The chapter discusses the role of digital twins (DT) in the energy transition process, focusing on examples from Poland. DTs, which are virtual representations of objects, processes, and systems, enable real-time monitoring, analysis, and optimization of energy infrastructure operations. The applications of this technology include energy production optimization, grid load forecasting, integration of renewable energy sources and energy storage, microgrid management, and predictive maintenance. The chapter also presents the benefits of DT implementation, including increased efficiency, reduced operating costs, and better investment planning, as well as barriers such as high implementation costs, lack of standards, cybersecurity issues, and data quality. The conclusions emphasize the necessity of coordination among technological, regulatory, and organizational activities in order to maximize the potential of DT in achieving the objectives of decarbonization, digitalization, and decentralization of the energy sector.