When it comes to green technology, Volkswagen is hedging its bets.

In addition to promoting its line of TDI diesels, the German carmaker is launching hybrids like the Jetta Hybrid and electric cars like the e-Golf.

Now, VW is looking as well to another oil alternative: natural gas.

The company is considering selling natural-gas-powered cars in the United States, the Detroit News reports.

VW is asking the EPA to help develop the refueling infrastructure for compressed natural as (CNG).

Few natural-gas stations

2012 Honda Civic Natural Gas

2012 Honda Civic Natural Gas

Volkswagen hopes to take advantage of the large supply of natural gas in the U.S., but feels that without a network of refilling stations, CNG car ownership would be impractical.

As it is, natural-gas cars lose a great deal of storage space to the large, high-pressure tanks required to store enough of the compressed gas to provide ranges of 200 miles or more.

And few natural-gas fueling stations exist today; the U.S. has roughly 1,000 in total, but only about half of them are open to the public. That compares to more than 100,000 gasoline stations.

It's a similar dilemma to the one faced by makers of plug-in and hydrogen fuel-cell cars, which are hindered by a lack of charging and fueling stations, respectively.

The offset for plug-ins is that they can be charged from a home's electricity supply, whereas home fueling equipment has not yet been widely deployed for the half of American homes that use natural gas for heating or hot water.

Urging regulatory change

To solve the problem, Volkswagen is urging the EPA to promote the use of CNG.

It's part of an overall effort by VW to encourage alternatives to electrification; its Audi unit has made a similar effort to encourage diesel-friendly regulations, though Volkswagen CEO Martin WInterkorn has also said it will dominate hybrid and electric car sales by 2018.

Volkswagen has been selling CNG cars in Europe for 10 years; the CNG model accounts for 10 percent of Up city car sales. Corporate sibling Audi showed a CNG-powered A3, the A3 g-tron, at the 2013 Geneva Motor Show, even producing its own "e-gas" fuel for the car.

The only CNG car currently sold in the U.S. is the Honda Civic Natural Gas; it's also available on fleet and commercial vehicles.

Natural-gas industry gets in gear

Natural-gas vehicle prototypes, Los Angeles, May 2013 - group shot at Playa del Rey storage field

Natural-gas vehicle prototypes, Los Angeles, May 2013 - group shot at Playa del Rey storage field

Still, Volkswagen isn't alone in promoting CNG.

The natural gas industry has developed prototype vehicles that use gasoline as a range-extender, Chevrolet Volt-style. The vehicles are designed to be used in regions where natural gas is plentiful, so they can be topped off with CNG at home.

Earlier this year, a U.S. Senate bill was introduced to boost CAFE ratings for these cars, encouraging their production.

Volkswagen will not use this dual-fuel technology; it will most likely convert an existing production model to CNG.

Even if CNG cars don't work out, VW will still have plenty of other green cars in its lineup: It will have 14 plug-in electric cars and hybrids on sale by next year, and says it could offer 40 of them if customers show interest.

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