Acciona Energía is a Spanish renewable energy company, a subsidiary of the ACCIONA Group with over 11 GW of wind, solar, hydro, biomass and solar thermal capacity and no fossil fuel legacy. In July 2026 it scaled up a hybrid storage pilot combining ultracapacitors with lithium-ion batteries at its Barásoain wind farm and Tudela solar plant in Navarra, testing whether renewable plants can deliver grid stability services once supplied by conventional power stations.