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All else being equal, floating solar has several advantages over land-based arrays, but site selection can become complicated in terms of wildlife conservation.
Floating solar is a subset of the solar industry in which solar panels are moored on the surface of water. While the practice can add more renewable energy to the United States grid without taking up valuable space on land, bodies of water are not free of conflict. Solar projects can encounter competition from recreation and habitat conservation priorities, for example. Still, new opportunities for site selection that prioritizes the local environment and biodiversity are emerging as the technology improves and the knowledge base grows.
All else being equal, floating solar has three key advantages over land-based solar arrays. For the developer, water presents a flat surface, reducing site preparation costs. For the property owner, it can provide an opportunity to extract more value from underused facilities. And for land conservationists, it presents a significant means of expanding the nation’s renewable energy profile without impinging on land.
The situation is more complicated in terms of wildlife conservation. Solar panels can have a beneficial cooling effect on aquatic life, helping to prevent algae blooms while reducing evaporation. But researchers at Oregon State University recently found that water conditions can vary greatly in a study of 11 reservoirs across six states. 
“Different reservoirs are going to respond differently,” Evan Bredeweg, lead author of the study, told the university’s newsroom. “There’s no one-size-fits-all formula for designing these systems. It’s ecology — it’s messy.”
Similarly, researchers warn that sites for floating solar must be carefully selected to avoid impacts on bird populations, particularly water birds. A Cornell University study of 16,000 sites along the Atlantic flyway bird migration route from New England to Virginia indicates that larger sites with higher energy potential are not as likely to come into conflict with birds, while still cautioning that smaller bodies pose a greater risk of bird interactions.
“Based on our findings, it could be possible to reduce risk to birds via ecologically informed siting, and that might not instill a reduction in energy production,” Steven Grodsky, assistant professor at the university, told the Cornell Chronicle.
As Grodsky suggests, the case for applying a rigorous, ecology-centered site selection regimen is supported by the large number of potential sites in the U.S., providing solar developers with many opportunities to expand their business while avoiding high-risk locations.
An initial study by the U.S. Department of Energy, for example, found that floating solar panels on a selected pool of 24,000 human-made reservoirs could meet about 10 percent of the county’s electricity demand, a figure that would otherwise require more than 5 million acres (2.41 million hectares) of land.
More recently, researchers focused on a smaller group of reservoirs owned or regulated by the federal government. They found a technical potential of 1,475 terrawatts of electricity annually, or enough to power 100 million homes. Even if only a small fraction of that amount is actually usable, it would still result in a substantial addition to the U.S. solar portfolio.
In a recent conversation with the Florida-based floating solar startup AccuSolar, TriplePundit learned how the floating solar industry is evolving to explore new opportunities at additional sites.
AccuSolar CEO and founder Jason Harrison recounted how his company builds on the experience of AccuDock, a floating dock company launched by his father in 2007 and co-owned by Harrison. AccuDock provided the floats for the nation’s first-ever “floatovoltaic” project, which went into operation in 2009 on an irrigation pond at a Napa Valley winery in California.
“We didn’t think anything of it at the time. We sent them the floats and moved on,” Harrison said. “Then we started looking at what floating solar has done globally. Coming from our background of producing structures that float, we can do better.”
By 2020, Harrison was fully engaged with the idea, seeking new opportunities to partner Accudock’s extensive flotation experience with solar firms. Based on the company’s track record of more than 8,000 installations, reservoirs and commercial irrigation ponds are just some of the available opportunities, Harrison said. 
One example involves stormwater retention sites and flood zones. “The floats will be on dry ground most of the time, but when it rains and the water collects, the floats will then float,” Harrison said. “We have experience in putting things in rivers via AccuDock, and flood zones could be a huge application.”
Irrigation canals and residential developments with water features are two other areas of potential expansion, and industrial sites offer another opportunity. Last year, AccuSolar was tapped to partner in a 2.4-megawatt project at a mining facility in Florida and a 1.8-megawatt contract at a manufacturing facility in Oklahoma. 
“It makes a lot of sense when you can use unusable land,” Harrison said. “It’s a perfect example of why floating makes sense and will be self-sustaining.”
The transfer of land-based solar technology to water also provides the floating solar field with new opportunities. As the solar conversion efficiency of solar panels increases, less land — or less water surface — is needed to harvest the same amount of solar energy.
The solar trackers commonly used in land-based systems, which enable solar panels to follow the optimal angle of the sun throughout the day, have the potential to boost solar collection in floating solar farms. The U.S.-based floating solar firm Noria, for example, is pilot-testing its AquaPhi tracking system at multiple sites in the U.S. 
As for the future, the global research firm DataM Intelligence summarized recent floating solar activity in the U.S., taking note of “renewed interest in maximizing reservoir surfaces for clean energy as part of broader solar capacity build‐outs.” Reservoirs are just the tip of the iceberg as the U.S. solar industry continues to draw on new partnerships — and new ecosystem research — to continue expanding.
Tina writes frequently for TriplePundit and other websites, with a focus on military, government and corporate sustainability, clean tech research and emerging energy technologies. She is a former Deputy Director of Public Affairs of the New York City Department of Environmental Protection, and author of books and articles on recycling and other conservation themes.

TriplePundit brings solutions journalism to sustainability news, reporting the under-told stories of how business, environmental conservation and social good connect.


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