The purpose of this project with is to develop and perform initial field validation tests of highly stable and gas-selective sensors for in situ monitoring of gases produced via on-site steam reforming in solid oxide fuel cell (SOFC) systems. Knowledge of the gas composition will enable an accurate SOFC control to reduce the risk of coking and cell cracking, and will result in lower operating costs for SOFC customers. The overall program objective is to achieve highly desired selective and stable gas sensing in SOFCs by implementing a new generation of gas sensors, known as multivariable sensors. During Phase 1 of the project, the team will focus on sensing of several gases that are critically important for SOFC monitoring. GE Global Research will develop several types of sensing materials, perform laboratory sensor tests (with gas mixtures) and stability tests, down-select gas sensor designs based on their gas selectivity and stability and, field-validate the developed sensors on an SOFC system at GE–Fuel Cells. The project will result in a sensor system that will be field-validated on a 50 kW SOFC system. The in-situ data generated by the sensor system will inform a future Phase 2 project to investigate higher sensor temperature and sensing of additional gases.