The city explored a potential virtual power purchase agreement from a solar developer in Texas. It made more sense financially, but the downside was no additional benefit or connection to the city of Indianapolis itself.
“We'd be farming out jobs, we'd be investing in another locality outside of Indiana,” Mickelson says. “I’m looking at all the different angles to get more solar in general. But at the end of the day, we also need to see all those intersectional benefits of creating jobs for our community and relying less on coal here locally.”
Now Mickelson is considering an increasingly common solution for municipalities: building a solar farm on top of a landfill.
“Our state doesn't have the most friendly policies,” Mickelson says. “But [with landfills] if you're able to determine there's no other better reuse for this land, it seems like a really smart investment for the community.”
Backers of the idea of putting more utility-scale solar farms on brownfield sites — landfills, old coal mines, superfund sites and closed industrial plants — include the U.S. Environmental Protection Agency. Despite thousands of landfills across the U.S., solar installations at these sites haven’t grown at the same rate as the wider industry over the past 10 years.
That might change, with additional tax credits available for landfills and other brownfield sites, through the Inflation Reduction Act (IRA). But will the all-around benefits to renewables included in the law mean just more solar overall?
Building Differently
Closed landfills are unavailable for traditional redevelopment and are often owned by local governments. That makes it an attractive alternative amid increasing neighborhood opposition against solar developments. Landfills also tend to have greater sun exposure, as well as access to power lines and other infrastructure nearby.
But placing solar modules on these sites requires a different kind of installation: a ballasted system that doesn’t drive foundations deep into the ground, avoiding piercing the landfill cap and unsettling the waste below.
The site’s settlement patterns also need to be tracked to make sure the panels don’t become out of whack, and depending on the locality, building on a landfill can involve additional permitting questions and the agreement of multiple agencies. All of this adds up to often more time and cost spent than a greenfield site, like a farm.
While the IRA offers incentives for all solar installations, it also includes additional tax credits specifically available to projects on brownfields, as well as for renewable energy projects sited in or benefiting low-income communities.
In the past, targeted state-level policies have made a difference. New Jersey included a specific brownfield carve out in its renewable portfolio standard and Maryland excludes large brownfield solar projects from its net-metering cap.
Massachusetts created additional subsidies for renewable projects on landfills and offered direct technical assistance. Going further, the state also specifically disincentivized solar built on undeveloped land, subtracting some of the financial benefits associated with building solar in the state in the first place.
Solar developers and towns in Massachusetts responded: by 2020, 52 percent of the utility-scale landfill solar projects in the U.S. were in the state, despite the state having only 7 percent of the landfills in the U.S., according to EPA data analyzed in a report by Rocky Mountain Institute (RMI). Three other northeastern states — Connecticut, New Jersey and New York — made up another quarter of the total projects.
Since then, the EPA has tracked at least two dozen more completed solar landfill projects across the U.S., with others under construction or planned. As of the end of 2022, solar landfills have a capacity of about 2.4 GW, or enough to power an estimated 500,000 homes. RMI estimates existing landfills could grow that capacity at least 25-fold.
‘Reverse Commuting’
“Unquestionably, the IRA is going to change the economics of all solar projects,” says Matthew Popkin, an author of the RMI report and manager of its urban transformation program.
But Popkin believes the specific tax credits for brownfields and projects that benefit low-income communities will also encourage more landfill solar, especially given existing land-use debates.
“When I look at the closed landfill, I see a really interesting opportunity where [solar energy] is not going to conflict with where that next park, where the next housing project will be.”
Combining the IRA incentives could mean a brownfield site could receive anywhere between a 40 percent-70 percent investment tax credit.
A planned landfill solar project in Houston’s Sunnyside neighborhood checks all the IRA boxes: It’s sited on a brownfield, it’s located in a low-income neighborhood and part of its power will be sold through a community solar project to nearby residents.
But Sunnyside was already in the works before the IRA passed. How did it happen without these incentives?
The size of the installation — 52 MW — is the largest solar landfill currently planned in the U.S., and that helps with the economies of scale. But the developer working on the project says the location is especially important.
