A uniquely designed floating solar trampoline manufactured by Norwegian startup Ocean Sun has been purchased by Statkraft’s Albania unit for deployment at the Banja reservoir in Albania. The 2 megawatt array consists of four floating units of 0.5 MW each, at a total cost of €2.3 million.
The contract is the first major commercial sale of Ocean Sun’s floating solar technology, and the project will demonstrate the viability of the technology, the Lysaker, Norway-based company said in a statement.
Unlike other floating solar designs based on individual panel floats that are linked together, the Ocean Sun design attaches a large number of panels on the membrane as a modular unit, which typically includes a rigid circumference frame for anchoring.
“Testing new technology for floating solar power panels fits very well with Statkraft’s strategy to grow our renewable energy generation from hydro, wind and solar. If the technology is proven successful and the potential for cost-competitiveness can be achieved, a wider application of floating solar may take place in other Statkraft locations,” said Christian Rynning-Tønnesen, CEO of Statkraft, in a companion statement.
A sale to a global energy company as large as Statkraft bodes well for Ocean Sun. Statkraft owns shares in 353 power plants with a total installed capacity of over 19 gigawatts, and owns shares in 17 district heating plants with an installed capacity of 789 MW.
Statkraft Albania received a preliminary authorization from the Government of Albania for the implementation of a floating solar plant at Banja with a feed-in-tariff in December 2018. Subject to final regulatory approvals, the solar plant will be constructed during the 2019/2020 period, Ocean Sun said.
The design of the Ocean Sun array includes dual-glass, silicon crystalline modules with customized junction box, cables and attachment features. The modules are attached to the membrane using a unique fixation mechanism, the company explains. This enables good thermal contact with the water body, and the membrane is carefully designed to withstand mechanical stress and sun exposure, it adds.
Since the modules are in close contact with the water, the low water temperature provides excellent cooling of the cells, which permits energy generation at higher efficiency levels than a module fixed in the air.
The anchored membrane system is hydro-elastic, which allows the PV modules to move with the harmonics of the waves, resulting in a wind drag of the central floater area at virtual zero, Ocean Sun says. Basin tests and computational fluid dynamics (CFD) analysis has shown that the system is able to withstand typhoon category 4 winds of 275 km/h, or over 170 miles per hour.
One side benefit of the membrane design, which will readily support the weight of several workers, is that the floaters will reduce underwater sunlight exposure, the company says. This can mitigate the problem of algae growth, often harmful to marine life, and will reduce evaporation, a growing concern in many warm and dry geographical areas, Ocean Sun says.
While the system is available for use world-wide, it is designed for peak efficiency at 45 degrees latitude, due to the horizontal orientation of the modules and the solar elevation angle, the company notes. This latitude ring encompasses central portions of Europe, China, and North America.
Ocean Sun offers three sizes of modular arrays, starting with the CF 500, the flagship circular design with 500 kilowatt-peak, a diameter of 72 meters and an area of about 4,000 square meters. The CF 200 is a 200 kWp circular floater with a diameter of 50 meters and an area of about 2,000 square meters, the company says.
Finally, the RF 100 is a 100 kWp rectangular floater with a width of 12 meters and a length of 80 meters. This design was developed for benign waterbodies such as rivers and ponds. The unit is not able to withstand the same wave conditions as the circular versions, Ocean Sun says.
Ocean Sun was founded in 2016 to enable large-scale solar developments on coastal seawater, lakes and reservoirs. The company has received grants from Innovation Norway and the Norwegian Research Council.
Statkraft is a leading company in hydropower internationally and Europe’s largest generator of renewable energy, a profile statement says. The Group produces hydropower, wind power, solar power, gas-fired power, and supplies district heating. Statkraft is a global company in energy market operations and has 3,600 employees in 15 countries.