The facility has already successfully completed its first pumping operations. This ‘gigabattery’, created by linking two of Europe’s largest reservoirs, Alcántara and Valdecañas, enables the absorption of surplus energy from intermittent renewable sources (solar and wind), which can then be returned to the system when these sources are unavailable and demand requires it.

The new configuration at Valdecañas also includes a 15 MW/7.5 MWh hybrid battery, further increasing the Tagus system’s storage capacity by up to 210 GWh – equivalent to the average annual consumption of 60 000 households. This increase will improve energy demand management, particularly during periods of high demand.

Furthermore, the co-ordinated operation of the Valdecañas, Torrejón, Alcántara, and Cedillo reservoirs – supplemented by control of the Tiétar tributary through pumping – helps to regulate flood peaks, reduce flood risk, preserve ecosystems, and create strategic water reserves throughout the year.

The Torrejón–Valdecañas system operates as a giant hydraulic battery, capable of pumping water to higher elevations during periods of surplus renewable energy (for example, at midday when solar generation is high). This energy is used to pump water into an upper reservoir. When demand rises, the water is released to generate electricity. This follows the same principle as a battery – storing energy for later use – and enables:

• The use of surplus solar and wind energy to pump water, ensuring that otherwise curtailed renewable generation is stored for when it is most needed.
• The use of stored energy during peak demand, avoiding the need to activate carbon dioxide-emitting generation.
• The optimisation of water reserves by transferring water to reservoirs with available capacity from those depleted by rainfall.

According to the company, the works were carried out exclusively within an electromechanical scope, involving equipment upgrades to provide greater flexibility, without the need for new civil infrastructure or changes to reservoir levels. No new electricity transmission lines were required, as existing infrastructure has been utilised.

For more news and technical articles from the global renewable industry, read the latest issue of Energy Global magazine.

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Read the article online at: https://www.energyglobal.com/energy-storage/06052026/iberdrola-espaa-increases-tagus-rivers-energy-storage-capacity/