Alongside substituting fossil fuels with renewable energies and increasing energy efficiency, the utilization of electricity-based hydrogen or its derived synthetic fuels is a potential strategy to meet ambitious European climate protection targets. As synthetic hydrocarbons have the same chemical properties as their fossil substitutes, existing infrastructures and well-established application technologies can be retained while CO2 emissions in energy conversion, transport, industry, and residential and services can be reduced. However, the conversion processes, especially the generation of hydrogen necessary for all e-fuels, are associated with energy losses and costs. To evaluate the techno-economic hydrogen production potential and the impact of its utilization on the rest of the energy system, a supply curve of electricity-based hydrogen in a greenhouse gas emission-free European energy system in 2050 was developed. It was found that hydrogen quantities of the order of magnitude envisaged in the 1.5 °C scenarios by the European Commission's long-term strategic vision (1536–1953 TWhH2) induce marginal hydrogen production costs of over 110 €2020/MWhH2 and electrolyzer capacities of more than 615 GWel. Although the generation of these amounts of hydrogen using electrolysis provides some flexibility to the electricity system and can integrate small amounts of local surplus electricity, an additional 766 GWel of wind power and 865 GWel of solar power must be installed to cover the additional electricity demand for hydrogen production. It was furthermore found that the most important techno-economic properties of electrolyzers used in an energy system dominated by renewable energies are the ability to operate flexibly and the conversion efficiency of electricity into hydrogen. It is anticipated that the shown analysis is valuable for bothpolicy-makers, who need to identify research, subsidy and infrastructure requirements for a future energy system, and corporate decision-makers, whose business models will be significantly affected by the future availability of electricity-based fuels.