Utility and infrastructure company Acciona has inaugurated Spain’s first floating solar plant, on the Sierra Brava reservoir in the southern province of Extremadura, aiming at a larger commercial market on Spanish hydro-power reservoirs.

The company with the 1.125MWp demonstration project consisting of 3,000 PV modules of different types that are distributed across five floating structures plans to test technical solutions for solar panels on lakes or reservoirs, such as the inclinations and floating systems in a combined manner and in a real environment.

Among the most novel elements are double-sided panels, modules with a transparent rear surface to allow sunlight to act on the reverse side, and the totally vertical layout with an inclination of 90 degrees, Acciona said.

Although still a niche technology, floating solar is slowly taking off.

Norwegian energy giant Statkraft in June started to build a 2MW floating solar array in Albania that is linked to a hydropower plant.

Several Asian countries are already betting on much larger floating solar power plants, among them Vietnam, where state-owned oil and gas firm PetroVietnam plans to build floating PV arrays on hydro-electric reservoirs, and South Korea, where a giant 2.7GW floating solar array is planned behind a sea wall in the Yellow Sea.

The much smaller Sierra Brava plant in Spain is located on the southern shore of the Sierra Brava reservoir in the municipality of Zorita (Cáceres) and covers 12,000 square metres, equivalent to 0.07% of the total surface area of the reservoir (1,650 hectares).

But Acciona said test results from the Southern Spanish demo project will serve as a basis for the development of larger commercial plants.

The company sees floating solar becoming economically viable in regions with low availability of land or strong competition from agricultural uses. The floating plants also show higher performance at lower ambient temperature, while the flat sites have a high solar exposure and fewer shadows.

The arrays also reduce water evaporation in reservoirs and improve water quality as a result of lower algae growth, Acciona said.

Spain has a network of large hydro-electric reservoirs that have a “clear potential” for floating solar, the company added.