[matkoniecz]

https://pl.wikipedia.org/wiki/Plik:Zar_zbiornik.jpg https://pl.wikipedia.org/wiki/Elektrownia_Por%C4%85bka-%C5%B... - another one from Poland, likely one of the largest batteries in the world (build in 1979 - 2 000 000 tons of pumped water, 440m height difference, typical working duration is 4 hours and 5.5 hours for pumping water back)

https://pl.wikipedia.org/wiki/Plik:Dlouhe_strane_horni_nadrz... and another one

General concept: https://en.wikipedia.org/wiki/Pumped-storage_hydroelectricit...

If it would be actually climate emergency then we would be building in mountains all where reasonable. No matter the damage to some rare species, panorama and tourism.