'Spain Must Expand Pumped Storage'

Why It Matters

Accelerating pumped storage will reduce renewable curtailment, lower electricity costs, and safeguard grid reliability, positioning Spain as a European energy‑transition leader.

Key Takeaways

• Renewable curtailment may exceed 3 TWh, powering 3 million homes
• Balancing costs rose to 57% of electricity price in May 2025
• IHA proposes distinct targets for long‑ and short‑duration storage
• Revenue‑stabilisation mechanisms aim to attract private lenders
• Streamlined permitting could cut project timelines dramatically

Pulse Analysis

Spain’s rapid expansion of wind and solar has outpaced its ability to store excess generation, creating a looming curtailment problem. Pumped‑storage hydro, a mature technology that can shift energy from low‑price periods to peak demand, offers a cost‑effective solution. By converting surplus electricity into potential energy in reservoirs, it can absorb the intermittent output of renewables, reducing the estimated 3 TWh of wasted power projected for 2026. This not only preserves the environmental benefits of clean energy but also improves the economics for generators facing low wholesale prices.

Policy inertia, however, threatens to stall deployment. The IHA’s four‑point plan emphasizes the need for clear differentiation between long‑duration (seasonal) and short‑duration (hourly) storage in national targets, providing investors with predictable revenue streams. Introducing compensation for ancillary services and stabilising cash flows can lower financing costs, while extending concession periods for projects linked to existing hydropower assets makes long‑term returns more attractive. Streamlined permitting, backed by increased administrative capacity, could shave years off development timelines, accelerating the build‑out of strategic infrastructure.

If Spain implements these reforms, it could set a global benchmark for integrating large‑scale storage into a high‑renewables grid. The resulting reduction in curtailment would lower electricity prices for consumers and businesses, while enhancing grid resilience against supply shocks. Moreover, a robust pumped‑storage fleet would enable Spain to export balancing services across the interconnected European market, reinforcing its role in the continent’s energy transition and creating new revenue opportunities for domestic developers.