Drive through any American county and you'll pass one, even if you don't know it. A low rise in the landscape, a chain-link fence, a monitoring well barely visible in the grass. Beneath that engineered cap lies decades of buried waste — and above it, an opportunity that's finally getting the attention it deserves.
The United States closed thousands of municipal solid waste landfills between 1988 and 2009. In 1988, roughly 8,000 landfills were actively accepting waste. By 2009, that number had dropped below 2,000. The math is simple: more than 10,000 former landfills now sit in various stages of post-closure care across the country, collectively covering millions of acres of land that cannot be conventionally developed — but doesn't have to stay empty.
The Solar Opportunity: 63 Gigawatts Waiting
The most dramatic transformation happening on closed landfills is solar energy. According to the EPA's RE-Powering America's Land Initiative, as of December 2024, 624 renewable energy projects have been built on formerly contaminated lands, landfills, and mine sites. Landfill solar alone has reached 972 megawatts of installed capacity — nearly a gigawatt powering homes across the country.
The numbers tell a compelling story. A 25.6-megawatt solar facility on a former landfill in Mount Olive, New Jersey powers approximately 5,000 homes. In Pittsburg, California, a 25.4-megawatt array sits atop what was once a dump. In Ohio, a 50-megawatt project announced in September 2024 became one of the three largest landfill solar installations in the nation.
In January 2026, Waste Management partnered with Reactivate, an Invenergy company, to develop solar on more than 50 former landfill sites — a pipeline that could add hundreds of megawatts by 2028. Republic Services currently operates six closed landfill solar sites. The industry is accelerating.
But the true scale of the opportunity dwarfs what's been built. Analysis by the Rocky Mountain Institute estimates that closed landfills could host up to 63 gigawatts of solar capacity — enough to power roughly 7.8 million American homes annually, according to RMI's analysis — without competing with agricultural land or natural habitat.
Engineering the Impossible
Building on a closed landfill isn't as simple as dropping panels on flat ground. These are engineered containment systems, and any development must preserve the integrity of the cap that keeps contaminants from migrating into soil and groundwater.
The challenges are real. Differential settlement — the uneven sinking that occurs as buried waste decomposes — can shift the ground 1 to 2 feet per year in the first few years after closure. Methane and other landfill gases migrate upward and laterally, requiring collection systems and monitoring wells. The cap itself, typically a low-permeability clay or geomembrane liner, cannot be penetrated.
Solar developers have adapted. Instead of driving steel piles into the ground (standard practice on greenfield sites), landfill solar uses ballasted racking systems — heavy concrete blocks that hold panels in place without breaking the cap. Arrays must account for slopes (typically 3:1 to 5:1), which reduces density and yields by 10 to 20 percent compared to conventional sites. Overall, these constraints add 20 to 50 percent to project costs.
But here's what makes the economics work: the land costs nothing. These sites have no competing use. And the Inflation Reduction Act's energy community tax credit adder — a 10 percent bonus on the Investment Tax Credit for projects sited on closed landfills and brownfields — has fundamentally changed the math since 2023.
The IRA Adder: Policy That Actually Moves Markets
Under Section 48E of the Internal Revenue Code, as expanded by the Inflation Reduction Act of 2022, solar projects on closed landfills qualify for a 10 percent Investment Tax Credit bonus on top of the base credit. For projects meeting prevailing wage and apprenticeship requirements, the full ITC can reach 30 percent plus the 10 percent energy community adder — a 40 percent tax credit that makes landfill solar competitive with greenfield development despite higher engineering costs.
Sites that also qualify as EPA-defined brownfields under CERCLA can stack an additional 10 percent, pushing total credits to 50 percent. Direct pay provisions allow tax-exempt entities like municipalities to claim these credits, opening the door for community-owned projects on publicly held closed landfills.
The result: by 2025, the IRA had spurred approximately 1 gigawatt of new landfill solar development nationally, lowering the levelized cost of energy by 15 to 25 percent in pilot projects compared to pre-IRA baselines.
Beyond Solar: Parks, Trails, and Community Space
Not every closed landfill becomes a power plant. Some of the most beloved public spaces in America were built on buried garbage.
Freshkills Park on Staten Island — at 2,200 acres, nearly three times the size of Central Park — is being built atop what was once the world's largest landfill. Closed in 2001 after receiving debris from the September 11 attacks, the site is being transformed into wetlands, trails, and wildlife habitat. The north mound opened for public access in 2023, with full buildout expected through the 2030s. Methane capture systems continue operating beneath the park's restored grasslands.
Mount Trashmore Park in Virginia Beach, built on a landfill closed in the 1970s, draws more than a million visitors annually to its 165 acres of lakes, playgrounds, and the largest skatepark on the East Coast. In Chicago, Park 608 — announced in November 2025 — will transform the city's southernmost lakefront toxic dump into public parkland. The Puente Hills Landfill Park in Los Angeles County received an ASLA honor award in 2024 for its implementation plan.
In Louisville, Kentucky, and Clarksville, Indiana, former landfills along the Ohio River are becoming botanical gardens and cultural destinations. The Waterfront Botanical Gardens in Louisville, built on a closed landfill, opened its first phase in 2019 and continues expanding.
The Southeast Opportunity
The Southeast — Georgia, Alabama, the Carolinas, Florida — has hundreds of closed landfills, many dating to the pre-regulation era before Subtitle D standards took effect in 1993. These older, unlined sites present both greater environmental risk and greater opportunity for beneficial reuse.
Florida leads the region in landfill-to-park conversions, with more than 20 "mound parks" built on former disposal sites. In Georgia, emerging pilot programs are exploring landfill mining — excavating old, unlined sites to recover recyclable materials and eliminate ongoing contamination risks. A 2023 pilot project at a Georgia landfill by Advanced Plasma Partners extracted aggregates and plastics, with commercial-scale operations planned for 2026.
For communities in the rural Southeast where these sites often sit — near small towns with limited tax bases — redevelopment represents both environmental restoration and economic opportunity. A 10-megawatt solar installation on a closed county landfill can generate property tax revenue, construction jobs, and clean energy for decades.
The 30-Year Watch
Under RCRA Subtitle D (40 CFR 258.61), closed landfills require a minimum of 30 years of post-closure care: quarterly groundwater sampling across dozens of monitoring wells, methane monitoring, leachate management, and cap maintenance. Financial assurance — typically $1 to $5 million per acre in trust funds — ensures these obligations survive even if the original operator disappears.
This isn't an argument against reuse. It's an argument for smart reuse. Solar installations and parks can coexist with monitoring infrastructure. In fact, productive use often improves site stewardship — an actively managed solar farm or public park gets more oversight than a fenced-off field that nobody visits.
The key principle: beneficial reuse must never compromise containment. Cap integrity, gas management, and groundwater monitoring continue regardless of what's built on top. Every successful project demonstrates that protection and productivity aren't in conflict.
What EPR Foundation Believes
We see closed landfills as America's most underutilized environmental asset. These sites represent past decisions — waste buried before we knew better, caps installed with the best engineering available at the time. They will require monitoring and care for decades regardless. The question isn't whether to manage them. The question is whether we let them sit idle or put them to productive use while maintaining every protection.
The path forward requires three things: continued federal incentives that make the economics work (the IRA adder should be permanent, not temporary); streamlined permitting that acknowledges the unique engineering of landfill reuse; and community engagement that gives neighbors a real voice in what these sites become.
Nearly eight million homes powered. Thousands of acres of public parkland. Millions of dollars in local tax revenue. Groundwater still monitored, caps still maintained, communities still protected — but the land above, finally, serving the people around it.
That's not a compromise. That's restoration done right.