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Comment by xbmcuser | Hacker News Reader

AT grid scale, sodium quickly closes the gap on lithium. The safety overhead, active cooling, and physical spacing needed to control lithium’s thermal runaway risk eat away most of its energy density advantage. Plus, CATL is hitting cost parity between full sodium BESS and LFP BESS systems.

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The other big reason is the longevity. LFP life span gives you about 2000-5000 cycles depending on where your application can't tolerate the capacity reduction. Sodium Ion can go to 10,000 cycles (27 years) with a 70% capacity reduction at that life.

This makes financing a large grid scale storage plant look way better to the bean counters because the investment continues to work and make money, after the 5 year amortization, typical of a corporate investment. This will be the kicker IMHO.

Does it really look more favorable? My understanding was that such far future returns had minimal Net Present Value

Net Present Value isn't quite the right thing to look at. Inflation-adjusted energy prices have been rising over time, so the thing these batteries are projected to deliver (fixed impact on that electricity grid) increases in value over time even after the NPV discount. The more important component is the "risk-adjusted" NPV, which may or may not make tech like this effectively worthless.

why dont you think revenue from energy prices isnt baked into the NPV? The time discout is applied, on top of whatever the revenue model is.

I saw an interview with I think the CATL ceo and he was saying it's quite a headache ensuring the batteries last that long. Grid storage companies want 25 or 30 year guarantees. It sounds like sodium may have the advantage there.

> Sodium Ion can go to 10,000 cycles (27 years) with a 70% capacity reduction at that life.

The article claims much better:

> the company’s GS1.1 [Sodium Ion] system will store energy for 20 years, over roughly 20,000 cycles, and still retain 80 percent of its capacity. For LFP, a basic durability benchmark pegs them at 70 percent capacity after 8,000 cycles.

Excellent. I stand corrected. I was using published Chinese numbers.

SIBs have TR risks as well, no?

https://www.sciencedirect.com/science/article/abs/pii/S24058...

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