Impact of power supply fluctuation and part load operation on the efficiency of alkaline water electrolysis

Contrary to traditional electrolysers which operate continuously at their nominal load, future alkaline need be able over a wide load range due the variability of renewable electricity supply. We have investigated how residual ripples from thyristor-based power supplies are influenced by operating system, and these affect efficiency electrolysers. For this, simulation tool was developed combines six-pulse bridge thyristor rectifier model with closed-loop current control semi-empirical electrolysis models. The models can simulate potential response both direct high amplitude alternating currents for lab-scale industrial electrolyser validated experiments square wave input. show that without filters result in total system loss 1.2–2.5% full 5.6–10.6% part 20% depending on type electrolyser. implementation an optimized L-filter suppresses reduces losses 0.5%–0.8% 0.8–1.2% minimum load.