“A number of fleet operators want to present a green presence to the public,” Rick Spina, GM’s vehicle line executive for full-size trucks, told Automotive News. “They want to be known as green companies, especially those on the retail side.”

AT&T is one such company -- the telecommunications firm reportedly just ordered 8000 Ford E-250 vans, which will be converted to CNG. GM still isn’t sure if it will perform the CNG conversion in-house, or subcontract it out to its usual conversion firm, Roush Enterprises. Regardless, the automaker says the conversion requires minimal changes to the existing vehicle.

“We have to harden the valves, harden certain things for durability reasons,” said Spina. “Pretty much it is a gasoline engine.” Other engineering factors also come into consideration on these vehicles -- for instance, transmissions need to have their shift points recalibrated, as running an engine on CNG yields a different power curve.

Apart from the green image, fleets typically shop for CNG vehicles in a move to reduce costs. Although many companies incur the cost of installing their own CNG fueling station (helping negate the impact of a limited public CNG refueling infrastructure), CNG fuel is less expensive than standard gasoline, often bringing lower operating costs despite slightly lower mileage.

Buck