Renewable energy projects, particularly those using solar technology, have been on the rise, helping to empower municipalities across the country.

In May 2014, Casella Waste Systems Inc. along with two solar energy firms launched a solar power project at Casella’s Coventry, Vt., landfill. A solar farm at the Victorville Sanitary Landfill in San Bernardino County, Calif., opened in January, and just this month, New Jersey’s Public Service Electric and Gas Company (PSE&G) put two new landfill solar farms in service. By developing solar energy projects at closed or capped landfills, companies are getting new life out of otherwise unusable land.

PSE&G, New Jersey's largest regulated gas and electric delivery utility that serves nearly three-quarters of the state's population, gained experience developing solar projects on landfills and brownfields through its Solar 4 All program.

“A properly closed landfill such as those PSE&G has identified for solar development typically offer vast amounts of open space that has limited if any development potential beyond a solar farm,” says Fran Sullivan, spokesperson for PSE&G. “Solar provides a productive use for these properties.”

PSE&G currently has three landfill solar sites in service in Kearny, Bordentown, and Deptford, N.J. They generate more than 24 megawatts-dc of electricity, which is enough to power about 4,000 average-size New Jersey homes per year.

“Landfill owners can receive a lease payment for development of a solar facility on their landfill,” says Sullivan. “Further, the State of New Jersey benefits because additional solar generation is added without using limited open space in the state.”

Joe Fusco, vice president of Casella Waste Systems, based in Rutland, Vt., says that solar project siting at a landfill just makes sense.

“It represents an additional, efficient economic use of the landfill’s footprint—particularly buffer property that won’t be developed as a landfill, and areas of the landfill that have been closed and capped,” he says. “Landfills have some of the same physical, topographical and locational qualities that make solar … installations desirable.”

Paul Pabor, vice president of Waste Management Renewable Energy, agrees.

“The landfill final cover represents open space that is otherwise not useable for commercial or industrial applications, so renewable energy can be the highest and best use,” he says. “The top of the landfill is unencumbered by obstructions that may reduce solar panel exposure.”

Houston-based Waste Management has executed six leases for solar fields that will produce a total of 40 MW at landfills in the U.S.

 “There are of course areas of the country that have … higher efficiency for solar, and these regional variations would also apply to installations at landfills,” Pabor says. “For solar, the success of utility-scale projects depends on the state incentives available.”

But launching a landfill solar project can come with its own set of challenges including identifying the proper site, obtaining permits and following appropriate construction protocols.

“Construction challenges involve the application of appropriate civil engineering solutions to ensure the solar facility is in compliance with the requirements of the landfill specific closure plan as well as other applicable codes and standards,” says Sullivan. “This includes sound storm water management practices to assure proper runoff is achieved to limit erosion and ponding, leveling areas where differential settlement has occurred such that the landfill is suitable for solar construction and facility layout considerations to allow for the continued, uninterrupted operation of the landfill engineering controls, like a gas collection and control system.”

Additionally, the design of the solar facility must incorporate a ballasted racking system, electrical conduit trays, inverter pads and other elements that do not compromise the engineered cover system that is present at properly closed landfills, according to Sullivan.

“For solar projects there are a number of considerations related to engineering, site security, potential staffing needs, permitting, access to existing site infrastructure and ongoing site maintenance. All factors should be addressed and considered prior to pursuing a project,” says Pabor.