Comment by tialaramex
6 hours ago
It's nowhere close to 50%. Round-trip (so that's after both ways) efficiency is about 70-80% for a pumped storage scheme. Buy 10MW to pump the water, and get back 7-8MW when you release it. Contrast that with a reality here in the UK where the gas dominated spot price this morning when I woke up was about £180 per MWh, yet yesterday afternoon solar and wind had it down to £25 per MWh, so you could buy 100MWh of energy for £2500 but sell it less than a day later and make 400% on your investment in under 24 hours despite the efficiency loss. Very silly to insist this can't be profitable.
For the cost and expense of building a pumped hydro plant though, you could just deploy batteries which will do the same thing for a much lower capital and management investment and vastly simplified engineering. And a higher round-trip efficiency.
LiFePO4 works to demand shift on a daily cycle just fine and scales better to solar input (where you need much higher power handling so you can charge it on limited sunlight - a pumped hydro system is limited to charging at about half its discharge rate).