Floating solar power plants on small water bodies add to greenhouse gas emissions

Floating solar power plants are one of the fastest-growing trends in the solar industry in recent years. The competition for space often leads to disputes between solar energy investors, farmers, local communities, and environmentalists, making water-based panel installations an appealing solution. However, the technology’s environmental impact and its effects on aquatic ecosystems have not yet been sufficiently studied.

Steven Grodsky, an assistant professor at Cornell University, conducted an experimental study with his team. They covered 70% of the surface area of three small ponds at the Cornell Experimental Pond Facility with solar panels. The study revealed that methane and carbon dioxide emissions increased by 26.8% while oxygen levels in the water significantly dropped compared to ponds without solar panels.

“There has been a flurry of papers about floating solar, but it’s mostly modeling and projections”, Grodsky said. He explained that placing solar panels on small water bodies drastically reduces oxygen availability for organisms, disrupts ecological processes, and alters how wind moves across the water’s surface.

The findings are particularly important, as many floating solar power plants in the United States are currently being installed on small lakes and ponds, Grodsky noted.

In New York state, floating solar power plants are also being considered as an alternative to terrestrial solar farms.

Panels should not cover more than 70% of the water surface

The authors also highlighted the positive aspects. When comparing overall emissions – including site development, maintenance, and disposal of used or broken panels – floating solar power plants are expected to produce lower greenhouse gas emissions per kilowatt-hour of electricity generated than terrestrial solar farms and energy from fossil fuels.

Researchers believe that 70% coverage is the upper limit. Solar panels should not occupy a larger area, as it could have negative effects on the ecosystem, they emphasized.

To mitigate the impact, researchers recommend reducing coverage or installing a bubbler to agitate the water, although more research is needed.

Floating solar market to reach 77 GW by 2033

According to the study’s lead researcher, it all comes down to tradeoffs. “If you look at the history of energy transitions – from wood to fossil fuels, for example – everything was based on energy production, and the environment wasn’t taken into consideration, and now we have environmental injustice, we have climate change,” Grodsky said, adding his research aims to rethink the approach to the current energy transition.

It remains uncertain whether scientific research will keep up with the rapid growth of the technology. Wood Mackenzie forecasted in a new report that floating solar power market would reach 77 GW by 2033. The Asia-Pacific region is expected to dominate the particular segment of the solar industry. In contrast, the US is projected to experience significantly slower growth, reaching just 0.7 GW by 2033.