KWh used Tesla battery for 6-10k NZD, then spend another 1-2k for additional gear + labour to hack it (overall $116-200/KWh) or 15KWh for 3.5k ($233/KWh) with warranty and safety guarantees.
The typical EV industry trade show has a small handful of cars and a vast amount of tangential businesses including many finance options, a vast amount of home charger gizmos, fast charging gizmos, electricity suppliers and the companies promising grid-scale storage, either from actively used cars or recycled EV batteries. There is a vast constellation of this stuff, with specialist insurance companies that nobody really asked for outnumbering the car brands or even e-bike brands present.
In time there will be consolidation. This constellation of EV startup bottom-feeders will be decimated along with the 'excuses' to not make money.
I don't think the problem is that EV batteries are lasting longer, it is just that the EV market from before the Model 3 came along is miniscule. Hence not many second hand batteries to recycle.
As for EV batteries and their availability, when was the last time you saw an OG Tesla Model S with the fake grill? Those cars used to be everywhere, but where are they now? The German EVs that came out to compete, for example, Taycan and eTron, those things are not going to last the distance since the repairs cost a fortune and the parts supply is limited.
All considered, there will come a time before 2040+ when there are large quantities of these electric car batteries to upcycle, by which time the EV business will be consolidated with only a few players.
If there was money in recycling cars then every auto manufacturer would be in on it.
There is one constant to all these conversations and that is Silicon Valley tech dudes are grossly misinformed about the lifecycle of things. Solar panels don't wear out, batteries don't wear out as fast as they used to. This is evidenced both by undertaking weird dead-end startup ideas, and being susceptible to propaganda about the supposed downsides of solar energy and batteries.
> "most people"
"most people" even now are just parroting dumb FUD they read on facebook. You really shouldn't give any weight to the opinions of laypeople on topics that are as heavily propagandized and politically charged as renewable energy.
Tesla batteries fail after 8 years at least from models up to 2014
The number of Teslas sold up to 2014 is less than 1% of all Teslas sold.
Tesla has an 8-year battery and drivetrain warranty but they don't necessarily fail after that date.
there is an ubiquitous failure of Panasonic-created cells for Tesla. I made a research on forums, because I wanted one, and investigated why there is such a price drop. Cars getting close to the age of 8 years immediately drop on price to even 10k usd. It's because if you get your battery replaced on warranty - you won. Otherwise it often deteriorates suddenly.
It’s understandable that people would avoid out of warrant EVs, we don’t have that many years of data on old EVs yet.
Anecdotal forum posts are not a great source of statistical data.
Prius Plugin 2015 (last year of that model) - full charge/discharge at least 3-4 times a week, currently still a bit more than 80% of capacity (granted the battery seems somewhat overbuilt, yet it is normally does 10-15C which is much tougher mode than in a pure EV where 2-3C is usually enough and only high-end Teslas and the likes would do 5-6C). There has been large continuous improvement in lithium batteries over the last couple decades.
What does any of this mean?
What is c in this context?
From my model airplane experience, I believe it's "capacity per hour". So, a 1Ah battery discharged at 1c would mean 1 amp; discharged at 10c would be 10 amps. The higher the C, the harder the batteries are being used.
1 C current fully discharges battery in 1 hour. Thus 4KWh battery running 60 KW engine means 15C current, and it would discharge the battery in 4 minutes (in a very simplified linear model).
[citation needed]
In 2040 fusion energy advancements will have gotten far enough to be the next technological step and make this redundant anyway
There's currently no technological path for fusion to be cheaper than fission. It would require a technological breakthrough that we have not yet imagined.
And already, solar plus storage is cheaper than new nuclear. And solar and storage are getting cheaper at a tremendous rate.
It's hard to imagine a scenario where fusion could ever catch up to solar and storage technology. It may be useful in places with poor solar resources, like fission is now, but that's a very very long time from now.
The low energy future that was envisioned is not happening.
The AI arms race, which has become an actual arms race in the war in Ukraine, needs endless energy all times a day.
China is already winning the AI cold war because it adds more capacity to its grid a year than Germany has in a century.
If we keep going with agrarian methods of energy production don't be surprised that we suffer the same fate as the agrarian societies of the 19th century. Any country that doesn't have the capability to train and build drones on mass won't be a country for long.
You have that exactly backwards: solar + storage is what will give us energy abundance at less money than we could ever imagine from nuclear fission or fusion.
China is winning the AI Cold war because it's adding solar, storage, and wind at orders of magnitude more than nuclear.
I'm not sure who's doing your supposed "envisioning" but there is no vision for cheap abundant energy from fusion. Solar and storage deliver it today, fusion only delivers it in sci fi books.
Nuclear is 20th century technology that does not fit with a highly automated future. With high levels of automation, construction is super expensive. You want to spend your expensive construction labor on building factories, not individual power generation sites.
Building factories for solar and storage lets them scale to a degree that nuclear could never scale. Nuclear has basically no way of catching up.
China has been building out nuclear capacity at 5% a year for 25 years.
Solar and wind capacity had shot through the roof in the last five years because they can't sell hardware to the west any more.
The other big item is hydro power, which China has a ton of untapped potential for. Unfortunately for the West every good river has already been damed so we can't follow them there.
> Solar and wind capacity had shot through the roof in the last five years because they can't sell hardware to the west any more.
"can't sell hardware??" hah! I've never heard that weird made-up justification, where did you pick it up from?
China installed 277GW of solar in 2024, capacity factor corrected that's 55.4 GW of solar power. That's equivalent to the entire amount of nuclear that China has ever built. One year versus all time. And then in the first half of 2025, China installed another 212GW of solar. In six months.
Nuclear is a footnote compared to the planned deployment of solar and wind and storage in China.
Anybody who's serious about energy is deploying massive amounts of solar, storage, and some wind. Some people that are slow to adapt are still building gas or coal, but these will be stranded assets far before their end of life. Nuclear fusion and fission are meme technologies, unable to compete with the scale and scope that batteries and solar deliver every day. This mismatch grows by the month.
> China installed 277GW of solar in 2024, capacity factor corrected that's 55.4 GW of solar power.
The problem is not just the mean capacity factor, but the capacity factor in _winter_. It's terrible for China, less than 15%. And more importantly, you can have _weeks_ with essentially zero solar power when you need it most.
This is not an issue in China as they overprovision demand by 50 percent. Their grid can run off baseload generation alone in their 2060 plan.
Trying to explain that a grid build by electrical engineers, rather than financial engineers, has resilience build in to people whose whole idea about electricity generation is greenwashed bullshit from McKinsey and Co is at best a waste of time and at worst an excellent way to raise one's blood pressure.
> It's terrible for China, less than 15%.
55.4 GW per 277 GW is an (annual) capacity factor of 20%, so the response here is "yes, and?"
> And more importantly, you can have _weeks_ with essentially zero solar power when you need it most.
Half the country is a mid-latitude desert. What makes you think the whole country has "weeks" with zero solar? And it does have to be the whole country in this case, because one thing a centrally planned economy can do well is joining up the infrastructure, which in this case means "actually make the power grid the USA and the EU keep wringing their hands over".
