Over the past three decades, significant efforts have been made toward the development of cleaner and more efficient technology for power generation. Coal gasification technology received a big thrust with the concept of combined cycle power generation. The integration of coal gasification with combined cycle for power generation (IGCC) had the inherent characteristic of gas cleanup and waste minimization, which made this system environmentally preferable. Commercial-scale demonstration of a cool water plant and other studies have shown that the greenhouse gas and particulates emission from an IGCC plant is drastically lower than the recommended federal New Source Performance Standard levels. IGCC also offers a phased construction and repowering option, which allows multiple-fuel flexibility and the necessary economic viability. IGCC technology advances continue to improve efficiency and further reduce the emissions, making it the technology of the 21st century.