Frequently Asked Questions


CNG, or Compressed Natural Gas, is a transportation fuel that can be used in all types of vehicles (cars, vans, and light- and heavy-duty trucks). Natural gas—the same fuel used to heat your home and cook dinner on your stovetop—is compressed and stored in on-vehicle fuel tanks, similar to scuba tanks.

There are three key reasons why CNG is such a compelling fuel option these days. First, CNG offers a cheaper alternative to gasoline and diesel. In fact, in the U.S., CNG typically costs $0.85 to $1.25 less per gallon than gasoline or diesel. In addition, 98% of the natural gas that is consumed in this country is produced in North America, thus lessening our dependence on foreign oil. As an added benefit, using CNG produces fewer harmful emissions than gasoline or diesel, helping to protect our Treasure Valley air quality.

The Honda Civic GX is one of the personal CNG vehicles in the U.S. directly available from the manufacturer. GMC and Chevrolet offer CNG vans for commercial fleets.  In addition, there are three options for converting other vehicles to CNG: 1) Convert a new vehicle, 2) Retrofit an existing vehicle, or 3) Purchase a previously owned CNG vehicle at auction or through a dealer.

Conversions are available through approved Small Volume Original Equipment Manufacturers (SVMs).  Currently, there are about 10 manufacturers offering EPA-certified systems. The number of SVMs continues to increase as new companies take advantage of the aftermarket retrofit opportunities. Visit NGV America for an up-to-date list of EPA-certified retrofitters and the vehicles they can convert.  

A Shift to CNG outreach consultant can help you or your company learn more about vehicle options and conversion costs. For more information or a free assessment, email us.

The net cost of a new CNG vehicle or conversion of an existing vehicle depends on the type of vehicle and the available tax credits. Please contact a CNG outreach consultant via email for a free assessment of CNG vehicle options and costs, as well as potential fuel cost savings and the payback period for upfront vehicle costs.

Two CNG fueling stations are located in Idaho--one in Boise and one in Nampa. Although there is a growing network of CNG fueling stations around the U.S., Many new CNG fueling locations are being built in the U.S. The expectation is that there will be a country-wide network within the next few years. The Department of Energy maintains a list of CNG stations around the country.

Natural gas engines work essentially the same way as gasoline engines. An air-fuel mixture is injected into the intake manifold, drawn into the combustion chamber, and then ignited by a spark plug. Most engine service requirements are very similar and can be handled by a dealer, automotive shop, or trained mechanic. If there is a retrofit repair needed, such as a faulty injector or loose compression fittings, these would be taken care of by the installer.

CNG vehicles are considered as safe as gasoline or diesel powered vehicles. They must pass safety tests just like traditionally fueled vehicles. The National Highway Traffic Safety Administration requires that all CNG fuel storage cylinders have a label stating the date of manufacture and the date the cylinder is required to be removed from service (typically 15-20 years). The label also instructs the owner/operator to have a qualified visual inspection of the tank every 36,000 miles or 3 years (whichever occurs first), as well as after an accident or fire.

Generally, vehicle warranties offered by the original automotive manufacturer are not impacted by the installation of an engine retrofit system certified by the EPA. The engine warranty for all items related directly to the retrofit system is covered by the retrofit system manufacturer. In addition, the federal government requires that the retrofit system manufacturer warranty cover all the major emissions-related components of the vehicle (including the catalytic converter) for the vehicle’s useful life. Useful life varies between vehicles—for most manufacturer warranties, a sedan’s useful life is considered to be eight years/80,000 miles and a pick-up truck’s is eight years/110,000 miles.