Like many other European cities, Malmö has set ambitious goals to become Sweden’s first carbon-neutral city by 2030. This objective is aligned with several public entities such as the Öresund Region, the Swedish Energy Agency, the European Union, and the UN within the Agenda 2030 for Sustainable Urban Development. However, statistics show that this goal is very difficult, if not, impossible to reach, as the city has achieved 32% of renewable energy by the end of 2020. Furthermore, the region of Skåne is currently facing problems regarding electricity shortage due to the lack of production in the region and network capacity in the national grid. This study identifies at least two major causes to explain why the energy transition in the city of Malmö does not see the light at the end of the tunnel. First, there is a dominant political narrative in Sweden that favors centralized and intensive capital solutions that may result in the lock-in of alternatives that aim for a more decentralized energy system. Second, the high trust in technological innovation to solve societal challenges has reduced Social Innovation (SI) as a tool that only complements technological advances (e.g., offshore wind turbines and smart grids). Therefore, this mainstream eliminates the capacity of Social Innovation in the Energy Sector (SIE) as an opportunity to contest dominant structures and make transformative changes at the institutional level within the energy system. Within this context, regime actors such as Large-scale Energy Companies (LECs) have an important role in impeding but possibly also enabling SIE and facilitating the sustainable and just energy transition in Sweden. Drawing on the Transformative Social Innovation-framework, this thesis analyzes three SIE-initiatives developed by E.ON Group in collaboration with other actors. An embedded-case study approach and mixed methods (mapping, document review, semi-structured interviews, and thematic and discourse analysis) were the basis of this research to understand the transformative potential of each initiative. The results of the study conclude that LECs participate actively in the development of SIE. It shows that projects like SWITCH/CoordiNET change internal social relations but not institutional relations, while others such as Sege Park and Smart Cities Accelerator+ have big potential of transformative change and may replace and alter dominant informal and formal institutions. It also demonstrates how E.ON and the City of Malmö are challenging the dominant political narrative in Sweden. Building on the latter empirical findings, this thesis suggests recommendations for city actors (public sector, businesses, organizations, and individuals) to create alliances and reach the goal of producing 100% renewable energy while aiming for a more sustainable and just energy system in the city of Malmö.