The pressure to decarbonise is prompting the expansion of solar energy production worldwide. The additional pressure to maximise use of land has led to solar panels now being deployed on lakes and reservoirs. Floating solar panels, ‘floatovoltaics’, have been, or are being, installed in several countries around the world, including US, Japan, China, India, Brazil and the UK. Added incentives to installation are that the cooling effect of water improves efficiency of solar panels, while the associated reduction in evaporation from installing floatovoltaics is particularly attractive in sunny, dry countries. Nevertheless, the impacts of floatovoltaic deployment on lake ecosystems and function are poorly known. As floatovoltaics alter the amount of sunlight, wind mixing energy and oxygen entering the water, such impacts are likely to be profound and could be both positive and negative. Together with partners at Lancaster University we are collecting data and utilising modelling techniques in order to understand the consequences of floatovoltaic deployment on different aspects of lake ecosystems, particularly the lake temperature structure and the phytoplankton community. An Industrial Strategy Studentship award is funding associated PhD research.
We are developing the CEH phytoplankton simulation model, PROTECH, to enable modelling of lakes or reservoirs which are part or wholly covered by floating solar panels. The model simulates the growth of a wide variety of phytoplankton taxa. Different taxa are better adapted to differing environmental conditions so the presence or absence of floatovoltaics will likely have a large effect on which phytoplankton are able to proliferate.
We are also running an experiment at the CEH mesocosm facility where we have covered replicated sub-sets of mesocosms with full, partial or no covering with solar panel proxies. By measuring relevant meteorological variables, underwater light, and the temperatures at different depths of the mesocosms we are collecting a primary data series indicating the impact floatovoltaic deployments could have on lake temperature structure and light attenuation.