Now that this past summer's oil-price shock has awakened a new desire in Americans to find a cheaper way to fill up, we should finally see a larger-scale movement toward a fuel that's not only less expensive than gasoline but is also cleaner burning and sourced largely from within North America: compressed natural gas (or CNG). Yes, good old natural gas - the same stuff that provides heat to 52 percent of American homes - also works as a fuel for cars, and the good news is that the technology to make it happen already exists.
More than 95 percent of the natural gas used in the United States comes from domestic or other North American sources, so prices aren't subject to sudden spikes caused by political instability. Natural gas is an abundant resource. In rough terms, there are estimated to be about forty years of known crude oil reserves worldwide versus eighty years of natural gas reserves.
Moreover, natural gas can be a renewable source of energy. Natural gas is a biogas that can be produced from livestock waste, agricultural waste, human waste, and garbage. Already, some landfills have adjacent electrical power stations that use methane emissions as fuel.
Switching to natural gas also helps the environment. Compared with burning gasoline or diesel, using natural gas reduces a whole panoply of emissions, including nitrogen oxide (NOx), carbon dioxide (CO2), carbon monoxide (CO), and particulate matter.
Even some of today's gasoline vehicles can be converted to run on CNG, although such conversions are not the province for backyard mechanics, nor are they cheap. CNG conversion requires an onboard fuel-storage and delivery/injection system to be installed in place of the gasoline-use components. CNG vehicles use fiberglass-girdled steel tanks (they look like large scuba tanks) that are rated at up to 3600 psi and are refueled at dedicated locations.
Producing dedicated CNG vehicles is something the automobile industry already knows how to do. Nationwide, there are currently more than 120,000 vehicles running on CNG. That's a tiny fraction of America's rolling stock, but numerous fleets run on it. Today, only one CNG-powered vehicle is marketed directly to consumers, the Honda Civic GX, which is available in New York and California. Rated America's "greenest vehicle" by the American Council for an Energy-Efficient Economy, its sticker price of $25,760 is about $7000 more than a comparable gasoline Civic and $1540 more than a Civic Hybrid, but federal tax credits can help offset some of the extra cost.
From 1997 to 2005, Ford, Chevy, Dodge, and Toyota all offered CNG options. In the used-car marketplace, these dedicated-CNG vehicles are enjoying a growing following among shoppers on eBay and Craigslist.