A mathematical model of long-term solid oxide fuel cell (SOFC) degradation is proposed based on a cross-cutting meta-study of SOFC degradation research available in the open literature. This model is able to predict long-term SOFC performance under different operating conditions, and it accounts for the main degradation mechanisms, including Ni coarsening and oxidation, anode pore size changes, degradation of anode and electrolyte conductivity, and sulfur poisoning. The results of the study indicate that SOFCs initially degrade quickly, but that the degradation rate diminishes significantly after approximately 1000 h of operation. Consequently, the effects of different factors associated with degradation rate are investigated, including current density, temperature, and partial pressure of H 2 in a fuel source. Sensitivity analyses show that current density and H 2 partial pressure have the highest and the lowest impact, respectively. In addition, the model has been developed to assess sulfur poisoning within pre-reformed hydrocarbon-fuel-based SOFCs, while previous models have mostly focused on performance loss in H 2 -fueled SOFCs. H 2 S deactivates catalytic activity of the SOFCs by reducing electrochemical activity and hydrocarbon conversion. Therefore, sulfur affects SOFCs that use different fuel sources in different ways. As a result, the models developed for H 2 -fueled SOFCs cannot be used for hydrocarbon-fueled ones.

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This paper presents an eco-technoeconomic analysis (eTEA) of hydrogen production via solid oxide electrolysis cells (SOECs) aimed at identifying the economically optimal size and operating trajectories for these cells. Notably, degradation effects were accounted by employing a data-driven degradation-based model previously developed by our group for the analysis of SOECs. This model enabled the identification of the optimal trajectories under which SOECs can be economically operated over extended periods of time, with reduced degradation rate. The findings indicated that the levelized cost of hydrogen (LCOH) produced by SOECs (ranging from 2.78 to 11.67 $/kg H2) is higher compared to gray hydrogen generated via steam methane reforming (SMR) (varying from 1.03 to 2.16 $ per kg H2), which is currently the dominant commercial process for large-scale hydrogen production. Additionally, SOECs generally had lower life cycle CO2 emissions per kilogram of produced hydrogen (from 1.62 to 3.6 kg CO2 per kg H2) compared to SMR (10.72–15.86 kg CO2 per kg H2). However, SOEC life cycle CO2 emissions are highly dependent on the CO2 emissions produced by its power source, as SOECs powered by high-CO2-emission sources can produce as much as 32.22 kg CO2 per kg H2. Finally, the findings of a sensitivity analysis indicated that the price of electricity has a greater influence on the LCOH than the capital cost.

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