1MW-Class Solid Oxide Electrolyser System Prototype for Low-Cost Green Hydrogen

Abstract

Ceres has developed a novel and highly differentiated SteelCell™ solid oxide fuel cell technology based upon the use of thick-film ceramics deposited upon a ferritic stainless-steel substrate, using doped ceria as the predominant oxygen-ion conducting ceramic within the cell. The use of ceria allows operation of the SteelCell at lower temperatures (500 - 620 °C) than conventional SOFCs, and the use of a metal support allows much greater mechanical robustness and lower production cost than is typically the case with a planar ceramic SOFC, whilst maintaining the high volumetric power density typical of planar SOFCs.Ceres Power are now qualifying their SteelCell™ technology for use in steam electrolysis operation with encouraging results. Tests suggest that functional electrochemical and physical processes of the SteelCell are equally efficient in SOFC and SOEC mode meaning there is no major difference in the area specific resistance and degradation within the nominal operating space.As a next step, the development of a 1MW-class Solid Oxide Electrolysis (SOEL) system is proposed that offers a path to green hydrogen production costs of <$2/kgH2 with equally compelling capital equipment costs enabled by the SteelCell technology. One of the clear advantages of solid oxide electrolysis systems is the ability to thermally integrate with industrial processes such as steel, ammonia and e-fuels production. Integration with existing low pressure “waste” steam feeds available at industrial plants combined with available high grade heat streams may enable system efficiencies of greater than 90% to be achieved. A study of predicted system efficiencies and associated techno-economics of green hydrogen production under various industrial use cases is presented.The first-of-a-kind 1MW-class Solid Oxide Electrolysis system under consideration will be packaged within a 40ft ISO shipping container and is expected to produce approximately 600 to 800kg of green hydrogen per day. The system will be made up of a number of Electrolysis Cell Modules (ECM). Each ECM will contain an array of Ceres’ standard Gen1B stacks along with hot balance of plant components such as heat exchangers and heaters. This modular approach allows each module to be constructed and tested prior to installation at the demonstration site. It also allows for a high degree of fault tolerance and redundancy that is particularly valuable for prototype systems. Furthermore, it also enables a distributed supply chain to be developed for various elements up and down the system structure.Finally, a roadmap to the first commercial SOEL systems is presented setting out predicted system CapEx costs, hydrogen production costs and possible arrangements for systems in the 100+ MW range.