Investigation of performance of proton exchange membrane electrolysis with photovoltaic systems

Attention towards green hydrogen production has recently risen due to global warming and energy dependency concerns. Green hydrogen production relies on renewable energy sources to generate hydrogen for various applications, such as industry, transport, heating, or energy storage alternatives. Proton electrolyte membrane (PEM) electrolyzers are well-suited for such applications as it is one of the two commercially available electrolyzer types that could be scalable in the near future and also could be operated at varying loads due to its ability of quicker response. This thesis focuses on the design and steady-state modeling of PEM electrolyzer systems to investigate the impact of balance of plant (BoP) components on the overall system efficiency and hydrogen production under varying power supply conditions from renewable sources. The modeling of the electrolyzer and system components were performed in MATLAB and design parameters were fed by spreadsheets. Power supply data fed to the model was generated from solar PV plant modeling data performed in System Advisory Model (SAM). System capacities ranging from 1 MW to 1 GW were designed and simulated for different locations, allowing for the observation of the effects of capacity factor, weather conditions, system scale and design on system performance. The results show that the effect of designing a larger system has negligible impact, and that capacity factors have larger impact on hydrogen production and efficiency of the system. Uncertainties regarding the system were determined and it was observed that the factors affecting the hydrogen production and system efficiency where the PEM stack I-V curve, DC-DC converter losses and the hydrogen dryer/purifier losses. Best and worst case scenarios were studied and it showed that hydrogen production can vary about -2.5% and +4.5% the average system efficiency can also vary around -2.5 and +1.5 kWh/kg depending on design and equipment quality.