In the face of escalating environmental and social crises, the potential for a sustainable transition within the current sociotechnical system has emerged through innovation and alternative technologies. Despite offering diverse perspectives, sustainable transitions remain uncertain in terms of their nature and pathways. The research aims to bridge theory and reality through a case study to investigate the potential for sector-specific businesses to contribute to a sustainable transition within the current sociotechnical system. This study focuses on five Icelandic energy-related companies and two governing bodies within the energy value chain, and examines the sustainability of companies' business models and their contributions to different futures, and contextualizes the results within economic theory. The study identified two alternative economic paradigms, Green Growth (GG) and Post Growth (PG), as potential frameworks for achieving sustainable futures. The findings suggest Icelandic energy-related companies align with GG and predominantly prioritize energy efficiency, transparency enhancement, and environmental impact reduction, reflecting contributions to medium-term tactical level changes within the sociotechnical system. Challenges arise in fully implementing PG principles due to the complexities of reconciling energy production, consumption, and growth goals. The findings underscore the pivotal role of energy-related companies in sustainable transitions but emphasize the need for policy interventions to guide macroeconomic activities towards environmental and social wellbeing. The theoretical contribution of this study is the identification of alternative economic paradigms and construction of a sustainable business model for energy related companies. The practical contribution of this study is the framework used in evaluating the business model of companies in the energy sector which can provide practical understandings of the implementation of sustainable business models and a company's sustainability performance.