UPS will be the first company to use delivery trucks powered by a new hydraulic hybrid power train. The trucks will not use the conventional battery system that is used in electric hybrid cars. A diesel engine will be used in conjunction with a hydraulic propulsion system that will replace the drivetrain and transmission. Hydraulic pumps and storage tanks will capture and store energy to be used later by the vehicle. The pressure from the hydraulic fluid is converted by the motor into rotating power sent to the wheels. The system will also recover 70 percent of the energy wasted during braking.

The technology was developed by the Environmental Protection Agency (EPA) at the fuel-emissions lab in Ann Arbor, Michigan. Engineers from Eaton Corp, who design hydraulics systems, also aided the EPA in the system.

The hydraulic hybrid will allow the diesel engine to shut off when the truck is stopped or decelerating. During tests in Detroit, Michigan the EPA found that the trucks used 45 percent less fuel and reduced the carbon emissions by one third.

“There is no question that hydraulic hybrids, although little known to the public, are ready for prime time use on the streets of America,” said David Abney, UPS chief operating officer, in a news release. “We are not declaring hydraulic hybrids a panacea for our energy woes, but this technology certainly is as promising as anything we’ve seen to date.”

UPS ordered 7 trucks to use in Minneapolis, Minnesota. They currently have 90,000 vehicles in the company fleet and by next year 2,100 of those will be alternative-fuel vehicles. Trucks that run on electricity, compressed natural gas or other forms of energy will be used.