e-XPlore: A High-Pressure Solid Oxide Cell Electrolyser in a Sea Container for Offshore Power-to-X Applications

Abstract

Green hydrogen and synthesis gases are one of the main energy carriers in our attempts to combat global warming and to fulfill the transition of our fossil fuel-based society and industrial activities to carbon neutral alternatives. One of the promising technologies for the production of these gases is the high temperature electrolysis with solid oxide cells (SOCs). At the German Aerospace Center’s (DLR) Institute of Engineering Thermodynamics we experimentally investigate how SOC stacks1 and modules2 (up to 120 kW input) and use transient system simulations3 to develop operation strategies. Particularly when syngas is needed by downstream processes at elevated pressures, it can be advantageous to pressurize the electrolysis as well. Therefore, DLR is building up a transportable test environment called e-XPlore4 for an experimental analysis of a pressured electrolysis system. It comprises a system built in a 40 foot-sea container with an SOC module in a pressure vessel and includes almost all the required auxiliary components for nearly self-sufficient operation, such as cooling water, air supply, climate system, gas heaters, controls and safety system. The system only requires tap water, renewable electricity and some gases like hydrogen and nitrogen for heat-up or emergency cases. Steam electrolysis and co-electrolysis can be performed for hydrogen and syngas production with pressures up to 25 bar, an operating temperature of ca. 900 °C, and with a maximum electrical power input of 10 kW. This system supplies the synthesis gas for downstream processes, such as Fischer-Tropsch-synthesis to produce synthetic fuels within a Power-to-X context. This presentation will showcase the latest updates of planning and engineering of this system, as well as the relevant technical challenges. Operation strategies for different operating points will also be discussed. Furthermore, the off-shore application near a wind farm in the German North Sea as part of the H2Mare5 project will be presented.