Natural gas is the Rodney Dangerfield of transportation fuels. It's cheap. It's clean. But consumers don't have much of a chance to use it it because there's only one model of natural gas car for sale.

Billionaire investor T. Boone Pickens has been beating the drum the loudest lately about the merits of natural gas as a clean(er) fuel that can also make the U.S. more energy independent. His argument was bolstered this week by the discovery that the U.S. may have 35 percent more natural gas underground than previously estimated.

Natural gas is relatively inexpensive, as the national average price was about 20 percent less than gasoline in April, according to the DOE.

Congress is waking up to the possibilities of natural gas in reducing emissions. House bill 1835, introduced in April, would extend the national excise tax credit that goes to natural gas is due to expire at the end of the year. It would also provide a tax credit for manufacturing and purchasing natural gas vehicles.

While natural gas is a carbon emitting fossil fuel, it is much cleaner than petroleum-based fuels -- even hybrids. For six years running, the road-ready passenger vehicle rated greenest has been the Honda Civic GX, a car that runs on natural gas. The Civic GX carries a $10,000 premium, but a federal tax incentive of $4,000 nearly cuts the gap in half. While there are 120,000 natural gas-powered vehicles in the U.S., nearly all are trucks, buses and fleet vehicles.

One of the reasons more automakers haven't jumped on the bandwagon is the scarcity of refueling stations. California is the only state with more than 100 natural gas refueling stations, and only 1,100 nationwide. Of course if they built the cars, they will come. This may change soon as companies may look to take advantage of federal incentives for building alternative fuel stations.

If at least one of the other big auto manufacturers doesn't jump in and make one of its fleet CNG vehicles available to consumers, you might see a startup try to draft behind Mr. Pickens plan for natural gas vehicles. The technology is already proven; it's just a matter of will.

John Gartner is Editor in Chief of Matter Network and an Industry analyst for Pike Research