Study on effects of improving flexibility of thermal power generators on supply-and-demand control in case of high penetration of renewable energy sources

Flexibility expresses the extent to which a power system can change electricity production (supply) or consumption (demand) in response to variability and uncertainty. Introduction of renewable energy sources, such as photovoltaic and wind turbine, increases variability and uncertainty and might cause supply-and-demand imbalance. Therefore, a coun-termeasure for improving flexibility is needed. In this paper, flexibility of thermal power generators is evaluated by using the simulation model which can calculate the supply-and-demand imbalance. The parameters of operation/planning and equipment modification are changed in the simulation. Flexibility parameters regarding operation/planning include supply capacity"and spinning reserve". The flexibility can be improved as these reserves are changed properly. Flexibility parameters regarding equipment modification include ramp-rate", minimum output", minimum operating time", minimum shutdown time"and duration of start-up process". The flexibility is high as ramp-rate"is fast, minimum output"is small, minimum operating time"is short, minimum shutdown time"is short, and duration of start-up process"is short. The simulation results reveal that flexibility can be improved by changing operation/planning and equipment modification. © 2021 The Institute of Electrical Engineers of Japan.