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Comment by treis | Hacker News Reader

Half the time you get 0 solar power.

If only data centers had some kind of backup systems to prevent power interruptions, like inverters with batteries attached to them. They could call it an Uninterruptible Power Supply and then charge the batteries when other power is available and run on them when it isn't.

UPSes are designed to run for minutes not hours. I guess enough Megapacks to run overnight would be more expensive than gas generators.

If grid storage batteries are economical in the general case then why wouldn't they be doubly so in a place where the inverters are a sunk cost and you're saving the transmission costs because the load is at the same site as the batteries?

The competition isn't the cost of generators, it's the cost of grid power, or the cost of operating gas generators every day.

They aren't economical in the general sense. They are economical to provide frequency stabilization, grid efficiency, and maybe a few hours of demand shifting. They're not yet economical to store solar power during the day and discharge it at night. We are getting closer but I don't think we are quite yet there.

As far as I can work out, the cost is competitive as long as you're using the capacity every day, especially when it lets you avoid paying transmission costs. The thing that doesn't work is to have enough battery storage to handle extended periods of low generation, because for that you need dramatically more storage capacity while only using the surplus on rare occasions. But a data center could use the grid or backup generators on those rare occasions while still using batteries overnight every night.

Not nearly big enough for data centers approaching 1 GW. Largest is 3 GWH which gets you 3ish hours.

Theoretically you can put as many batteries together but it'd be enormously expensive and run into the same supply chain issues.

Anything using 1GW of power is going to be "enormously expensive". The all-in cost of a 1GW data center is on the order of $50 billion. A billion dollars in storage batteries is ~2% of the cost, which is completely reasonable.

~1600 GWh of lithium batteries are produced each year and hundreds of GWh/year of production capacity have been added in each of the last few years, so ~12 GWh isn't going to upend the market.

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