The urgency to transition to a fossil-free energy system has been underscored by ecological, economic, and geopolitical factors. The escalating global warming crisis necessitates complete decarbonisation, with renewables being the only technology capable of scaling up sufficiently. Economically, renewables have become the most cost-effective power generation technologies with significant growth potential. The recent gas crisis in Europe has highlighted the geopolitical implications of energy production. A successful energy transition would not only significantly reduce CO2 emissions and contain global warming but also provide cheaper energy and resilience against geopolitical crises by decentralizing energy production. However, the current pace of transition is insufficient to maintain global warming within the IPCC’s limit of 1.5°. Current projections suggest a likely exceedance of 2° by 2050, necessitating accelerated global efforts to mitigate this trend. This research project aims to develop a methodology for creating collaborative models to formulate policies for a decarbonized and sustainable society, generating a framework for the so-called Society 5.0. These models should provide technically and economically viable solutions for a fossil-free energy mix, tailored to Catalonia’s specific situation.