en.Wedoany.com Reported - During the eclipse, Red Eléctrica, Spain's grid operator, mobilized stored energy from the La Muela I and II pumped-storage hydro plants to compensate for the 5 GW of lost photovoltaic generation over the nearly 120-minute event. The process occurred around sunset and posed no significant impact on electricity supply.
The La Muela pumped-storage plant, located within the Cortes-La Muela hydroelectric complex and operated by Iberdrola, is currently the largest pumped-storage facility in Europe. Coordinated operations between the system operator and the plant ensured stable supply during the decline in photovoltaic output.
On the operational side, Red Eléctrica required the plant to prepare in advance and issued instructions for it to run at full load for over an hour, generating power by releasing water from the upper reservoir. In the secondary reserve phase, the grid operator requested an additional 300 MW from La Muela, and after several 15-minute dispatch intervals, a total of 1,800 MW of capacity was ultimately mobilized for compensation.
Looking at the operational curve, starting one hour before the eclipse began (18:30), the grid operator progressively increased the injection power of the pumped-storage plant from just over 150 MW to more than 2,000 MW, reaching its peak at the event's center (around 20:35) and maintaining it for several hours, injecting cleaner, lower-cost electricity into the system.
Pumped-storage plants play multiple roles in power system management. Beyond this eclipse compensation, such plants helped restore power during the DANA (heavy rainfall) event in Valencia and contribute to enhancing the integration capacity of renewable energy. In normal operating mode, these plants pump water to the upper reservoir during sunlight hours for storage, and then release it to generate power upon instructions from the system operator based on supply-demand conditions, reducing system costs or ensuring supply security. According to El Periódico de la Energía, all plant responses during this compensation operation were completed as instructed.
