The Combined Cycle Plant (CCP) offers the best solutions to curb air pollution and the greenhouse effect, and it represents today the most effective heat engine ever created. At Graz University of Technology work is being conducted in close cooperation with industry to further enhancement of CC systems with regard to raising output and efficiency. Feasibility studies for intake air climatization, overload and part-load control, introduction of aeroderivate gas turbines in conjunction with high-temperature steam cycles, proposals for cooling, and the use of hydrogen as fuel are presented.