In Massachusetts there’s a “Race to Solar,” a push for residents and businesses to take advantage of lower prices and streamlined permitting processes to put solar panels on roofs.

Old Colony Housing Project in South Boston was once a decaying, 16-acre development. Today, you can see it’s being rebuilt and transformed– brick has turned into new siding, concrete to grass, narrow alleys to open spaces. And it’s topped with gleaming new solar panels.

But what about the price? Behind the solar array is DeWitt Jones of the nonprofit Boston Community Capital, which fronted the million-dollar cost to install and maintain the panels. He said it’ll take about 10 years to recoup that cost.

The installation at Old Colony provides more than 10% of the development’s electricity, according to Jones.

“We actually own the solar panels, we aggregated all the financial benefits, and we sell low-cost, fixed-price electricity from the panels back to the development,” he said.

The price of electricity for residents here is lower than what they’d pay the local utility company. It’s a complicated set-up, but one the city is encouraging.

“This is a cutting-edge example of bringing energy efficiency to an older public housing stock," said Brian Swett of Boston City Hall.

The governor has set a goal of 1600 megawatts of solar capacity by 2020. That’s about the same as a power plant. In an effort to meet that goal, Brian Swett of City Hall says Boston and Cambridge are providing incentives for commercial solar installation.

“Every sun-splashed roof in the city of Boston needs to be looked at as a potential asset to put solar panels on,” Swett said.

But looking around the city, you don’t see many solar panels. From the historic brownstones in the Back Bay, to multifamily homes in Mattapan, to ranch-style houses in Hyde Park.

“I think it is an ambitious goal to have something on every roof but eventually we will,” said Paul Lyons, a Cambridge engineer. “Maybe not in my lifetime but eventually every building that has sun on the roof, will have some sort of device.”

Lyons evaluates commercial properties for solar installation. He said solar projects usually pay off in fewer than 10 years. But Lyons says only one out of every five consultations goes forward. That’s because of the challenge of working in a historic city like Cambridge.

“Usually the building itself can’t support the extra weight,” he said. “Structurally many buildings were not made for the additional load on the roof. And it’s very expensive to reinforce a roof.”

While the solar panels are very light, about three pounds a square foot, they have to be weighted down to prevent them from flying off in New England storms. So, while projects like Old Colony are success stories, the growth of urban solar relies in part on new construction. Back at the development, DeWitt Jones says solar should be showing up on all kinds of rooftops.

“For the solar revolution to be really successful we need to make sure that solar is broadly and equitably benefiting all of our residents. And especially we need to make sure that cities and their residents can participate in the benefits of solar.”

Boston and Cambridge are setting a goal of 40 more solar installations – starting with nonprofits and small businesses - by the end of November.

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