The paper proposes a PEM electrolyzer test protocol for gaining insight into the degradation behavior of the electrolyzer specifically under dynamic load patterns as might occur by varying energy supply of renewable energy. PEM electrolyzer are able to achieve 40,000 hours of lifetime or more. However, this lifetime literally comes at a cost. Long lifetimes can only be achieved using expensive materials. Degradation can be limited by using high catalyst loadings, thicker membranes, complex fabrication technology for the separator plate, etc. But the use of these materials adds excessively to the cost of the electrolyzer stack. Therefore durability has a double impact on the electrolyzer economics. Reduced lifetime increases the capital cost because of depreciation over a shorter period of time. But also because of the need to go to more expensive materials. In addition PEM fuel cell development has extensively shown that degradation may be much quicker under impact of rapid load changes, start‐stop cycles and operation close to open cell voltage. Although there are a number of important differences between fuel cells and electrolyzers, durability needs to be assessed both under full‐load and under transient and off‐design conditions. In particular if the electrolyzer is used to manage a varying supply of renewable energy, it will be operated under varying loads. How these will vary, depends on the application. Determining durability is challenging, especially when dynamic load patterns are used. It is time‐consuming to do a single lifetime measurement and the time required to determine the impact of several variables rapidly becomes an issues. The “holy grail” regarding lifetime is to be able to accelerate degradation in such a way that it allows prediction of the durability of components under real conditions (Accelerated Stress Testing (AST)). Operating at a higher temperature, a higher impurity level or higher current density will accelerate degradation. In this paper a proposal for an AST test protocols will be given based on an extensive study on degradation mechanisms from literature. The feasibility of the proposed AST-protocols will be validated experimentally.
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