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Comment by vorpalhex | Hacker News Reader

Batteries require some pretty rare and gnarly materials and still hold only a tiny, tiny bit.

It still gets dark for about a third of the day.

Grid storage has different constraints than, e.g. electric vehicles; in particular, size and weight is less important since they aren't moving. This makes it viable to use battery tech which is less efficient, but cheaper/safer/etc. For example, flow batteries or iron/air batteries.

You can always store energy by pushing rocks uphill.

The issue is then recovering the energy from said rocks, or not wasting too much energy lifting the rocks in the first place.

Gravity is an incredibly feeble force; storing large amounts of energy this way requires a lot of rocks and a lot of land.

https://en.m.wikipedia.org/wiki/Fengning_Pumped_Storage_Powe...

Pushing water uphill is relatively cheap and ~80% efficient. We can build more 2x nuclear power station equivalent "batteries" like fengning fairly easily.

Are there many sites with appropriate geology to build any substantial number of pumped storage stations?

Cant find it now but there was a study i remember seeing that suggested that there were 100x as many as needed.

How about any of the reservoirs in drought-stricken North America? Water could be pumped to Lake Mead, power generated at Hoover Dam, and then enter irrigation for farmland. Same for almost the entirety of the Snake River and tributaries.

Maybe you weren't aware, but those sites are drying out thanks to climate change, and have some other important responsibilities like drinking water

Hydro is failing worldwide. Look it up before responding please, thanks.

I love when people who have no familiarity with the long and failed history of water batteries assume it's easy

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