According to new research, floating solar farms could protect reservoirs and lakes from some of the negative effects of climate change.
But given the different designs of solar technologies and the complex nature of water bodies, the placement of floating solar arrays can also have detrimental effects on the ecosystem.
Traditional solar farms are a debatable topic because of the amount of land they have occupied. This creates a growing interest in floating solar farms – taking advantage of the extra space provided by water bodies.
To date, three commercial-sized floating solar arrays are available in the UK, and there are hundreds more around the world. The number of installations is likely to increase significantly in the years to come, as demand for renewable energy sources increases and more and more countries commit to zero-carbon targets.
But so far little has been known about the effects – both negative and positive – of these floating solar farms installed on reservoirs and lakes.
Researchers from the University of Lancaster and the University of Stirling have completed the first comprehensive modeling of the impact of floating solar installations on water bodies on the environment.
As the demand for land increases, water bodies are increasingly focused on renewable energy sources. The introduction of solar energy into water increases the production of electricity, but it is crucial to know whether there will be some positive or negative consequences for the environment. ”
Mr. Giles Exley, lead author of the study and researcher of the Doctor of Science, Lancaster University
“Given the relative immaturity of floating solar farms, further scientific evidence of impacts is important. Our results provide an initial insight into the key effects that will help inform water bodies managers and decision makers“, Added Mr. Exley.
Computer modeling was performed by the researchers using the MyLake simulation program, as well as data obtained from the British Center for Ecology and Hydrology from the largest English lake in Windermere.
Although researchers believe that floating solar farms are unlikely to be set up at Windermere, this nonetheless represents a rich array of data as it is one of the most extensively explored lakes in the world.
The team’s results show that floating solar arrays can cool water temperature by sifting water from the sun.
To a greater extent, this could help reduce the dangerous effects caused by global warming, such as the blooming of poisonous blue-green algae and increased water evaporation, which could pose a risk to water supply in certain areas.
The researchers further noted that the installation of the floating sun also reduced the period of “stratification” – where the water is heated by the sun, creating clear layers of water at different temperatures.
This scenario usually occurs more during the warmer summer months and can cause deoxygenation of the lower water layer, which worsens water quality – an obvious problem for drinking water supply.
But the picture is more complex, and there are situations under which stratification, and thus the detrimental effects on water quality, could increase if floating solar farms are installed.
The effects of the floating sun on water body temperature and stratification, which are the main drivers of biological and chemical processes, could be compared in magnitude with the changes that lakes will experience with climate change. Floating solar energy could help mitigate the negative effects that global warming will have on these water surfaces.
Mr. Giles Exley, lead author of the study and researcher of the Doctor of Science, Lancaster University.
Mr Exley added, “However, there are also real risks of harmful effects, such as deoxygenation that causes unwanted increases in nutrient concentrations and killing of fish. We need to explore more to understand the likelihood of positive and negative impacts. ”
Impacts on water temperature have led to larger solar installations, with tiny arrays measuring less than 10% of the lake’s surface area that usually have minimal effects. But this model focused on one lake.
Additional analyzes will be needed to determine the optimal design, range of sizes and their impacts on separate reservoirs and lakes – all of which have special qualities. In addition, different solar installation designs have different shelter and shading effects for wind and sun.
Ranges spanning over 90% of lakes could increase the chances of the lake freezing in the winter months, the study found – although such effects would be specific to the water body and installation design and additional analysis would be needed.
Field analyzes and additional modeling are underway to build on these preliminary results.
A study entitled “Floating photovoltaic elements can mitigate the effects of climate change on temperature and water body stratification” was published in Solar energy magazine.
The authors of the study are Giles Exley, Alona Armstrong and Trevor Page of the University of Lancaster and Ian Jones of the University of Stirling.
Exley, G., and others. (2021) Floating photovoltaic elements could mitigate the effects of climate change on water body temperature and stratification. Solar energy. doi.org/10.1016/j.solener.2021.01.076.