A country like France would need ~20 STEPs like Grand’Maison to provide for a single winter night (~60GW for ~14h). That’s 100-200km² to put under water, a massive ecological disaster, and a massive hazard.

And you must find a way to produce enough energy and find enough water to recharge your STEPs in the next 10h before the next night.

And that’s with the current France needs, with only 25-30% of its energy being decarbonized electricity.

Powering an entire country without hydro, geo, nuclear or fossils is just plain science fiction. And hydro and geo cannot be built everywhere, so realistically, you either go fossils, or nuclear to have clean electricity.

And you can verify it empirically: even with trillion invested in solar and wind, the only countries which have decarbonized their electricity have massive hydro/geo/nuclear.