Evaluating electrolyser setups for hydrogen production from offshore wind power : A case study in the Baltic Sea

Abstract: As part of the transition towards a fully sustainable energy system, green hydrogen shows great potential to decarbonise several hard-to-abate sectors. To provide the fossil-free electricity required for electrolysis, offshore wind power has emerged as a suggested option. In this report, four scenarios using different electrolyser placements and technologies are compared and applied in a 30-year case study considering a 1 GW offshore wind farm in the Baltic Sea. The scenarios are evaluated through the optimisation of electrolyser capacities, full system modelling and simulation, a techno-economic assessment, as well as a literature review of technological readiness, safety aspects and operational considerations. It is shown that a range of installed capacities offers only slight differences in levelised costs and that the optimal sizes to a large part depend on future electrolyser cost developments. A 1:1 sizing ratio between electrolyser capacity and maximum available power is not suggested for any of the studied configurations. Further, the simulations indicate that electrolyser inefficiencies constitute 63.2–68.5% of the total energylosses. Power transmission losses are relatively small due to the short transmission distance, while the power demands of several subsystems are nearly insignificant. Onshore H2 production using an alkaline electrolyser system is highlighted, offering the highest system efficiency and largest hydrogen production, at 55.93% and 2.23 Mton, respectively. This setup is further shown to be the most cost-efficient, offering a levelised cost of hydrogen at 3.15 €/kgH2. However, obstacles in the form of social and environmental concerns and regulations are seemingly larger compared to the scenarios using offshore electrolysis. Further, rapid future cost developments for electrolysers are likely to strengthen the case for offshore and PEM electrolyser configurations. A range of research opportunities are highlighted to fill the identified knowledge gaps and enable further insights.