High Quality Content by WIKIPEDIA articles! An integrated gasification combined cycle (IGCC) is a technology that turns coal into gas—synthesis gas (syngas). It then removes impurities from the coal gas before it is combusted and attempts to turn any pollutants into re-usable byproducts. This results in lower emissions of sulfur dioxide, particulates, and mercury. Excess heat from the primary combustion and generation is then passed to a steam cycle, similarly to a combined cycle gas turbine. This then also results in improved efficiency compared to conventional pulverized coal.