Maui Mayor Charmaine Tavares is test-driving a plug-in hybrid vehicle to promote cutting back on fossil fuel consumption.

The converted Toyota Prius is part of a national study run by the Idaho National Laboratory and the U.S. Department of Energy. The survey has cars in a variety of locations to test how they do in different environments.

In April, the first month, Tavares' test car averaged 64 miles per gallon. Maui Electric also has a car, and four more are on Oahu, including one used by Hawaiian Electric Co.

In other states the cars averaged between 44 and 59 miles per gallon.

Like conventional hybrid cars, Tavares' converted Prius recharges its battery when the driver brakes. But the vehicle also contains an additional battery pack that can be recharged at an ordinary electrical outlet.

This allows the car to use less gasoline. It also lets the vehicle harness wind, solar and other resources collected by Maui Electric Co.

The mayor hopes to give renewable energy use maximum exposure, said Victor Reyes, Maui's energy commissioner. “;She's really a champion for this,”; he said.

Tavares drives the car to all her public functions and is ready to show people she meets brochures and posters that she stores in the trunk. In a news release, the mayor said the study aimed to demonstrate that advanced technology could help communities pare down their fossil fuel use.

“;As Maui increasingly generates electricity from renewable sources,”; she says, “;we can make even more progress in decreasing our dependency on imported oil.”;

Maui is home to the state's largest commercial wind farm, Kaheawa. At full capacity the farm generates about 10 percent of the electricity sold by MECO.

Lanai, which is part of Maui County, hosts the state's largest single-site solar farm.

Private companies have proposed building wind farms on Molokai and Lanai that would serve those islands as well as deliver power to Maui and Oahu by undersea cable.

Tavares said she has spent nearly $87 driving 1,175 miles in her hybrid. That includes less than $47 for gas (at about $2.70 per gallon) and $40 for electricity. Going the same distance in a gas-only car that gets 25 miles per gallon would cost about $126.