Abstract: Disclosed herein is a method of producing hydrogen, the method comprising: receiving a feed gas comprising hydrocarbons; performing one or more reforming processes on the feed gas so as to generate a reformed gas comprising hydrogen and carbon monoxide; performing a water-gas-shift process on the reformed gas so as to generate a shifted gas comprising hydrogen and carbon dioxide; performing a hydrogen separation process and a carbon dioxide separation process on the shifted gas to thereby generate separate streams of hydrogen, carbon dioxide and a rest gas; and the method further comprises recycling at least part of the rest gas by feeding at least part of the rest gas back into one or more of the one or more reforming processes, the water-gas-shift process, the hydrogen separation process and the carbon dioxide separation process; wherein the portion of the rest gas that is recycled is at least 50%, preferably at least 80%, and more preferably at least 90%.