Abstract: Hydrocarbonaceous fuel, such as coal, oil or gas, is gasified to produce syngas comprising H2 and CO, scrubbed free of particles, and saturated with water. The syngas is then treated in an acid gas removal unit as desired to remove any impurities in the syngas. After processing the syngas in the AGR, it is routed to a hydrocarbon synthesis reactor. In the hydrocarbon synthesis reactor, the bulk of the H2 and CO in the syngas is converted to synthetic hydrocarbons, the makeup of which is generally dependent on the type catalyst used in the reactor. The unreacted gas, or tailgas, exiting the reactor, is sent to the gas turbine as fuel. Optionally, N2 or natural gas can be added to the tailgas prior to the combustion turbine. N2 may also optionally be mixed with the hydrocarbon synthesis reactor feed to help control the reaction temperature. After being combusted in the combustor of a gas turbine, the combustion products are expanded to produce power.