In order to achieve net zero emissions in Europe by 2050, hydrogen will play a vital role. Naturally, in order to mitigate climate issues green hydrogen, produced by water electrolysis with renewable energy, must be employed instead of grey hydrogen, produced from natural gas. However, with current prices of 2.5 to 5.5 €/kg, green hydrogen is far more expensive than grey hydrogen which only costs 1.5 €/kg. A major factor herein is the power usage, which determines 80% of the green hydrogen price. In order to lower the power usage, research focus typically lies on improving the electrocatalyst, while reactor engineering remains underdeveloped. With this proposal I would tackle this knowledge gap and investigate how structured 3D electrodes can improve the performance of water electrolysers. With the combined effect of a high surface area and structured geometry, a reduced ohmic resistance, an efficient bubble release, a small pressure drop and a uniform current distribution can be obtained, tackling the power usage of today’s water electrolysers. Through 3D printing and the use of coating techniques such as electrodeposition, the influence of the electrode geometry and surface structure on the efficiency losses in water electrolysers will be characterised, yielding insight in parameters such as the ohmic resistance, hydrodynamic properties and bubble release size.