Green light for Iberdrola's new reversible pumped-storage hydroelectric power plant in Alcántara

The Spanish Ministry for Ecological Transition and the Demographic Challenge has issued a favorable EIS for the construction of the 440 MW new Alcántara II reversible hydroelectric pumping station, located in Alcántara (Extremadura, in southwest Spain).

This reversible pumped-storage power plant will have a 440 MW capacity, enabling 16 million kWh of reversible energy storage—sufficient for the daily average consumption of over 4 million people. It will provide up to 37 hours of stability to the electricity grid when operating at full capacity. The plant will generate over 1,000 additional GWh annually using the same water resources, preventing an estimated 355,000 tonnes of CO2 emissions per year. 

These ‘reversible’ or pumped-storage plants have two reservoirs that operate as a ‘closed loop’. The upper reservoir acts as a ‘giant battery’ storing potential energy in the form of water that is turned to the lower reservoir to generate electricity when the system requires it. Once turbined, this water, now contained in the lower reservoir (lower reservoir), is pumped during off-peak hours to the higher reservoir (upper reservoir) following the same route, but in the opposite direction, operating as a closed loop.

In July 2024, the project was awarded EUR 44.9 million (US$ 50 million) by the Institute for Energy Diversification and Saving (IDAE) for its top score in economic viability and technical integration of renewables under the EU’s Recovery, Transformation, and Resilience Plan.