On the CHP Flexibility Expansion in the Power System with High Share of Variable and Nuclear Generation

Abstract

Climate change has impacted our energy supplies and electricity infrastructure, and in response, the Korean power sector is rapidly increasing the share of renewable energy. However, the output of renewable energy has variability and uncertainty. Furthermore, the Korean generation mix has a large share of nuclear power plants and combined heat and power (CHP) plants. A CHP plant in the heat supply mode is an inflexible resource. Therefore, flexibility expansion of the CHP and its economic effects analysis are required. In this study, we classify the CHP's flexibility as 1) turbine-governor response, 2) ramping-up/down capability, and 3) reduction of heat-constrained minimum output level. Various scenarios based on the CHP flexibility are set up and unit commitment simulations are performed for the economic analysis. Based on the simulation results, it is determined that securing the primary reserve in the heat supply mode has the greatest effect on the generation cost savings. © 2023 IEEE.