Oxygen (O2) production is a major part of the energy consumption and capital cost of power stations and industrial processes using oxy-combustion and pre-combustion gasification of fossil fuels with carbon dioxide (CO2) capture. O2 requirements range from 3.0 tonne/day/MW net electrical power to about 20tonne/day/MW. O2 purities are from 90% to 97% and delivery pressures are from 1.7 bar to 70 bar. O2 is currently produced by cryogenic distillation of air in efficient optimized plants. A new process for O2 production under development uses a mixed metal oxide ceramic membrane (ITM or OTM) operating at temperatures above 700oC integrated with a high temperature and pressure air source such as a gas turbine. Reducing conditions on the permeate side of the membrane allow the production of hydrogen plus carbon monoxide (H2+CO) gas at elevated pressure.