Session: 15-13

Paper Number: 135808

135808 - Seasonal-Weekly Energy Mix Simulation Model for Carbon Neutrality Incorporating Nuclear and Renewable Energy 

Abstract: 

To cope with drastic climate change, it is important in the energy sector to derive a national energy mix which can meet the carbon neutrality goal. The previous Government of South Korea announced the 2050 Carbon Neutrality Scenarios in 2021 highlighting the role of renewable energy. The current Government is planning to expand the nuclear energy sector, emphasizing its role in carbon neutrality with new a initiative, CF100 (Carbon Free 100) Policy. In this context, technical and economic analysis for various scenarios is essential for the future to compare and validate the energy policies based on numerical data and logical reasoning. However, the existing methodologies based on Long Duration Curve (LDC) or Screening Curve (SC) with integrated analysis of 8,760 hours cannot fully reflect the variability of the current electric system. In this regard, the authors have previously developed a seasonal-daily electricity supply-demand simulation model and analyzed the South Korea’s 2050 Carbon Neutrality Scenario with other scenarios containing different energy mix. The seasonal-daily model, though, did not reflect the day-to-day deviation as it averaged out the whole season in one day, and applied the simplified assumption of producing hydrogen only with the daytime excess power. In this study, therefore, we advanced our previous simulation model into a seasonal-weekly supply-demand model, applying the change of power supply-demand in a week. The new model deals with a volatility of each season’s week, thereby reflecting the weekday-weekend difference in generating and consuming electric power. Also, hydrogen is assumed to be produced for 24 hours, while the seasonal demands are adjusted in accordance with the excess power each season has. These properties enable us to assess the specifics of day-and-night asymmetry in the generation and consumption of electric power, allowing to calculate the necessary amount of ESS capacity and reasonable distribution of power demand for hydrogen production in a more realistic way. The scenarios analyzed in this study are categorized in accordance with the relative ratios of nuclear and renewable energy (from 3:7 as Scenario 1 to 7:3 as Scenario 5). All scenarios assume a daily asymmetry of power supply-demand to be covered by Energy Storage System (ESS), Pumped Storage Hydropower (PSH) and carbon-free gas turbine, with weekly asymmetry covered by ESS and carbon-free gas turbine and seasonal asymmetry by changing the demand of hydrogen production in the electric system. The economic analyses were performed by calculating the investment cost and the generation cost. The investment cost is estimated to be 1,886.9 trillion KRW (1,432 billion USD) in Scenario 1 and 920.8 trillion KRW (707 billion USD) in Scenario 5. The generation costs were also calculated as 218.4 KRW/kWh (0.167 USD/kWh) in Scenario 1 and 137.4 KRW/kWh (0.105 USD/kWh) in Scenario 5. In addition, the system stabilities of each scenario were also analyzed; the dominant ratio of nuclear energy over 50% would lead the overproduction of the electricity in the nighttime, while the increased ratio of renewable energy over 40% would cause the negative demand in duck curve (meaning that the power production by the only solar power exceeds the total of energy demand in daytime). With the view point of economy, security and the stability of energy supply system, the authors and Seoul National University Nuclear Energy Policy Center suggested that optimal mix for 2050 carbon neuturality in Korea is about 40-50% of the nuclear energy, 30-40% of the renewable energy and about 20% carbon-free gas turbine. This model has its significance as a numerical methodology to harmonize the energy mix including nuclear energy, renewable energy, hydrogen production, et cetera. Still, the model should further describe the details such as dynamic operation of carbon-free gas turbine, adjustment of hydrogen production, and the load-following control in nuclear power. Therefore, detailed investigation with further scenario considerations on each energy source’s characteristics would make the model more realistic and exquisite in deriving the optimal energy mix for the future.

Presenting Author: Pilhyeon Ju Seoul National University

Presenting Author Biography: Mr. Pilhyeon Ju is a Graduate Student in Department of Energy Systems Engineering (Nuclear), Seoul National University. He is also on the course of Integrated Major in Sustainable High-Level Radioactive Waste Management. He is currently working as an intern in Department of Safeguards, International Atomic Energy Agency from August 2023. He started his undergraduate course with his first major of Hispanic Language & Literature, and chose Nuclear Engineering as his double major. In 2022, He received his Bachelor’s Degree of Art (B.A.) in Hispanic Language & Literature in College of Humanities, with his double Bachelor’s Degree of Science (B.S.) in Nuclear Engineering in College of Engineering, both from Seoul National University. His research interest covers various fields, including (1) Future energy mix analysis and economic evaluation with optimization of nuclear and other energy sources, (2) Nuclear nonproliferation and security with regard to peaceful utilization of nuclear power, and (3) Used nuclear fuel disposal with performance analysis on deep geological repository system.

Authors:

Pilhyeon Ju Seoul National University
Sungyeol Choi Seoul National University
Jongho Lee Seoul National University