Deep geothermal energy (DGE) holds promise to become a widespread and abundant energy source for heating and power, representing a key technology in the transition to climate neutrality by 2050. However, the widespread roll-out of DGE is challenged in many nations because of closely interrelated concerns about induced earthquakes, decreasing societal acceptance and economic viability due to inadequate production rates and high costs. Digital Twins (DTs) offer an innovative solution to these challenges of optimizing and de-risking deep geothermal energy generation. DTs are calibrated virtual replicas of physical systems that enable the physical interpretation of real-time monitoring data and predictive analyses using high-fidelity models to support decision-making. GEOTWINS aims to create modular and interoperable digital twin components (DTC), tailored for geothermal systems, and demonstrate them at TRL levels 7-8 in diverse operational environments. By integrating prior experience, data and physics-based models, we aim to comprehensively represent geothermal systems as calibrated and validated DTC. The DTC-based workflows can then guide operators and regulators in every project stage, from exploration and licensing to stimulation, circulation, and post-production. GEOTWINS will also develop open-source visualization and decision-making tools to facilitate clear communication with both the population and stakeholders. Ultimately, the objective of GEOTWINS is to create for the first time an accurate and dependable digital representation of deep geothermal reservoirs connected to real-time data flows. GEOTWINS tackles this ambitious goal by bringing together into a multi-disciplinary and multi-national team leading scientists in DGE-related processes, experts in DTC technologies and practitioners from industry.