Abstract: A hydrogen-rich hydrocarbon fuel gas can be separated into a methane fuel stream and a hydrogen product stream. The methane fuel stream can be fed to a methane fuel fired furnace, combustion of the methane fuel stream can produce a carbon-dioxide-rich flue gas, and a carbon capture process can be performed on the carbon-dioxide-rich flue gas. The hydrogen product stream can be fed to a hydrogen fired furnace or elsewhere. Combustion of the hydrogen product stream in a hydrogen fired furnace can generate a flue gas the is low in carbon dioxide. Electrolysis of water obtained from the hydrogen fired furnace flue gas can produce hydrogen for a desired use, such as fuel for the hydrogen fired furnace, and can produce oxygen for enriching the fuel gas fed to the methane fuel fired furnace.