UPS announced Tuesday that its fleet of alternative-fuel vehicles had expanded with the deployment of 200 hybrid-electric delivery trucks in eight U.S. cities.

The 200 new hybrid electric vehicles (HEV) join roughly 20,000 low-emission and alternative-fuel vehicles already in use and have been deployed in Austin, Houston, Philadelphia, Chicago, Washington, D.C., Long Island, Minneapolis and Louisville. Before this latest deployment, UPS operated 50 hybrid electrics in Atlanta, Dallas, Houston and Phoenix.

"We're proud of this large HEV deployment to major cities in the United States," said Bob Stoffel, UPS senior vice president of supply chain, strategy, engineering and sustainability. "This technology, where properly used, can yield a 35 percent fuel savings, the equivalent of 100 conventional UPS delivery vehicles."

The 200 new HEV delivery trucks are expected to reduce fuel consumption by roughly 176,000 gallons over the course of a year compared to an equivalent number of traditional diesel trucks. The hybrids also should reduce by 1,786 metric tons the amount of CO₂ gases released annually into the atmosphere.

The new hybrid power system utilizes a conventional diesel engine combined with a battery pack, saving fuel and reducing pollution-causing emissions. The small diesel is used to recharge the battery pack and to add power when necessary.

The HEVs also use regenerative braking. The energy generated from applying the brakes is captured and returned to the battery as electricity. The combination of clean diesel power and electric power, supplemented by regenerative braking, allows dramatic improvements in fuel savings and emissions reductions.

The HEV fleet features two different size vehicles from Workhorse Custom Chassis and Freightliner Custom Chassis Corporation and a hybrid power system from Eaton Corporation. The external truck bodies are identical to UPS's other signature brown trucks, although they feature additional labeling identifying them as hybrid electrics. The trucks use lithium ion batteries, which offer a faster re-charging capability and last longer than previous generation HEV batteries. Additionally, these vehicles are much quieter than conventional UPS trucks and feature keyless entry.

The UPS alternative fuel fleet is a diverse one with multiple technologies, including compressed natural gas, liquefied natural gas, propane, electricity and hydraulic hybrid technology. Since 2000, the alternative fuel fleet has traveled more than 165 million miles.

"The wide variety of technologies in our green fleet is indicative of UPS's 'rolling laboratory' philosophy to energy efficiency and reduced fuel consumption," Stoffel said. "Our goal is to reduce dependence on fossil fuels, but there is no silver bullet technology to achieve this. This dependence will rely on a multi-modal approach."