A method and system for high temperature fuel cell system or electrolysis cell are disclosed which include recirculating a fraction of gas exhausted from at least one of sides an anode side and a cathode side; accomplishing a desired flow rate of the recirculated flow by using an ejector via at least one primary feedstock fluid to a nozzle of the ejector, which nozzle has a convergent-divergent flow channel through which fluid is expanded from an initial higher pressure to lower pressure; providing supplementary fluid to the nozzle of the ejector; regulating respective ratio of the fluids of the ejector to maintain a desired motive flow and pressure at the nozzle of the ejector in order to accomplish desired recirculated flow rate; and cutting off the supplementary fluid when a level of system loading is the primary feedstock fluid alone maintains desired flow and pressure at ejector inlet.