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It is entirely infeasible to used pumped hydro alone to solve our energy storage problems. They’re a great component of the solution but they’re big expensive e

• grues-dinner 1y ago
  They're also quite inefficient (75% ish, which is not horrible, but still something) as you lose energy both in pumping and generation. So the more you use them, the more energy you need in the first place, so you try not to use them too much. And the worst thing for a capital intensive business is to not get used much. Even with the arbitrage advantage, it takes a long time to pay it off. The grid may pay a "retainer" to sweeten the deal but you can't just build more and expect them all to get that benefit. It's similar to the problem that "use excess energy to electrolyse water into hydrogen" has: no-one running a multi-billion electrolyser really wants to run it a few hours a day only when the grid is oversupplied. And in top of that, risk being cut off at the knees decades before breakeven if someone comes along with a cheaper/more profitable way to deal with the oversupply.