| Work Detail |
Germany’s Fraunhofer Institute for Solar Energy Systems (Fraunhofer ISE) has conducted new research on the impact of floating PV and water temperature and evaporation. Scientists at Fraunhofer ISE have investigated the impact of floating PV on water temperature and evaporation and have found that the lower solar radiation under floating PV systems led to lower water temperatures in summer. At the same time, the floating PV reduced heat loss from the lakes in winter, keeping water temperatures slightly higher. This could have a positive influence on the lakes as temperatures in summer rise due to global warming. Both effects were most pronounced at the largest floating PV system that had been monitored for research in Sekdoorn near Zwolle, Netherlands. At this site, the PV modules are arranged in an east-west orientation on a metal sub-structure that is kept afloat by floats. The change in water temperature and other factors, such as oxygen content and nutrient composition, on three lakes with floating PV plants were recorded in a research project called “FPV4Resilience, funded by the Freiburg Center for Sustainability (LZN). They had no significant impact on the water quality of these bodies of water during the two years of measurements and were often within the range of measurement inaccuracy. “However, in view of climate change and increasingly hotter summers, this effect could be positive for the lakes in the future. Initial simulations suggest this, although more research is needed”, concludes a research summary. Mussel colonies have settled on the substructures of two of the floating systems. A closer look at the mussels on one system showed that their breathing lowers the oxygen concentration in the water, but at the same time, the mussels filter the water and bind phosphorus. The research team also noticed that other human-made influences often overlap the effect of the floating photovoltaic system. This shows how complex the interaction between economic use, flora, fauna, and the floating PV system is. ”We are therefore not yet at the stage where we can transfer the results of the last three years to other lakes with floating PV”, the research group states. Structured observations of the bird population at the lake in the Netherlands documented 25 bird species on and around the water. Eleven of these were found on the floating PV system, including rare bird species such as the lapwing and the snipe. The birds used the system as a resting place, a starting point for hunting, or for nesting. The three artificial lakes studied are located in different climate zones in Leimersheim, Ger-many, in the Alpine Toules, Switzerland, and Sekdoorn in the Netherlands. They differ greatly in terms of their photovoltaic coverage and system design and are used as hydroelectric reservoirs and for sand and gravel extraction, respectively. Two of the floating PV systems have been in operation since 2019, and the floating PV system in Leimersheim has been in operation since May 2021. |
