Hydrogen is the lightest and most basic element in the universe. It’s made up of a single proton and a single electron. Hydrogen is also the most abundant element in the universe: it accounts for 75% of its mass and more than 90% of the number of atoms. However, hydrogen (H2) molecules never come on their own and are always combined with another element, as with water (H2O) or methane (CH4). 95% of hydrogen - which is now mainly used in chemistry, refining and manufacturing - is produced from fossil fuels. Hydrogen can also be produced by electrolysing water. If the electricity used comes from a renewable source, you can then say that the hydrogen is “green”.
