<P> Combined cycle power generation using natural gas is currently the cleanest available source of power using hydrocarbon fuels, and this technology is widely and increasingly used as natural gas can be obtained at increasingly reasonable costs . Fuel cell technology may eventually provide cleaner options for converting natural gas into electricity, but as yet it is not price - competitive . Locally produced electricity and heat using natural gas powered Combined Heat and Power plant (CHP or Cogeneration plant) is considered energy efficient and a rapid way to cut carbon emissions . </P> <P> Natural gas generated power has increased from 740 TWh in 1973 to 5140 TWh in 2014, generating 22% of the worlds total electricity . Approximately half as much as generated with coal . Efforts around the world to reduce the use of coal has led some regions to switch to natural gas . </P> <P> Natural gas dispensed in a residential setting can generate temperatures in excess of 1,100 ° C (2,000 ° F) making it a powerful domestic cooking and heating fuel . In much of the developed world it is supplied through pipes to homes, where it is used for many purposes including ranges and ovens, gas - heated clothes dryers, heating / cooling, and central heating . Heaters in homes and other buildings may include boilers, furnaces, and water heaters . Both North America and Europe are major consumers of natural gas . </P> <P> Domestic appliances, furnaces, and boilers use low pressure, usually 6 to 7 inches of water (6" to 7" WC), which is about 0.25 psig . The pressures in the supply lines vary, either utilization pressure (UP, the aforementioned 6" to 7" WC) or elevated pressure (EP), which may be anywhere from 1 psig to 120 psig . Systems using EP have a regulator at the service entrance to step down the pressure to UP . </P>

What is the percentage of methane in natural gas