Don’t know the difference between CNG and C-3PO? We’re here to help. Here, we translate alternative-fuel jargon into language that’s easy to understand, and we tell you who can and can’t use it. You can also find stations that carry the gasoline substitutes mentioned here using the Alternative Fuels & Advanced Vehicles Data Center’s handy locator website at afdcmap2.nrel.gov/locator/.
By Z.C

ETHANOL Made mostly from corn or sugarcane (for vehicular use, it’s known asE85 -- 85 percent ethanol, 15 percent gasoline). Many major carcompanies have models that can run on E85 and conventional fuel;they’re called flexible-fuel vehicles (FFVs).

BIODIESEL Created from vegetable oils and animal fats. Various blends of the fuelare denoted with a B followed by a number, indicating the amount ofbiodiesel present. (B99 contains 99 percent biodiesel and 1 percentpetroleum diesel.) Side effect: It might make you hungry for acheeseburger and fries. All diesel engines can use biodiesel, though itis not recommended that older diesel engines (pre-1993) operate onhigher blends of biodiesel.

COMPRESSED NATURAL GAS (CNG) It’s natural gas that has been … compressed. We won’t pretend tounderstand the science behind CNG, but we can tell you it takes a lotof room to store. Your choices are limited: The Honda GX CNG is theonly dedicated natural gas vehicle, though other cars can be modifiedto use it.

PROPANE Also known as liquefied petroleum gas. The Roush F-150 pickup truck --the only dedicated propane-powered vehicle on the market -- wasreleased during the 2007 model year, but most cars can use it ifthey’re properly retrofitted. Depending on where you live, it’s alsoplentiful.

HYDROGEN The gold standard for alternative fuels, hydrogen releases no harmfulpollutants into the air beyond water vapor. It’s versatile, too, ableto be used in electric vehicles or burned in traditional internalcombustion engines. Alas, it’s expensive to produce and only a handfulof cars (the new Honda FCX being one) use it. Unless your name rhymeswith “Shmeorge Shlooney,” it’s going to be a while.

ELECTRICITY Pretty much the same story as hydrogen -- clean, versatile, andpractically a rumor. There are plenty of gas-electric hybrids, inaddition to a variety of smaller, all-electric models (calledneighborhood-electric vehicles) or low-speed vehicles that have beenavailable for several years. But full-speed, purely electricautomobiles are a few years from being a common sight on the highway.