The major challenges confronting thermal power technology, namely improvement in thermal efficiency, utilization of coal and reduction of pollution, come from future environmental and resource constraints. Recently, steam temperature of the steam turbine plant has began to climb to 600°C after thirty years stagnation at 566°C. Improvements of key support technology in the areas of metallurgy, aerodynamics and cycle chemistry are necessary. Gas turbines enable us to introduce a higher temperature heat cycle on the conventional steam cycle. Operating gas temperature is increasing to 1300°C, and in the next decade, it will reach to 1500°C. Blade cooling methods and high temperature materials are the key to high temperature gas turbines. Clean coal technologies such as fluidized bed combustion (FBC) and integrated coal gasification combined cycle (IGCC) will come into practical use in the near future. In a more distant future, we may expect to see very high temperature systems. However, we must bear in mind the fact that the steam water cycle will be likely to perform an important role as a basic heat cycle in any future technology.