Fiat Chrysler Automobiles recently unveiled a fleet of natural-gas vehicles, but they won't be sold to consumers.

That's because they're semi trucks, used to deliver parts to assembly plants from FCA suppliers and component-manufacturing facilities.

The company is investing $40 million to convert 179 trucks operating throughout the Detroit area to compressed natural gas--or CNG, for short.

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Chrysler says this will give it the largest private fleet of CNG-powered heavy-duty vehicles operating in the state of Michigan.

The investment includes $5 million for a CNG fueling station at Chrysler's fleet-vehicle hub in Detroit, located on Lynch road just across from the Detroit City Airport.

The station--built by TrueStar Energy--is the largest private CNG fueling station in North America, Chrysler says.

Fiat Chrysler Automobiles Detroit CNG fueling station

Fiat Chrysler Automobiles Detroit CNG fueling station

FCA also spent $1.8 million on a 36,000-square-foot maintenance facility for the CNG trucks, at the same location.

It estimates that the transition from diesel to CNG for its Detroit-area fleet will reduce CO2 emissions by more than 16,000 tons per year.

That's equivalent to the CO2 emissions from burning 17 million pounds of coal, or the annual energy use of 1,500 homes, the company claims.

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Previously, the fleet used nearly 2.6 million gallons of diesel fuel annually, to cover 16 million miles for parts deliveries.

Chrysler expects fuel-cost savings of around 35 percent per year with CNG.

Reducing emissions from parts-hauling trucks is one way carmakers can cut the overall environmental impact of the vehicles they sell.

Fiat Chrysler Automobiles unveils fleet of CNG trucks

Fiat Chrysler Automobiles unveils fleet of CNG trucks

Last year, Honda installed an automated CNG fueling station near its Marysville, Ohio, assembly plant.

It was built in the hopes that--with a guaranteed source of fuel--suppliers would consider switching some of their delivery vehicles to CNG.

Lack of fueling infrastructure was dampened interest for natural-gas vehicles in the U.S., despite their lower emissions.

MORE: Natural-Gas Vehicle Sales Globally Won't Quite Double In 10 Years: Analyst

And while natural gas is often cheaper than gasoline, the extra initial cost of CNG trucks makes the fuel a dubious financial proposition for many operators.

FCA apparently believes it can recoup money spent on converting trucks to CNG, and of course has the new Detroit fueling station to support them.

The company does sell a handful of CNG vehicles to customers as well. They're Ram 2500 heavy-duty pickups converted at the factory to run on natural gas.


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