Power Generation

February 14, 2020

Have you considered a landfill for your next utility-scale solar power development project? Increasing renewable energy standards, along with decreasing land availability, are making closed landfills an attractive option for utility companies that want to develop clean energy projects. But how do you know if a landfill is suitable for solar development?

Consider these factors when evaluating a landfill’s potential to support utility-scale solar power projects:

Waste Stability
A ground surface that settles differentially is not suitable for a solar project, and typical municipal solid waste (MSW) landfills can see significant settlement as waste degrades, especially right after closure. Older landfills typically have less settlement, making them a better choice for a solar installation. Industrial waste or coal combustion residuals (CCR) landfills may not be as prone to settlement issues as MSW landfills and can be more suitable for solar installation immediately after closure.

Landfill Cap
Landfill caps are designed to keep the waste in and liquids out, and typical caps are not designed to account for the solar panels, electrical conduits, and foundations associated with a solar power project. But with a few modifications to the solar design, the typical landfill cap can accommodate the infrastructure of a solar power project. You can replace a traditional post-driven foundation with an at-grade ballast foundation and run electrical conduits underground within the soil zone above the landfill’s geomembrane liner, or at-grade.

Landfills are typically closed with around 4:1 (25%) final slopes.  However, some landfill owners are designing their final cap grades with alternative end uses in mind, with flatter slopes that will facilitate future development.  These proactive landfill owners can help you maximize the number of panels and subsequently the revenue stream from your solar power project.

Like all power generation projects, you need a suitable interconnection point to connect the generated power to the electrical grid. CCR landfills are often positioned near existing power plants, and therefore near the infrastructure necessary for a suitable interconnection point. MSW or industrial landfills may be located in rural areas where interconnection is more challenging.

Regulatory Requirements
State and local regulators may still be catching up to the idea of putting solar power projects on landfills. The projects bring together a unique mix of solid waste, zoning, electrical, and other regulatory requirements and approvals. Be aware of the regulatory requirements in your jurisdiction and, if in doubt, reach out to your local regulator.

More and more landfills are being developed with solar power projects in mind, and you may be increasingly looking at alternative spaces for your next project. Will your next solar development be on a landfill? Contact SCS Engineers to evaluate a landfill’s solar feasibility today. Find a professional near you, or send us an email at .

In 2016 the 2.3 MW Rock River solar project near Beloit became the largest solar farm in Wisconsin. Do you need help evaluating a landfill for your next utility-scale solar power project? Contact Eric Nelson, SCS’s Utility National Expert.



Posted by Diane Samuels at 6:01 am