Renewable hydrogen for oil refining: a technical, economic and environmental optimisation approach

Despite advances in optimising isolated hydrogen production units, few studies evaluate multiple renewable routes with refinery logistics and demand. This study evaluated the technical, economic, and environmental feasibility of four technologies for the production of renewable hydrogen for use in refineries. The technologies analysed were: ethanol steam reforming (Ethanol_ESR), proton exchange membrane electrolysis (PEM_Electrolysis), biomethane reforming from vinasse (Vinasse_BD_SMR) and wood gasification (GS_WGS). Mixed integer linear programming (MILP) with a single objective was used to minimise costs and identify the most advantageous alternative. The results indicated that routes based on biomass and waste (GS_WGS and Vinasse_BD_SMR) remained economically attractive, even with hydrogen sales prices between 50% and 100% higher than those of grey hydrogen. These routes had an IRR of over 35% and a CAPEX payback period of approximately 3 years, demonstrating their competitiveness. In contrast, the Ethanol_ESR and PEM_Electrolysis technologies faced greater economic challenges. Electrolysis had the highest CAPEX and the lowest IRR (9%), with a payback period of 14 years. Ethanol_ESR, despite the lower CAPEX, had its performance affected by the high cost of raw materials, resulting in a payback period of 7 years. The sensitivity analysis showed that waste-based routes are less vulnerable to variations in the minimum rate of return and sale price. In environmental terms, all routes showed a reduction of more than 60% in emissions compared to grey hydrogen. It is concluded that the valorisation of agro-industrial waste and the use of biomass are promising strategies for the sustainable production of hydrogen in refineries.