Mitigation of peak oil is another alternative, and combined cycle power generation using natural gas is the cleanest source of power available using fossil fuels, producing about 30% less carbon dioxide than burning petroleum and about 45% less than burning coal. The major difficulty in the use of natural gas is transportation and storage because of its low density. Natural gas pipelines are economical, but are impractical across oceans. Due to its high energy density and ease of handling, oil has a unique role as a transportation fuel. There are, however, a number of possible alternatives. Among the biofuels the use of bioethanol and
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