Materializing international trade of decarbonized hydrogen by optimizing economic and environmental aspects

Hydrogen (H₂) has been regarded as a promising alternative energy carrier to replace fossil fuels. It is also important as a future clean energy source to achieve carbon neutrality since it does not emit carbon dioxide (CO₂). However, the cost of storing and transporting H₂ have been the major challenge for the realization of H₂ economy.

A research team, led by Professor Hankwon Lim from the Graduate School of Carbon Neutrality at UNIST has presented optimal supply chains considering economic and environmental aspects to materialize international trade of decarbonized H₂.

In this study, a comprehensive optimization for the overseas H₂ supply chain considering the three major importing countries including Korea (KOR), Japan (JPN), and Germany (DEU) was conducted with mixed-integer linear programming considering both economic and environmental aspects simultaneously. Through this optimization study, the research team verified the most feasible H₂ supply chain for each importing country according to years and case scenarios.

According to the research team, the optimization proceeded, respectively, for three case scenarios (base, conservative, and optimistic) and three years (2030, 2040, and 2050) by considering the demands of three major importers (KOR, JPN, DEU), capacities and resource prices of 16 exporters (AUS, BRA, CHL, and so on), amount of comparison of supplied H₂, and H₂ carriers (LH₂, toluene/MCH (TOL/MCH), and NH₃).

Their findings showed that in 2030, blue H₂ from QAT is the most feasible supplier for JPN, while green H₂ from ZAF is the most feasible supplier for KOR and DEU. In 2040, green H₂ from AUS also becomes one of the feasible suppliers for KOR and JPN together with ZAF and finally dominates the supplies after 2050, while green H₂ from ESP is considered to be the most feasible one for DEU after 2040.

“Although the difference between scenarios is not significant, the overall costs are different,” noted the research team. “One difference is that green H₂ from AUS is selected as a more feasible supplier for KOR rather than ZAF in 2040 with the optimistic case scenario.”

The study also found that ammonia (NH₃) turns out to be the most feasible carrier for H₂ and the total cost including the carbon tax has a range from 2.15 to 3.43 $ kgH₂–1 which is between the current green H₂ and blue H₂ price ranges.

The study also found that ammonia turns out to be the most feasible carrier for H₂. According to the results of the economic and environmental assessments conducted, the price of hydrogen supply, including carbon taxes generated by greenhouse gas emissions, ranged from 2.15 to $3.43 per kilogram. Based on the results, countries that are scheduled to introduce hydrogen (Korea, Japan, and Germany) have derived scenarios for optimizing the hydrogen supply chain that are needed in the future.

The work is published in the journal ACS Sustainable Chemistry & Engineering.