Natural Gas Myths
1. Cars running on natural gas are only available for fleets.
Natural gas is normally used in the U.S. to generate electricity, heat houses and businesses, and as a component in a variety of industrial processes. In the United States, a very small amount of natural gas—just one-tenth of 1% of all gas consumed—is also used as a fuel for vehicles. Traditionally, CNG vehicles have been used in private and government fleets, but private citizens also own some of these vehicles.
According to the Natural Gas Vehicle Coalition, there are more than 120,000 CNG vehicles in use in the United States, and nearly 9 million worldwide.
If you're thinking of joining the league of CNG drivers in the U.S., your choice of new vehicles is limited to one: The Honda Civic GX, a natural gas-powered version of the Civic. Compared with a Civic Hybrid, you'll pay about $3,000 more for the Civic GX, although you'll be eligible for a $4,000 tax incentive. (Buyers of the Civic Hybrid receive no tax credit, because Honda has reached the cap for hybrid credits.) In addition, CNG vehicles such as the Civic GX are eligible for most of the same parking and carpool lane privileges as hybrids; in many states, CNG vehicles were using HOV lanes long before hybrids were eligible and after hybrid carpool lane stickers ran out.
Is it possible for individuals to pump CNG into their vehicle from home? Yes. FuelMaker developed Phill, the world's first home-based fueling appliance, which can be mounted to a garage wall, indoors or outdoors, to allow natural gas-powered vehicles to be refueled overnight directly from a homeowner's existing natural gas supply line.
2. CNG cars beat out hybrids on emissions.
This is only a partial myth. Natural gas, which is 90 percent methane, has a much higher octane rating than gasoline, allowing for higher compression ratios and therefore greater efficiency in the engines that use it. Natural gas burns so cleanly that CNG vehicles rival hybrids in producing extremely low levels of smog-forming pollutants. The Honda Civic GX, which burns CNG, is the perennial winner of green car awards.
However, CNG vehicles tend to have higher greenhouse gas emissions than hybrids. The CNG version of the Civic, for example, emits nearly 30 percent more greenhouse gases than the Civic Hybrid during a typical year of driving.
3. CNG cars are cheaper to run than conventional vehicles.
As petroleum prices erratically jump up and down and up again, it's tempting to look at compressed natural gas as an economic alternative. Buyer beware: the math is tricky.
Since CNG is normally sold as a gas rather than a liquid, it isn't measured in gallons, but can be converted on an energy basis that equals a gallon of gasoline. The term used for this conversation is GGE, or "gallon of gasoline equivalent."
When gasoline was about $2.25, the average price of CNG in the United States was $1.99 per GGE. While a 24 cent-per-gallon price advantage sounds attractive, CNG vehicles have lower fuel efficiency than hybrid vehicles. A Civic GX, for example, averages 32 mpg, while a Civic Hybrid is rated at 43 mpg. So while a GGE of CNG is cheaper, the Civic GX needs more fuel to operate, and therefore costs per mile are actually higher.
4. Pumping CNG into your car, and driving around with a gas-based fuel, is dangerous.
CNG is as safe, if not safer, than liquid gasoline. Although CNG is a flammable gas, it has a narrow flammability range. If released in an accident, CNG disperses rapidly, making it less likely to ignite than gasoline. CNG is also non-toxic.
The prospect of a flammable gas leaking into your garage when you are filling up, and causing an explosion or flash fire is certainly disconcerting. But according to U.S. Department of Energy studies, the annual probability of an explosion or other deflagration when the filling equipment is used properly is 1 in 7 million. An individual is 10 times more likely to be struck by lightning. Even if the system is intentionally misused, an individual is still more than twice as likely to be struck by lightning than for the Phill home refueling station to cause a deflagration.