Hydrogen is the most abundant element in the universe, but it is generally bonded together with other elements such as oxygen (in water, H20) or with carbon in methane, CH4. Hydrogen is used extensively in industries such as glass making, oil refining, fertilizer and food production, although this hydrogen comes from natural gas, which is a fossil fuel. To free the hydrogen from either water or methane requires the input of energy. If we split out hydrogen from methane, carbon dioxide is released adding to global emissions. If we split out hydrogen from water, only oxygen is released but electrical energy is needed to do this.