The current design of energy systems lacks standardization and transferability. Similar challenges were successfully addressed in other industries via a platform-based design (PBD) approach. Applying the PBD approach to energy systems has a significant impact potential. It will enable rapid and transferable innovations and implementations at different scales for energy system transformations from the subsurface to the city scale. The holistic approach will lead to the cost-optimal integration of geothermal energy in existing and new urban areas. And most importantly, it leads to a significant CO2 emission reduction of heating and cooling supply. The PBD defines the interfaces between the scales and standardizes the information exchange between different levels of abstraction and thus enables the effective implementation of Geothermal-based Optimized Energy Systems (GOES). The PBD framework will be developed, validated, and applied by the highly interdisciplinary and transnational consortium using four pilot -and five case study sites.