Drew Lent, a certified professional geologist who specializes in energy and waste projects, discusses the benefits of siting solar facilities on closed landfills. He covers the various planning and permitting considerations of these energy-generating opportunities. This blog post originally appeared on CornerPost. All opinions are the author’s own.
Let’s face it—there are only so many revenue-generating uses for a closed landfill. Unless you generate enough landfill gas (LFG) to make power generation or other LFG use feasible, the closed landfill sits not generating any revenue for at least 30 years. That is why siting a solar array on a closed landfill can be a great win-win opportunity. Landfill owners pick up money for leasing the land to the solar company, while also showing they are doing something for the environment and climate change.
Regulators are beginning to see the light, and some have worked cooperatively with owners and solar developers to encourage developing solar projects on landfills. Recently, New York State proposed streamlining the regulations for siting solar facilities on both brownfield and greenfield sites. As of the date of this post, draft revisions to New York’s State Environmental Quality Review Act (SEQR) call solar facilities a Type 2 action—one that is assumed to have no significant adverse impacts.
But—and this is a big but—placing a solar facility on a landfill is not the same as putting it on an under-utilized agricultural field. You will need to do a lot more thinking and planning ahead of time. Make sure those who design and permit the facility work closely with the landfill operator and the EPC contractor. Get everyone together to work through the details ahead of time before submitting the application to the permitting entity. It is best to work with solar developers who want to design, build, and operate the solar projects. Developers who are more interested in permitting and flipping a project instead of building and operating the solar project can result in wasted effort—and no solar project at the end of the day.
Having worked on a few of these projects, I have a few tips on what to look for.
First a bit of background about a typical solar facility
Solar is a diffuse energy source—6 acres generates about 1 megawatt of power. The ideal solar development site should be close to a point of interconnection. There should be no wetlands or significant threatened or endangered species issues. Look for compatible zoning, with receptive neighbors and community. The ideal site would be one with slopes of less than 8 percent, though there are exceptions.
Solar facilities are a very low impact closure use. They are quiet and low profile. They generate little traffic, and there is little potential for post-closure spills or fires. They require little maintenance and can provide positive corporate and media attention.
Strategies for developing solar projects on landfills
Those interested in developing a facility should begin by conducting a feasibility assessment to evaluate the landfill cap construction, the thickness of waste, and the potential for differential settlement. The evaluation also will determine the facility’s compliance history, LFG generation rates and management, any potential stormwater management issues or post-closure use restrictions, and the state and local regulatory requirements.
In general, the solar facility should include non-penetrating structures, like concrete ballasted systems that minimize any damage to the landfill cap. Conduits should be managed using cable trays rather than trenches. Upgrades to the landfill cap may be required. And of course, the plan will need to avoid LFG vents, monitoring wells, drainage swales, and leachate conveyances. And last, but not least, no large, enclosed electrical equipment should be located on the landfill cap.
Planning and design considerations for siting a solar facility on a landfill
I cannot emphasize enough the importance of starting early and teaming with an experienced and well-capitalized development partner. Consider several types of electrical and racking systems before starting the permitting effort.
Be sure to communicate with internal and external stakeholders early in the process, including the utility interconnection team, municipality, and neighbors. Wherever possible, design the landfill closure with solar as an anticipated end use. Keep in mind during your planning that various permits typically will be required for a ground-mounted solar facility. Here is my list of permits typically required for facilities in New York. Other states may or may not require these—or undoubtedly will have their own:
General stormwater discharge permit
U.S. Army Corps of Engineers stream and/or wetlands disturbance permit
Local site plan approval and building permit
Special use permit (applies if solar is not mentioned in the local zoning code)
Brownfields change of use plan approval (in New York, this is called a Landfill Post-Closure Use Modification Request)
Natural Resources and Cultural Resources Sign Off
Holding a pre-application meeting with local officials is important. During that meeting, find out what permits are required, who the decision makers are, and what issues most concern them. (If you are working in New York, be sure to find out if the community signed a Climate Smart Communities Pledge.)
Be prepared to conduct a variety of design studies. Examples include:
Electrical interconnection impact study
Solar feasibility assessment study
Environmental due diligence (required by solar investors and developers)
Final cover system verification testing
Wetlands delineation and related studies (if necessary)
You also will have to show how the solar project will be installed to prevent damage to the landfill cap and probably conduct a geotechnical settlement and stability analysis to show the collective maximum dead load of the ballast, racking, and solar modules.
Look at closed landfill properties in a new light
Whether you are a landfill operator or a brownfield owner, I hope these tips will help you look at closed landfill properties in a new light. Some may consider placing solar facilities on closed landfills as risky, since the sites may have a legacy of contamination. I disagree, since the environmental liability has already been tied to the landfill operator, who has long-term maintenance responsibilities. So if something goes wrong from the landfill, the landfill operator will be responsible for mitigation.
About the Author
Drew Lent, certified professional geologist, is a senior project manager at Tetra Tech’s Rochester, New York, office. He has worked on solid waste landfills with both the New York State Department of Environmental Conservation (NYSDEC) and in the private sector. Drew has worked on several solar-on-landfill projects in New York, Florida, Maryland, Massachusetts, New Jersey, Vermont, and Wisconsin.