What Is Small Hydropower ?
Small hydropower typically refers to hydroelectric plants with installed capacity up to 10 MW (this is a commonly used definition in Spain and European reports). These plants are usually run-of-river installations without large reservoirs, meaning they generate electricity from the natural flow of rivers with limited storage.
Installed Capacity & Distribution
- As of 2021, Spain had about 2,145 MW of small hydropower capacity, spread across roughly 1,098 plants nationwide.
- This capacity represents a few percent of total Spanish hydro capacity (when compared with conventional large hydro), but small hydro still contributes regionally to renewable generation.
- The geographic distribution is spread across many autonomous communities, with notable contributions from Catalonia, Aragon, Castilla y León, Andalusia, Cantabria, Asturias, and Castilla-La Mancha.
Investments and Asset Transactions
Elawan Energy – Small Hydro Portfolio
- In 2024–2025, Elawan Energy closed financing of 175 MW of hydropower capacity in Spain across 23 small plants (some run-of-river, some with storage), structured under long-term concessions.
- This deal is one of the largest recent investments in small hydropower in Spain, demonstrating ongoing interest from international renewable investors.
Iberdrola Asset Rotation
- Iberdrola, a major Spanish utility, has historically operated a wide portfolio of small hydro plants (over 90 units totaling ~300 MW) and has been modernizing some of them to improve efficiency.
- Recently, Iberdrola sold several small hydro plants (about 35 MW) in the Castellón area to Austrian company Kelag as part of its strategic asset rotation.
Micro & Pico Hydropower
- There are also very small micro-hydro projects (a few kW), often used for local purposes like powering dam operations or small communities. For example, Endesa has installed micro-hydro units (~6 kW) to power auxiliary equipment and ecological flows at small installations.
Regulatory & Development Context
- The potential for small hydro in Spain is estimated to be slightly above current capacity (a few percent growth potential) because much of the economically feasible sites are already developed.
- Regulatory procedures for authorisation and environmental assessments can be lengthy due to water use rights and ecological flow requirements (this is consistent with broader EU trends in hydro permitting).
Role in Spain’s Energy Mix
- Small hydro is part of Spain’s broader hydraulic energy sector, which also includes large dams and pumped storage (the latter often plays a storage role to balance wind/solar).
- Although small hydro contributes less than wind or solar in overall generation, it provides renewable baseload and flexible production, especially in wetter regions.