Of all the fossil fuels, natural gas has the lowest specific CO2 content. Combined cycle power plants (CCPPs) using natural gas have the highest efficiency of all fossil fuel-fired power plants because they generate electricity in two stages from both (exhaust) gas and steam. These are therefore alternatively known as combined cycle gas turbine plants (CCGT plants). They require very little time from standstill to full load and thus flexibly supplement the fluctuating electricity generated from renewable energies. These technological strengths face certain limits, however, in terms of availability and the economic dependence on natural gas.
Global natural gas reserves are concentrated in just a few supply countries such as Russia and the Arabic countries. However, even with increased production they will still last for much more than 50 years. (Source: BGR)