An Allegiant Air flight bound for St Petersburg-Clearwater, Fla., lifts off near a solar panel farm recently installed at the Chattanooga Metropolitan Airport.

Work will start later this month to double the size of Chattanooga Airport's solar farm after it received a $3 million federal grant Tuesday.

The FAA Airport Improvement Program grant will fund the second part of the three-phase project at the airport, said U.S. Transportation Secretary Ray LaHood in a news release.

According to the airport, phase two should be online in early 2013. While the power will go into the electrical grid, the solar farm will produce enough energy to power 250 homes a year.

Terry Hart, the airport's chief executive, said in an email that the environmental savings achieved through the solar farm cuts costs long-term for airport users.

In addition, he said officials recognize that aviation leaves a large carbon footprint.

Hart said that "it was incumbent upon us to seek out responsible ways to mitigate our industry's impact on the environment."

The airport is putting in a 10 percent match to the grant, or $300,000.

Lovell Field is the only commercial airport in Tennessee with a solar farm, officials have said.

Phase two will put in place 4,000 solar panels to join that number already installed.

When the solar farm is complete, it will yield 3 megawatts of electrical power and provide one-third of the airport's energy needs, according to the FAA.

The reduction in greenhouse gas emissions will be equivalent to taking 200 cars off Chattanooga's roads each year, officials said.

The FAA helped fund the first phase with a $4 million grant last year.