National Grid proposes more solar power

National Grid's more than 1 million Massachusetts customers may soon have the option of using power generated by the sun.

Under a proposal expected to be filed with the state today, the utility company next year wants to install five megawatts of solar capacity on properties it owns, which could generate enough electricity to power 1,200 homes. It also is seeking to lease rooftop space from large commercial customers for solar panels and eventually wants to help residential customers install and maintain solar panels on their homes.

"It's intended and designed to facilitate the deployment of solar in a quicker fashion than the market or other vendors trying to go roof by roof," said Tom King, president of National Grid in the United States.

Under the Green Communities Act - one of five "green" bills signed by Governor Deval Patrick this year - companies such as National Grid may eventually own up to 50 megawatts of solar generation facilities. If approved by the state Department of Public Utilities, National Grid's proposal would be Massachusetts' first such solar program on this scale and could help the state's effort to reach two of its environmental goals: having 250 megawatts of solar capacity by 2017 and requiring utilities to obtain 15 percent of their power from renewable sources by 2020.

According to National Grid's plan, the company has identified four company-owned sites that could accommodate solar panels with a combined capacity of five megawatts. The panels would be installed starting next year, at a total cost of about $38 million. They could generate up to 6.2 million kilowatt hours of electricity annually, about $1 million worth of power.

The commercial and residential portions of National Grid's proposal are still in the planning stages, and officials do not know when they will begin offering a solar option to all customers. However, on the residential side, National Grid officials say the company will guide customers through the installation process, which can often be complicated and costly.

A typical home solar installation - generating 3,000 to 5,000 watts - would cost $18,000 to $35,000, based on a $6 to $7 per watt estimate, according to Richard M. Feldt, head of Evergreen Solar of Marlborough.

Feldt said he has long favored enlisting utilities to help solar power become a mainstream energy source on par with natural gas and electricity.

"Utilities are in an ideal position," said Feldt. "They already have an infrastructure in place to market, sell, and install solar."

Ian Bowles, the state's secretary of energy and environmental affairs, called National Grid's plan "impressive" in terms of scale.

When Patrick first took office, Bowles said, there were about four megawatts of solar capacity in the state. That will have more than doubled by year-end, he said, and National Grid's proposal to install solar on its properties, including at its liquefied natural gas facility in Dorchester, would significantly add to that total.

"Governor Patrick's goal has been to make Massachusetts a national leader on clean energy, and solar is an important part of that puzzle," Bowles said.

Erin Ailworth can be reached at eailworth@globe.com.