In a future sustainable and greenhouse gas-free energy system, the primary energies of sun and wind will only occur intermittently, so that a constant security of supply can only be achieved with large storage systems in the range of several TWh (for a medium-sized transmission grid). This is only possible with hydrogen in large caverns, and the intercontinental transport of these amounts of energy will also only be possible with hydrogen. Via the fuel cell, the use of hydrogen as a fuel for mobility, for working machines, but also for the stabilization of the power supply via uninterruptible aggregates is of great technical and economic importance. The advantages and disadvantages of hydrogen and fuel cells compared to alternative drive systems (e.g. battery-electric drives for road vehicles) are also presented. For the economic considerations, a study by the “International Hydrogen Council” was preferred because it already examined the international trade in hydrogen and its costs. The conclusion is that hydrogen as a fuel has very high market potentials, but requires different lengths of introduction depending on the complexity of the application and the infrastructure required for it.