Large amounts of offshore wind energy shall be integrated into the future electricity grid in Germany, creating the need for long-term energy storage. This analysis assesses the options of load leveling and clean fuel supply by producing, storing and partially re-electrifying hydrogen. Optimum operation strategies and infrastructure layouts have been identified to maximize wind utilization.
Statistical wind energy data from the North Sea and recent studies on the offshore potential utilization were used to predict wind energy availability and typical load profiles against time. Results from the hydrogen roadmap project HyWays and technical specifications from equipment manufacturers were applied to predict the ramp-up of hydrogen vehicle fuel demand and the system behavior of electrolyzers, hydrogen underground storage and distribution systems.
It was found that underground storage of hydrogen in salt caverns is a relevant technology for Northern Germany providing sufficient bulk energy storage potential for short-term load leveling and fuel production with seasonal storage.
In a scenario where wind power exceeds electricity demand at times, the primary-to-final energy system efficiency can be maximized by adjusting the amount of hydrogen used for re-electrification (load leveling) and for the production of transportation fuel. An energetic optimum is reached at a fuel-to-electricity ratio of about 3:1. Then, 67% of the total wind power can be retained in hydrogen fuel and leveled electricity, most losses owing to electrolysis. Assuming high but realistic wind energy and hydrogen demand ramp-up rates all of Northern Germany can be supplied with hydrogen fuel from offshore wind energy.