For decades, Canton residents hauled their trash to the local landfill. Then, 25 years ago, it was capped, covered with a lining and buried under a layer of soil and grass.
The land lay unused until last year, when the town decided to turn the former dump into what officials say will be the largest solar array in New England.
Across the state, dozens of other cash-strapped communities are also hoping to install solar panels on their landfills. Massachusetts, which requires utilities to purchase a percentage of power from renewable sources, is hoping to spark a national trend.
Victor Del Vecchio, chairman of Canton's Board of Selectmen, said the town began accepting bids for the solar project last year after it decided that plunking panels on the landfills made sense. He said that over the next 25 years, the project could generate up to $70 million for the town from a combination of new revenues and energy savings.
"From our perspective, it's a no-brainer," he said.
Southern Sky Renewable Energy, the company that plans to install the 24,000, three-foot by five-foot panels, is also hoping to cash in. The panels are expected to generate up to 5.6 megawatts of power by 2012, making it the largest installation in the region.
Southern Sky Managing Director Frank McMahon said the project is the company's first on a landfill.
"We're hoping to start construction in late spring, based on snow and a final agreement with NStar," said McMahon, referring to the utility that will buy the power.
The key to the project's finances is the state's Solar Renewable Energy Certificates program, established to help the state reach a goal of producing 250 megawatts of solar power by 2017. The state is currently producing about 76 megawatts.
Massachusetts requires utilities to purchase at least 6 percent of their power from new renewable energy sources in order to boost the state's reliance on "green" energy. Solar renewable energy certificates are one way of helping increase those energy sources.
Under the program, solar projects generate one solar credit for each megawatt hour. Those credits are then sold at auction to utilities that need them to help meet their renewable goals.
To guarantee the value of the credits, the state sets a minimum of about $285 for each credit, although the price can rise as high as $550.
A one megawatt project can produce about 1,140 megawatt hours of power a year. If those 1,140 credits were auctioned at the minimum of $285 each, that would translate into nearly $325,000 in credits annually.
Energy Secretary Richard Sullivan said the certificate program puts Massachusetts ahead of other states.
"There is an enhanced value for producing solar energy," Sullivan said. "It really makes Massachusetts the leader."
Other communities are also working to put their capped landfills to use.
Fairhaven officials are working with New Jersey-based Blue Sky Power to install a smaller array of panels on their old landfill. That array is designed to generate up to 600 kilowatts of power.
Jeffrey Osuch, the town's executive secretary, said part of the energy could help supply power to a nearby middle school or could be fed directly into the NStar grid.
Osuch said capped landfills have turned out to be a prime location for solar panels since they tend to be raised, can't be built on and have to be clear of trees to protect the integrity of the lining.
"Once you cap and close them, they have a tendency to look like a mini-pyramid," he said. "You don't have any trees or building shadows."
The town of Greenfield is following a similar model. Last year, the town put out a request for proposals to build a two megawatt solar project on their former landfill.
Sandra Shields, Greenfield's public works director, said that as part of the deal, the town will be able to buy the power at a reduced rate. She said the town hopes to save up to $275,000 in electricity costs a year out of annual budget of about $41 million.
Shields said the two megawatts produced by the solar panels would be enough to power 40 percent of all the public buildings in the town, including schools and streetlights. She said building is expected to start on the project "as soon as the weather breaks."
Although Massachusetts has been more aggressive in using its laws and regulations to encourage solar power, the trend toward building solar arrays on landfills or so-called "brownfields," industrial and commercial sites that may be contaminated, is starting to catch on.
Axio Power, the company building the Greenfield project, is also working on solar projects on landfills or brownfields in California and Hawaii. One of its first projects was on a landfill in Colorado.
Paul Curran, chief development officer for California-based Axio, said landfills present a unique technical challenge because the solar panel supports can't be driven into the ground.
Unlike a house that requires a foundation, he said, the shape of the solar panels makes them vulnerable to being lifted up in a strong wind.
