• Energy Research

Abstract 3D printing technologies are being called on to revolutionize the manufacturing industry of the energy sector, especially when involving functional materials and complete devices. These additive manufacturing technologies show competitive advantages over conventional processes, however only a few studies have assessed their environmental implications. In this work, the environmental performance of a Solid Oxide Fuel Cell stack produced using a novel 3D printing approach is conducted for the first time using Life Cycle Assessment. In addition, a comparative study with conventional manufacturing methods is carried out. The results reveal that the production of the 3D printing materials has the highest environmental impact (between 50% and 98%) in half of the categories studied. In contrast, the end-of-life stage represents less than 1% of the total impact. End-of-life scenarios are also presented and discussed, indicating that a recycling rate of 70% for Nickel and YSZ materials performs better than the defined landfill and incineration disposal scenarios. Furthermore, 3D printing shows the best overall environmental performance compared to other conventional methods. The main improvement is seen in the material production stage, where a savings ranging from 37% to 97% (depending on the category analysed) is observed. This is mainly due to the use of a ceramic material for the interconnects instead of Chromium-based alloys used in a more conventional approach. Finally, it was observed that the energy required for 3D printing in the manufacturing stage is a sensible parameter to the environmental performance of the SOFC 3D printing technology.

Abstract This work evaluates the relevance of the carrier gas in the performance of micro-tubular SOFCs and describes its role in improving the fuel cell efficiency of these systems. Initial dual operation mode analyses revealed a strong influence of the carrier gas flow on the fuel cell degradation rate, showing a higher degradation rate when low fuel utilization (FU) conditions were employed under low total flow conditions. These experiments evidenced that a suitable fuel-to-carrier gas ratio must be satisfied in order to avoid mass transport limitations. A decrease of this relation, accomplished in this case by an increase in the amount of gas carrier flow (high total flow conditions), allowed to reduce the degradation rate even at high fuel utilization conditions (80%), breaking the limitations traditionally observed for this technology. This approach improves system efficiency –in terms of fuel consumption– while decreases the degradation rate.