Experimental Characterization of a Small-Scale PEM Water Electrolyzer for Hydrogen Production

Proton Exchange Membrane water electrolyzer (PEMWEs) are expected to play a pivotal role in supporting the energy transition due to their efficiency and capabilities to handle dynamic loads, which makes them suitable for integration with renewable energy sources. This work presents experimental tests on a 2 kW PEM electrolyzer stack operating at 100kPa, with an active area of 28.3 cm2 and 15 cells connected in series implemented at the University of Trieste Energy System Lab. The overall activity, carried out in collaboration with ENPHOS s.r.l., aims also to develop a test bench for the performance characterization of the stack and the balance of plant components. In this paper the authors focus on the description of the plant and the preliminary stack tests. The methodology to characterize the performance of the stack consists of a first polarization curve to assess the beginning of life performance, then start-stop cycles are applied to evaluate possible initial degradation of the performance detectable by polarization curve variations. The test rig results to be suitable to test the performance of the stack. The preliminary experimental data show the stack efficiency is 60% at low load (56 kWh/kg) and decreases to 40% at the maximum load (2 kWel). There was no appreciable degradation in terms of efficiency from the beginning and the end of the tests.