Floating Solar Panels Can Supply Clean Power to Spots Where Land Is Limited

Officials at Del-Co Water Company, a nonprofit cooperative in north central Ohio, were looking for ways to add solar power to reduce the carbon footprint of their energy-intensive pump systems. But development pressure on the outskirts of Columbus made land for a solar farm scarce.

"Growth is happening at such a pace that land is incredibly valuable," Del-Co Chief Legal and Strategy Officer Jason Rafeld told Newsweek. Then, he said, someone floated an idea for placing the solar somewhere other than on land. "Well, what if we put it on our reservoirs?"

Construction scheduled to begin soon will do just that. Rafeld said a 32-acre Del-Co reservoir will have a three-acre grid of floating photovoltaic solar panels, the latest example of a technology that is expanding renewable energy in places where land is limited.

With the 1.2-megawatt installation, Del-Co is dipping a toe into floating solar, and Rafeld said if testing shows it to be a good fit, the company plans to add more floating arrays to its other reservoirs. So far, he said, he's seen no indication that the plastic rafts and panels will negatively affect water quality or reservoir performance, and they might even have some benefits.

"A lot of algae growth happens because of sunlight and so if we block the sun on a portion we might experience less algae growth," he said. That could lower maintenance costs and require fewer chemical treatments to counter algae growth. In drier areas, the panels can also reduce water loss due to evaporation.

"We have a lot of confidence this is going to be successful," Rafeld said.

Floating solar has been growing slowly in the U.S. over the past few years and could soon make a much bigger splash as more companies want to tap into federal incentives for solar while avoiding land-use conflicts and high cost.

Researchers at the Department of Energy's National Renewable Energy Lab found that adding floating solar to just a small portion of the country's lakes, ponds and reservoirs could provide 10 percent of the current electricity generation in the U.S. The NREL assessed potential for floating solar and found more than 24,000 man-made water bodies were suitable for the technology, and many are in places with high land costs and high electricity prices.

Countries in Asia have been leading deployment of floating solar, and a study by scientists at Southern University of Science and Technology in Shenzhen, China, found enormous global potential on nearly 115,000 reservoirs around the world. The researchers identified 6,256 communities in 124 countries that could become energy self-sufficient by using floating solar.

Miami-based D3Energy is supplying the units that Del-Co will install. Development Director Stetson Tchividjian told Newsweek that the solar panels and electronics are all the same as what would go into any other installation, they just go on a floating rack instead of a rooftop or ground mount. The rack is made from molded HDPE plastic and resembles a floating dock.

"We build it all onshore row by row, almost like a giant Lego set, and then feed it out into the water," he said, and the rafts are then anchored in place. Tchividjian said the units are cost-competitive with land-based ones and because they fit together more closely, require less space to generate power. (The higher racks for land-based arrays cast a shadow on neighboring panels, requiring extra spacing. The low-lying floating arrays don't shade one another and can fit together snugly.)

"We're actually just under two acres per megawatt versus the ground system at five acres," he said.

D3Energy has had a wide range of clients, including water utilities like Del-Co, the Army's Fort Liberty base in North Carolina (formerly Fort Bragg) and electric utility companies such as Duke Energy, which added floating solar to a cooling pond beside its fossil fuel power plant in Bartow, Florida.

Florida is an especially good place for floating solar, Tchividjian said. It is the Sunshine State, after all, and Florida has limited land but lots of water.

Justin Kramer manages emerging technologies for the Orlando Utilities Commission, which had D3Energy add floating solar to help power water systems and supply power to its 240,000 customers.

"We have a lot of stormwater ponds throughout our territory," Kramer told Newsweek. "These ponds are right along roads which have distribution power lines and everything."

Kramer said the floating arrays form a beneficial feedback loop as the shade keeps water cooler. That helps some aquatic wildlife while the cooler water, in turn, improves the efficiency of the solar panels, which perform best in temperatures just under 80 degrees.

OUC has partnered with the Orlando Airport and the Florida Department of Transportation to identify more water bodies suitable for the technology, and Kramer said floating solar will be a big part of helping the company meet its goal to be net carbon zero by 2050.

Tchividjian said he's enjoyed watching the technology go from a novelty to a proven power source. He said each new project adds to the body of knowledge about how floating solar performs and the growing confidence in the technology, and the boom in solar incentives have made this the company's busiest year.

"Wherever there's water, this is becoming a huge point of interest for a lot of different customers," he said.