Combined cycle power (CCP) plant using LNG is the one of highly efficient and clean energy generation systems, and plays key role in domestic electric supply including nuclear and coal power generation systems. In Korea, LNG based CCP is categorized in peak load facility rather than base load facility. Due to this, the operability is relatively low. However, if the operability increases it can also contribute to energy economy by producing electricity using more efficient systems. Furthermore, if the price of shale gas drives the reduction in LNG price in the future, its benefit will be much greater than the present application.

Power reduction of gas turbine during summer can be recovered by max 75% if gas turbine intake cooling system can be implemented in existing LNG based CCP plants. Furthermore, steam injection, turbine cooling air precooling and turbine case cooling technologies can be considered for enhancing power and efficiency of CCP plants. Such approaches are being widely studied in global gas turbine society.

The present study aims to investigate net benefit of implementing advance technologies for enhancing power and efficiency of existing LNG based CCP considering the recent shortage of domestic power generation. For performance comparison, (1) gas turbine intake cooling system, (2) steam injection, and (3) turbine cooling air precooling technologies are implemented to Busan LNG CCP plant. The cycle of gas turbine and also CCP plant are modeled using Gatecycle. To validate the cycle model, the analysis results are compared with the operation data of the CCP plant and it matched well within max 3%.

Among those technologies, steam injection showed net increase of 7.8% on both of power and efficiency of gas turbine. However, at CCP plant level, the net benefits are just around 1.3%. The power and efficiency gains from other technologies are less than steam injection. These results are somehow considerably lower than what had been reported in the literatures. Some technical literatures reported the potential net increase of 20%~40% in power with max 6% increase in efficiency applying gas turbine intake cooling and steam injection.