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Posted: Nov 19, 2013
Hydrogen economy - promise of solid oxide electrolysers
(Nanowerk News) A promising way to alleviate global climate change is a transition to hydrogen economy. Improvements in technology to produce hydrogen from electrolysis of water may soon make that possible.
Hydrogen is an energy carrier that can produce lots of energy with almost no pollution. However, although hydrogen is the most abundant element in the Universe, it does not occur naturally as a gas on Earth. It is bound to other elements to form compounds such as water and hydrocarbons (in fossil fuels).
Solid oxide electrolyte cells (SOECs) are solid oxide fuel cells (SOFCs) that run in reverse. SOECs perform high-temperature electrolysis (HTE) of water to produce oxygen and pure hydrogen gas from renewable electricity sources. SOFC technology has advanced significantly in recent years, resulting in advances in SOECs as well. Nevertheless, there are issues with degradation when the cells are incorporated into stacks. As this is necessary to produce industrially-relevant quantities of hydrogen, this has hampered its commercialisation.
Scientists initiated the EU-funded RELHY project to overcome the challenges of integrating currently in-use SOECs into industrially-relevant efficient, cost-effective and durable stacks. The research and development team focused on optimisation of cell materials and innovative SOE stack designs.
Investigators demonstrated important enhancements in stability and cellsí performance with the new SOEC materials. Two test campaigns with single repeating units and short stacks produced promising results in terms of efficiency and degradation. The design was scaled up to the 25-cell stack envisioned in the project proposal with limited degradation and stable electrolysis under certain conditions. This not only proves the feasibility but also elucidates important issues for future optimisation and electrolysis operation. Finally, cost and environmental impact analyses supported the competitiveness of high-temperature steam electrolysis (HTSE) for hydrogen production.
Extracting hydrogen from water molecules through electrolysis powered by renewable energy and using that hydrogen to produce carbon-neutral synthetic fuels makes adopting hydrogen economy enticing. RELHY proved the technical and economical viability of hydrogen production via the electrolysis of steam. Perhaps a hydrogen economy is just around the corner.