The present disclosure relates to a power production system that is adapted to achieve high efficiency power production with carbon capture when using a solid or liquid hydrocarbon or carbonaceous fuel. More particularly, the solid or liquid fuel first is partially oxidized in a partial oxidation reactor that is configured to provide an output stream that is enriched in methane content. The resulting partially oxidized stream can be cooled, filtered, additionally cooled, and then directed to a combustor of a power production system as the combustion fuel. The partially oxidized stream is combined with a compressed recycle CO2 stream and oxygen. The combustion stream is expanded across a turbine to produce power and passed through a recuperator heat exchanger. The recycle CO2 stream is compressed and passed through the recuperator heat exchanger and optionally the POX heat exchanger in a manner useful to provide increased efficiency to the combined systems.