The Tucson International Airport is installing five acres of solar panels to replace about 40 percent of its electrical energy needs.

The project broke ground today, and is part of a plan to get the airport to 100 percent solar-powered electricity, said Bonnie Allin, the president and chief executive officer of the Tucson Airport Authority. That goal could take three or four years, she said, and depends on funding availability.

"Phase one will cover about 35 percent of the parking lot," she said. "And feed directly to the central plant of the terminal building."

This phase of the project costs $6 million, paid for with money from the Federal Aviation Administration and the Arizona Department of Transportation, she said.

"It'll be a tremendous emission savings and power savings for us, and it will provide covered parking for our customers as a side benefit," Allin said.

Future solar panel installations will cover the front short- and long-term parking area completely.

The airport has been working on energy reduction programs since the 1980s, including converting to electric and natural gas-powered vehicles.