gasoline engines. These included the Hyundai Accent, Kia Rio/Rio 5, Mazda3 (pictured), and the Chevrolet Cobalt. The Honda Civic GX, which placed second, uses natural gas.

It isn't "buying" the fuel per se, rather it has rights to research the fuel's performance in racing and other use cases. So the "price" is unknown, but expensive (roughly $45/gallon).

[Source: NADAguides.com] You Can Be 'Green' with Gasoline, Says NADAguides.com COSTA MESA, Calif., July 19 /PRNewswire/ -- Everybody is going green these days, especially in the automotive world.