Closed landfills are being renewed as solar farms across North America

There are more than 10,000 closed and inactive landfills across the U.S. alone that could be given new lives as solar power hubs, according to RMI, an independent non-profit focused on energy.

Landfills typically have good sun exposure, due to a lack of vegetation. Reinvesting in them as solar farms, often called brightfields, could help revitalize local, often lower-income, host communities, suggests a report from RMI.

“While some closed landfills have been repurposed as open space or golf courses, most do not have any future planned use,”  states the RMI report, The Future of Landfills is Bright. “Thus, installing solar on landfills avoids land-use conflicts with other economic, agricultural, housing, or recreational activities.”

Closed landfills, which take up a tremendous amount of land, could host an estimated 63 gigawatts (GW) of solar capacity in the near future. But to date, just 500 megawatts (MW) have been installed on landfills in the U.S.

“This 63 GW would be equivalent to 70% of all the solar capacity installed in the United States through 2020 (89 GW), and could produce 83 terawatt hours (TWh) annually—enough to power 7.8 million American homes or the entire state of South Carolina,” the report states.

The practice is also catching on in Canada, where the Shepard Landfill in Calgary provides some 1,080 kW of power directly to the city’s composting facility. Officials say that the combined project will produce some 4,392 kW, enough electricity to power almost 750 average Calgary homes every year while helping to avoid the generation of over 3,600 tonnes of greenhouse gas emissions per year.

And last year, Yukon’s Dawson City announced it would be transforming the municipality’s former landfill into a solar farm, or “brightfield”, capable of generating 280 MWh of energy annually, reducing the city’s dependency on back-up diesel generation, and displacing 91.6 tonnes of annual GHG emissions.

A solar project is also located at Saskatoon’s Landfill Gas Collection and Power Generation System as part of the city’s goal to generate 10% of its energy from local, renewable sources.

Back in the U.S., the solar landfill concept has drawn interest, but only in select regions, particularly New England and the mid-Atlantic, where 86% of all solar landfills exist.

What seems to have been gaining more popularity in recent years is the practice of local governments using brownfield sites to house solar panels.

Another advantage listed in the RMI report for using solar at landfills is the extent of existing infrastructure already available, often including connections to electric distribution and access roads necessary for construction and operations.

Additionally, landfills can often be located in lower-income areas of a municipality, so the report’s authors note that “reuse of these sites not only provides a sustainable, non-hazardous reuse, but also an opportunity for community solar, education, and non-hazardous reinvestment.”

The U.S. Environmental Protection Agency determined in 2016 that closed and capped municipal solid waste landfills “often offer an ideal location for solar installations.” Through 2019, the EPA identified 205 completed solar projects on or adjacent to landfills that, collectively, are capable of generating approximately 500 MW of electricity.

While solar farms are not booming on capped landfills, there has been a 10-fold increase in energy capacity compared with recent years, and it includes the three largest projects in the U.S. to date. One solar landfill farm in Ohio, announced last September, will generate 50 MW of energy. Another project announced last year is being developed on 240 acres of landfill in Houston.

But there are some challenges with landfills compared to a standard parcel of undeveloped land, the report suggests. Project designs must account for landfill cap characteristics, site grading, and land settlement as waste decays over time.

This article appears in ES&E Magazine’s August 2022 issue: