Due to the emerging energy crisis and the ever-increasing consequences of climate change, a change in energy supply is necessary. The new energy system should become independent, sustainable and climate-neutral with the help of renewable energies. However, since renewable energies are usually not constant, a storage method must be found that is as efficient as possible so that periods of low electricity can also be bridged. The production of hydrogen is recommended here. The electrolysis process uses surplus electricity and water to produce hydrogen and oxygen, which can then be easily stored. When there is a shortage of electricity, these two gases can be converted back into electricity in a fuel cell. However, this process also entails technical difficulties. In order to achieve the highest possible efficiency with this method, the processes at the electrolyser and in the fuel cell must run at maximum efficiency. In order to realise this, versatile and complex knowledge in various fields is required, which is extremely challenging in practical implementation. With the construction of an electrolyser that separates and stores the two gases, part of the cycle was practically recreated in my work. Question 1: How can hydrogen make our energy system independent, climate-neutral and sustainable in the future? Question 2: Is it possible to develop a cost-effective electrolyser using a 3D printer? After a detailed theoretical section on hydrogen and its potential in our future energy system thanks to electrolysis, the construction of an electrolyser is described. In the process, the function of the electrolyser construction is to be demonstrated in a feasibility study, which then forms the basis for the construction of the electrolyser. Programmed 3D constructions, which were printed with a 3D printer, enable the precise enclosure of the further developed electrolysis construction to the electrode diaphragm part in the electrolyser box. This is then added by the printed gas separation. The electrolyser is completed by the 3D-printed separated gas storage. Finally, the quadruple electrolyser is simplified to a single electrolyser so that the effects of the 3D design on efficiency can be studied. The feasibility study indicated that the electrolyser design, with an efficiency of about 13 percent, is workable. The following complex development of the electrolyser was a success, because the efficiency-oriented design proved that the electrolyser could function with four electrolysis cells. With the simple electrolyser, it became apparent that the efficiency was hardly affected by the developed 3D design, as the average efficiency was still above twelve percent. The 3D design fulfilled all expectations, as it had no remarkable influence on the efficiency. This made it obvious that the increase in efficiency must take place at the electrolysis construction. The electrode materials are extremely decisive for the efficiency. In my electrolyser, stainless steel sheet was chosen because it was suitable in price for a low-cost variant. But the corrosion and heat generation on the cheap electrode material has a negative impact on the efficiency. If materials were selected for highest efficiency, platinum or gold would be the best choice. However, this would increase the price more than a hundredfold, which no longer corresponds to a low-cost electrolyser. Low-cost and simple electrolysers can be built in the simplest way with 3D printers. However, the efficiency is greatly reduced due to the savings in materials and the safe handling of the hydrogen must be carefully observed during operation. This is because hydrogen can diffuse through the plastic of the 3D printer and it is therefore necessary to keep the hydrogen concentration below the critical values with ventilation. The application of cheap and simple electrolysers in society is still questionable and must therefore be investigated in more detail.