Hydroelectric power has been around for a long time. With pumped hydro, water is pumped up to a reservoir during times of excess power production. When power is needed, the water is released to power turbines and create electricity, and it is available almost instantly. This is increasingly important in an era when wind and solar produce power on a variable basis.
Vendo Nova III in Portugal will be completed in 2015 with 760 MW of available pumped-storage power as well as hydro.