Solar Tribune

Solar Panels Helping Old Landfills Embrace a Greener Future


As the solar industry has matured over recent decades, solar panels have found their way onto more and more unusual places. Cars, lakes, airports, and Disney World are just a few examples. Although notably less sexy than those examples, solar arrays placed on capped landfills are definitely becoming “a thing” that continues to gather more and more momentum in solar energy circles.

Giving Landfills a New Lease on Life

Any hope of meeting near-term decarbonization goals in the U.S. will require millions of acres of new solar energy capacity, and will necessitate putting solar panels in places never thought of before. Capped landfills are a unique option to meet the growing demand for more solar energy capacity in the United States.

A capped landfill is a landfill that is past its useful life as a site for storing waste and has been capped at the surface to minimize deleterious environmental impacts from water seepage . The “cap” is usually comprised of concrete/asphalt, soil, clay, a gravel-based drainage layer, a geomembrane, or some combination of these options.

According to a report from RMI, a non-profit renewable energy research organization, the potential for repurposing capped landfills into solar energy producing mega sites is significant. This was the report’s main takeaway:

“Out of the 10,000 closed landfills across the country, at least 4,000 of them could host solar projects, the report concludes. The total generation capacity of solar at these sites could exceed 63 gigawatts, more than two-thirds of the country’s entire solar capacity installed through 2020.”

The total number of solar arrays installed on capped landfills and the amount of megawatts they produce has steadily been increasing over the past decade, and yet, it is still just a fraction of what is possible. The room for growth is significant.

Photo Source: RMI

The optics of converting an old, capped landfill site into a solar energy producing juggernaut are very appealing. These brownfield sites are limited in their future use given contamination concerns and environmental monitoring requirements. What better way to lead on climate change then to turn these symbols of excess waste and overconsumption into hotbeds of renewable energy activity?

Pros and Cons

Here’s a look at some of the primary pros and cons of putting solar arrays on capped landfills.


  • For better or for worse, landfills are often located near low-income neighborhoods. By placing a solar energy source near these areas, low-income residents can benefit from reduced energy costs and greater energy reliability.
  • Landfills have good sun exposure given their sheer expansiveness and lack of nearby vertical obstructions.
  • Solar production can be combined with landfill-generated methane gas conversion to create a “double whammy” effect and turn old landfills into potent energy producers.
  • The symbolism of converting brownfield sites formerly used for waste storage into solar energy producing powerhouses is incredibly appealing.


  • There are engineering challenges associated with placing large-scale solar arrays on capped landfills, especially if the landfills have been capped with concrete or asphalt.
  • There is additional environmental liability that comes with placing solar panels on capped landfills since monitoring groundwater contamination and methane gas and carbon dioxide emissions are necessary.
  • Settling over time is common with capped landfills as the waste decomposes over time. This can cause complications to the otherwise rigid infrastructure used to house solar arrays. One way around this is to target solar for landfills that have been capped for at least 10 years as that is when the bulk of the decomposing process takes place.
  • When combined together, the increased environmental liability and engineering challenges associated with placing solar panels on capped landfills can add costs to such a project. Solar projects placed on landfills are typically 10-20% more costly than traditional ground mounted solar energy systems.

Key Strategy for Solar Equity

A priority in recent years for solar energy stakeholders has been to highlight the growing need to place equity at the heart of the push for increased solar energy capacity. Even amidst historically low solar energy costs, there is a perception that residential solar is something that is reserved for the well-heeled. Connecting low-income communities to the myriad of benefits of solar energy has been and should be a top focus of the industry. The whole concept of “community solar” is predicated on this very belief, aiming to democratize the availability of solar energy. Solar projects placed on capped landfills represent a key potential strategy to drive these more equitable solutions.

The Sunnyside Solar Project in Houston, TX is one such example of an equity-focused capped landfill solar project that led to widespread community benefits. In April of this year, the City of Houston gave the greenlight to convert a vacant landfill in the low-income Sunnyside neighborhood into a massive solar farm. The $70M project will include 70 MW of solar panels installed over 224 acres that will produce enough energy to power 5,000 to 10,000 homes. The project is the largest brownfield solar project in the country.

Photo Source: Houston Chronicle

The project will result in a number of ancillary benefits that will be felt by the Sunnyside community. Those benefits include:

  • Power discounts will be made available to residents in the Sunnyside neighborhood.
  • Increased local job opportunities. A partnership between Houston Community College and Lone Star College will train 175 Houstonians for solar jobs related to the Sunnyside Solar Project.
  • The project will include investments in bioretention areas, an integrated biking and walking path, an electric vehicle charging station, and battery back-up to the Sunnyside Community Center
  • The project will include an Agricultural Hub and Training Center that will have an aquaponic greenhouse and promote other biodiversity training opportunities focused on beekeeping and native plant preservation.

Environmental justice and racial equity were at the heart of the Sunnyside Solar Project. The project had the support from key local organizations like Population Education and the Houston chapter of the NAACP. The project also has a strong supporter in the city’s mayor, Sylvester Turner. In a press release celebrating the project, Turner stated:

“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. 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.”

Nexamp’s Solar Star Urbana Landfill project offers another promising example of the broader community benefits of landfill-based solar projects. This 40-acre, 14,000 solar panel project sits on a capped landfill and produces 5.3 MW of solar energy for residents in Illinois. The project delivers subsidized energy to low- and moderate-income residents in Illinois through the Illinois Solar for All program, a community solar program that incentivizes low income residents to connect to solar power.

Photo Source: Nexamp

Another positive example can be found in Annapolis, MD. There, a 16.8 MW solar project placed on an 80-acre capped landfill sells some of the power generated on its site to the City of Annapolis, Anne Arundel County, and the county’s board of education.

Placing solar projects on brownfield sites like capped landfills represents a real low-hanging opportunity for the industry to further add to the nation’s capacity and connect more underserved communities to the benefits of solar industry. We at Solar Tribune have documented similar efforts to place solar projects on old coalfields in Kentucky and the benefits this has brought to economically distressed parts of Appalachia. These projects help generate local jobs and wealth, make vulnerable communities more resilient in the face of growing grid disruptions brought on by climate change, and bring much-needed investments to communities who need them most. This is an industry trend that we can all get behind.


Cover Photo Source: Biz Times

Recent Posts