> Half the country is a mid-latitude desert. What makes you think the whole country has "weeks" with zero solar?
The "whole country" is irrelevant. You can't transmit arbitrary amounts of power across the large geographic areas, most of energy has to be generated in a reasonably close proximity.
> And it does have to be the whole country in this case, because one thing a centrally planned economy can do well is joining up the infrastructure
Transmission lines are expensive, regardless of your ideology.
> The "whole country" is irrelevant. You can't transmit arbitrary amounts of power across the large geographic areas, most of energy has to be generated in a reasonably close proximity.
Only technically correct because you said "arbitrary": it's well within China's manufacturing capabilities to make a grid that can transmit 3 TW over 40,000 km, with a conductor cross section so thick it only has 1 Ω resistance.
As in: all the world's current electricity demand, the long way around the planet.
I have, in fact, done the maths on this.
> Transmission lines are expensive, regardless of your ideology.
"Expensive" but not "prohibitively expensive".
All infra is "expensive". Nations have a lot of money.
> Only technically correct because you said "arbitrary": it's well within China's manufacturing capabilities to make a grid that can transmit 3 TW over 40,000 km, with a conductor cross section so thick it only has 1 Ω resistance.
And it'll turn out to cost more than building a nuke in each backyard.
> I have, in fact, done the maths on this.
No.
> Solar and wind capacity had shot through the roof in the last five years because they can't sell hardware to the west any more.
They can't sell as much as they would like, specifically to the USA, due to tariffs/trade war, but there's a much bigger world out there than just the US, and the overall exports are up over the last five years: https://www.canarymedia.com/articles/solar/chart-chinas-sola...
There's a Chinese-made Balkonkraftwerk sitting a few meters away from me on my patio, it cost €350, of which €50 was delivery and another €50 was the mounting posts, the remaining €250 got me 800 W of both panel and inverter.
> Unfortunately for the West every good river has already been damed so we can't follow them there.
For generation, yes. For storage, no.
> Unfortunately for the West every good river has already been damed so we can't follow them there.
You don't need a river for hydro power storage. All you need are two reservoirs with a height difference between them. Typically one of the two reservoirs is preexisting and the second is constructed. ANU identified ~1 million potential sites.
https://re100.eng.anu.edu.au/global/
> sci fi books
I blame these for the unquestioned belief that fusion is desirable. It's a trope because it enables stories to be told, and because readers became used to seeing, not because science fiction has a good track record on such things.
The fact that the volumetric power density of ARC is 40x worse than a PWR (and ITER, 400x worse!) should tell one that DT fusion at least is unlikely to be cheap.
With continued progress down the experience curve, PV will reach the point where resistive heat is cheaper than burning natural gas at the Henry Hub price (which doesn't include the cost of getting gas through pipelines and distribution to customers.) And remember cheap natural gas was what destroyed the last nuclear renaissance in the US.
It's hard to imagine a form of energy production less desirable than fusion.
Okay, sure, burning lignite and using the exhaust as air heating in the children's hospital. You got me.
> It would require a technological breakthrough that we have not yet imagined.
Maybe, but not necessarily. The necessary breakthrough might have been high-temperature superconducting magnets, in which case not only has it been imagined, but it has already occurred, and we're just waiting for the engineering atop that breakthrough to progress enough to demonstrate a working prototype (the magnets have been demonstrated but a complete reactor using them hasn't yet).
Or it might be that the attempts at building such a prototype don't pan out, and some other breakthrough is indeed needed. It'll probably be a couple of years until we know for sure, but at this point I don't think there's enough data to say one way or the other.
> And already, solar plus storage is cheaper than new nuclear.
It depends how much storage you mean. If you're only worried about sub-24h load-shifting (like, enough to handle a day/night cycle on a sunny day), this is certainly true. If you care about having enough to cover for extended bad weather, or worse yet, for seasonal load-shifting (banking power in the summer to cover the winter), the economics of solar plus storage remain abysmal: the additional batteries you need cost just as much as the ones you needed for daily coverage, but get cycled way less and so are much harder to pay for. If the plan is to use solar and storage for _all generation_, though, that's the number that matters. Comparing LCoE of solar plus daily storage with the LCoE of fixed-firm or on-demand generation is apples-and-oranges.
I think solar plus storage absolutely has the potential to get there, but that too will likely require fundamental breakthroughs (probably in the form of much cheaper storage: perhaps something like Form Energy's iron-air batteries).
One can discuss base load and season shifting all day long. But ultimately fusion will fail for two simple reasons; time and money.
If we started building a fusion commercial scale plant today (ie started by planning, permits, environmental assessments, public consultation, inevitable lawsuits, never mind actual construction and provisioning) it'd come online in what? 10 years? 15 years? 20 years?
Want to deploy more batteries? It can be online in months. And needs no more construction than a warehouse.
Financially fusion requires hundreds of billions, committed now, with revenue (not returns) projected at 10 years away (which will slide.) Whereas solar + storage (lots and lots of storage) requires anything from thousands to billions depending on how much you want to spend. We can start tomorrow, it'll be online in less than 2 years (probably a lot less) and since running costs are basically 0, immediate revenue means immediate returns.
Of course I'm not even allowing for fusion being "10 years" from "ready". It's been 10 years from ready for 50 years. By the time it is ready, much less the time before it comes online, it'll be redundant. And no one will be putting up the cash to build one.
High temperature superconducting magnets are not a panacea for the problems with DT fusion. Those issues follow from limits on power/area at the first wall, and the needed thickness of the first wall; these ensure DT reactors will have low volumetric power density, regardless of the confinement scheme used.
With HTSC magnets, a tokamak much smaller than ITER could be built, but ITER is so horrifically bad that one can be much better than it and still be impractical.
And these are not new issues, they've been known for more than 40 years, but never addressed. From the 1983 Led
> But even though radiation damage rates and heat transfer requirements are much more severe in a fusion reactor, the power density is only one-tenth as large. This is a strong indication that fusion would be substantially more expensive than fission because, to put it simply, greater effort would be required to produce less power.
https://orcutt.net/weblog/wp-content/uploads/2015/08/The-Tro...
In terms of cost of materials to build a reactor, sure, that seems right. But most of the cost of fission is dealing with its regulatory burden, and fusion seems on track to largely avoid the worst of that. It seems conceivable that it ends up being cheaper for entirely political/bureaucratic reasons.
Relaxed regulatory burden doesn't seem to be making fission competitive in China; renewables are greatly overwhelming it now, particularly solar.
We might ask why regulations are so putatively damaging to nuclear, when they aren't to civil aviation. One possibility is that aircraft are simply easier to retrofit when design flaws are found. If there's a problem with welding in a nuclear plant (for example) it's extremely difficult to repair. Witness the fiasco of Flamanville 3 in France, the EPR plant that went many times over budget.
