Reliability Analysis of Coupled PV-Electrolyser Systems – Evaluation of Onsite Factors

Renewable Hydrogen is seen as the trail blazer for reaching the goals for decarbonization in 2030, 2050 and beyond. The share of renewable hydrogen production globally is below 1% of the hydrogen produced. [1] To guarantee a large-scale implementation, reliable operation of coupled photovoltaic-electrolyser systems was investigated in the present study via a reliability and risk analysis. Among other things, the sensitivity of risk changes in the system components to the overall risk of failure was examined. This allows conclusions to be drawn about the susceptibility of the systems investigated to failure due to site-specific environmental influences on the electrical equipment and, subsequently, to optimize system designs for different PV electrolysis application scenarios. The study shows that a 10-fold increase in failure rate of several components (PV-inverter, air blast cooler, power electronics, chiller, gas treatment) results in a total system failure already in the first year of operation of the coupled PV-electrolyser system. Grid failure, junction box, PEM stack failure and photovoltaic module failure lead to a total system failure if increased by a factor of 100, 1,000 or more. In general, it has been shown that the photovoltaic system is more prone to faults than the electrolysis system. Measures to reduce sensitivity can be derived from this and are for instance the use of a higher number of inverters on site for higher redundancy, ensuring minimal environmental influences on the level of the inverter or regular maintenance of the inverter.