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/kg(SNG) in 2030 and 2.6-3.0 EUR2023/kg(SNG) 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/kg(SNG) with the average conversion efficiency of 68%.