What would this imply for fusion? Nothing good. A fusion reactor is very complex, and any design flaw in the hot part will be extremely difficult to fix, as no hands on access will be allowed after the thing has started operation, due to induced radioactivity. This includes design or manufacturing flaws that cause mere operations problems, like leaks in cooling channels, not just flaws that might present public safety risks (if any could exist.) The operator will view a smaller problem that renders their plant unusable nearly as bad as a larger problem that also threatens the public.
I was struck by a recent analysis of deterioration of the tritium breeding blanket that just went ahead and assumed there were no initial cracks in the welded structure more than a certain very small size. Guaranteeing quality of all the welds in a very large complex fusion reactor, an order of magnitude or more larger than a fission reactor of the same power output, sounds like a recipe for extreme cost.
Regulation is not a problem, and even the construction costs are not terrible. We can take the Rooppur NPP as a base, it produces reliable energy at 6-7 cents per kWh. The reason for cost overruns is simply because NPPs are one-off products, the Western countries don't have a pipeline for NPP production.
For comparison, utility-scale solar with 16 hours of storage is 21 cents: https://www.utilitydive.com/news/higher-renewable-energy-cos...
Just raw solar without storage can be as low as 2-3 cents per kWh.
If I understand correctly, the cost/year of an engineer in India is maybe 1/3rd that in the US, and for general labor the disparity is even larger. So it shouldn't be too surprising NPP construction in India is cheaper than in the US. India doesn't have a large NPP pipeline, they just have cheaper labor.
(Bangladesh, not India)
Yes, but solar power panels are also mostly produced in China, where engineers still get less than 1/3 of the US/Europe salary.
European power plants will be more expensive, but even with the LCOE of 12 (twice that of Rooppur) it's still going to be way cheaper than storage for areas that get cold weather (Midwest, Germany, most of China).
Anything south of California? Yeah, just get solar+wind, no need to bother with nuclear.
As we pointed out, PV is still trouncing nuclear in China. So if the difference is smaller there, it's still in favor of solar.
Storage is another matter here, but even there costs for batteries have simply collapsed. Understand that massive storage is needed even in a nuclear-powered economy. If all the 283 million cars and trucks in the US were replaced with 70 kWh BEVs, the storage would be enough to power the US grid (at its current average consumption) for 40 hours. That's a lot of batteries. So the demand is there to continue to drive them down their experience curves. In China, they're already around $50/kWh for installed grid storage systems (not just cell price).
The final storage problem, the only reed that nuclear can be clinging to at this point, is long term/seasonal storage. That's needed either to smooth wind variability (~ week scale) or to move solar from summer to winter (~6 months). There are at least two different ways this could be solved: hydrogen and heat. As mentioned elsewhere in these threads, the latter is very promising, with capex as little as $1/kWh of storage capacity and a RTE of about 40%. Should that work out anywhere close to that nuclear would be in a hopeless position anywhere in the world, even at very high latitudes.
> As we pointed out, PV is still trouncing nuclear in China. So if the difference is smaller there, it's still in favor of solar.
Sure. Solar is easy to scale when you don't care about reliability, nobody is arguing with that. But it's another issue entirely when you need a stable grid.
I'm not aware of any countries (even tropical ones) that managed anything close to 100% renewables with solar. E.g. Hawaii has to pay for extremely expensive diesel generation even though they have plenty of solar potential.
And nuclear is scalable if you force other sources off the grid in favor of nuclear (and force customers to not use renewables "behind the meter").
In a fair grid, solar and wind get built out, and the residual demand has no baseload component. Unless nuclear is given the right to force other sources off the grid it becomes inappropriate.
In Texas now there is no chance of new nuclear construction. ERCOT is a competitive market and new nuclear simply doesn't make sense.
> And nuclear is scalable if you force other sources off the grid in favor of nuclear (and force customers to not use renewables "behind the meter").
Not really? Nuclear is not any different from coal. And plenty of countries have coal generation in the mix. France also is majority-nuclear.
And so far, nuclear is the second known technology (after hydro) that actually demonstrated close to 100% fossil-free grid.
So far, there is nothing similar for solar. Even though it's supposed to be oh-so-cheap.
> In Texas now there is no chance of new nuclear construction. ERCOT is a competitive market and new nuclear simply doesn't make sense.
Well, yeah. Because they can just allow the grid to die during the next Arctic air blast.
Nuclear is quite different from coal.
First, coal has a much larger share of its cost as variable cost which is avoided if you don't run the plant. 40% for coal, only 10% for nuclear. This makes integrated a coal fired plant into a renewable grid easier than a nuclear plant. China is increasingly doing this with its coal plants.
Second, coal is much more forgiving of maintenance sloppiness, and even in the event of catastrophic malfunction the plant remains repairable.
Nuclear has been available in its current (and no longer competitive) state longer than solar/wind have been in their current economic state, so if you look at historical data you might conclude nuclear is better. But that's backward looking and says little about what's better in the future.
You are aware that a nuclear plant tripping offline was part of the cause of ERCOT's last winter cold problem?
The nuclear power plant wear-and-tear is roughly proportional to the number of hours it runs at full power. By not running the plant, you can extend its service life (probably to more than 100 years, with periodic annealing). The main limiting factor is the reactor vessel, its steel walls can only tolerate so much neutron bombardment before becoming too brittle for service.
Nuclear power plants have similar behavior to coal plants in another regard, they take approximately the same time to ramp up/down.
> You are aware that a nuclear plant tripping offline was part of the cause of ERCOT's last winter cold problem?
They just need to build more of them. Problem solved.
Anyway, nuclear power plants went from 0% to 70% generation in France within 20 years in 70-s. We don't see anything like this happening with solar, even in smaller island countries. Solar is successful only when it's backed by fossil fuels and government subsidies to keep that fossil fuel generation running.
Sure, you can save some maintenance cost by operating at low capacity factor. But this is a minor part of the cost of nuclear energy, so you don't save much. Nuclear simply isn't constituted to be useful as a dispatchable source.
The technical ability to ramp up/down is beside the point; it's the financial ability to do so that matters.
What nuclear did in France half a century ago is irrelevant. What matters is if nuclear makes sense today. It doesn't, even if it could be done.
Nuclear can be made flexible, that's my point. It works best as a constant baseload, but it's mostly because the current plants were not designed for dispatchable use (except for some plants in France).
Nuclear plants do not degrade at a constant rate, regardless of their power. By idling the plant, you extend its service life, essentially amortizing the capital cost over a longer period of time. And the capital cost is the main driver in the cost of the nuclear power, as you're pointing out yourself.
You ignore the counterargument I already gave you to what you're saying there.
Nuclear can be made technically flexible. It can't be made economically flexible. The large fixed costs prevent the technical ability you are describing there from being useful. It's pyrrhic engineering, straining to achieve an outcome that's useless. Even France depends largely on the rest of Europe to deal with variations in demand rather than spooling their power plants up and down.
Oh, and even in the US, a coal power plant might cost $1400/kW; nuclear is at least a factor of 5 higher.
