In the last few years the number of renewable energy sources (e.g. wind or solar energy) increased drastically. The availability of solar energy depends on the amount of daily sun light and the availability of electric power from wind turbines is linked to the available wind offered by nature. The increase of power from renewable energy sources has to be combined with innovative energy storage systems. Solar, wind and other renewable energy sources are intermittent energy sources. Consequently, with more renewable energy sources the amount of intermittent energy increases, too. Due to this, there is a need for more and more flexible and efficient energy storage systems with high capacities to guarantee the stability of the electric grid. Such energy storage systems, which are discussed right at the moment, are so called flow batteries. This article presents an experimental set-up that demonstrates the functionality of Redox-Flow-Batteries to students in chemistry lessons. Such efficient organic Redox-Flow-Batteries can use hair dyes like Phenylenediamine and pharmaceuticals such as Paracetamol. The decomposition product of Paracetamol, p-Aminophenol proved to be a particular suitable candidate, which is shown via cyclic voltammetry.