Design of an Electrolyzer Integrated in an Offshore Wind Turbine System

To limit our society’s environmental impact, the world is transitioning away from a fossil-based energy system. In this transition, considerable efforts are being made in implementing renewable technologies for electricity generation. While these efforts have large benefits by decarbonizing direct power consumption, they do not address sectors where electrification is currently difficult or not feasible, such as heavy transportation and the chemical industry. Green hydrogen, when produced via renewable electricity through electrolysis, increases the reach of renewables to those sectors. However, its current high production cost impedes its large-scale implementation in our energy system. A concept that is currently gaining attention is the integration of electrolyzers with offshore wind turbines. The integration reduces electrical losses, increases wind farm load factors, and replaces the transportation cost of electricity with the lower transportation cost of hydrogen, all of which reduce the production cost of green hydrogen. In this PDEng, a conceptual design of an electrolyzer integrated with an offshore wind turbine was developed. In this concept, the electrolyzer, heat management, purification and desalination systems are integrated onto an enlarged external platform located at the transition piece of the turbine substructure. The design process was divided into 3 main phases: A preliminary system design was performed to identify requirements, select technology, and define logical architectures and system interfaces. A system integration analysis was made to assess the technical feasibility of the preliminary design concerning operational flexibility, physical & electrical integration and to generate and select potential integration concepts. Finally, an economic assessment was performed to determine the benefits of the integration on the Levelized Cost of Hydrogen (LCOH). The design process concluded that integration of the electrolyzer system is technically possible with existing technologies, and at this stage of development, no technical limitations were found. Regarding economics, the current LCOH of the integrated system is estimated at 4 €/kg, which is still higher than for grey hydrogen (2€/kg). However, a 2025 projection found that efficiency improvements and CAPEX reductions could reduce this to 3.4 €/kg. Moreover, the market and need for sustainable hydrogen production and industry decarbonization exist today. Thus, green hydrogen can eventually become the dominant type of hydrogen in our society.