> The reason for cost overruns is simply because NPPs are one-off products
But there's no fundamental reason they _have_ to be one-off products. They just historically have been for at least partly regulatorily motivated reasons: because each reactor's approval process starts afresh (or rather, did until quite-recent NRC reforms), there's little advantage in reuse, and because many compliance costs are both high and fixed, there's an incentive to build fewer huge reactors rather than more small ones, which makes factory construction difficult to achieve and economies of scale hard to realize.
Civil engineering involves adapting any design to the local geology. This has to be custom for each site.
Regulatory costs and waste disposal are not significance cost centers for nuclear, at least as far as I can tell from any cost breakdowns.
One doesn't need super high quality welding and concrete pours becuase of regulations as much as the basic desire to have a properly engineered solution that lasts long enough to avoid costly repairs.
Take for example this recent analysis on how to make the AP1000 competitive:
https://gain.inl.gov/content/uploads/4/2024/11/DOE-Advanced-...
There are no regulatory changes proposed because nobody has thought of a way that regulations are the cost drivers. Yet there's still a path to competitive energy costs by focusing hard on construction costs.
Similarly, reactors under completely different regimes such as the EPR are still facing exactly the same construction cost overruns as in the rest of the developed world.
If regulations are a cost driver, let's hear how to change them in a way that drives down build cost, and by how much. Let's say we get rid of ALARA and jack up acceptable radiation levels to the earliest ones established. What would that do the cost? I have a feeling not much at all, but would like to see a serious proposal.
> let's hear how to change
One approach would be to reduce the size of the containment building by greatly reducing the volume of steam it must hold. This would be done by attaching Filtered Containment Venting Systems (FCVS) that strip most of the radioactive elements from the vented steam in case of a large accident.
The containment building is a significant cost driver, costing about as much as the nuclear island inside of it.
If such a system had been attached to the reactors that melted down at Fukushima exposure could have been reduced by maybe two orders of magnitude. And if the worst case exposure is that low, perhaps much more frequent meltdowns could be tolerated, allowing relaxation of paperwork requirements elsewhere.
Interesting! Would that require any regulation change?
I believe the NRC currently requires that the containment remain leak-free for 24 hours after a design basis accident.
Now, I have not checked if shorter lived radioisotopes would ruin the idea I'm suggesting. It's possible.
Oh for sure, I'm not claiming that CFS (or Tokamak Energy or Type One or whoever else) will for sure succeed, or if they do, that they've already solved all the problems that will need solving to do so. My only assertion/prediction is that I think if they end up succeeding, when future historians look back and write the history of this energy revolution or whatnot, HTSC magnets will turn out to have been the key breakthrough that made it possible.
Fusion reactors are self destroying, just ask any star.
More seriously: what to do about the neutron flux destroying the first wall inside the reactor vessel?
> needed thickness of the first wall
I meant, needed thickness of the tritium breeding blanket.
> If the plan is to use solar and storage for _all generation_, though, that's the number that matters.
And that's the problem with these Internet discussions: that's almost never the plan, but commenters trying to make solar look bad assume it is (to your credit, you made it explicit; many commenters treat it as an unspoken assumption).
In real life, solar and batteries is almost always combined with other forms of generation (and other forms of storage like pumped hydro), in large part due to being added to an already existing large-scale grid. The numbers that matter are for a combination of existing generation (thermal power plants, large-scale hydro, etc) with solar plus storage. Adding batteries for just a few hours of solar power is enough to mitigate the most negative consequences of adding solar to the mix (non-peaking thermal power plants do not like being cycled too fast, but solar has a fast reduction of generation when the sun goes down; batteries can smooth that curve by releasing power they stored during the mid-day peak).
In the end we're still making steam and running a turbine. Just the steam turbine part of the power plant has a hard time competing with solar in sunny locations.
Fission is expensive for regulation reasons more than technological reasons, so if fusion doesn't face the same barriers then it could be cheaper than fission.
But I agree that it doesn't look like fusion is going to be cheap any time soon.
Fission is also expensive for several mundane reasons, like the fact that massive steam turbines are expensive, and because any large construction project in the West is expensive. Neither fusion nor regulatory reform are going to solve those.
The regulatory hurdles are probably bigger than the difficult enough technological ones you mention.
The steam generator that the fusion generator connects to might be more expensive than solar at this point. That would be even if fusion cost nothing and had infinite amounts of fuel, there would be no customers for its energy on a sunny afternoon.
With solar, fusion energy is already here! There is just a bit of wireless transmission involved after generation.
This is like a “fusion is only 20 years away” (or 15 in this case) joke, right?
It used to be 30. So fifty more years?
Yep, it was 30 years at the 60s. If it keeps halving every 85 years, we'll get it approximately never :)
Zeno's Fusion Paradox
Having worked extensively with battery systems, I think the grid storage potential of second-life EV batteries is more complex than it appears. We found that typical EV batteries retain 70-80% capacity after 8-10 years of vehicle use, but the real challenge is standardization and integration. Different manufacturers use vastly different battery management systems (BMS) and cell configurations - a Tesla pack is fundamentally different from a Nissan Leaf pack.
The economics are interesting though. New grid storage batteries cost around $200-300/kWh, while second-life EV batteries can be acquired for $50-100/kWh. However, you need to factor in significant integration costs (~$50-75/kWh) to build compatible BMS systems and thermal management. We also found cycle life degrades about 20% faster in repurposed packs compared to new ones, likely due to accumulated stress patterns from automotive use.
Has anyone here successfully integrated mixed second-life batteries at scale? I'm particularly curious about how you handled thermal management across different pack designs while maintaining safe operating parameters.
> New grid storage batteries cost around $200-300/kWh
That doesn't sound right. You can already get high-quality, prismatic LFP cells for ~50 US$/kWh [1] from European distributors at low-volumes, so bulk from China should be even cheaper. And there's no way that balancing and BMS cost an additional 150-250 US$/kWh at scale, not even a tenth of that.
[1] https://www.nkon.nl/novat/eve-lf230-prismatic-230ah-230a-lif...
Right, $200-300/kWh is more the range for ~16kWh residential stationary energy storage systems.
How can this be a real issue?
We don't have a lot of car makers and we do not have a huge amount of EV models.
Either you are doing this on small scale, than you can select one or two specific EV models and use these batterie packs or you do it in big scale, than you can also easily adapt the most x batterie packs and only use these across your system.
If you go down to the cell level, its more effort true but then you probably only handel cell types of a handfull of manufacturer again.
You can't really mix different types of cells together in the same pack. Even cells with the same manufacturer and chemistry can be problematic to mix if they are at different wear levels (or even from different batches from the same factory).
This is only practical if you reuse the whole pack, or at least the modules. And for that to work well you also need a lot of complex software to keep the packs working well with each other (like balancing power levels between the packs).
BMS software is no joke, it is already hard and complex enough when using brand new battery packs and cells of the same chemistry and manufacturer and wear level. Any kind of mixing massively increases the complexity and safety concerns.
So they already come with a BMS.
