Floating solar is more cost-competitive than ground-based PV in Southern Europe

The researchers assessed the economic viability of utility-scale floating solar arrays in Europe, determined that such projects are cost-competitive in several southern European countries, and claimed that if capital costs were reduced by 12 per cent, the competitiveness of floating PV would be pushed across Europe.

BayWar.e. floating photovoltaic plant in the Netherlands. Photo: BayWar.e.

Researchers from Italy and Spain have estimated the power and cost potential of floating photovoltaics (FPV) in suitable water bodies in Europe and compared it with land-based photovoltaics (LPV) at the optimum inclination.

Researcher Leonardo Micheli told PV magazine: "We also demonstrated that FPV can be economically competitive with conventional LPV in Mediterranean countries, where the sun is positioned higher and the temperature is higher. However, if capital costs are reduced by 12 per cent, FPV is cost competitive in all simulated scenarios and countries."

The scientists used water surface data available for Europe from the Global Reservoir and Dam Database (GRanD) to estimate the potential installed FPV capacity in Europe and considered only reservoirs for hydropower, water supply, irrigation and flood control. They simulated the power generation of single-sided modules using the PVWatts DC power model with data from the CAMS irradiance service in terms of hourly irradiance.

For the FPV application, the model considered scenarios with tilt angles of 10 and 20 degrees and an albedo of 0.06. LPV was assumed to use the optimum tilt angle and an albedo of 0.25. Both simulations used Trina Solar modules with 21.4% efficiency, inverters with 96% efficiency, DC to AC losses of 14%, all modules facing south and the PV system life was set at 25 years. The lifetime of the PV system was set at 25 years. The scientists took data from the IRENA Renewable Energy Cost Database to calculate capital expenditure and annual operation and maintenance expenditure (omex) for different locations in Europe.

The study looked at the performance of FPVs and LPVs in four heat scenarios and showed that FPV systems could achieve between 640 and 1688kWh/kW/year, corresponding to capacity factors of 7.3% to 19.3%.

The researchers said, "Surprisingly, the higher power generation occurs in the southernmost countries, where the solar potential is higher due to limited angular and reflection losses caused by the lower tilt angle."

The worst performance occurs in Scandinavia and the high mountain regions of Switzerland, Austria and Italy, where FPVs have the highest electrical performance in the most optimistic heat exchange scenarios, generating two per cent more electricity than LPVs.

In several countries in this scenario, FPVs with a 20 degree tilt also generated more electricity than LPVs with the optimum tilt, however in other configurations and scenarios, FPVs typically generated less electricity than LPVs, especially at a 10 degree tilt," the researchers said. The results highlight that the tilt angle has a significant impact on energy conversion."

The study estimated that the value of each additional degree of tilt angle in FPV installations ranged between €2.50 ($2.62)/kW and €7.50/kW.

The competitiveness of FPVs in terms of levelised cost of energy (LCOE) depends on capex and omex considerations, given the difference in generation capacity. The results show that overall if racking and installation costs are excluded, the LCOE of LPVs is competitive in all scenarios in most European countries. If grid connection costs are also excluded - for example by blending with hydropower - FPVs are cost competitive in all modelling scenarios in all countries.