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,
South African gas-electric locomotive experiment. Combustion gases, rich in carbon monoxide and known variously as water gas, producer gas and mond gas, are generated by passing air and steam through some kind of red-hot burning carbonaceous fuel, usually coal. The gas generator consists of a combustion portion, where the fuel is initially burned to generate the required steam. The steam is then blown through this same burning fuel, taking air with it, and the producer gas is then liberated as a by-product of this combustion. Ordinarily, burning produces carbon dioxide, but by forcing steam through the burn a certain amount of incomplete combustion is