LIFE CYCLE Assessment OF carbon capture and sequestration 

• Our research analyzes greenhouse gas emissions across the entire CCS value chain, including carbon capture, international CO2 export tailored to Korea’s specific geographical conditions, and offshore geological storage. The objective is to evaluate the feasibility of implementing such CCS technologies in Korea as a pathway toward net-zero emissions. Furthermore, we explore strategies to minimize life cycle emissions to enhance overall environmental performance.

• Funding: Integrated CCS System for Network Optimization (Ministry of Trade, Industry and Energy), 2025-2028.

• Taegyeong(태경) is working on this project.

Well-to-Wake greenhouse gas emissions of SAF

HyoYoung Kim, Yujin Jung and Wonjae Choi

Journal of Cleaner Production, 2026. DOI: 10.1016/j.jclepro.2026.148030

• The expansion of SAF is essential for aviation net-zero, but energy-import-dependent countries may face higher life cycle GHG emissions due to complex supply chains. This study assesses UCO-, tallow-, and e-fuel-based SAF in South Korea using a Well-to-Wake approach.

• Results show that UCO-based SAF is a reliable low-carbon option, while e-fuel SAF requires careful planning of hydrogen supply pathways to reduce emissions and uncertainty.

Well–to–Wheel greenhouse gas emissions of E-gasoline

Yujin Jung, Gyuna Kwak and Wonjae Choi

Energy Conversion and Management, 2026. DOI: 10.1016/j.enconman.2025.120692

• The WTP/WTW GHG emissions of E-gasoline vary significantly depending on the carbon capture source, hydrogen production pathway, electricity mix, and emission allocation method, with the DAC–green hydrogen–renewable electricity pathway showing the lowest emissions.

• For HEVs using E-gasoline to achieve WTW emissions comparable to BEVs, comprehensive decarbonization across the entire E-gasoline production chain is required; this study provides an LCA-based framework for evaluating E-gasoline policies.

LCA OF HYDROGEN and ammonia imported From Abroad

Gyuna Kwak, Juha Lee, Yujin Jung and Wonjae Choi

Energy Conversion and Management: X, 2025. DOI: 10.1016/j.ecmx.2025.100887

• Hydrogen imports are evaluated for South Korea by comparing five production pathways and two import routes, showing that electricity emissions in the exporting country affect life-cycle GHG emissions more strongly than transport distance.

• Ammonia is generally a more favorable import carrier than liquid hydrogen, and the results suggest that clean hydrogen certification should adopt a more flexible threshold depending on end-use benefits.

LIFE CYCLE Assessment OF STEEL PRODUCTION TECHNOLOGIES

Juha Lee, Gyuna Kwak, Yujin Jung and Wonjae Choi

Energy Conversion and Management: X, 2025. DOI: 10.1016/j.ecmx.2024.100865

• This study compares life-cycle GHG emissions of coal blast furnaces, natural gas direct reduction, hydrogen direct reduction, and electric arc furnaces in import-dependent countries such as South Korea, highlighting the added emissions from maritime transport, liquefaction, and upstream energy supply.

• Electric arc furnaces using scrap steel showed the lowest emissions, while hydrogen direct reduction varied widely depending on hydrogen and electricity production pathways, indicating that upstream energy decarbonization is essential for low-carbon steelmaking.

GREENHOUSE GAS REDUCTION and ECONOMIC COST of technologies using green hydrogen in the steel industry

Wonjae Choi and Sanggyu Kang

Journal of Environmental Management, 2023. DOI: 10.1016/j.jenvman.2023.117569

• Four methods using green hydrogen in steel mills were analysed and compared.

• Both GHG reduction and economic cost of four methods were evaluated.

• Hydrogen steelmaking has both the largest GHG reductions and economic cost.

• Making methanol is better than making methane in both GHG and cost points of view.

• Four methods were evaluated not only for the present but also for the future (2040).

WELL-TO-WHEEL ANALYSIS OF CONVENTIONAL AND ALTERNATIVE VEHICLES 

Wonjae Choi, Eunji Yoo, Eunsu Seol, Myoungsoo Kim, and Han Ho Song

Applied Energy, 2020. DOI: 10.1016/j.apenergy.2020.114754

• Well-to-wheel (WTW) analyses were conducted for present and future vehicle pathways.

• Six future scenarios were made to show each case that each energy policy is in act.

• Gaps between the WTW GHG emissions of various vehicle types reduce in the future.

• The impacts of policies regarding electricity and hydrogen production were analysed.

• A framework to assess a policy of electricity and hydrogen production was proposed.

WELL-TO-WHEEL ANALYSIS OF BATTERY ELECTRIC VEHICLES

Wonjae Choi and Han Ho Song

Applied Energy, 2018. DOI: 10.1016/j.apenergy.2018.08.092

• A case of countries dependent on fuel imports via maritime transportation is studied.

• 5 power generation fuels, 10 generation methods, and 2 electric grids are analysed.

• Importing raises the GHG emissions of power generation fuels, especially natural gas.

• WTW GHG emissions of BEVs with each generation fuel and method are calculated.

• The average WTW GHG emissions of BEVs are lower than those of ICEVs and HEVs.

WELL-TO-WHEEL ANALYSIS OF NATURAL GAS

Wonjae Choi and Han Ho Song

The International Journal of Life Cycle Assessment, 2014. DOI: 10.1007/s11367-014-0704-7

• The environmental impact associated with the use of natural gas in Korea was analysed.

• The well-to-wheel analysis on natural gas in Korea is far different from that of the U.S, because ~99 % of natural gas used in Korea is imported from the oversea countries in the form of liquefied natural gas (LNG).

• The well-to-pump GHG emissions of city gas and compressed natural gas are calculated as 25,717–30,178 and 28,903–33,422 g CO2 eq./GJ_Final_fuel, respectively.

• The WTW GHG emission of compressed-natural-gas-fueled city bus is calculated as 1,348–1,417 g CO2 eq./km.

• These values are relatively larger than those of the U.S., because most of the natural gas used in the U.S. is transported by pipeline in a gaseous state as compared to the import of LNG in Korea.