Steam-Injected GT Cycles Offer More Power in a Hot Season

It is said that gas turbine generating plants on simple cycle reduce the power output by 3% in variation with 1% increase of ambient temperature change. When maintaining maximum cycle temperature, i.e., turbine inlet temperature (T4), the reduction of temperature ratio cannot be avoided by increasing minimum cycle temperature, i.e., ambient temperature (T2). Accordingly, the useful power output must be reduced and the thermal energy would be emitted into the atmosphere. The widely used combined cycle plant is an idea to recover the not-used thermal energy into the power, and it is still losing power by 2% in variation with 1% of the ambient temperature. In order to recover effectively such waste thermal energy into the power output, many ideas are adopted to mainly aim the thermal efficiency exceeding 60%, like “Steam-Cooled Combined Cycle”, “Kalina Cycle” etc. It was confirmed that the water/steam-injected WI/GAS3D GT version of modified LM6000 could produce 106 MW with 56% thermal efficiency at ISO conditions ^*6, and it is demonstrated, this time, that the power curve of the plant in variation with ambient temperature is very flat, comparing with those of conventional GT plants. It might be recommended to establish advantageous cycle plants using the more advanced gas turbines derived from like GE90, PW4000, and Trent800, in order to get exceeding 60% thermal efficiency in hot climate conditions, and it would be expected that such technology application might contribute to execute the worldwide COP3 agreement by saving the fossil fuel usage, resulting in minimal CO2 emissions.