This dissertation focuses on the intersection of two defining issues of contemporary international relations: an ongoing global energy transition and the rise of China. As energy has historically been a strategic source of state power, the research aims to connect these two processes by investigating how China’s energy transition toward low-carbon sources influences its position in the international system. This 21st century energy transition is a complex and multifaceted process, connected to broader climate-related goals and therefore it involves notions of purpose, urgency, and responsibility. This plurality of elements and the fact that it is still an ongoing process bring theoretical and methodological challenges that have resulted in little progress in the study of the current energy transition within the discipline of International Relations. Therefore, the study adopts an exploratory approach and proposes an eclectic theoretical framework that departures away from assumptions commonly used in energy studies in the fossil fuels era toward approaches that take into account the specificities of the 21st century energy transition. This framework is mainly constructed by eclectically revisiting and pragmatically combining strands of some IR theories, such as international political economy, geopolitics and energy security studies, global energy governance, and soft power. In order to operationalize the research question, the study places three mediating variables between China’s energy transition (independent variable) and the country’s position in the international system (dependent variable): technology, energy security, and image in global climate governance. The empirical analysis of each variable helps to explain how the current transition influences China’s power dynamics in the international system.