Clean coal refers to the process of reducing carbon emissions and other harmful pollutants that arise from the burning of coal for power generation to the minimum possible level. SC, USC, and IGCC technologies are clean coal technologies that are widely used for setting up new-build coal-fired power plants. The more sophisticated the technology, the higher the steam pressure and temperature requirement is for operating the plant. As a result, the thermal efficiencies improve with the usage of more sophisticated technology. As well as these three technologies, CCS is also an upcoming technology, which is capable of reducing carbon emissions drastically by 80-90 percent. This technology is used in conjunction with SC, USC or IGCC plants.