The City of Boston has added XL Hybrids' XL3 gasoline-electric hybrid powertrain to four of its vans and plans to convert a fifth vehicle today, the city's fleet manager told Government Fleet magazine.

The converted vans are being used by the Boston Transportation Department’s Enforcement Division, the Elderly Affairs Department’s Senior Shuttle Service, and the Central Fleet.

"The ability to retrofit vans from our existing fleet allowed us to see immediate benefits," said Jim McGonagle, the city's director of central fleet management. "There were no driver training or maintenance requirements."

If funding permits, the city will continue to convert several of its later-model vans, and a hybrid option will be included in all future van procurement, he added. The fleet consists of more than 160 full-size passenger and cargo vans.

The city is seeing up to a 20% increase in fuel mileage on its first four converted units. The fleet will continue to compare the hybrid and non-hybrid units for one full year, McGonagle said.

The hybrid vans support the city’s goal of reducing greenhouse gas emissions by 25% by 2020 and 80% by 2050. The City of Boston hopes to replace 10% of its fleet each year with alternative fuel vehicles. The city's diesel-powered vehicles now use a B-20 biodiesel blend.

Boston has been replacing older sedans with alternative fuel vehicles over the past three years. In addition, the city initiated a vehicle sharing pool in 2012 as part of its commitment to lowering greenhouse gas emissions by reducing fuel usage.

XL Hybrids adds an electric motor, a lithium-ion battery pack, and control software to the vehicle without making significant modifications to the OEM’s internal combustion engine or transmission, according to the company. It doesn’t need special plugs or charging or fueling infrastructure, and the system can be installed in six hours.