These remarkable floating solar panels solve one of the biggest problems with sun-based energy — here’s how they work

Solar power innovators in Europe, Asia, and North America are launching flotillas of solar panels on open water with shocking results.

In this case, electricity and water are a great combination, sometimes providing new life for forgotten lagoons that were created for past industrial efforts. Bloomberg reported that an old coal pit can be turned into a “green powerhouse” when covered with floating panel systems, and such a project has the potential to replace fossil-fuel generation entirely in certain communities.

It’s part of the effort to expand sun-catching surfaces while limiting the land acreage needed for solar farms. Floating systems can be placed on reservoirs, lakes, or other man-made water bodies, according to the U.S. Energy Department. When deployed, the panels can also help conserve water by reducing evaporation.

Bloomberg’s report detailed projects in Europe that are using floating systems to help meet solar demand with limited land.

“Most of these former gravel and sand pits aren’t used anymore. They’re low-hanging fruit,” Matthias Taft, CEO of European renewable energy developer Baywa r.e., told the outlet.

The water-based projects have a lot of room to grow, accounting for 1% of all solar panels installed worldwide last year. But, the report added that “their use has grown more than 2,000%” in the last 10 years. What’s more, there are more than 6,600 water bodies around the world that could float a solar system, Bloomberg noted. They don’t work on turbulent water or in the ocean.

When operational, these systems could make towns self-sufficient energywise. A paper in the journal Nature Sustainability claims that more than 6,200 “communities and/or cities in 124 countries” could provide all the power needed with floating solar energy systems.

Cohoes, New York, is an example of how these projects can work in America’s towns.

Here, with no land available for a solar farm, city planner Joe Seaman-Graves looked to an unused 14-acre reservoir in his town, according to a PBS report. A floating solar energy system is slated to be completed in Cohoes, which has a population of about 17,000, this year at a cost of about $6 million to $6.5 million. PBS reported that the federal government and other incentives are covering about half the cost.

The price tag to get a floating system running is higher than other solar operations, and experts are studying aquatic ecosystems to ensure the projects don’t impact life under the water. Once completed, however, the returns can be great. The solar energy system in Cohoes could power the town’s government buildings and street lighting, realizing a $500,000 yearly savings, all per PBS.

“We are an environmental justice community and we see a big opportunity for low-to-moderate income cities to replicate what we’re doing,” Seaman-Graves told PBS.

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