A method for producing energy including: producing fuel gases from biomass raw material in a main receptacle unit (8), feeding produced fuel gas to a consumer unit (2,3), transferring energy from the consumer unit to at least one energy user (7). The method includes recovering heat and producing pressurized superheated steam, intermittently loading biomass raw material into at least one vessel (8′), being included in the main receptacle unit (8), pressurizing the loaded at least one vessel (8′) with pressurized superheated steam, passing pressurized superheated steam through the loaded and pressurized at least one vessel (8′), thereby contacting and heat treating said biomass raw material with the pressurized superheated steam for the production of said fuel gases, supplying produced fuel gases together with still superheated steam to the consumer unit (2,3). The invention also concerns a plant.