Life Cycle Assessment of Greenhouse Gas Emissions in Hydrogen Production via Water Electrolysis in South Korea

This study evaluated the greenhouse gas (GHG) emissions associated with hydrogen production in South Korea (hereafter referred to as Korea) using water electrolysis. Korea aims to advance hydrogen as a clean fuel for transportation and power generation. To support this goal, we employed a life cycle assessment (LCA) approach to evaluate the emissions across the hydrogen supply chain in a well-to-pump framework, using the Korean clean hydrogen certification tiers. Our assessment covered seven stages, from raw material extraction for power plant construction to hydrogen production, liquefaction, storage, and distribution to refueling stations. Our findings revealed that, among the sixteen power sources evaluated, hydroelectric and onshore wind power exhibited the lowest emissions, qualifying as the Tier 2 category of emissions between 0.11 and 1.00 kgCO2e/kgH2 under a well-to-pump framework and Tier 1 category of emissions below 0.10 kgCO2e/kgH2 under a well-to-gate framework. They were followed by photovoltaics, nuclear energy, and offshore wind, all of which are highly dependent on electrolysis efficiency and construction inputs. Additionally, the study uncovered a significant impact of electrolyzer type on GHG emissions, demonstrating that improvements in electrolyzer efficiency could substantially lower GHG outputs. We further explored the potential of future energy mixes for 2036, 2040, and 2050, as projected by Korea’s energy and environmental authorities, in supporting clean hydrogen production. The results suggested that with progressive decarbonization of the power sector, grid electricity could meet Tier 2 certification for hydrogen production through electrolysis, and potentially reach Tier 1 when considering well-to-gate GHG emissions.