[C Tech Now] Find Hidden Methane in Manholes and Industrial Complexes... South Korea's Emissions Decrease by 9.8%

Methane Accounts for 4% of Greenhouse Gas Emissions
Declining Compared to 1990s Emission Levels
Diverse Sources Including Power Plants and Landfills
Urgent Need to Establish 30% Reduction Plan by 2030

According to the "2023 National Greenhouse Gas Inventory" released last month by the Ministry of Environment's Greenhouse Gas Comprehensive Information Center, South Korea's total greenhouse gas emissions in 2021 amounted to 676.6 million tons (CO2eq·carbon dioxide equivalent, hereinafter the same), representing a 131.6% increase compared to 1990. Among these, carbon dioxide accounted for the largest share at 91.3%, while methane accounted for 4.0%.

As of 2021, total methane emissions were 27.3 million tons, showing a 9.8% decrease compared to 30.2 million tons in 1990. Compared to the previous year, there was a 0.8% increase. The decline in domestic methane emissions is mainly attributed to the reduction in rice paddy cultivation area and decreased use of solid fuels for household purposes. By sector, agriculture accounted for the largest share at 43.0%, followed by waste (30.9%), energy sector (23.8%), and industrial processes (2.3%).

Although domestic methane emissions are decreasing, comprehensive measures are needed to achieve the 30% reduction by 2030 compared to 2020 as stipulated by the International Methane Pledge. In particular, accurately identifying methane emission sources must precede these efforts. Some have raised the possibility that many emission sources may be missing from the Ministry of Environment's greenhouse gas inventory.

In fact, recent research by Professor Jeong Su-jong of Seoul National University's Graduate School of Environmental Studies confirmed the existence of various methane emission sources within urban areas, including power plants, landfills, sewage treatment facilities, complex shopping malls, manholes, sewers, old houses, industrial facilities, and restaurants. Professor Jeong's research team investigated 786 manholes in Seoul and found methane emissions in 259 of them (33%). Methane leakage was also detected through aging city gas pipes in residential areas. Methane leaks were observed at the Incheon Liquefied Natural Gas (LNG) combined power plant and the Incheon Songdo LNG production facility.

In January of this year, Seoul National University, the National Institute of Environmental Research, the National Institute of Meteorological Sciences, and the Chungnam Institute of Health and Environment conducted the CANIFFER project to measure methane gas emissions in the Daesan Industrial Complex in Chungnam using satellites, aircraft, vehicles, and ground observation stations. NASA, the Japan Aerospace Exploration Agency (JAXA), and the European Space Agency (ESA) participated as international collaborators. The research team explained that this is the world's first three-dimensional greenhouse gas emission observation campaign for a petrochemical industrial complex. As a result, methane concentrations exceeding 15 times that of the general atmosphere were observed in the Daesan Industrial Complex.

Professor Jeong is currently conducting additional research to observe methane emissions in the Ulsan and Yeosu petrochemical industrial complexes. In the Ulsan complex, high concentrations of methane up to 3376 ppb (1 ppb = one billionth) were confirmed, and in the Yeosu complex, 2228 ppb was detected. Professor Jeong explained, "It is necessary to establish a scientific and systematic monitoring system that can advance methane emission estimation," adding, "Reducing methane emissions from industrial complexes allows companies to achieve the dual benefits of cost savings and contributing to carbon neutrality."