[chha]

That depends on how you want to store the energy. There have been some talk in Norway about using excess energy to pump water from ground level to fill up existing lakes as a form of energy storage. There seems to be quite a few power plants based on hydro power other places in Europe as well, so it could be a feasible strategy there as well [1, page 5]

[1] - https://wwfeu.awsassets.panda.org/downloads/hydropower_press...

[lagadu]

In Portugal and Spain we have pumping stations doing exactly that. I couldn't find a link in English but maybe you'll find this useful: https://www.iberdrola.com/sustentabilidade/central-hidreletr...

[chha]

Nice! It turns out we have a few (12) pumping stations here as well, but there is little information on how often they've been used. The high electricity prices we've seen lately have reactualized this, with spikes of around $1 USD/kWh.

Current water levels are at approx 47% capacity [1], compared to around 64% same time last year. Unless we get a wet spring and summer it could get exciting come next year...

[1] - https://www.nve.no/energi/analyser-og-statistikk/magasinstat...

[lagadu]

Same, we're also facing issues with water level this year, to the point that several of the dams were ordered to stop producing electricity in order to save the water.