A renewable energy system developed to preserve agricultural land has been found to increase greenhouse emissions.
A study in the United States found that floating solar, the emerging practice of putting solar panels on bodies of water to spare agricultural and conservation lands, increased greenhouse gas emissions on small ponds by nearly 27 percent.
Cornell University Assistant Professor Steven Grodsky said this was the first manipulative study of floating solar which produced empirical results.
“It’s saying, here’s what’s actually happening. And what we found was that there was increased greenhouse gas emissions from ponds with floating solar,” Assistant Professor Grodsky said.
He said researchers covered three ponds with solar panels, at 70 percent coverage, and found that, almost immediately, methane and carbon dioxide emissions increased – by 26.8% compared to ponds without solar panels – and dissolved oxygen throughout the ponds substantially decreased.
“If you put floating solar on there, you’re drastically reducing oxygen availability for organisms, you’re messing with ecological processes, how decomposition takes place, the microbes, the way wind moves across the surface of the water. It’s all connected.”
Assistant Professor Grodsky said the data was important because much of the floating solar development in the United States was currently happening on small lakes and ponds.
He said the study did offer some bright sides for floating solar.
“When comparing floating solar to terrestrial solar in total emissions cost, from site development to maintenance and disposal, the floating solar’s greenhouse gas emissions (per kilowatt hour of energy generated) are likely still lower than terrestrial solar and fossil fuel-based energy production.”
Assistant Professor Grodsky said 70 percent coverage also represented an outer limit, and the panels’ impacts may be offset by reducing coverage or installing a bubbler to agitate the water, although more research was needed.
“It’s all about trade-offs. But we need to be aware of what’s happening to be able to adapt – maybe siting differently, or designing the panels differently, or changing the percentage of cover,” he said.
Read the full paper: Immediate Effect of Floating Solar Energy Deployment on Greenhouse Gas Dynamics in Ponds.