Create a MetaBMS. The BMS of the cell pack doesn't care if a car requests energy between 0 and max and a BMS doesn't care either if it gets 0-100 kWh.
My car can easily charge from a household plug up to fast charger. My car consumes very random amounts of energy while i drive.
> Having worked extensively with battery systems, I think the grid storage potential of second-life EV batteries is more complex than it appears.
Complex, by t very much doable. Toyota implemented such a system with enough packs to power a Mazda factory [1]
> However, you need to factor in significant integration costs (~$50-75/kWh) to build compatible BMS systems and thermal management.
Shouldn't this be a once-off cost per battery-pack version? Or was this your armortized cost for your deployment capacity. If you've written the BMS for a 2019 Model 3 Panasonic battey pack once, won't you reuse it for all the subsequent battery packs of the same model/SKU?
1. https://news.ycombinator.com/item?id=44998010
> Shouldn't this be a once-off cost per battery-pack version?
A BMS isn't just software. It requires a µC, voltage and temperature sensors for cell monitoring, and power electronics for cell balancing. However, those are all comparatively cheap, especially at scale, and the quoted cost of 50–75 US$/kWh looks ridiculously overpriced to me.
I expect EV batteries to have all those components preinstalled already, and naively thought the grid-integration involves reverse engineering the battery's protocol, and perhaps bypassing/replacing a µC or 3.
> the real challenge is standardization and integration. Different manufacturers use vastly different battery management systems (BMS) and cell configurations - a Tesla pack is fundamentally different from a Nissan Leaf pack.
Isn't that exactly what the article is about? Have you actually read the article?
> the real challenge is standardization and integration
In what sense? I'm a newbie, but curious because I'm working on stuff related to https://mesastandards.org/mesa-der-std/.
Personally speaking, having just bought an Ioniq 5 and installing solar at home what I see as the near future improvement is adding V2L functionality, which I can hook up to the generator input of my solar inverter, essentially adding another 60kWh buffer to my grid storage.
Considering how expensive residential batteries are and how quickly EVs depreciate, I think soon it'll be cheaper to get a used EV as a cheap source of cells that accidentally happens to be able to drive itself around.
Imo V2G, and V2H is unnecessary and add too much complication, I think for the future, solar inverters already have the necessary hardware and certifications to be able to take power and safely connect to the grid - something that requires different hardware and standards compliance in basically every country (yes even within the EU).
Residential batteries are not that expensive anymore, at least not all of them. That's a misconception I also held until a few years ago ;-)
My first 14.3 kWh pack cost about 2800$ DDP from China, delivered 03/2023. For that one I did calculate how long it took for amortization, which I projected at about 5 years.
The second, identical pack was delivered 08/2024 and cost 2000$ DDP. Since we got an EV that's drawing about 14kWh per day, I didn't bother doing the math and just ordered it.
These are 280Ah 16S 51.6V packs, based on the EVE LF280K. In an enclosure, with a BMS (Seplos, 200A) and a dedicated balancer. They are good for 6000 cycles at 140A or less [each]. Mind these were both part of small bulk orders - I think each time we ordered 6 to 8 of these, which reduced shipping costs.
Today you can already get 51.2 V, 16 kWh batteries complete with balancer and BMS from a European supplier for 1200 € (1400 US$): https://www.nkon.nl/novat/nkon-ess-eco-s-51-2v-16-1kwh-thuis...
And the nice thing is, prices will only get lower. They also have a 32.15kWh system for €3500,- which is insane.
Unfortunately, almost all three-phase [1] on-grid inverters that are on the market, especially hybrid inverters, only support batteries with much higher voltages, like 150 V or even more.
[1] Three-phase wiring in homes seems to be very rare in the US, but is extremely common in Europe.
The trick is to get an inverter with a 48V battery interface, that's not locked down to a specific manufacturer.
But you're right, most installers do high voltage batteries.
That looks quite a bit cheaper than the pricing I'm used to seeing, like less than half - not saying they're bad, but probably there's a DIY and risk factor involved compared to buying a more established brand like BYD or Huawei.
I'm just pointing out this is way lower than typical pricing
Maybe, but I think the premium charged by the main manufacturer's is unjustifiably high. Those battery boxes are relatively dumb: besides the cells, they just need some voltage and temperature sensors for monitoring, some power electronics for balancing, a microprocessor, and an enclosure with connectors. Unlike a grid-tied inverter, this is a really simple system, and there's no way a 500–700% price premium over the cells is reasonable.
My new batteries were about 250EUR/kWh - my 10KWh unit cost 2500 EUR - scaling it up to a decent used 5 year old EV price - you can have one for 15k with 60+ kWh batteries, so I'd say it's at a very similar price.
Do you mind citing providers/product names?
You wanna check how much V2G inverters cost first.
If you don't work from home it makes 0 sense either.
IMO we are long way from proving V2G usefulness. Micromanaging your car SOC every night to save $2 is nuts.
I would take that further and say that residential solar without batteries has been proven to be a bad solution. Solar with batteries allows utilities and consumers to schedule when power can be sent to the grid. California utilities consider solar without batteries a PITA, and incentive structures have changed to reflect that shift in policy.
https://www.canarymedia.com/articles/distributed-energy-reso...
https://enphase.com/blog/homeowners/understanding-nem-30-and...
> Imo V2G, and V2H is unnecessary and add too much complication
I believe that's more a function of auto makers (and charger cos) not trying to do much about it (and grid cos not caring), than a technical issue. The benefits (especially if V2G) are quite significant.
I doubt any car owner will say no to earning revenue from something that costs them almost nothing. The problem is more of "how do we get there at scale". (Disclaimer, I studied this topic in my thesis.)
EVs are probably not going to depreciate as much in the future. The depreciation mostly happened because new electric cars have become cheaper.
As an example, let's say a 2 year old car is only worth 80% of an identical brand new car. The old car was bought for $50k at new, leading to a expected depreciated value of $40k. But since manufacturing has become more efficient a brand new car of the same model can be had for the same $40k. Nobody would be willing to buy the 2 year old car at the same price. You'd probably have to charge only $32k [0]. But then it looks to you as if it has depreciated 36%.
The question is how much new electric cars will fall in price in the future. And if they continue to fall, at some point the dollar value of the depreciation will be too small to care about.[1]
0: $32k = 0.8 * $40k
1: E.g. if a new car is $10k, $3600 in depreciation over two years is annoying, but not a big deal.
In the US, V2L limits your ability to output power from the car to about 1500 W. It's not going to power your house as more than a stopgap, even if you do have supplementary house batteries. V2H/V2G justify their complexity by solving that problem, along with all the ancillary grid benefits.
Not sure if that's the case - however doing V2L requires the manufacturer to add an inverter to the car, and making that powerful probably adds extra cost most customers wouldn't pay. TI just looked it up and my Ioniq can only do about 2kW sustained - but since this charges the house battery, that's enough - idle load is just a couple hundred watts.
If the car charges the house battery, what charges the car?
You pointed out a significant limitation of my current setup - right now there are 2 plugs - one for discharging the car through a proprietary manufacturer's V2L adapter, and one for charging.
