Taum Sauk, an artificial pumped storage facility which famously failed, was rebuilt to 3600 MW·h for $490 million. So that was like $136 per kwh capacity, thoug

Taum Sauk, an artificial pumped storage facility which famously failed, was rebuilt to 3600 MW·h for $490 million. So that was like $136 per kwh capacity, though I think they didn't have to do much for the lower reservoir (which was built in the 60s). Seems to be a lot better than batteries, though still requires appropriate terrain. https://en.wikipedia.org/wiki/Taum_Sauk_Hydroelectric_Power_Station https://en.wikipedia.org/wiki/Taum_Sauk_Hydroelectric_Power_...