Plans exist to reuse reservoirs as energy stores by feeding them back into the grid, turning them into public power assets. In a future electricity system powered largely by renewables, the Ministry of Ecological Transition aims to treat reservoirs as a kind of power plant—massive renewable batteries. To move this forward, the department led by Teresa Ribera, the third vice president and Minister for Ecological Transition, intends to test the idea within state-owned reservoirs and assess their suitability as recycled hydroelectric plants. The update to the National Energy and Climate Plan (PNIEC) has been submitted to the European Commission this week.
National Energy and Climate Plan sent to Brussels proposes retrofitting pumped hydroelectric power plants
This roadmap targets 2030 with 81% renewable electricity generation, phasing out coal and keeping nuclear at current levels, while adding 22 GW of storage through hydroelectric plants and other methods. Today, conventional hydropower sits around 20 GW of installed capacity, with pumping capacity near 3.3 GW. The largest installation is the Cortes-La Muela complex in Cortes de Pallás, Valencia, boasting a turbine capacity of 1.7 GW and a pumping capacity of 1.2 GW.
Pump stations rely on two reservoirs arranged at different elevations within a closed loop. Water is stored when demand is low and released to generate power when needed, reusing the resource. The challenge of storing energy without sun, water, or wind remains, yet reversible hydroelectric plants offer a path to behave like a giant renewable battery.
According to the energy sector, Spain could become “Europe’s largest battery with this technology”
Using energy storage via reversible hydroelectric plants is described as the cornerstone of a renewable-led electricity system. Higher penetration scenarios would require development of such facilities, enabling gradual reductions in fossil-fuel generation and contributing to energy autonomy within the Spanish system. The plan explains Ribera’s aim to incentivize a shift in how state-owned reservoirs are used, viewing them as a bottom water tank for new reversible installations. Spain hosts roughly 1,300 hydro plants, about 1,000 of them mini plants under 10 MW. Most are publicly owned, with concessions granted (and often extended) for about 75 years dating to the early 20th century. The first wave of concessions to expire in the next decade accounts for roughly 720 MW, with Iberdrola, Naturgy, and Endesa owning about 90% of that capacity. Industry sources note that concession expiry can trigger economic and environmental viability questions, while some investors may lobby to retain the premises.
“New hydroelectric pumping measures require evaluation, promotion, and expansion of this technology,” said Miriam Good, deputy director general for energy forecasting, strategy, and regulations at the Ministry of Ecological Transition, speaking at a Wind Congress event. In addition to public reservoirs, the administration also seeks to encourage private participation and speed up permitting by removing regulatory and administrative barriers, as outlined in the PNIEC draft.
“Europe’s Big Battery”
Building a pumping plant takes time. Industry sources estimate it at about ten years from the start of administrative procedures to operation, with current processes often extending to seven years. Many project developers hesitate, seeking extensions due to tight timelines. The Spanish Energy Storage Association notes that current facilities are blocked by grid access constraints, with storage technologies lagging behind conventional generation in grid planning. The PNIEC envisions adapting the grid through Red Eléctrica planning, adding new evacuation nodes and strengthening existing ones. The association argues that Spain’s geography and corporate dynamism can make the country Europe’s big battery with this technology.
The challenge of batteries and capacity markets
Beyond pumping stations, the government views batteries and combined cycles as integral to full renewable integration. A 5 MWh wind storage battery owned by Iberdrola in Abadiño demonstrates that storage is in early stages, with only a single plant currently operating on the market. Industry leaders note growing interest and demand, yet only a few projects have secured grid access. OMIE’s market operations chief notes a surge of inquiries, while Red Eléctrica’s system studies team reports significant appetite for storage capacity. A target network of roughly 11 GW of standalone storage is discussed, though only a fraction has received permission. In practice, gas-fired combined cycles remain a key backup option, capable of managing generation when multiple resources are needed. The energy crisis triggered by the Ukraine conflict has intensified interest in storage, with policymakers and companies advocating capacity markets that reward available supply rather than production alone. Brussels is considering market reforms, while Spain contemplates amending domestic rules to standardize and expand these services.
Related posts:
How Long To Charge A 12 Volt Battery Renewable storage and Spain’s pumped hydro evolution Understanding Car Battery Chargers and Charging Times Hydropower in Spain Under Pressure: Drought Slashes Output and Raises Costs Floating Solar and Hydropower Integration in Spain: A 2030 Renewable Roadmap Spain’s Renewable Energy Surge: A Transformation of the Grid and Emissions Brussels weighs green hydrogen rules including nuclear power EU hydrogen rules update aims to boost renewable energy sourcing and targets across the bloc Floating solar farms on reservoirs: a path to cleaner energy Spain’s Renewable Surge Shifts the Electricity Landscape in 2023–24 Floating solar projects in Extremadura and beyond could reshape regional energy capacity UAE-Albania-Italy green energy pact via Adriatic cable