Storage energy

The most relevant aspects of electricity storage by autonomous communities in 2025 include:

• In Comunidad Valenciana, pure pumped storage facilities enabled the integration of 3,256 GWh in 2025, the highest volume in the country.
• In Castilla y León, mixed pumped storage systems integrated a total of 2,095 GWh into the Spanish electricity system, which allows for greater utilisation of renewable generation.

Map of storage energy by autonomous communities

Regarding operating patterns, pumping was traditionally carried out during night-time hours, when electricity demand was low and there was excess generation. However, with the increase in solar photovoltaic generation, pumped storage consumption patterns have changed significantly. Nowadays, pumped storage consumption is mainly concentrated during the central hours of the day, from 10:00 to 18:00, coinciding with high levels of solar power generation. This shift has enabled greater integration of renewables, particularly in spring and summer.

For their part, batteries show a charging pattern during solar hours and discharge in the evening. This complements pumped storage and points towards a future scenario with greater technological diversity and responsiveness across different time scales.

Monthly hourly average of pumped storage consumption and solar photovoltaic generation

Annual hourly average of pumped storage consumption and solar photovoltaic generation

Storage also plays an active role in the electricity market: Pumped storage and batteries purchase electricity at low prices and sell it during high-price periods, acting as energy arbitrage tools. This behaviour gives them a strategic role in price formation, while also contributing to system stability.

Annual hourly average of pumped storage consumption and average price on the day-ahead market

At a time when renewable energy has reached a high level of deployment, the way pumped storage is used has evolved.

Unlike the traditional approach, where pumped storage consumption mainly took place during low-demand night-time hours, the current approach focuses on maximising efficiency and the integration of clean energies. Given the growing penetration of solar photovoltaic energy, pumping is now primarily carried out during periods of high solar electricity generation, i.e. during the day.

The following chart shows the annual hourly averages of pumped storage consumption and average demand. Although pumped storage consumption still occurs during off-peak hours, its highest consumption now takes place during the central hours of the day, when demand is no longer at its lowest levels. As can be observed, peak consumption now occurs between 09 and 21 hours.

Annual hourly average of pumped storage consumption and demand