Life Cycle Assessment of Hydrogen Production from Imported Green Ammonia: A Korea Case Study

To decarbonise the transportation sector, South Korea is looking forward to evaluate possible cross-regional hydrogen supply pathways to meet the future hydrogen demand and reduce carbon emissions to ‘zero’ under Paris agreement by 2050. The use of ammonia as hydrogen carrier to meet hydrogen demands is under consideration and the goal of this paper is to evaluate environmental aspects of green hydrogen production from green ammonia imported from Australia. In the present work, a cradle to gate life cycle assessment of hydrogen production from imported green ammonia imported is carried out by using commericial life cycle assessment software Simapro. The scope of life cycle assessment includes; green ammonia production in Australia, shipping to South Korea, ammonia transportation from port to hydrogen refuelling stations in Korea, and hydrogen production through catalytic craking of ammonia. Mass and energy balance data obtained from process flow modelling are used as an input for life cycle assessment. In terms of energy consumption, hydrogen production through water electrolysis consume more than 90% of total power while ammonia synthesis only consume 5.5%. The results of life cycle assessment show that transportation of the green ammonia was the major contributor having 95% of total CO2 emissions while hydrogen production through water electrolysis was producing about 4.5% of total carbon emissions. This study reveals that considering environmental sustainability, using imported green ammonia is not a viable option until transportation fuel is replaced with an environmental friendly fuel. However, if marine fuel is replaced by a green fuel it can further reduce the transport related emissions turning this case into a viable option to meet the hydrogen related demands.