You can use fuels that can burn (which are stored energy), or over build and waste (spilling) that which you don't need, or store energy. Hydro power with dams has the storage built in, but there is also rotating mass, batteries, and pumped storage (can be used with hydro).

Super grids has a place in improving connections on the continent to decrease the need for storage (when it blows to much in Spain and to little in Ireland or vice versa), to use existing storage better and to make it easier to construct more storage.

I think the European mountain ranges are really more important here then the African desert.