Hydrogen produced with electrolysis technology is 100% water saturated and contains traces of oxygen. Both have negative impact on lifetime and efficiency of fuel cells meaning we have to apply several purification steps before utilisation of the hydrogen is possible. To enable safe and efficient use of hydrogen, these impurities must be reduced to levels defined by ISO 14687:2019, which limits water and oxygen content to a maximum of 5 ppm(v). Our presentation provides insight into available purification technologies, costs of purification as well as efficiency considerations that guide the selection of certain technology.