You don't need rivers or even much of a slope for pumped storage. Just water and a few hundred feet.

https://en.wikipedia.org/wiki/Ludington_Pumped_Storage_Power...

Hmm, apparently that is more demanding for locations than I thought

Though

> The plant takes advantage of the natural steep sand dune landform of eastern Lake Michigan

See the study linked to in my comment above.

In Europe there's some geography known as "the alps" which has been used for years this way by the countries surrounding it.

Poland's environmental record is atrocious on almost every level. I guess the coal lobby must run the government or something because nobody else in Europe that reliant on fuel that dirty. They're a model of how not to do anything right.

> In Europe there's some geography known as "the alps" which has been used for years this way by the countries surrounding it.

Well, that is hardly solution for Poland.

This doesn't make any sense. Just use fossils when there are no renewables available. Gas peakers for short term unavailability and others for medium unavailability.

You don't need pumped hydro. Batteries + hydrogen would work fine in combination, and Europe (and in particular Poland) has enormous underground salt formations that could store millions of gigawatt-hours of hydrogen.