This work explores the implementation of coordinated control for a portfolio of electrolyzers.

The Power-to-X technologies are expected to become an important part of Offshore Energy Hubs (OEH), offering demand-side flexibility, optimizing wind energy production and providing power balancing services. The latter implies the implementation of a control strategy for a large-scale electrolysis plant, which can consist of a variety of electrolyzers with different flexibility capabilities. The identical control strategy implemented for electrolyzers with different parameters within one electrolysis plant can lead to non-optimal operation of electrolysis plant and can cause negative consequences, such as power oscillations between the two types of electrolyzers.

The dynamic models of 4 electrolyzers were implemented with different characteristics, including different 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 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.

This work results and conclusions are based on the master's thesis work.