Incremental vs. lifecycle price: NGVs, similar to other alternatively fueled vehicles, have a higher sticker price than a conventional vehicle. This accounts for the natural gas storage tanks and other NGV-specific components. However, because the fuel is approximately $2/gallon cheaper than gasoline or diesel, the cost savings over the life of the vehicle can make up for the initial investment and save owners money over the vehicle’s lifecycle. The return on investment will correspond directly with the amount of fuel used—the more fuel used, the bigger the return on investment. In addition, the State of Colorado offers up to $6,000 for the purchase of a new light or medium duty NGV, or the CNG conversions of an older vehicle to natural gas.
Vehicles currently running on petroleum can convert to natural gas using qualified retrofitters. CNG conversion (NGV conversion) kits are available for many types of vehicles, from pickup trucks to transit buses, and many allow for bi-fuel operation. Conversion costs vary significantly depending largely on the size of the vehicle tanks (Source).