SOUTH PORTLAND — City officials on Tuesday will start operating the largest municipal solar project in Maine.

A switch-flipping ceremony will be held at 8:30 a.m., when Mayor Patti Smith is expected to turn on the system that was built on the city’s capped former landfill. Members of the public will be invited to walk through the facility afterward and learn how it works.

Portland-based ReVision Energy installed the 2,944 photovoltaic panels on the 34-acre former landfill, which is behind the city’s solid-waste transfer station and the public services facility that’s being built at 929 Highland Ave.

Julie Rosenbach, the city’s sustainability coordinator, said completing the solar array fulfills one of South Portland’s climate action goals.

“Our partnership with ReVision Energy on this project has enabled us to take a large step forward in the transition to clean, renewable energy,” Rosenbach said in a statement.

ReVision project manager Josh Baston said it’s the largest municipal solar array in the state, expected to generate 1.2 million kilowatt-hours of energy per year, roughly 12 percent of the electricity used by the city’s municipal and school buildings.

Rosenbach developed the project with ReVision in tandem with Portland officials, who negotiated a similar agreement for a solar array on that city’s capped landfill off Ocean Avenue. As a private, for-profit company, ReVision could build the arrays using federal tax credits that aren’t available to municipalities, which are nonprofits.

ReVision started installing South Portland’s solar array in July. Portland has delayed installing its 2,800-panel array so it can address structural and ventilation problems at its 35-acre closed landfill.

Each community will purchase the electricity from ReVision at rates higher than market prices for the first six years, before being able to buy the equipment outright for nearly $1.6 million.

In the long run, the cities could save money – and possibly make money – because they would generate their own power rather than purchase it from the grid.

Kelley Bouchard can be contacted at:

kbouchard@pressherald.com