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Elcogen is a manufacturing company of solid oxide fuel cell (SOFC) and solid oxide electrolysis (SOE) unit cells and stacks. The competitive advance of Elcogen unit cells and stacks are their performance characteristics at reduced operating temperatures between 600°C to 700°C. The unit cells and stacks are based on conventional material solutions and manufacturing processes, which together with reduced operating temperature, provide cost benefits both for Elcogen’s products and system integrators.

Major current research trends in alkaline electrolysis are targeted toward improving efficiency, extending the durability and decreasing the price of the electrolyzer units. The novel atmospheric plasma spraying (APS) production method for Raney nickel coatings demonstrated good efficiency for the hydrogen evolution reaction (HER). The research work performed focused on the investigation of the degradation/deactivation mechanisms of these APS electrodes. The formation of hydrides was recognized as a key contributor toward cathode deactivation and to prevent it, in-situ activation in the electrolyte as well as hydrides oxidation, through controlled switching of the cell potential were carried out. Both techniques showed some effect in suppressing the deactivation process but failed to eliminate it completely. The APS Raney nickel cathodes also presented good stability for variable load operations during the cycling.Long term, variable load operation is one of the major challenges that need to be faced by electrolyzers. Achieving the highest performance over as long period of time as possible was always a key criterion, but today's electrolyzers are additionally aimed to operate with highly time variable renewable energy sources. This particular application necessitates the need for electrolyzer durability under highly variable load environments.Current literature does not appear to provide adequate information on the degradation issues relating to such operation of commercial alkaline electrolyzers. Indeed, only one, publicly available research work dealing directly with this issue has been identified. The doctoral dissertation and associated paper of A. Bergen 1,2 investigated the effects of variable power and intermittent operation on the lowpressure Stuart SRA 6 kW electrolyzer. In these experiments, it was observed that an intermittent load had a negative impact on the electrolyzer efficiency. Its performance decreased during operation when a full shut-down was instigated in each cycle. This was not found for uninterrupted operation or operation where the device was kept at a minimum holding current of 10 A. Additionally, it was observed that after turning off the device, there was a marked fall in the voltage over time before it stabilized at a much lower value. The paper concluded that the introduction of control techniques, such as that of a minimum holding current as well as a rest period could minimize the deterioration in the electrolyzer performance.The findings of Bergen et al. 1,2 were partially confirmed by data from Hydrogenics 3 where it was shown that although the electrolyzer still suffered from degradation effects on intermittent load operation, the impact on performance was reduced if certain procedures were followed. The Hydrogenics electrolyzer, operated under constant current mode, saw an increase in the voltage of the electrolyzer with the number of on/off cycles performed. The data indicated that after 10,000 cycles (∼over 200 days of operation), the performance dropped by only around 7%. ...