Feasibility study and techno-economic assessment of power-to-gas (P2G) technology based on solid oxide electrolysis (SOE).

Power-to-Gas (P2G) is considered as a promising energy storage technology in a long-time horizon. The rapid growth in the share of intermittent renewables in the energy mix is driving forward research and development in large-scale energy storage. This paper presents a feasibility analysis of a power-to-gas system in terms of various operating points and capacities. The analysis was performed using a system model, which features a solid oxide electrolyzer (SOE), a CO2 separation unit, and a methanation reactor as the key components. For the purposes of the techno-economic assessment (TEA) of the system, the CAPEX/OPEX estimation was performed and the cost structure defined. The model proposed in the study enables system-level optimization, including technical and economic criteria, considering two nominal scales: 10 kW and 40 GW, which corresponds to the nominal capacity of SOE in each case. According to the study, in an SOE-based P2G system, the cost of synthetic natural gas (SNG) production will fall by 15-21% by 2030 and 29-37% by 2050. SNG production would cost 3.15-3.75 EUR2023/kgSNG in 2030 and 2.6-3.0 EUR2023/kgSNG in 2050 for systems with SOE power >10 MW. Generally, product cost reductions occur as a result of material development and large-scale production, which influences the system's CAPEX. According to the research, the technology will break even by 2050. The large-scale power-to-gas system with a total of 40 GW installed capacity delivers a product price of 2.4 EUR2023/kgSNG with the average conversion efficiency of 68%.

Novel Hybrid Modeling and Analysis Method for Steam Reforming Solid Oxide Fuel Cell System Multifault Degradation Fusion Assessment.

Steam reforming solid oxide fuel cell (SOFC) systems are important devices to promote carbon neutralization and clean energy conversion. It is difficult to monitor system working conditions in real time due to the possible fusion fault degradation under high temperatures and the seal environment, so it is necessary to design an effective system multifault degradation assessment strategy for solid oxide fuel cell systems. Therefore, in this paper, a novel hybrid model is developed. The hybrid model is built to look for the system fault reason based on first principles, machine learning (radial basis function neural network), and a multimodal classification algorithm. Then, stack, key balance of plant components (afterburner, heat exchanger, and reformer), thermoelectric performance, and system efficiency are studied during the progress of the system experiment. The results show that the novel hybrid model can track well the system operation trend, and solid oxide fuel cell system working dynamic performance can be obtained. Furthermore, four fault types of solid oxide fuel cell systems are analyzed with thermoelectric parameters and energy conversion efficiency based on transition and fault stages, and two cases are also successful by using the built model to decouple the multifault degradation fusion. In addition, the solid oxide fuel cell multifault degradation fusion assessment method proposed in this paper can also be used in other fuel cell systems.

Glass-Zirconia Composites as Seals for Solid Oxide Cells: Preparation, Properties, and Stability over Repeated Thermal Cycles.

This study focuses on the preparation and characterization of composite gaskets designed for the sealing of the solid oxide cell stacks operating below 700 °C. The seals were fabricated with the addition of various amounts (10-90 wt.%) of 3 mol.% yttria partially stabilized zirconia to a BaO-Al2O3-CaO-SiO2 glass matrix. The sample gaskets in the form of thin frames were shaped by tape casting. The quality of the junctions between the composites and Crofer 22APU steel commonly used as an SOC interconnect was evaluated after thermal treatment of heating to 710 °C, then cooling to the working temperature of around 620 °C and then leaving them for 10h in an air atmosphere, before cooling to room temperature. The samples were also studied after 3, 5, and 10 thermal cycles to determine the changes in microstructure and to evaluate the porosity and possible crystallization of the glass phase. The compression of the seals was calculated on the basis of differences in thickness before and after thermal treatment. The influence of zirconia additions on the mechanical properties of the seals was studied. The experimental results confirmed that glass-ceramic composites are promising materials for gaskets in SOC stacks. The most beneficial properties were obtained for a composite containing 40 wt.% of YSZ.