Leveraging electrolyzer portfolio for power balancing in offshore energy hubs

This paper explores the operation of an electrolyzer portfolio (such as alkaline and proton exchange membrane) for power balancing on the offshore energy hub. The dynamic models of 4 electrolyzers were implemented with different characteristics, including ramp-rates, partial loading limitations, and hot-startup ramp rates. The electrolyzer portfolio was connected to a 4 GW offshore energy hub and equipped with AGC control to mitigate power imbalances and shutdown control for prolonged frequency disturbance. At first, the non-coordinated setup, meaning the identical control settings, was simulated with several positive and negative power imbalances, caused by tripping of the HVDC line and the wind power plant, respectively. The simulation showed fluctuations related to two different problems: one is an identical AGC coefficient that causes hunting between electrolyzers, the other is the same shutdown time that can cause the reverse imbalance and, hence, provoke the startup procedure. Both problems were addressed by applying control settings in a coordinated manner, considering electrolyzers’ ramp rate capabilities and partial load limitations. The coordinated electrolyzer portfolio showed improvement in response to power imbalance.