Qualifying Tests of Electrolysers for Grid Services - System Behaviour and Scalability

As part of the European project QualyGridS, drafts for standardized testing protocols for electrolysers to perform electricity grid services are defined or elaborated. These protocols are designed to be used by alkaline and proton exchange membrane (PEM) electrolysers up to the Megawatt scale. European grid services were integrated into testing protocols for evaluation of the suitability for a certain grid service existing in the market as well as basic characterizations identifying the most relevant capabilities for this application like dynamics and stability. Testing results using these protocols on a state-of-the-art PEM electrolyzer system in 50 kW with 1500 cm2 area stack are presented with considerations of the influence of balance of plant (BOP) components. System behaviour of 10 kW, 50 kW and 1.5 MW PEM electrolysers are compared to determine the influence of their scale in performance and response time. While the stack behaviour is comparable at all scales and highly dynamic the system architecture, control strategies, volumes and dynamics of components have a strong influence on the ramping rates and the stability of the total power consumption.