Nuclear power plants were the source of energy that generated the most electricity to the Spanish electric system up until mid-December 2015. This amount was 21.7 % according to data from Red Eléctrica de España (REE).

Nuclear energy is followed by carbon (20.3%), wind (19.1%), hydraulic (11.1%), cogeneration and others (10.6%), combined cycle (10%), solar (5.2%) and renewable thermal (2%), according to "The Spanish Electricity System, Preliminary Report 2015" by REE.

The peninsular demand of electric power in 2015 has been increased by 1.9% compared to the previous year, amounting to 248,181 GWh. If the effects of calendar and temperature are taken into account, the electricity demand has increased by 1.5% compared to 2014. At the end of 2015, the installed power capacity was 102,613 MW (an increase of 0.4% compared to 2014).

One more year, the balance of international exchanges of electric power has maintained its export sign of 467 GWh, 83.3% lower than in 2014. In 2015, exports amounted to 15,119 GWh and imports 14,652 GWh. As regards the national electricity transport network, 443 km of new line circuits came into operation during 2015, with the result that the national electricity transport network has reached 43,153 km of circuits.