The rapid expansion of scholarly research on green energy, energy efficiency, and sustainability policy reflects the intensifying urgency of global environmental challenges and the political and economic transformations driven by climate change mitigation efforts. Bibliometric analysis has emerged as one of the most powerful methodological frameworks for understanding how scientific knowledge in these domains is produced, structured, and diffused across countries, institutions, and intellectual traditions. This study presents an extensive, theoretically grounded, and methodologically rigorous bibliometric investigation of global green energy and sustainability research using only the foundational and contemporary literature provided in the reference set. Drawing on classical bibliometric theory as articulated by Garfield, De Bellis, Diodato, and Drake, and integrating applied bibliometric studies in energy efficiency, renewable energy, and green economy research by Du et al., Ziabina and Pimonenko, Alsmadi and Alzoubi, and Mentel et al., this article constructs a comprehensive analytical narrative of how sustainability knowledge systems have evolved over time.

Rather than limiting bibliometric inquiry to mere counting of publications or citations, this research interprets bibliometric patterns as sociological, economic, and political signals embedded within the scientific communication system. Green energy research is shown to be deeply shaped by policy instruments such as the European Green Deal, technological innovation cycles, and shifting geopolitical investment priorities in renewable infrastructure. At the same time, the internal dynamics of scientific communication, including journal hierarchies, citation networks, and disciplinary boundaries, play a crucial role in determining which sustainability narratives become dominant and which remain marginalized.

The findings demonstrate that green energy research has moved from a narrow technical focus on energy efficiency toward a complex, multidisciplinary knowledge field integrating economics, innovation studies, policy analysis, and social sustainability. Bibliometric mapping reveals not only growth but also structural transformation in research agendas, where renewable energy is increasingly framed as a socio technical system rather than a purely engineering challenge. The article also critically examines the limitations of bibliometric approaches, including their reliance on citation behavior, database coverage, and language biases, while arguing that these limitations do not diminish their analytical value when interpreted within a strong theoretical framework.