The Forbes Street solar array, once the largest in Rhode Island, recently doubled in size.

Phase I of the landfill project opened in December 2013. At the time, the 3-megawatt array was one of the biggest in New England, with 12,848 solar panels. It has since been eclipsed by larger solar farms across the region with more on the way.

Phase II is nearly a duplicate project, with 12,296 ground-mounted panels. Each phase has the capacity to power 500 homes.

Both arrays sit atop the 227-acre former Forbes Street municipal landfill that operated between 1970 and 1980. A portion of the landfill is still used by the city for composting leaf and yard waste.

The panels are affixed to above-ground ballasts, which prevent disruption of trash buried in the landfill. Phase I was secured with cement blocks. In all, 2,212 tubs of cement anchor the panel brackets.

Prior to installation, the landfill was capped with 28 inches of soil, through a shared project with the city and the solar developers, Boston-based CME Energy and Hecate Energy LLC of Chicago.

Phase I secured a 20-year power-purchase agreement at 23.9 cents per kilowatt-hour. Phase II receives 16.6 cents per kilowatt-hour for 20 years. Both agreements were made through the Renewable Energy Growth tariff program, which is run by National Grid.

A total of 2,112 tubs of cement secure the ground-mounted solar system. The foundations are above ground so that the capped landfill isn’t punctured.
A total of 2,112 tubs of cement secure the ground-mounted solar system. The foundations are above ground so that the capped landfill isn’t punctured.

The overall project received a $200,000 grant from the state Renewable Energy Fund, managed by the Rhode Island Commerce Corporation, and $100,000 from the state Office of Energy Resources.

Janet Coit, director of the Rhode Island Department of Environmental Management, called the project “a shining example of excellence” for addressing runoff and turning a blight into a productive renewable-energy effort.

“You were the first out of the gate,” Coit said. “You are the ones who really showed that a major solar array could go on a landfill.”

While landfill solar projects such as the Forbes Street project and one in North Providence have avoided controversy, many large projects, especially those that require tree cutting or loss of farmland, have created bitter fights between residents, local government, and developers.

Cranston has struggled with projects in recent years, including a 21.5-megawatt project proposed for farmland. The Cranston City Council recently approved a resolution asking for a moratorium on new solar projects. The moratorium wouldn’t stop approved projects such as the Lippitt Avenue and Hope Street solar facilities. Hopkinton is mired in debate, as several utility-scale solar projects have been proposed for open space. The Tiverton Town Council recently voted to repeal its solar ordinance until the town can rework it.

The East Providence landfill project removed a small number of trees and is engineered with swales and gravel trenches to reduce polluted runoff and curtail leakage from the landfill from leaving the property.

“We can turn an environmental difficulty into an environmental win,” said Walter Mahla, an electrical engineer with Megawatt Energy Solutions of Pawtucket.

At the Nov. 29 dedication of Phase II, Mahla held a monitor showing that the new solar installation was already delivering more than 90 percent of it electric capacity, despite the cold and windy weather.