Long-term Transmission Availability Analysis of Thermal Power Plants Considering North-South Transmission Constraints

In response to the global climate crisis, South Korea is pursuing reductions in coal-fired power generation and expansion of renewable energy to achieve its 2050 carbon neutrality goal and Nationally Determined Contributions (NDC). This calls for a quantitative assessment of the long-term operational viability and timing of business transition for thermal power plants. This studyproposes a method for assessing the long-term transmission capacity of thermal power plants located along the North-South Power Flow Corridor, which supplies renewable energy from the Honam region and the southwestern maritime region to the Seoul metropolitan area. The study explicitly incorporates renewable energy site selection and North-South transmission constraints into the analysis. The analysis reveals that the transmission capacity of the targeted coal-fired power plants decreases by approximately 30.63-47.31% during daytime hours, when renewable energy output is concentrated, while it increases by approximately 1.2% during early morning and late-night hours. Furthermore, the maximum daily and annual combined transmission capacity was derived, and the patterns suggest that the transmission capacity of coal-fired power plants can vary significantly depending on the timing of grid reinforcement and the pace of renewable energy expansion. These results provide quantitative basis and key parameters for developing investment strategies for the closure, conversion, or continued operation of coal-fired power plants.