Optimizing hydrogen systems for far offshore applications: a comprehensive analysis

Large-scale energy storage is one of the major challenges facing the energy transition. Hydrogen is considered to be a promising solution. This paper proposes a decision-support tool for optimizing hydrogen system sizing in offshore applications. A techno-economic model of the hydrogen production and storage chain is proposed. A hybridization with batteries is considered to smooth the intermittences, and the energy management is done using a separation frequency method. The feasibility of using a battery as buffer storage is evaluated from both technical and economic perspectives. A bi-objective optimization using the Non-dominated Sorting Genetic Algorithm (NSGA-II) is conducted to minimize the annual cost while maximizing hydrogen production. Optimization Results show that the lowest Levelized Cost of Hydrogen (LCOH) of 11.26 €/kgH₂, is obtained without battery storage using an electrolyzer size close to the maximum power capacity of the renewable source. In this configuration, electricity cost accounts for 48% of the LCOH, electrolyzer CAPEX 24%, tank 22%, and compressor 6%. Although batteries are traditionally expected to smooth intermittent power and improve system efficiency, the optimization results reveal that their integration offers no economic benefit. The presented techno economic analysis of the optimal solutions describes how the hydrogen system sizing affects the LCOH, the hydrogen production, and other performance indicators. A sensitive analysis is investigated to assess the influence of key technical and economic parameters on the optimization outcomes. The result demonstrates that LCOH is mainly driven by electricity cost and electrolyzer CAPEX. Overall, the optimal sizing showed a consistent robustness.