Closed Landfills Generate Solar Energy and Win for Local Government

January 14, 2023

Reston, VA − Success in renewable energy projects helps municipalities move closer to achieving their sustainability goals. These two Maryland solar projects provide value to their communities by lowering greenhouse gas emissions, providing renewable energy and environmental integrity, and creating jobs and savings for taxpayers. That’s a win for Maryland and its citizens.

Closed landfills require significant maintenance and environmental compliance expenditures for many years, more often decades. Recent changes in federal tax law under the Inflation Reduction Act have dramatically improved opportunities for public and private sector landfills to convert a liability to an income-producing asset.

The Inflation Reduction Act includes provisions for a 30% investment tax credit for solar projects, with other provisions that can increase this incentive to as much as 50%. There are also equivalent provisions for direct payment to non-taxpaying entities such as cities and counties. An excellent summary has been prepared by the law firm of Holland & Knight and is available here.”

Two Maryland counties are among recent SCS Engineers’ clients who are converting their idle properties into revenue-generators that serve their communities—they are installing solar farms, a growing trend on closed landfills. The Oaks Landfill in Montgomery County, MD, is one.


Siting solar energy installations

Ideal sites for these facilities are relatively flat (preferably less than 15% slope) with open spaces conducive to photovoltaic system installation. Favorable sites are also in close proximity to utility connection points providing developers a viable means to bring their product to market and consumers. While properties like closed landfills provide ideal locations, the projects command a robust multidisciplinary redevelopment approach. Important skills for successfully engineering and permitting these projects include landfill engineering expertise and experience with state and local permitting processes.

solar array on landfill
Solar array at the Oaks Landfill

The Oaks Landfill Photovoltaic Array project will be a 6-megawatt (MW) system on 170 acres of the closed landfill, the largest solar project on county property. Governed through a power purchase agreement, two MWs are allocated for the County. The other four MWs are for a community solar project, with 100% of the electricity generated, provided to low and moderate-income subscribers.

It will be one of the largest solar farms nationwide to allocate all power to disadvantaged communities. The array is on schedule to operate in 2023.

Ameresco selected SCS Engineers to obtain the required state and local permits, prepare construction plans and provide construction-engineering services. Ameresco, the solar developer, performs turnkey services, including solar design, financing, operation, and utility interconnection to sell electrical power.


Understanding local regulations and proven engineering designs are key

Processes involve gathering complex engineering components to secure state and local permit approvals. Understanding the regulatory environment and potential impacts of design and construction are keys to more efficiently navigating the permitting approval processes.

Safely expediting the process creates value for the community and the County, which benefits from the solar power, and for Ameresco, which invested significant capital. SCS’s expertise with landfills and regulations helped avoid costly site investigations and assisted in adapting the design of the solar arrays to field conditions.

SCS’s design provided for the maintenance of the cap’s integrity and, ultimately, its closure certification. Working with Ameresco and the County, the firm developed a holistic plan to maintain the cap’s integrity and achieve consistency with other landfill features such as drainage structures, landfill gas control systems, and environmental monitoring systems.

SCS provides comprehensive services in developing designs that meet regulators’ requirements but also in verifying, documenting, and demonstrating environmental compliance while considering the long-term needs of all stakeholders. For instance, by proactively addressing the fire marshal’s codes regarding access to emergency vehicles, we avoided delays in the approval process.

SCS, in coordination with sub-consultants and Ameresco, minimized impacts on adjacent forest land in compliance with forest conservation regulations. As a sustainable environmental solutions firm, maximizing development while protecting sensitive resources and capital assets is always a priority.


The SCS and Ameresco Team

SCS Engineers works with Ameresco, one of North America’s largest renewable energy project developers. SCS and Ameresco have very complementary skills. Whereas SCS has decades of experience in landfill engineering and permitting, including varied post-closure uses for landfills such as solar, Ameresco has extensive experience with renewable energy to provide comprehensive turnkey services from electrical design to managing the interconnect to the grid and negotiating purchase agreements for sale of power to utilities. The teaming relationship is vital to executing successful projects from feasibility study to design, all the way to completion.

Ameresco is a large player in renewable energy, and SCS is a pre-eminent firm in the landfill engineering space. Both companies have offices nationwide. SCS works on over one-third of the landfills in the United States. SCS and Ameresco have an expansive reach and breadth of experience in every essential competency to develop successful solar projects.