Hydrogen production for a net zero refinery

Abstract

In this thesis, a techno-economic cost-optimization model is applied to evaluate the interaction of a blue hydrogen system, which incorporates a steam methane reformer (SMR), carbon capture and storage (CCS), and a green hydrogen system. The green hydrogen system comprises an electrolyzer, hydrogen storage, battery storage, and an offshore wind farm with a power purchase agreement (PPA). The assessment focuses on achieving a net zero refinery in the year 2035. The model minimizes the total cost of investments and operation of CCS, and all technologies comprising the green system while meeting a continuous hydrogen demand. Sensitivity analysis is carried out to answer the two following questions; (i) What flexibility measures can reduce hydrogen production costs; and (ii) how do sensitive parameters affect the system composition and sizing of components? The results reveal that flexibility measures can be found in the electrolyzer, energy storage, and partly the SMR to manage wind variability. Furthermore, the model and its system composition are sensitive to the operational cost of the SMR. The resulting green hydrogen system consists of a 263 MWH2 electrolyzer, 469 MW offshore wind farm, 14 GWh hydrogen storage, and 2.3 MWh battery energy storage. It does together with a 297 MW SMR, employed with a 90 % capture rate CCS, meet a continuous hydrogen demand of 377 MW. Higlights • A resilient continuous hydrogen production system can be constituted of a blue and green hydrogen system. • The green hydrogen is resilient to PPA prices but sensitive to OPEX of SMR. • Employment of hydrogen storage is crucial for mitigating total system cost. • Variability of different years has a small impact on the model’s system composition.