Recent major discoveries of gas and oil in the United States in shale plays have significantly increased the amount of ethane available for steam-cracking to produce ethylene; and numerous large petrochemical companies have built new ethane crackers on the U.S. Gulf Coast since 2016. Steam-cracking, however, is energy intensive; and there is a need to develop more-energy-efficient processes to produce ethylene. Oxidative dehydrogenation of ethane to ethylene in an oxygen-ion-transport-membrane reactor is thought to be one such process; and experimental work has demonstrated that (1) a mixed ionic and electronic conducting membrane with the stoichiometry BaFe0.9Zr0.1O3-delta is capable of splitting steam into gaseous hydrogen and oxygen ions on the feed gas-membrane interface, and (2) the oxygen ions can diffuse through the membrane to react with ethane on the fuel-side gas-membrane interface, producing ethylene in yields ranging from 46 to 77% at ethylene selectivities as high as 98%.