Zero-dimensional model of a reversible solid oxide fuel cell system with methanation

Abstract

This paper investigates the use of Reversible Solid Oxide Cells (RSOCs) as a connection between electricity and gas networks. The system integrates an RSOC with a catalytic reactor for methane production via electrolysis and power generation in fuel cell mode. A 0-D computational model developed in Matlab, assesses its performance. In electrolysis mode, excess electricity is stored as hydrogen, which is then converted to methane for injection into gas infrastructure. In fuel cell mode, RSOC generates zero-emission electricity from methane or methane-hydrogen mixtures, as hydrogen is increasingly blended into natural gas grids. System’s performance improves with higher hydrogen content, yielding 1.3–1.8 times more power and 11.8 % greater stack efficiency compared to pure methane. Fuel utilization, operating temperature, and steam-to-carbon ratio also impact performance. The roundtrip efficiency of the RSOC decreases with rising current density, dropping from 70.9 % to 28.6 %, with the overall system's roundtrip efficiency peaking at 0.14 A/cm².