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Comment by mbgerring | Hacker News Reader

Why do people keep writing comments like this as if utility scale batteries don’t exist?

Because they don't at close to the necessary scale. This site shows a projected July load profile for ERCOT (Texas) in 2035:

https://www.spglobal.com/marketintelligence/en/news-insights...

Note that Storage contributes for about four hours and at its peak comprises less than 7% of the total load serving capacity in the state.

I'm not saying batteries don't exist and aren't useful, but the scale is very small at the moment. Too small to be a comprehensive way to balance out the low load factors of Wind and solar. (Which are also a useful but incomplete component of the overall electrical portfolio.)

Going by that projection, they should build a lot more solar and wind rather than worry about batteries.

It costs somewhere around $300/kwh to build utility-scale storage. Say they can cycle 3000 times. We find that just the storage costs $0.10/kwh, which is in the range of generation costs themselves (probably double wholesale generation costs). So one cannot assume to be able to cheaply store power in utility-scale batteries.

That 3000 number is 0 - 100 - 0 cycles. You can get almost an order of magnitude more by using the sweet spot of the battery: 20 - 80 - 20 for standard nickel Li-ion batteries, and 30-100-30 for LiFePO4 batteries.

Is that an order of magnitude of cycles or energy throughput?

Cycles. Li-ion goes from ~600 -> ~3000, LiFePO4 from ~2000 -> ~9000. So "order of magnitude" is a bit of an exaggeration, and the 5x reduces to 3x when you use energy instead of cycles. But 3x is still pretty significant...

If storage costs are the same as generation costs, you’re just saying that storage is currently cost effective. Sounds like we should build a lot of it!

They exist and are finite in cycles.

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