In industrial gas engines and dual-fuel engines (natural gas and diesel) for the extraction of natural gas and the production of electricity, natural gas is a colorless, odorless, and clean-burning fuel. Natural gas of pipeline quality, which is generally used to heat homes and power automobiles, trucks, and industrial gas engines, typically includes more than 90% methane. Other hydrocarbon gases, including ethane, propane, and butane, as well as inert amounts of carbon dioxide, nitrogen, and hydrogen sulfide, make up the remaining fraction of the gas.