I'm planning to make a 'box' that can switch between the 2 functionalities on the same cable.
The whole setup is a bit clunky as it is right, now, but I'm kinda more surprised that it works at all, and how well the fundamentals work.
This whole thing was more of an experiment in 'no way you can do this' to actually doing it, but I think this is HUGE, and will transform the way people think about electric cars.
If you have solar panels or time-of-use electrical rates, you charge the car when power is cheap/free, and spend stored power when the grid costs are high. During a protracted outage, maybe you drive the car to a fast charger.
A typical house averages less than 1500W. And most of the higher usage overlaps the sun being out. So if you have supplemental house batteries to handle bursts then 1500W of V2L can go a very long way.
the average hides a lot of information. the largest peak load is often an electric stove, which is regularly greater than 1,500 kW.
Also, this idea that higher usage overlap with the sun being out is laughably wrong. Solar noon is between 11 AM and 2 PM. Very few people are home at that time. There is a reason that peak grid demand in almost every country is in the early evening.
> the largest peak load is often an electric stove, which is regularly greater than 1,500 kW.
Does that change anything about what I said? This is specifically about "if you do have supplementary house batteries".
> Also, this idea that higher usage overlap with the sun being out is laughably wrong.
The reason we have the duck curve is that insolation and demand largely overlap (especially when we're talking about the worst case part of the summer), but then for part of the evening they really don't overlap.
The peak use is evening, but there's a significant ramp up when the sun rises and the whole day is much higher than night. https://ars.els-cdn.com/content/image/1-s2.0-S03062619173137... (This isn't the US but finding household graphs in particular is annoying, and most of the US has more summer heat than denmark)
Anyway evening is one of those bursts where you use the supplementary battery to handle the rest of the load. Even 10% of the car's capacity, 6kWh, could cover almost all use above 1500W.
Everything you describe is true only in some places, likely California. In much of the rest of the world, electricity demand peaks in the evening, when the sun is low in the sky and continues well into the evening, when the sun isn’t out. Notice how even the Wikipedia page about the duck curve lists mainly California. Even in Australia and the UK, daylight hours and electricity demand mostly do not overlap.
>> The peak use is evening
> In much of the rest of the world, electricity demand peaks in the evening
Huh?
And again my chart showing that the entire day has much higher use than at night, then an extra high peak in evening, was Denmark.
> And most most of the higher usage overlaps the sun being out.
Aren’t most people at work / school when the sun is out?
Yes but high electricity use days correlate with air conditioning, and most people don't turn that off in the middle of the day.
If you're not worrying about A/C then 1.5kW goes an extra long way. Outside of cooking you'll rarely exceed it.
Very interesting - I did not know this was possible. A few questions:
1. Does the solar inverter do away with the need for a V2G or V2H unit?
2. What are the limitations vs a dedicated V2G/H unit?
3. Is generator input on your solar inverter a common feature across inverters?
1. It does. The only issue is that the car can only output about 2kW sustained (this is a model limitation). That's fine since I have batteries in the house.
2. Tbh not super familiar with V2G/V2H, other than it being super expensive for both the wall box and the car (only high end models tend to support it)/
3. No idea, but it's not a high end feature, I wouldn't count on any inverter to just have it, but if you're looking to buy one that does, I don't think you'll be breaking the bank.
Imo the future is for solar inverters to offer a dedicated DC car charger port, as once again all the hardware is already in there.
Thanks for the answers. I used to work for a EV smart charging company (Kaluza) that ran a V2G trial. V2G was financial success for the users, but I always thought the wall box was a potential blocker. I don't think the 2kW output is a big issue as the customer could still reduce there load when required, but the elimination of a wall box makes onboarding much easier.
As long as the inverter can also provide charging this definitely has some potential.
> Can "second life" EV batteries work as grid-scale energy storage?
Yes
is it profitable? probably not.
Looking at the price for brid battery storage, and its dropping precipitously. The cost isn't as much in the batteries them selves, it packaging, placing and then controlling them.
For example if you want to have a 200Mwhr 100Mw storage site, you'll need to place it, join it to the grid, all doable. Then you need the switch gear to make it work as you want it to.
For day ahead, 30 minute trading, thats fairly simple.
For grid stabilisation, thats a bit harder, you need to be able to lead/match/lag the grid frequency by n degrees instantaneously. which is trivial at a few kw, much harder at 100Mw
Sounds like what https://www.basepowercompany.com/ is doing
'probably not'?
Based on what numbers?
Germany alone had to pay 2 billion in dispatch measures to energy providers. And in the last 6 month we had news about a HUGE request of companies wanting to build grid stabilisation and grid market battery systems in a range of over 100GwH.
Also we do have industries which would be able to save a ton of money if the invest in smaller but similiar systems today already due to energy prices.
And in germany for example, we do have a lot of wind energy in the north but not enough live transit capacity to get it into the south. In this scenario the market would again stabilize the grid by charging at night from cheap / free wind energy production in north and transfering it to the south and then using it at day.
I think car cells will be much more useful if they are packaged as replacement batteries for all the various battery powered tools, ebikes, etc.
There's a consumer profit margin to absorb the repackaging and teardown.
Maybe for home grid batteries they'll work too. Again, a consumer margin.
Sodium Ion and other grid-specific storage will simply be too cheap for secondhand EV batteries to compete. And the retiring cells won't be any better in density and will be less safe than the higher density sodium ion and LFP that is hitting the market.
I've got a 13 year old EV and nobody has told me how to cash my EV in for reusable energy storage. (No, seriously, hit me up.)
Just sell it though normal channels. If your battery is with more than your car then there would be people making money on the arbitrage.
I totally get that, but as the owner, perhaps I'd like to make the money on the battery before the arbitragers.
You are getting a base price but the rest needs to be enough to motivate people to handle your batterie and to install it somewhere.
You can convert your batterie yourself into a grid support batterie for your own house to maximize your personal gain.
But you are not doing things on scale, so you need to ignore your personal labor time.
People look for used car parts at wreckers. EV batteries are no different.
Wire it up to a solar panel and use it for home energy?
I've spoken to people about starting a Tesla EV battery replacement business here. Battery replacement on a Tesla is a pretty simple process that can be done by one person in about 4 hours.
The problem is that it's still really hard to get your hands on salvage Tesla batteries. Enthusiasts and hackers snatch them up quickly and the used price is not very competitive with a new EV replacement from Tesla.
>So top of the list for us, of course, designing this thing is safety.
Funny issue I learned after talking to a founder at a similar company: although the battery packs were certified safe for cars (passing crash tests, wild heat differences from AK to AZ, people sitting on top of the battery packs in the car) ... the founder had issues re-certifying the batteries for safe use in a static location for grid storage.
The certification process treated his company like the batteries were made from scratch even though they used the same BMS/coolant lines/etc. already proven and tested.
