SHAW AIR FORCE BASE, S.C. -- It may refuel aircraft the same as the other 17 fuel trucks on the flight line, but for the hybrid refueler an extra battery puts this truck in a league of its own. 

In an effort to 'go green,' the federal government awarded a $1.2 million contract to Mack Trucks, Inc. for the development of a cutting-edge hybrid diesel electric truck to help refuel Air Force planes. 

"This truck is more fuel efficient," said Senior Airman David Harris, who works in petroleum, oil, and lubricant distribution. "Because it's a hybrid, the government spends less money filling trucks and can spend it on fueling aircraft." 

The R-11 refueler weighs roughly 72,000 pounds and is the only one of its kind in the Air Force. It is currently in its second year of evaluation here. 

Although the Air Force is making efforts to conserve energy by testing fuel alternatives like this hybrid refueler, some Airmen here aren't sure the truck makes a significant difference in saving money. 

"It's not too feasible here because we don't drive it far enough or fast enough," said Tech Sgt. Luke Salkeld, refueling maintenance NCO in charge. "They're trying to see if it's making a difference. It's probably more expensive for the upkeep with the batteries than the cost of gas." 

Once the two-year trial period is complete, an analysis will show whether or not the hybrid refueler is truly cost-effective and energy efficient. 

"It's a great truck," Airman Harris said. "This hybrid is a lot better and I enjoy driving it. I think there should be more fuel efficient trucks for our shop."