Energy system modelling is a data-intensive activity and the quality of results strongly depends on the availability of reliable data. In order to reinforce the transparency of the project findings and to provide information for further research, a selection of the most important data collected and generated during the project will be made available to stakeholders from policy, industry and science in the REflex data repository. These are mainly the (compiled) survey data and the results from the literature review as well as the input and output data for the model-based analysis and LCA approaches.