«Spain has a total reservoir capacity of 55,000 hm3, of which 40% of its capacity corresponds to hydroelectric dams, one of the highest proportions in Europe and the World.»
Being one of the technologies with the greatest participation in the electrical mix of the country, hydro energy is characterized with having low prices, historically, and a guarantee of supply according to the regulation of the flow by the companies that control the operation of the numerous hydraulic dams.
According to Red Eléctrica de España (REE), the operator of the national electricity system, there are 20.4 GW of hydro installed capacity, third in ranking only being wind and CCGTs, accounting for just under 20% of the total.
Castilla y Leon, Galicia, Catalonia and Aragon are the communities that together provide more energy due to their
increased hydroelectric resources.