Floating solar is now creating major opportunities to scale up solar energy production around the world. According to a recent report from the World Bank, the global potential of floating solar, even under moderate assumptions, is 2000 GWp on man-made reservoirs alone. When adding coastal waters, the potential becomes enormous. Ocean Sun made a video in 2017 describing the advantages of floating solar.
Our design is inspired by nature. The giant water lilly, Victoria Amazonica, sits on the water surface just like our floater. Both are anchored to the seabed. Both thrive in the sunlight. Plant cells versus solar cells. Photosynthesis versus photovoltaics.
A thin polymer membrane is used to carry the PV modules. This represents the minimum use of materials to achieve the required buoyancy. The amount of materials is what determines the lowest theoretical cost of a floating PV installation. The cost structure greatly affects the levelized cost of energy.
By lowering the operating cell temperature in the PV modules the system efficiency may increase as much as 15 per cent compared to regular ground-mounted installations. The cell temperature is lowered through direct heat transfer to the waterbody below the membrane. Consequently, the efficiency gain depends on the water temperature as well as the level of irradiation. The infrared image shows a test floater where six modules (to the right) are held at temperatures close to the water temperature whereas the other six modules (to the left) are lifted and air-cooled, The lifted modules run twice as hot.
Each floater unit is towable. Multiple floaters are anchored side-by-side to build larger power plants. A complete plant may take many shapes, all depending on shore line constraints and the available water surface area. The anchoring system is designed taking local water depth, wave, current and wind conditions into consideration.
WIND AND WAVE RESISTANT
The thin membrane makes the system hydro-elastic. This property allows the PV modules to move gracefully with the harmonics of the waves. The floating structure benefits from moving with the waves, as opposed to working against the forces from the waves. Basin tests and simulations have predicted the systems wave capabilities.
The wind drag of the central floater area is virtually zero. Nor does the rim hand rail cause a significant drag. Computational fluid dynamics (CFD) analysis has shown that the system is able to withstand typhoon category 4 winds of 275 km/h.
EASY TO INSTALL
The membrane itself is walkable when installed on water. Mounting the PV modules is fast and easy.
The floaters will reduce the underwater sunlight exposure. This can mitigate the problem of algae growth, often harmful to marine life. In addition, the floaters will reduce evaporation, which is a growing concern in many warm and dry geographical areas.