Facing the demand for deep peak shaving of power grids under the background of renewable energy consumption

increasing the peak shaving range has become an indispensable part of the development of gas turbines. An offshore hydraulic energy storage coupled gas turbine power generation system was proposed. Mathematical modeling and solving of a 11 410 kW gas turbine and energy storage system were carried out to obtain the operating characteristic curves of pump turbine under all operating conditions. The influence of output load ratio of gas turbines on the performance of the coupling system was analyzed. Moreover

the performance of the coupling system was compared with that of the conventional gas turbines. The research shows that

the optimal operating efficiency of the pump turbine reaches 72.88% when the head is 245 m under the designed filling and drainage flow rate. The peak shaving depth of the coupled system reaches 81.54%

which is 11.54% higher than that of the reference gas turbine unit. When the relative demand loads are equal

the operating efficiency of the coupled system is significantly higher than that of reference gas turbines. The output power and operating efficiency of the coupled system increases first and then decreases with the rise of the demand load

and reaches a peak at 9 336.98 kW and 25.98% at relative demand load of 0.52. Under delay-step demand load

the daily average efficiency of the coupling system gradually increases with the decrease of the peak-to-valley ratio and is comparatively higher than that of reference gas turbines. The relative efficiency increases with the decrease of the peak-to-valley ratio or increase of the valley charge frequency.