Hydro in Norway goes very well with windmills in Denmark.

Very simplified:

Wind blows mostly in Denmark during the day, so Norway stops hydro during the day and imports electricity from Denmark's windmills.

During night the wind is mostly still in Denmark so windmills don't produce much and Denmark imports from Norway's hydro.

In this way you can stretch the capacity from hydro using windmills even though Norway isn't a good place for windmills.

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 .