It's clear you still need strong safety regulations and practices in the rare case there's an event, but the founder noted the grid storage industry regulations were adding redundant safety testing and slowing down adoption. The founder also added it's difficult to compete on cost even with effectively free used EV batteries in this startup space of grid storage against the low cost of Chinese made grid-specific batteries due to the added testing + custom hardware + space constraints and other items. (Caveat: I didn't fact check any of their statements)
NO! first
only if industry and government grow some gonads and fully standardise the cells, and hardware for battery packs to allow for quick and easy dissasembly, testing, repair, and reuse, for off grid, and secondary mobile use, as industry will never trust used components for primary aplications, it is impossible to overstate how allergic industry is to this.....
second sodium is comming NOW!, and it is cheaper and safer.
"NO!" while companies already do this successfully.
But hey, why not being negative first eh? ;P
successfull?, maybe, we will see if fires, insurance, and end of life disposal costs leave any roe, plus there are no large scale used car battery grid storage plants, just green washing for data centers, where they are most definitly worried about fires, given the huge spacing between units, green washing/cred,scamenomics,, but most certainly, not grid scale
Not second life, but first life. All EVs and charging stations should be reversible. In a world where fossil fuels cost their true value (~10x as much) and people still drive this would be a necessity for electricity generation
This is great! Now I have a place to take my old puffy Li-Ion batteries.
https://www.redwoodmaterials.com/recycle-with-us/
Without being a battery chemistry expert, why do these battery packs become not useful for an EV yet could still be useful for energy storage. They keep saying that 80% of life becomes unusable for EV, but that's still a lot of life. Is it that grid energy is more of a constant drain while the EV is lots of hard pulls (for lack of better wording)? In an EV, the battery cannot provide the higher volts being requested within rating, but a grid is never demanding peak performance?
It's not just about capacity (80% is still a lot), it's that degraded batteries lose their ability to deliver high current under load—so acceleration suffers and voltage sags under hard pulls. For grid storage, you're doing slow, steady charge/discharge cycles over hours, so the same battery that can't handle aggressive driving anymore works perfectly fine. Plus, grid storage has virtually unlimited space and no range anxiety, so if you need 25% more packs to hit your capacity target, you just stack them in a warehouse where real estate is cheap.
Also, batteries will degrade faster over time when they start to degrade, because they need more frequent charging. Their internal resistance increase and that promotes heat buildup during fast charging/discharging, another thing that promotes degradation. Slow charge/discharge cycles also help with heat management.
> For grid storage, you're doing slow, steady charge/discharge cycles over hours.
Only if the feed in is a bottleneck. For peak shaving you could go faster.
Looking forward to the grid-scale warehouse fire of battery packs popping off...
They claim to have taken the Moss Landing fire into account with how they are placing their batteries. We won't know if they've really solved the problem or not until their first battery pack experiences a runaway thermal event.
Space and weight are serious constraints in the car space, but not such a big deal on the side of a house. That’s how they retain their usefulness.
80% could indeed be plenty of usable life for your EV use cases, but it strongly depends on usage patterns. More degradation means more trips to the charger on a road trip. It means trips that you’d regularly make just charging at home at the end of day now require you to plug in at the destination too. It means more range anxiety as a whole.
The load in an EV is very different than in storage. Basically the charge and discharge rate is what deteriorates the battery. EVs need a lot of power delivered quickly in bursts when you accelerate (tens/hundreds of kw). And then fast charging when the driver is in a hurry also puts a lot of stress on the battery. With storage solutions, the power requirements are much less intense. These high bursts of energy would actually blow the fuse in your house. They are simply not needed. And there is no need for fast charging them either. Instead they get charged over many hours when there is cheap power available.
Companies like Redwood are good at assessing the state of the battery and then managing it such that it is run optimally. Usually, it's just a few cells that are no longer working; the rest of the pack is still be fine. So that just means the max output of the pack drops a bit. But that's still more than fine for storage if all you need is a few kw of output.
Running the battery optimally also extends the useful life of the remaining cells.
For an EV you want a high energy density, because it impacts range. For grid storage, density doesn't matter as much.
Https://allye.com are assembling a 1 megawatt hour unit. I got a tour last week, super exciting.
They raised another $2.5M round too.
Fellten and Allye are the biggest two here in the UK I think.
> Can “second life” EV batteries work as grid-scale energy storage?
Yes.
Thank you
What we really need is standard two way charging on these cars. Every home with an EV should have a backup battery built into the deal.
Seems like the market is going the hybrid route. It's kind of easy to see why, best of both worlds. Some BYD hybrids have crazy ranges like 1500 km on a tank of gas. The more practical car is winning. They put in a much small battery in these for fast charge, and the daily commute range. And you have gas, for longer trips. Maybe smaller batteries would be better for grid-scale storage too. If they're lighter and easier to handle.
> best of both worlds
And the worst too: https://evclinic.eu/2025/09/27/if-you-drive-a-hybrid-may-god...
I don't have first-hand experience, but these guys have an EV repair shop for a while and do also hybrids, their articles always offer lots of insight.
Short run down:
- micro/mild hybrids are useless: batteries too small, engines too small to be the sole source of power, so contribution to emission reduction is very small, batteries tend to fail early because they're very small
- full hybrids have bigger batteries and engines large enough to run pure EV, but you still rely on ICE engine for everything, so there's no ability to charge at home or save on gas
- plug-in hybrids are full hybrids, but you can charge them externally; according to many studies the estimated emissions are much higher than declared, because people simply don't charge them at home and run on ICE the whole time
In all these types of hybrids the batteries are smaller than pure EVs, so they cycle faster and degrade faster. You're carrying two drivetrains all the time with added weight, one of which has plenty of maintenance items. So they're not drop-in replacements.
From what I've seen from EVClinic above, many manufacturers use custom pouch cells, not cylindrical modules like the more advanced pure EVs, so you can't repair an individual failed cell. That means full pack replacement. For many manufacturers you can't order replacement parts of the electric drivetrain, and if you do, they cost a huge chunk of the car.
So all in all if everything's well, you're good. If something goes wrong, be prepared to spend the same as you would spend for a battery replacement of a pure EV, or even more.
No, hybrid is just a temporary solution until the charging infrastructure becomes good enough. And depending where you live, it's already there.
Hybrid is the worse of both worlds in a way. You have a combustion engine to maintain, that is useless when using electricity. You have a heavy battery useless when using your combustion engine.
You don't get all the benefits of electric, and you don't get all the benefits of ICE.
Exactly this. Here in Denmark, 48k plug-in hybrids were sold in 2020, falling to 4k in 2025. The same numbers for fully electric cars were 38k in 2020 and 144k in 2025. Once the public charging infrastructure was here, the change was dramatic. I bought my first electric car this year and I haven't had trouble finding a public AC charger when I needed to, which is often since I live in a condo.
i have heard that hybrid's have a maintanance problem?
is not a concern, double the technologie in the same space?
It's possible it might actually be more reliable long term, once the technology matures. For example, in cold weather the gas engine might heat the battery for better battery performance, maybe even extend its life if it prevents it from being drawn down too much. The gas engine, would also likely last longer since its not used for daily commutes.
