CNG is a high pressure form of natural gas , the same fuel that is used in many households for cooking and heating. It is a combustible, gaseous mixture of simple hydrocarbon compounds, usually found in reservoirs formed by porous rock 3,000 to 15,000 feet below the earth s surface. Natural gas is an independent fossil fuel, it can also be found with crude oil.
Natural gas is abundantly available in North America.
Because natural gas is a fossil fuel, there is a finite supply with reserve estimates of 120 years at current levels of consumption. Natural gas has been used for many years in stationary internal combustion engines with high efficiency and reliability. Because of its domestic availability, low cost, and clean-burning combustion characteristics, it has become one of the leading alternatives to gasoline and diesel as a motor vehicle fuel. The major difficulties with natural gas in transportation applications have been onboard fuel storage and vehicle range. Because of its very low energy density, natural gas must be either compressed or liquefied, increasing its energy density, to make it a viable transportation fuel.