Latham, N.Y.-based Plug Power Inc. is developing hydrogen fuel cell range extenders for 20 FedEx Express electric delivery trucks, which would allow the vehicles to cover nearly double the territory.

The project is being funded by a U.S. Department of Energy grant announced in December to spur development of commercial fuel-cell technology.

The range extenders would be incorporated into an electric delivery truck produced by Smith Electric Vehicles, a Plug Power spokesperson confirmed. FedEx Express has been using Smith's all-electric Newton Step Van in the U.S. since mid-2012.

The hybrid vehicles produced by the project will be powered by lithium-ion batteries and a 10-kilowatt Plug Power hydrogen fuel cell system.

Currently, electric delivery trucks are limited to traveling about 80 miles on a charge. Doubling the vehicle's range should expand the role of electric-powered delivery trucks, as parcel delivery trucks, taxis, post office trucks, and port vehicles, according to Plug Power.

"Early customer experiences with electric delivery vehicles have been overwhelmingly positive," said Andy Marsh, Plug Power's CEO. "But only 1 percent of these vehicles are electric today. We think that this range extender provides the added distance and quick refueling capabilities needed to really grow this market."