The GLITER project proposes an integrated and multi-scale investigation of the combined "geothermal and lithium" system in the perspective of a lithium-and-heat co-production, with an application in the deep geothermal system of the Upper Rhine Graben. From two fundamental pillars to the understanding of the system (the geodynamics of the rift and its control on the circulation of hot fluids and the geochemical investigations relating to lithium source and mobilisation), an exploration workflow based on the adaptation of the numerical tools from O&G and on multiscale modelling will be developed. This workflow will be relevant for the entire European Cenozoic Rift System, and even beyond. The close collaboration between the partners strategically gathered in the GLITER project (BRGM, IFPEN, Sorbonne University (SU), Lithium de France (LDF) and Compagnie Générale de Géophysique (CGG)) will make it possible to benefit from the knowledge and know-how of experts in the fields of energy and the community of fundamental geosciences. Indeed, SU, IFPEN, CGG and BRGM will specify the structural control on deep circulations while the experience of LDF and BRGM in mineralogy and geochemistry will allow the source of Li to be defined. The results of these first steps will be integrated into multi-scale numerical simulations of lithium mobilisation, and heat and lithium circulation in the Upper Rhine Graben (IFPEN, BRGM, CGG, LDF). For all of this work, the deployment of innovative tools such as U/Pb dating, in situ laser ablation "MC-ICP-MS", or even machine learning, associated with the application of robust O&G tools but with their original use in geothermal will contribute to significant progress in the understanding of this system. Finally, thanks to the holistic integration of knowledge and understanding acquired thanks to this workflow, GLITER will provide an overall model of the combined “geothermal and lithium” system, an unprecedented mapping of areas, where heat and lithium are sustainably available ("sweet spots"), and an adapted and tested exploration workflow.