Experimental characterization of a pre-commercial Anion Exchange Membrane electrolyzer and its techno-economic prospects for industrial-scale hydrogen production

As more countries pursue deep decarbonization strategies, hydrogen will have a critical role to play. This will be particularly so in harder-to-abate sectors, such as steel, chemicals, long-haul transport, shipping and aviation. In this context, hydrogen needs to be low carbon from the outset and ultimately. In recent years, research has been focusing on the development of technologies for green hydrogen production, but the cost of production is a barrier to the uptake of green hydrogen. Among the technologies available or under development, electrolysis from renewable sources is attracting lot of interest. In this scenario, the thesis project, developed in collaboration with Edison S.p.a, is born. The thesis is divided into two sections: in the first place it is performed an experimental assessment of a pre-commercial device based on AEM technology, located in the laboratory of ‘Officine Edison Torino’; secondly, the modelling and simulation of a 'power -to - hydrogen' system, using the real data of the AEM electrolyzer previously studied, is developed within the MATLAB environment. The first part aims to investigate the performances of the electrolyzer varying some operating conditions: the hydrogen flow rate production, the hydrogen production pressure, and the electrolytic solution temperature. In addition, the working point where the stack efficiency reaches its maximum value is identified. Firstly, within the limits of data confidentiality, the test bench and the main components of the device are described. Then, the carried-out experimental tests are explained, and the main results are shown: the stack efficiency varies mainly with the production level, while it is less affected by the hydrogen pressure and cell temperature. Furthermore, the highest stack efficiency, corresponding to 58.8%, is reached at a current density of 0.4 A/cm2 and a hydrogen production pressure of 1 bar. Finally, some results’ comments together with the experimental limitations are reported. Considering the second section, it is carried out a techno-economic analysis on a system producing hydrogen from a photovoltaic field without the power grid support. The hydrogen is then supplied in a blending with natural gas to an industrial plant, thus allowing partial decarbonization of its production. The objective is to opportunely size the main system components in order to satisfy the hydrogen request all year while keeping as low as possible the Levelized Cost of Hydrogen. In the thesis, first of all, the main system’s components and the assumptions done are shown and the implemented sizing strategy is explained. Afterward, the Levelized cost of hydrogen produced by the off-grid system is calculated to be equal to 15€/kgH2. Furthermore, a sensitivity analysis on the LCOH varying some characteristics of the AEM electrolyzer is carried out. Considering both stack efficiency and investment cost equal to the 2050 FCH JU targets, it is obtained that the LCOH decreases until the value of 8.7 €/kgH2. Finally, a techno-economic comparison between the off-grid configuration and grid-connected systems is carried out. The system, provided with the electrolyzer power supply from both photovoltaic field and electric grid, is the most economically favourable, with a LCOH equal to 7.24 €/kgH2.