I’m happy to be wrong about this globally, but in my neck of the woods the readily exploited hydro resources are already exploited to 90% of their capacity and have been for 100 years. Hydro is in many ways the ultimate renewable energy, but that’s been true since electrification and we’ve been using it as part of the energy mix since then. I’d love to be wrong but my understanding is that there isn’t a huge amount of untapped new hydro capacity available without having severe impacts on ecosystems
Also what is probably used in your country is Pumped-storage hydroelectricity .
During the day you pump water into the reservoir using wind/solar energy and discharge e.g at night .
Elsewhere in the country yes but lol not so much in the very flat part of Western Canada. I pulled out some topographic maps a few years ago and was quite dismayed at the lack of elevation change suitable for pumped hydro.
In the last decade or so hydro generation has grown about as much as solar and wind (they all basically grow about the same amount as global nuclear generation, hydro doubling and wind and solar growing exponentially from basically zero).
So it's not going to take off like solar but it's a big chunk of relatively clean electricity production and it's often basically a byproduct of managing water supplies. It also pairs really well with renewables as even without pumps it has a degree of flex and storage.
This is even more true with international grid connections. Europe in a cold spell? Solar countries import, wind & hydro export. Europe in a heat wave? Flip the switches the opposite direction.