"In many PHEV systems, there are different modes:
Electric mode (EV mode): The vehicle runs purely on the electric motor(s) and battery until the battery depletes to some extent.
Hybrid/Parallel mode: Both the petrol engine and electric motor(s) work together to drive the wheels, especially under high load, higher speeds or when battery is low. Ithy
Series mode (in some designs): The petrol engine acts only as a generator to charge the battery or power the electric motor(s), and the wheels are driven by the electric motor(s).
For the BYD Leopard 5 (and many BYD PHEVs) the petrol engine can drive the wheels (i.e., it is not purely a generator). It is part of the drive system, especially when high power or long range is needed.
At the same time, it likely can assist with charging the battery or maintaining battery state of charge (SOC) when needed (for example, to keep the battery at some reserve level or in “save” mode). User-reports show that the petrol engine will kick in to support the electric system, charge the battery, or assist the drive under certain conditions" -
It's not like reliable gas cars ever had substantial maintenance problem in the gas part. So removing the gas part didn't do much in practice.
People do/did have frustrations with gas car mannerisms and mental approachability, like, everything was written in a mix of translated foreign language documents and borderline insane gearhead languages. That lead them to imagine that removing the gas part would drastically change the industry, in their favor.
But, in the end, gas cars are good with regular maintenance for something like 100k miles over 8 years, so, I wouldn't know what consumer product were more reliable than a gas car in the first place.
Reliable gas cars still require a lot more maintenance than an EV does.
Oil and oil filter changes. Fuel filters. Air cleaners. Brake pads (that mostly goes away with hybrids too).
And this is what I'm referring to by approachability issues. Even HNers can't correctly enumerate maintenance items for a car.
If I said iPads are better than laptops because there's no need to regularly replace soft drive Window and repaste NPUs every 2000 hours, everyone knows what kind of person I would be. Yet, that just casually happen all the time when it comes to EVs.
Not that I'm aware of. I've heard that many hybrids actually require less maintenance - for instance, the car can use electric power for hard acceleration instead of stressing the engine, so oil tends to last longer, and regenerative braking causes the friction brakes to wear out more slowly.
Not sure about that, since I did never owned one either. But I watched a review BYD car yesterday. And it's supper nice.
https://www.youtube.com/watch?v=_6bqgR3NRHE&t=1s
Eh, my PHEV has a 2 year oil change interval, which is longer than my ICE only cars. You should probably bring in your EV every 2 years to get things looked at too.
The engine in a hybrid should live an easier life compared to an ICE. No extended idle, mostly running in the power band, etc. There are lots of different ways to setup the hybrid system, but typically, rather than a small stater motor, you have a larger motor/generator that also starts the engine; it's less likely to get worn out, because it's built for continuous use.
In my PHEV, it has a 'toyota synergy' style 'e-CVT' which eliminates gear selection and should be very low maintenance (although mine had to be replaced under a service bulletin due to bearing failure because of manufacturing error) again nicer than an ICE. But some hybrids have a more traditional transmission.
Certainly, you can do ICE only or EV only, but there's a lot of room to use the ICE for things it's good for, and the EV for things it's good for, and blend where there's overlap.
Ford Escape? I have a friend that needed the transmission on his 2023 PHEV replaced under warranty... no service bulletin, but mechanics caught a manufacturing error at a regular service. Hopeful my hybrid Maverick doesn't have similar problems.
2014? Ford C-MAX energi TSB 16-0105 [1] (although there's a similar TSB 22-2396 [2] with a wider range)
I'd just say, if it starts making bearing noises (loudest around 15mph), check in and get yelly. Cause apparently they keep screwing them up. HF35 is designed and built by Ford for Ford, so they really should have everything they need to do it right. sigh
I saw a picture somewhere where they had an extra hole carved through the casing from this, worked fine until it breached and the fluid came out, then it died pretty quick.
[1] https://static.nhtsa.gov/odi/tsbs/2016/SB-10092366-5448.pdf
[2] https://www.tsbsearch.com/Ford/22-2396
That two year oil change cycle is the minumum required to not void the warranty.
It shouldn’t be taken as the optimal interval to maximise engine life.
Of course, modern fully synthetic engine oils are longer lasting, and I believe the newer Toyotas, at least the hybrids anyway, have electric oil pumps, and use very thin engine oil to make sure the engine is well lubricated at startup.
In an ice storm and cold cloudy snap that sweeps the country, NO lithium batteries will save the grid. I'm weary of this tunnel vision of the absurd. The only 'storage' that works is to pump water uphill with 'surplus' energy, and there is not and never will be a surplus. And these evaporartion tanks are on a scale that ecologists have to remember countless horror stories (eg., Glenn Canyon Dam). And of course there's always "mfft!" (another scheme with no numbers behind it so it's credible because I'm talking about it).
The last time there was anything rational on the table was Perry under the Trump administration's 30-day rule proposal ( https://www.nucnet.org/news/nuclear-is-vital-to-us-national-... ). It gave a hard industry incentive to any energy supplier who can have 30 days' fuel on site. This means nuclear and coal. This was no gimmick, it was the first time anyone faced reality about National Security as related to Energy for the grid and survival. And now AI datacenter yadda yadda, we're also talking about the luxury of keeping schools heated in Winter. Adverse weather even for a week is grid down game over for wind and solar. Proven natural gas are ~300 years, joy! As soon as they get around to sending pregnant whales across the ocean (losing ~20% of the gas-energy in cooling) it may even last 50 years! Before we have to go to endless war again.
Alao you can get a 10kv new battery for less than 2.5 (deye)
The model makes intuitive sense. Just a question of timing and scale
> but what if they could drain every last drop of energy from those batteries before recycling them?
Again batteries are an energy store and not an energy source. The fact the author cannot distinguish that makes the their opinion less credible.
All I can think is embodied energy? That’s weird.
You are just not able to comprehend basic writing styles.
The author is a journalist and not the expert he is interviewing thats the first thing. So why would you even evaluate the journalists 'expertise' if you get the answers from the experts.
And secondly what he probalby meant was that what if this company can 'push out' all active lifecycle before they recycle them.
This is called a metapher.
> And secondly what he probalby meant was […]
If they can't precisely convey the intended meaning in written words, they shouldn't be a journalist.
Journalists write for an audiance which normally gets it.
You just might not be one of them.
And no no one needs to write everything so that everyone always gets it.
I for example do not write blog articles for kids. I also don't write very technical blog articles for people outside of tech.
> Journalists write for an audiance which normally gets it.
That's a bullshit justification. "It's factually wrong, but that's okay, the true audience knows what the author means anyway." Then why write it at all? It makes no sense. Stop making up excuses for clueless journalists.
We don't need ev batteries for this. We just need cheap enough LifePo4 so we're not burning more shit down. Prismatics from China are a start, Salt batteries showing some promise next.
see https://stabl.com/
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Betteridge's law of headlines finally fails? TL;DR: Yes, but you can also make it 'not work' if you choose to politicize the tech solution to the energy problem.