Impact of hydrogen electrolyzers on flexibility and network voltage profiles of a virtual power plant

Additional flexibility to accommodate the increasing share of intermittent Renewable Energy Sources (RES) is essential to guarantee reliable and stable operation of low-carbon power systems. The concept of virtual power plant (VPP) is central to the aggregation and coordinated control of heterogeneous Distributed Energy Resources (DER), as VPPs can offer aggregated DER capacity in various markets for the provision of energy and grid support services. Among emerging technologies, electrolyzers for hydrogen production could provide system support services and thus be integrated in a VPP framework as an additional source of flexibility. To do so, this paper first introduces, for PEM and alkaline electrolyzer technologies, their active and reactive (P-Q) power "feasibility charts" based on their underlying physical characteristics. These are then used within a broader VPP- based DER aggregation setup to describe its P-Q capability chart, also referred to as feasible operating envelope (FOE), while also considering relevant distribution network constraints, and studying the impact of electrolyzer location and operation on voltage profiles. Simulation results show how integrating electrolyzers into VPP schemes could potentially greatly expand their FOE, thereby opening up new opportunities for distributed hydrogen technologies to actively provide operational flexibility at scale.