Many places actually do pump water uphill into reservoir lakes for hydroelectric dams. In that case it is a form of energy storage, a literal water battery.

Unfortunately, it's not always a feasible option. For instance, in the great planes there's not much of an uphill to pump the water to.

[–] HowManyNimons@lemmy.world 1 points 6 months ago

Make hydrogen?

[–] queermunist@lemmy.ml 0 points 6 months ago

I've seen some interesting ideas from Low Tech Magazine - one that I found particularly interesting was flywheel energy storage. Take a heavy disk or drum and spin it up with excess electricity, then discharge the spin from the battery when the Sun goes down.