bryanlarsen
a day ago
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.
ACCount37
a day ago
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.
floxy
a day ago
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...
bryanlarsen
3 hours ago
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.
floxy
3 hours ago
The batteries in a hybrid are much smaller (~1.3 kWh for a Prius), and so cost much less to replace.
bryanlarsen
2 hours ago
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.
adrianN
19 hours ago
Why would you only assume 1000 cycles? Is the chemistry that bad? The LFP battery on my balcony is rated for 5000 cycles iirc.
Moto7451
18 hours ago
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.
jopsen
8 hours ago
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.
jbm
a day ago
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...
jgilias
11 hours ago
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...
MetaWhirledPeas
19 hours ago
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.
jbm
15 hours ago
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)
CursedSilicon
15 hours ago
>Dunking on Tesla is its own industry these days, it seems.
Are you suggesting Tesla is criticized without good reason?
jack_pp
13 hours ago
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?
fragmede
21 minutes ago
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.
cowsandmilk
10 hours ago
What are the bad reasons that bias electrek’s coverage?
bryanlarsen
6 hours ago
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.
1234letshaveatw
8 hours ago
extremist "journalists" and/or undisclosed sponsorship? Contrast their Tesla coverage with their almost giddy stories on anything China related.
seanmcdirmid
a day ago
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.
numpad0
20 hours ago
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.
sandworm101
6 hours ago
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.
hnuser123456
4 hours ago
I see you don't live in Michigan... my 22 year old car has growing rust holes in front of the rear wheels.
cogman10
a day ago
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.
MrRadar
a day ago
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
formerly_proven
a day ago
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).
numpad0
a day ago
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...
avhception
a day ago
It's nice to get a reminder about this problem once in a while, I've fallen into the trap myself at times.
formerly_proven
14 hours ago
Despite your ??? and ! the only article you posted that's about hybrids (and not PHEVs) mentions nothing about battery capacity.
close04
8 hours ago
> 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.
formerly_proven
7 hours ago
The page you are referring to is literally titled "Plug-In Hybrid Specifications"
/out
close04
6 hours ago
Sorry, I just saw you objected to the lack of information for battery capacity, not the type of hybrid or chemistry.
taneq
16 hours ago
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.
whaleofatw2022
5 hours ago
Early Hybrids used NiMH because Chevron was holding on to a lot of the patents around using Lithium Ion for the purpose IIRC.
ACCount37
a day ago
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.
wcfields
a day ago
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.
londons_explore
a day ago
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).
Marsymars
20 hours ago
Sounds like an old Roomba I used to have that could clean for about 2 minutes before it ran out of juice.
jbm
15 hours ago
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.
bluGill
8 hours ago
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.
xattt
a day ago
NiMH was used in Priuses for a very long time, and these seem to have lasted for ages.
cptskippy
19 hours ago
> 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.
guelo
21 hours ago
That's amazing good news for the environment, thank you I hadn't heard this.
jwr
14 hours ago
> 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?
jillesvangurp
13 hours ago
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.
JumpCrisscross
a day ago
> 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.
dylan604
a day ago
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.
jeffbee
a day ago
He's just talking his book. Their deployment this year was 1/4000th share of the BESS market.
dylan604
a day ago
Battery Energy Storage System for anyone else like me that has no knowledge of this world and their acronyms.
bryanlarsen
a day ago
Reading between the lines of the corporate speak will validate my point. Redwood was founded in 2017.
dylan604
a day ago
"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.
whatever1
a day ago
We are only 5-6 years into the car ev market. Tesla model 3 started being sold in 2018 in meaningful numbers
cogman10
a day ago
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.
bryanlarsen
a day ago
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.
beAbU
15 hours ago
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!
cogman10
10 hours ago
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)
rconti
6 hours ago
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.
cogman10
6 hours ago
There was about 2 years of rapid drop off that I experienced and I don't exactly know why.
beAbU
9 hours ago
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?
cogman10
8 hours ago
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.
dzhiurgis
11 hours ago
I agree, reads like carefully crafted FUD.
cogman10
10 hours ago
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.
pfdietz
a day ago
So, basically the same reason recycling of PV modules hasn't taken off.
