Degradation mechanisms in PEM electrolyzer and fuel cell: a comparative analysis and stress test evaluation

In the pivotal effort to decarbonise the global energy system and combat climate change, the advancement of technologies capable of supplanting fossil fuels is of critical importance. Among the various technologies currently under consideration, hydrogen has demonstrated its adaptability to several applications, making it a key component of the energy transition. Indeed, hydrogen can be employed as an energy vector to integrate multiple energy system, including electricity, gas, and heating, thereby improving their demand flexibility . Hydrogen appears to give a strong de-fossilization opportunity for the so-called "hard-to-abate" sectors. It can be employed to reduce the environmental impact of various of industrial sectors, including cement production, steelmaking, and the chemical industry. Nevertheless, for hydrogen to assume its role, it is essential to ensure that it is produced in a sustainable manner. This necessitates the utilisation of renewable energy sources to generate what is defined as "green hydrogen". In this context, electrolyzers assume a pivotal role in the production process. These systems employ water electrolysis to generate gaseous hydrogen. Despite the long standing existence of this technology, it continues to encounter constraints that impede its extensive implementation. The principal challenge remains the production cost of hydrogen, which remains considerably higher than that associated with hydrogen produced via methane steam reforming (6.61 €/kg with respect to 3.76 €/kg [1]). Additionally, the technology is not yet fully mature and there are still unknowns regarding its durability and performance maintenance. On the other hand, in the power generation sector, fuel cells play a key role in using hydrogen as a fuel, exploiting the reverse reaction of electrolysis. These two technologies can be helpful storing in the form of hydrogen, the energy surplus coming from the grid which can be later converted back into electricity when required by the grid.