Solar panels and farms are branching out in unexpected ways, and in the process, helping solve one of the earlier criticisms of solar farms – they take up land that could be used for things like farming and housing. 

Now increasing numbers of solar farms are floating on dams and lakes, and engineers and scientists are exploring how to put them on the ocean to bring electricity to places such as Indonesia, where more than a million people are without access to electricity.

The difficulty with floating solar panels on the ocean is that rough waves can damage solar panels, so research is being done to develop methods for keeping them operative in the high seas. “We believe near-shore locations, with more benign sea states, are more attractive,” founder and CEO of Ocean Sun, Borge Bjorneklett, told Ecowatch.

A research team led by Dr. Luofeng Huang, assistant professor of mechanical engineering at Cranfield University, is developing an offshore plant that will use a floating breakwater system located upstream from the panels to reduce the height of the waves by around 90%. The waves then enter an enclosed buffer zone that also reduces their power.

Floating solar farms may be the only renewable power option in some places, even though their installation and maintenance will be expensive. “[I]n Singapore the cost of land is very high and they have already utilised most of their rooftop surface area,” Bjorneklett said. “If they can utilise the ocean surface outside Singapore, it is actually the only way to provide affordable renewable energy.”

One of the largest solar farms in the world is located in China. The 320-megawatt Dezhou Dingzhuang Floating Solar Farm provides power to Dezhou, a city of about five million that is around 98% powered by solar electricity. In South Korea, a floating solar project on the Yellow Sea coast is predicted to be the largest in the world. It is expected to provide enough electricity to power a million homes with 2.1 gigawatts of electricity.

A study published in Nature found that if 10% of the planet’s hydropower reservoirs were covered with floating solar panels, 4,000 gigawatts of electricity could be generated — as much as all the world’s fossil fuel.

On land, increased attention is being paid to solar energy farms over old landfills known as “brownfields”— environmentally hazardous sites that can be repurposed for solar farms. These “brightfields” are growing in number and size. Last year, local governments across the US announced a combined 207 megawatts of energy from 21 landfill solar projects, according to the World Resources Institute 

Sunnyside Solar Project, City of Houston

Houston’s Sunnyside Solar Project is expected to become the largest landfill solar project in the US. Its 52 MW of solar panels will be able to power 5,000 homes and offset about 55,000 metric tons of CO₂ each year, WRI reports. Similarly, Columbus, OH will transform a closed landfill into a nearly 50 MW solar park.

“The Sunnyside landfill has been one of Houston’s biggest community challenges for decades, and I am proud we are one step closer to its transformation,” said Mayor Sylvester Turner early in 2021. “I thank the Sunnyside community because this project would not have come together without its support. This project is an example of how cities can work with the community to address long-standing environmental justice concerns holistically, create green jobs and generate renewable energy in the process.”

Based on an RMI brightfield analysis from late 2021, closed landfills could host more than 60 gigawatts of solar capacity—enough energy to power the state of South Carolina, Time Magazine reported in June 2022.

According to an October 2020 presentation, the U.S. Environmental Protection Agency has tracked an 80% rise in such projects over the previous five years, Waste Today Magazine reported in 2021. The agency’s RE-Powering America’s Land Initiative includes landfills along with “formerly contaminated lands” (brownfields) and mine sites as parcels of land that can serve as ideal hosts to solar energy or wind farms. The EPA identified more than 11,000 EPA-tracked sites and nearly 15 million acres that have potential for developing solar, wind, biomass and geothermal facilities.

Sunnyside, Houston

The RE-Powering Initiative is tracking 417 such projects representing more than 1.8 gigawatts of installed capacity. Some 91% are solar projects, and 59% are on closed landfill sites. Only Alabama, Alaska, Idaho, Louisiana, Mississippi, Washington and West Virginia were not home to any such projects as of October 2022. Massachusetts hosts 125 of the 417 projects known to the RE-Powering Initiative.

“Among the various technologies and available sites, solar photovoltaics on landfills has been a particularly attractive redevelopment option and, over time, has represented an increasing share of all RE-Powering sites,” the EPA says. The trend demonstrates that “communities, developers, and site owners are embracing this sustainable land development strategy,” it says.

Sources:

U.S. Landfills Are Getting a Second Life as Solar Farms. Time Magazine, Jun. 2, 2022

Solar panels offer landfills second chance at a useful life. Waste Magazine Today, Aug. 19, 2021

Scientists Developing Floating Solar Farms That Can Withstand Rough Oceans. Ecowatch, Jan. 10, 2023

3 Ways US Cities Broke Clean Energy Records in 2021. World Resources Institute, May 18, 2022

Cover image: This solar farm was built on top of a landfill located in Rehoboth, MA. The landfill had not been used for decades and will now provide clean renewable energy to customers nearby. The system size is about 2.4 MW DC. Photo by Lucas Faria, Dept. of Energy. Wikimedia Commons.