Rebelgecko
a day ago
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?
hnaccount_rng
a day ago
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.
ericd
a day ago
Yeah, we paid more for the little bits of metal that held up the panels than for the panels themselves (aluminum, but still).
dzhiurgis
11 hours ago
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).
namibj
9 hours ago
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.
ericd
9 hours ago
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.
hinkley
a day ago
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.
pfdietz
a day ago
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.
jopsen
7 hours ago
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.
maxerickson
a day ago
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.
pfdietz
21 hours ago
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...
mjevans
20 hours ago
I'm going to want that pile hot enough to kill all the bugs and pets that want to get near it.
pfdietz
19 hours ago
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 $.
cyberax
18 hours ago
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?
pfdietz
10 hours ago
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.
cyberax
5 hours ago
I don't believe it did? Delta of 550 degrees Kelvin multiplied by 1000J per kg per Kelvin.
maxerickson
4 hours ago
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.
pfdietz
4 hours ago
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.
kragen
17 minutes ago
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
> 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.
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°.
kragen
19 hours ago
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?
kragen
16 hours ago
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.
sandy234590
11 hours ago
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.
pfdietz
10 hours ago
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.
kragen
5 hours ago
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.)
formerly_proven
15 hours ago
Did you just reinvent electric night storage heaters?
kragen
14 hours ago
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.
pfdietz
19 hours ago
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).
kragen
18 hours ago
(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.
alvah
19 hours ago
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.
bluGill
8 hours ago
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.
kragen
5 hours ago
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.
kragen
an hour ago
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.
bityard
4 hours ago
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.
duskwuff
a day ago
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.)
Rebelgecko
a day ago
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
hinkley
a day ago
Find an installer who will warranty work using third party let alone used solar panels and then we can talk.
jeffbee
a day ago
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.
dzhiurgis
11 hours ago
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.
p1necone
a day ago
> "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.
Theodores
a day ago
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.
jeffbee
a day ago
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.
p0w3n3d
a day ago
Tesla batteries fail after 8 years at least from models up to 2014
stetrain
a day ago
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.
p0w3n3d
15 hours ago
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.
stetrain
2 hours ago
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.
trhway
a day ago
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.
nandomrumber
21 hours ago
What does any of this mean?
What is c in this context?
dtgriscom
21 hours ago
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.
trhway
21 hours ago
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).
Sohcahtoa82
a day ago
[citation needed]
JohnLocke4
a day ago
In 2040 fusion energy advancements will have gotten far enough to be the next technological step and make this redundant anyway
epistasis
a day ago
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.
noosphr
a day ago
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.
epistasis
a day ago
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.
noosphr
a day ago
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.
epistasis
a day ago
> 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.
cyberax
18 hours ago
> 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.
noosphr
18 hours ago
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.
ben_w
7 hours ago
> 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".
cyberax
3 hours ago
> 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.
ben_w
3 hours ago
> 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.
ben_w
7 hours ago
> 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.
bryanlarsen
5 hours ago
> 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.
pfdietz
a day ago
> 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.
formerly_proven
a day ago
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.
apendleton
a day ago
> 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).
bruce511
17 hours ago
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.
cesarb
10 hours ago
> 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).
adrianN
18 hours ago
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.
pfdietz
a day ago
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.
epistasis
a day ago
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...
apendleton
a day ago
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.
epistasis
20 hours ago
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.
pfdietz
7 hours ago
> 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.
epistasis
5 hours ago
Interesting! Would that require any regulation change?
pfdietz
5 hours ago
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.
pfdietz
21 hours ago
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.
cyberax
18 hours ago
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.
apendleton
17 hours ago
> 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.
pfdietz
10 hours ago
Civil engineering involves adapting any design to the local geology. This has to be custom for each site.
pfdietz
18 hours ago
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.
cyberax
15 hours ago
(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.
pfdietz
10 hours ago
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.
cyberax
3 hours ago
> 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.
apendleton
a day ago
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.
nandomrumber
21 hours ago
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?
pfdietz
5 hours ago
> needed thickness of the first wall
I meant, needed thickness of the tritium breeding blanket.
Dylan16807
a day ago
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.
bryanlarsen
21 hours ago
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.
BurningFrog
a day ago
The regulatory hurdles are probably bigger than the difficult enough technological ones you mention.
megaman821
a day ago
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.
throwaway270925
15 hours ago
With solar, fusion energy is already here! There is just a bit of wireless transmission involved after generation.
bee_rider
a day ago
This is like a “fusion is only 20 years away” (or 15 in this case) joke, right?
hinkley
a day ago
It used to be 30. So fifty more years?
marcosdumay
a day ago
Yep, it was 30 years at the 60s. If it keeps halving every 85 years, we'll get it approximately never :)
hinkley
21 hours ago
Zeno's Fusion Paradox
