In March, the U.S. Senate narrowly defeated a bill that would have provided billions of dollars in tax credits to boost deployment of natural-gas-powered vehicles. That won’t stop billionaire energy magnate T. Boone Pickens, who championed the plan. He still believes natural gas is the best way to help America reduce its dependence on foreign oil. Some 112,000 natural-gas vehicles — mostly trucks and buses — already occupy America’s roads, about 1% of the total. The bill in theory would have added some 700,000 more natural-gas-powered vehicles over the next decade and displaced more than 20 billion gallons of fuel, about 53 days’ supply. Backers say an amended bill will be resubmitted.

Despite wide adoption overseas, Honda’s Civic Natural Gas, starting at $26,155 (compared with $15,805 for a gasoline model), is the lone natural-gas passenger car on the U.S. market today, and the company sells only a couple thousand a year. But ample supplies of cheap natural gas should prompt many to take a harder look at this promising fuel.

Sources: CIA World Factbook; NGV Communications Group

For more on the Wheels of Tomorrow, click on the links below

Intro
Electrics
Self-driving cars
Fossil fuels
7 electric cars for the future
Why Boone Pickens loves gas

This story is from the April 9, 2012 issue of Fortune.