A gasification system including a gasifier operable to produce, from a carbonaceous feedstock, a gasification product gas comprising hydrogen and carbon monoxide, a Fischer-Tropsch synthesis reactor configured to produce Fischer-Tropsch synthesis products and a Fischer-Tropsch tailgas from a first portion of the gasification product gas, and power production apparatus configured to generate power from a second portion of the gasification product gas, at least a portion of the Fischer-Tropsch tailgas, or both. A method for operating the system is also provided.