Natural gas is a gaseous fossil fuel composed mainly of methane (CH4). It is formed alongside oil fields and coal beds. Natural gas burns with relatively low emissions and can be safely stored, making it a convenient and efficient source of energy for heating and electricity generation.
Natural Gas Formation and Extraction
The most common source of natural gas are oil fields and natural gas fields. Fields are a result of anaerobic (oxygen-lacking) digestion of dead plant matter deep under the Earth's surface. Much like oil, natural gas is drilled for, then pumped to processing stations. Processing stations will remove "heavy hydrocarbons" such as butane and propane to ensure that the gas burned will emit low pollution.
Natural gas can also be released from coal through the process of coal gasification. In coal gasification, coal is exposed to high temperatures and pressures in order to break it apart into gaseous components. However, cost is a main deterrent of this process.
There has also been research into capturing methane produced from landfills and biogas from cattle.
Generating Power from Natural Gas
Electricity is produced from natural gas similar to a way coal generates energy. Natural gas is burned to release heat, which boils water and creates steam. The pressure from the steam is used to turn a turbine and a generator. The efficiency of this process can be further increased by using a combined cycle system. This system uses a natural gas fuel turbine, along with heat-recovery generator and steam turbine. As a result, 60% of heat from natural gas can be harnessed to generate electricity.
Natural gas is the cleanest burning of all the fossil fuels, though its higher cost prohibits more widespread use. Since we rely less on natural gas for power generation, it may outlast coal and oil. Yet natural gas remains a non-renewable energy source making its long-term viability limited.