Compressed natural gas, or CNG, as an alternative to gasoline for vehicle fuel is not new, but CNG has enjoyed growth in popularity in recent years, particularly in fleet vehicles. If you're considering a CNG vehicle in the future or just wondering why your city has invested in a fleet of CNG buses, read on for basics on this alternative fuel.What is CNG?
CNG is made just like its name implies, by compressing natural gas till it becomes less than 1 percent of its volume at standard atmospheric pressure. CNG itself is mostly methane and as such, is virtually odorless, tasteless and colorless.
How prominent is its use as a vehicle fuel?
While the American Natural Gas Alliance and other industry proponents estimate that more than 12 million vehicles are powered by CNG today, don't expect to see many of those in the U.S. In fact, probably only about 110,000 CNG vehicles are in use in this country. And while the U.S. is seeing an increase in CNG vehicle use—to the tune of about 3.7 percent more each year—that's hardly impressive compared to the global growth rate of about 30.6 percent.
Why aren't there more CNG vehicles in the U.S.?
While there are a number of reasons why CNG vehicles have not been as popular in the U.S. as they have been in other parts of the world, most industry experts would agree that infrastructure is one of the biggest hurdles faced. Expanding the numbers of CNG fueling stations would allow for the increase of CNG vehicles on U.S. roads. Worldwide, the industry estimates thee are about 12,000 fuelding stations, but here in the the U.S., that number drops dramatically to only about 1,100 and they are not spread evenly across the country, so some regions are at a greater disadvantage than others when it comes to promoting natural gas vehicle use. So before you buy, be sure to consult with the U.S. Department of Energy's list of available CNG fueling stations to see what options are available in your area. If you have availability to a natural gas line, you might also consider a CNG fueling station at home.
Are there environmental drawbacks to CNG?
Like many fuels, CNG has its advantages and disadvantges. On the positive side, it's odorless, colorless and tasteless. Because it dissipates into the air when spilled rather than pooling on the ground, proponents say it's safer than gasoline in the event of an accident. It is also known to emit fewer emissions and to have a high ignition temperature. But there are also some environmental concerns. Natural gas extraction—particularly when utilizing a technique known as fracking—can have environmental consequences, causing some regions of the country to limit the types of techniques used for its extraction due to concern over environmental contamination. This concern could impact future supplies of natural gas for vehicle use, limiting the growth of CNG vehicles in the U.S.