QAZAQ GREEN.  According to a new report by energy think tank Ember, seven EU countries with the largest hydropower capacity could add up to 25 GW of wind and solar generation by using the existing grid infrastructure of their hydropower plants — without needing to build new transmission lines.

The approach, known as "hybridisation," involves connecting wind and solar installations to the same grid connection point already used by operating hydropower plants. The study covers Austria, Bulgaria, France, Italy, Portugal, Romania and Spain, which together account for 93 of the EU's 131 GW of total hydropower capacity.

Why hydropower plants are ideal candidates

Hydropower plants typically use only a fraction of their available grid connection capacity for most of the day — averaging just 19% of maximum output. Adding solar and wind generation could raise this utilisation rate to 36% and 31% respectively, and in some cases nearly triple the use of existing infrastructure.

According to Ember's calculations, the 25 GW of new wind and solar capacity that could be added this way covers around 18% of all the renewable generation these seven countries plan to bring online by 2030 — meaning nearly a fifth of new capacity could be deployed without any grid expansion at all.

Wide variation between countries

Hybridisation potential varies significantly by country — from 77% in Austria to just 7% in Bulgaria. Many hydropower plants are located in ecologically sensitive areas where new wind or solar development is prohibited, so the analysis only included sites outside protected zones.

Regulatory gaps

Despite the clear advantages, only two of the seven countries studied — Spain and Portugal — have dedicated regulations for hybrid projects. In Spain, hybrid projects can bypass the "first come, first served" grid connection queue, and financial guarantees for such applications are reduced by 50%. Elsewhere, regulatory support is absent, although commercial hybrid projects are already moving forward — in Bulgaria, for instance, state-owned utility NEK is converting hydropower plants into battery-coupled hybrid assets despite the lack of dedicated legislation.

"Political ambitions mean nothing if clean electrons are stranded in connection queues. For countries facing gridlock, hybridisation offers an immediate, zero-intervention solution," said Elisabeth Cremona, Energy Infrastructures Lead at Ember.

The report's authors recommend that EU countries develop national legislation for hybrid projects, streamline and accelerate grid connection procedures for such installations, and allow secondary generation capacity to exceed the nominal connection capacity of the existing plant, provided the combined output of both generators never exceeds the grid connection limit.