A MILP model for integrated circular hydrogen economy based in Malaysia with intermodal transportation

This study sought to construct a superstructure aimed at determining a optimal hydrogen supply chain based on both economic and environmental criteria, with a focus on utilizing potential biomass waste for hydrogen synthesis. To evaluate the mathematical model, four case studies were devised. Case 1 identified natural gas steam methane reforming as the preferred hydrogen production method due to its lowest overall cost of USD $51.96 million per year and an annual production of 1.90 × 10⁸ kg of H₂. In contrast, Case 2 favored a combination of empty fruit bunch (EFB) steam gasification and coal gasification technologies, which resulted in lower CO₂-equivalent emissions of 926.88 × 10⁶ kg CO_2-eq per kg of H₂ produced annually. Case 3 constituted a multi-objective scenario assessing both economic and environmental performances, while Case 4 served as a sensitivity analysis, assigning higher environmental weightage to identify sustainable pathways required toward net zero carbon emissions by 2050. In Case 3, steam gasification of palm kernel shell and empty fruit bunch, along with coal gasification were identified as the optimal hydrogen synthesis pathways, targeting a total cost of $ 309.31 million and emitting 938.50 × 10⁶ kg CO_2-eq emission per kg of H₂ produced annually. In Case 4, an annual total cost of $ 316.86 million was recorded, with 936.45 x 10⁶ kg CO_2-eq emitted per kg of H₂ produced. These findings underscore the importance of balancing economic considerations with environmental sustainability in hydrogen pathway selection.