Natural gas vehicle gas has the highest energy/carbon ratio of any fossil fuel, and thus produces less carbon dioxide per unit of energy. The major difficulty in the use of natural gas is transportation. Natural gas pipelines are economical and common on land and across medium-length stretches of water (like Langeled, Interconnector and Trans-Mediterranean Pipeline), but are impractical across large oceans. Liquefied natural gas (LNG) tanker ships, railway tankers, and tank trucks are also used. CNG is typically stored in steel or composite containers at high pressure (3000 to 4000 psi, or 205 to 275 bar). These containers are not typically temperature controlled,
Oil shale gas and oil shale gas usually occurs as a byproduct of shale oil production. The ratio of oil shale gas to shale oil depends on retorting temperature and as a rule, increases by the rise of temperature. There is no exact formula of oil shale gas. Compositions of oil shale gas depends of retorted oil shale and exploited technology. Typical components of oil shale gas are usually methane, hydrogen, carbon monoxide, carbon dioxide, nitrogen, and different hydrocarbons like ethylene. It may also consist of hydrogen sulfide and other impurities. Oil shale gas has served as a substitute for natural gas. In