The article explores how combining IGCC power generation with a carbon capture system can improve sustainability by reducing greenhouse gas emissions. The researchers used a model to study the impact of oxygen-coal ratio on IGCC performance and found that a ratio of 0.7-0.8 leads to high CO and H2 levels but decreases net power. They also conducted an emergy evaluation under a ratio of 0.8, showing that sustainability increases with higher CO2 taxes. The results suggest that CCS can enhance the sustainability of IGCC systems by lowering CO2 emissions.