Abstract: A method including obtaining biogas, treated water and oxygen from sewage and various wastes; feeding a boiler: in a first step, with biogas and oxygen, and in a second step, with treated water supplied at a very high pressure to the injectors of the boiler, while maintaining an input of biogas; producing superheated steam at a temperature above 650° C. and low humidity in a heat exchanger heated by the boiler; driving, by the produced steam, a steam turbine connected to an electric generator; and condensing the steam from the turbine and recirculating it to the heat exchanger.