Spain Must Fast-Track Pumped Storage to Avert 3 TWh Renewable Waste by 2026, IHA Warns

Spain has rapidly expanded its renewable energy capacity, with wind and solar doubling since 2019. Renewables met 46% of the country's electricity demand in the first half of 2025, driving wholesale electricity prices 32% below the EU average. However, this growth strains the national grid, which lacks sufficient infrastructure to manage variable supply.

The International Hydropower Association (IHA) projects Spain's renewable curtailment, or wasted clean energy, will surpass 3 terawatt-hours in 2026. This amount equals the yearly electricity consumption of approximately 3 million homes. This finding comes from an analysis by the IHA, an international non-profit institution focused on sustainable hydropower, which examined Spain's energy system stability and future needs.

Mounting system instability is evident in balancing costs. These costs, incurred to maintain grid equilibrium between supply and demand, reached 57% of Spain's final electricity price in May 2025. This figure is significantly higher than the typical 14% average. Such spikes signal an over-reliance on more expensive, often fossil-fuel-based, generation for stability.

Eddie Rich, CEO of the International Hydropower Association, stated Spain must act immediately to integrate pumped storage. Failure to do so risks losing its renewable energy gains and facing long-term economic and structural harm. Pumped storage acts like a large-scale battery, using water to store energy when supply exceeds demand and releasing it when needed.

This technology offers 8 to 50 hours of electricity storage and provides crucial grid services like frequency and voltage stability. Deploying more pumped storage reduces reliance on imported fuels, enhances energy independence, and creates domestic jobs. The IHA has outlined a four-point action plan for Spain, emphasizing policy adjustments to differentiate storage types, compensate for system services, update concession frameworks, and streamline permitting processes.

Spain's response to these warnings, particularly regarding policy changes and accelerated project approvals for pumped storage, will determine its path towards a stable, sustainable energy future.