Floating a New Solution for Solar Deployment | Article

At the Fort Bragg military base in North Carolina, the solar installation planned for 2021 may look different from a standard solar farm – the panels will float on water.

Floating solar panels, dubbed “floatovoltaics,” can conserve land and water, and are often more efficient than land-mounted solar power.

Floating solar is a relatively new technology. Before 2014, there were only three floating solar installations in the world. At the end of 2019, over 300 projects totaling more than 1,600 megawatts (MW) were up and running globally, with Japan and China taking the lead in number of installations.

The solar panels themselves are similar to ground- or rooftop-mounted panels, but are attached to rafts instead. They are most often installed on man-made lakes, where tides and saltwater do not damage the panels. According to the National Renewable Energy Laboratory (NREL), deploying floating solar on the more than 24,000 man-made reservoirs in the United States could generate 10 percent of the country’s annual electricity production.

Land conservation is the most straightforward benefit to installing floating solar projects on pre-existing reservoirs, according to Stetson Tchividjian, Director of Business Development at D3Energy, the company developing the project for Fort Bragg. The military base installation will consist of a 1.1 MW floating solar installation on Big Muddy Lake in Fort Bragg’s training site of Camp Mackall.

“Fast forward 20 years from now, and if we keep eating up land for solar, there is going to be pushback. It is getting harder and harder to find 500 acres of land. Floating solar is such a beautiful solution to that problem, where we have so many bodies of water that we can utilize for dual purposes,” says Tchividjian.

Utility-scale solar farms can take up to 5 to 10 acres of land per MW of solar installation, while floating solar only takes up about 2 acres per MW. Putting solar panels on water instead frees up land for agriculture, housing, natural lands, and other uses. In urban areas especially, land is often scarce and expensive, which is where Tchividjian says floating solar “really shines.”

The land at Fort Bragg is used for United States Army Special Forces training. Floating solar allows Fort Bragg to continue training soldiers while reaping the benefits of renewable solar electricity.

Despite having higher up-front costs, floating solar is nearing price parity with land-based solar. Operating and maintenance costs are cheaper since floating solar eliminates land upkeep expenses. Additionally, the cooling effect of the water can make the panels an estimated five to 15 percent more efficient, driving up how much power the panels can produce and feed into the grid.

The panels can also help improve reservoir ecosystems. Shading from the panels curbs unwanted evaporation and harmful algae blooms that kill fish and other marine life. With the right design, floating solar panels could bolster fish and energy yields from aquaculture ponds and broadly improve water resource management.

Experts are also looking into floating solar’s potential to be combined with hydroelectric power.

“There is a lot of synergy between the two,” says Tchividjian. “The interconnection is easy and you can generate solar during the day, and at night run the hydroelectric plant.”

Solar panels on hydroelectric reservoirs would connect to existing transmission lines that supply electricity from the plant to the grid. Solar and hydropower could trade-off with each other, where solar panels may produce more in dry seasons and hydropower in rainy ones. Pumped storage hydropower could then store excess solar generation. Overall, the combination would improve grid resilience and boost the amount of electricity generated at the site.

NREL estimates that if floating solar was widely combined with hydroelectricity, the power generated could fuel 16 to 40 percent of the world’s current total electricity demand.

These numbers from NREL are not intended to be predictions as much as they are estimations of the resources available to house floating solar. Floating solar projects currently make up less than one percent of solar’s total capacity.

The largest floating solar plant in the United States, at 4.78 MW, was just completed in Healdsburg, California, and upcoming projects are planned throughout the country. Fort Bragg’s project is expected to start construction in mid-2021 and operations in early 2022. Tchividjian is optimistic about floating solar’s continued growth and benefits.

“Five years ago, I was doing basic education on floating solar when I talked to people about it, but now it is widely implemented in the industry and a totally different conversation,” says Tchividjian. “Just think about five years from now. We believe it has a ton of potential.”

Author: Rachel Snead