Comparison of floating offshore wind and tidal range for green hydrogen production and storage for industrial decarbonization

Abstract

UK Government targets 5 GW of electrolysers by 2030, however the role of green hydrogen for decarbonisation is not explicit. The government identifies the need to research the “archetypes” of production, transport, storage, and use. This paper presents a techno-economic model, comparing Floating Offshore Wind (FLOW) to tidal range, supplying uninterrupted power and hydrogen for industrial decarbonisation. The model employs Levelised Cost of Electricity (LCoE) and Hydrogen (LCoH), with sensitivities for Discount Rate (DR) and electrolyser efficiency. Storage is essential; FLOW must overcome seasonal patterns and changeability between years, and tidal must bridge both the springs‑neaps, and equinox cycles. The Royal Society identifies salt caverns as optimal for GWh storage, and the British Geological Society (BGS) report halite beneath the Celtic Sea. The model includes an onshore electrolyser, desalination, compression, subsea pipeline, storage platform, Underground Hydrogen Storage (UHS), and Hydrogen Gas Turbine Generator (HGTG). Components are scaled to meet demands over 25 years. When renewable generation falls below demand, hydrogen is withdrawn from storage to top-up electrolyser production to meet the continuous gas demand, and as fuel for the HGTG. The study shows how marine renewables can provide continual power and hydrogen for decarbonisation, and hydrogen’s ability as an energy store and flexible fuel. FLOW was found to require a smaller generating and electrolyser capacity, with lower LCoE and LCoH. Tidal’s predictability results in a smaller storage. Costs are most sensitive to DR. Tidal merits further investigation due to its long asset life and compatibility with alternative storage technologies.