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Can “second life” EV batteries work as grid-scale energy storage?

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Re: Can “second life” EV batteries work as grid-scale energy storage?

#241

Post by bityard »

Rebelgecko wrote: post #17
pfdietz wrote: post #4

Earlier quoted context omitted.

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?

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.

Re: Can “second life” EV batteries work as grid-scale energy storage?

#242

Post by hnuser123456 »

sandworm101 wrote: post #225
numpad0 wrote: post #125

Earlier quoted context omitted.

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 fo…

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.

Re: Can “second life” EV batteries work as grid-scale energy storage?

#243

Post by maxerickson »

cyberax wrote: post #232
pfdietz wrote: post #192

Earlier quoted context omitted.

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.

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.

Re: Can “second life” EV batteries work as grid-scale energy storage?

#245

Post by bryanlarsen »

floxy wrote: post #47
ACCount37 wrote: post #8

Earlier quoted context omitted.

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…

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-sci…

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.

Re: Can “second life” EV batteries work as grid-scale energy storage?

#246

Post by cyberax »

pfdietz wrote: post #193
cyberax wrote: post #155

Earlier quoted context omitted.

(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+win…

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…

> 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.

Re: Can “second life” EV batteries work as grid-scale energy storage?

#247

Post by cyberax »

ben_w wrote: post #218
cyberax wrote: post #138

Earlier quoted context omitted.

> 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.

> 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 thin…

> 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.

Re: Can “second life” EV batteries work as grid-scale energy storage?

#248

Post by floxy »

bryanlarsen wrote: post #245
floxy wrote: post #47

Earlier quoted context omitted.

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-sci…

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.

Re: Can “second life” EV batteries work as grid-scale energy storage?

#249

Post by ben_w »

cyberax wrote: post #247
ben_w wrote: post #218

Earlier quoted context omitted.

> 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 thin…

> 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 joini…

> 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.

Re: Can “second life” EV batteries work as grid-scale energy storage?

#250

Post by Dylan16807 »

eldaisfish wrote: post #208
Dylan16807 wrote: post #74

Earlier quoted context omitted.

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.

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