FPV4Resilience

Project context

Floating PV (FPV) is a comparatively new technology in Europe with considerable global potential. Here, the PV modules are placed floating on substructures on the water, which can take place both on inland waterways and at sea.

An important aspect of the still unclear interaction between bodies of water and FPV systems is the climate resilience of the former. European lakes will experience changes in their thermal properties as a result of climate change. Impacts on water bodies may result in severe impairment and in some cases even complete loss of aquatic ecosystems. In addition, the function of lakes as carbon sinks and thus as climate regulators can be significantly influenced.

Project description

The aim of the project was to analyse the effects of several FPV plant configurations on different types of lakes.  This should be used to shield affected aquatic ecosystems from climate change-related changes in the best possible way when planning FPV systems. Based on various factors such as area coverage or module tilt angle, an influence on the energy balance in the lake is to be calculated, which both counteracts the effects of climate change as far as possible and maximises electricity yields.

Project results

In order to analyse the climate resistance of the lakes, some of which are covered with solar cells, the shading effect was observed. This was observed at all three locations and varied between 50 and 95 per cent. This shows that the shading effect is highly dependent on the installed FPV system design.

On the other hand, wind reduction was analysed. Similar, even more strongly fluctuating results were found here (39-95 per cent).

The water quality was also analysed, with data collected on water temperature, oxygen saturation, nitrate levels and turbidity. Here too, the results varied depending on the location, although no serious negative effects were observed.

These factors can have consequences for the flora and fauna of lakes, which were investigated further. This was done using mussels on floating bodies, aquatic plants and birds. However, generalised statements regarding the effects on these species cannot yet be fully made on the basis of the random number of installations.

Utilisation of the project results

Hydrodynamic modelling

Based on the measurement data collected, a GLM-AED2 model setup was created for all the lakes analysed, which can simulate the effects of the FPV systems in detail. This model provides a valuable basis for the planning of future FPV systems and for environmental impact assessments. With further scientific data collection in the future, hydrodynamic modelling could help to replace intensive monitoring procedures in the long term and thus make FPV projects more economical. The model can also be used to estimate water savings for water bodies in arid areas with FPV coverage.

Development of an optimisation tool

As an environmentally friendly implementation alone does not necessarily have to be sustainable in the broad sense, an optimisation tool for the sustainable integration of FPV systems was developed, which includes not only ecological but also economic and social sustainability aspects in the analysis in order to derive an optimal land use for FPV systems.

As part of the development process, surveys were conducted among experts and non-experts, the results of which were incorporated into the testing of the tool. The weightings of the various factors included in the model show some significant differences between the two groups: While factors such as electricity yield and evaporation reduction are of greater importance to experts, non-experts place greater emphasis on water quality and the thermal properties of the lake.

Despite these different priorities, the tool produces similar recommendations for the optimal area utilisation for the example location of Leimersheim. These results illustrate that the tool developed is suitable for integrating different perspectives and, on this basis, providing practical and balanced recommendations for the sustainable use of FPV facilities.