Analytical method for loads determination on floating solar farms in three typical environments

Abstract

Floating solar energy is an industry with great potential. Farms can be installed on lakes, reservoirs or offshore. Numerous projects are under study or have been realised. This study presents three reference cases for floating solar farms, with adapted environmental data: a small lake (2.5 MWp – Mega Watt Peak - island), a large lake (7.5 MWp island) and offshore (2.5 MWp island). Mooring is one of the biggest challenges of floating solar photovoltaics (PV), compared to ground-mounted solar PV. To date, most mooring designs of industrial projects have been performed by computing environmental loads using an analytical analysis. This study aims to present one of the methodologies currently used in industry to perform a mooring design and to highlight the areas where further research is necessary before continuing developing industrial projects. Wind and current loads are computed with drag forces, considering drag coefficients from norms, wind tunnel tests, computational fluid dynamics modelling and the literature. Waves drift loads are computed with the Maruo formula. Results show that wind loads dominate for all cases, except for the offshore conditions, where waves have a significant contribution to the total load (around 50%). Even though the large lake island is 3 times larger than the offshore island, the total load applied on the offshore island is higher. The main challenges in the mooring design for each case are also underlined.