“Most renewable energy in the state of Texas is trying to get power to downtown Houston,” says Paul Curran, founder of BQ Energy.
The power line build-out to do so has been a struggle, he adds, but the former landfill’s location “is like reverse commuting … It is the best place to do renewable energy and battery storage in the entire state of Texas,” says Curran. “It’s right in the middle of where there's an awful lot of people.”
BQ, bought by investment firm Clean Capital last year, is a repeat brownfield solar developer, building large-scale projects in Maryland, Massachusetts and New York. They make money by selling the electricity to a city, university or a utility over a long-term contract.
Originally a wind developer, Curran says his company can manage the costs of the additional work it takes to install solar on landfills because of their experience with the engineering particulars, and knowing when a site is more trouble than it’s worth.
“We don't fear a landfill. We don't fear a superfund site.” Curran says. “It's normal for us, but it's not normal for most solar energy developers.”
Getting It Right
While the solar panels themselves aren’t any different, there are a number of “not normal” factors when building on landfills.
For one, the landfills must be closed. Popkin says a site should be at least several years past its closure to better track rates of settlement. Landfills with steep slopes are unlikely to be good — or at least cheap — candidates.
Developers have to consider unique concerns around the design and construction of the project. The EPA’s best practices’ guide calls for limiting the overall system weight, avoiding penetrating the landfill cap, maintaining vegetation and stormwater management after the solar panels are in place, among other particulars.
The EPA and the National Renewable Energy Laboratory have pre-screened nearly 200,000 brownfield sites and done site-specific analyses of some potential landfill solar farms. But there doesn’t yet seem to be much in the way of long-term research on existing solar landfill projects compared to an average solar farm.
Getting it right matters, and not just for the immediate community.
“We talk to competitors because I don't want somebody to mess one up,” Curran says. Being able to point to a landfill solar project that went wrong would be an easy way for municipalities to go cold on the idea.
(Andre Malok/TNS)
‘Time Is Money’
Over the past few years, there’s been a marked increase in landfill projects — and the size of the installations being considered. That shows developers and communities are getting “more comfortable” with the idea, Popkin says.
Municipalities can also reduce costs by choosing sites where there’s less community pushback to build solar and offering lower-cost leases to the developers.
“Time is money,” he says. “The less time that is required for developers, planners, designers, engineers, city officials, municipal officials to have to spend working through this, that brings down the project soft costs as well.”
But a traditional solar project without much pushback or complication is still an attractive option — and will benefit from the extension of the federal tax credits.
In 2020, Ellsworth, Maine, sought to buy solar power to lower their electricity costs, and considered building on a local landfill. But the city decided against it, the Ellsworth American reported, because a solar landfill project was “more involved.” Instead, Ellsworth purchased credits for energy produced at two large solar projects on private lots along a nearby state highway.
Several years ago, Edgartown on Martha’s Vineyard didn’t go forward with a solar installation on its own landfill, even as many neighboring island communities prioritized their own landfill solar projects. But the town has recently approved a 3.7 MW project by another repeat landfill solar developer, Ameresco.
In New Paltz, N.Y., a landfill solar site has been held up for years, first over the site planning, then the county trash agency requesting a revenue share and now the high costs of interconnecting the project with existing electrical infrastructure.
While Curran once had a town’s model airplane club object to a project because they used the landfill surface for flying, he says most municipalities who decide against pursuing solar landfill do so because they’re just not ready.
In Indianapolis, Mickelson said the IRA has already been a factor.
“It's often been tossed around as, ‘What are we gonna do about that landfill?’,” she says. “And then for a number of years, I think leadership has thought about a reuse solution with renewables, but it's just not panned out.”
Now Mickelson says she’s received multiple recommendations to look into it because of the new federal law, and specifically a change that allowed public entities to receive the tax credits.
“It seems much more likely that we'd be able to pursue some of this,” Mickelson says.
Taylor Kate Brown is an independent journalist focused on local and state climate action. She's previously worked for The San Francisco Chronicle and the BBC and publishes a weekly newsletter, The Planet You Save May Be Your Own.
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