US Patent 7281590 Environmentally friendly method for generating energy from natural gas

The invention relates to an environmentally friendly method for generating energy from natural gas. Through the combustion of the natural gas with a mixture comprising substantially oxygen and CO2, a number of advantages are achieved with regard to the emission of CO2 and NOx. According to the invention, the CO2-rich product gas is injected into a natural gas reservoir from which natural gas has been extracted. By the underground replacement of natural gas by CO2, a pressure drop in the natural gas reservoir can be controlled, so that subsidence is prevented. Additionally, in this manner, the emission of CO2 is reduced or even wholly prevented.