Globally the amount of electricity generated from renewable energy sources is increasing. To integrate high amount of fluctuating energy into the existing energy grid, efficient and costcompetitive conversion of electricity into other kinds of energy carriers is needed. Solid oxide electrolysis (SOE) has the potential to become a key technology in enabling this integration. With solid oxide electrolysis cells (SOECs), electrical energy can be converted to chemical energy and stored as H2 or synthesis gas (syngas, CO+H2) via high temperature electrolysis of steam or co-electrolysis of steam and CO2. H2 and syngas can be further processed to a variety of synthetic fuels, which may be stored and later either reconverted into electricity or used in the transportation sector.
Within the last seven years, DTU Energy coordinated and participated in a number of Forsk EL projects funded by Danish transmission service operator (TSO) Energinet.dk, on developing the SOEC technology to gether with Topsoe Fuel Cells A/S, Haldor Topsoe A/S, and Aalborg University. In this talk results from two of the mostrecent Forsk EL projects (Forsk EL 2011-1-10609 “Development of SOEC cells and stacks” and Forsk EL 2013-1-12013 “Solid Oxide Electrolysis for Grid Balancing”) will be given. Performance and durability of different generations of SOEC cells and stacks will be presented, together with post-mortem analysis results. Potential problems in terms of life time limiting degradation phenomena in SOEC operation (both at the cell level and at the stack level) will be discussed in detail based on own findings as well as literature. As a high light, demonstration of full energy system balancing using reversible SOEC/SOFC stacks will be presented. Finally, some of the challenges (or possible research topics) faced in the future development of SOEC cells, stack components and stacks will be presented.