A new report from energy think tank Ember highlights the potential to combine wind and solar generation with existing hydropower facilities across Europe, helping increase renewable electricity production without requiring equivalent expansion of transmission infrastructure. The analysis estimates that hydropower plants in seven European Union countries could accommodate around 25 GW of additional wind and solar capacity through existing grid connections. Developing hybrid hydropower projects could therefore help address grid congestion while supporting Europe’s renewable energy targets for 2030.
The report examines Austria, Bulgaria, France, Italy, Portugal, Romania, and Spain, where grid operators expect approximately 138 GW of new wind and solar capacity to be deployed between 2026 and 2030. This represents an increase of more than 50% compared with their combined 235 GW of wind and solar capacity in 2025. Ember estimates that hybridising suitable hydropower facilities could accommodate around 18% of this planned growth without requiring additional grid capacity.
Existing hydropower connections are currently underused because plants do not continuously generate at their maximum capacity. Ember estimates that eligible facilities operate at an average of only 19% of their maximum output. Adding wind generation could increase grid connection utilisation to approximately 36%, while solar could raise it to 31%. This makes hybrid hydropower a potential strategy for extracting greater value from transmission infrastructure that has already been constructed.
Grid capacity has become a significant obstacle to renewable energy expansion. More than 2,500 GW of renewable generation, energy storage, and large electricity-demand projects are waiting for grid connections worldwide. In Europe, Ember estimates a gap of at least 120 GW between available grid capacity and anticipated renewable growth through 2030. Austria and Bulgaria reportedly have no available grid capacity for new generation, while Portugal and Romania also face significant constraints.
Hydropower itself remains an important component of global electricity generation. In 2024, hydroelectric facilities generated approximately 4,500 TWh of electricity, accounting for about 14% of worldwide production. Combining these facilities with variable renewable resources could allow hybrid hydropower sites to produce more clean electricity while reducing the need for new transmission connections and development locations.
Several European projects demonstrate how this approach can work. Portugal’s Tâmega wind farm is being developed to share a substation with the existing Tâmega hydroelectric complex. In France, the Lazer floating solar project installed approximately 50,000 solar panels on the reservoir of an existing hydropower facility, doubling the site’s renewable generation capacity while limiting additional land requirements.
However, regulation remains a barrier. Among the seven countries examined, only Spain and Portugal currently have established frameworks governing hybrid renewable projects. Ember argues that clearer regulations elsewhere could encourage investment and accelerate deployment. Expanding hybrid hydropower could help European countries make better use of existing infrastructure, integrate additional wind and solar generation, reduce pressure on congested electricity grids, and advance toward their 2030 clean energy objectives.