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With climate change mitigation and carbon emission reduction as global priorities, the expansion of renewable energy has become a core strategy globally. The purpose of this study is to identify trends in key renewable energy technologies, such as solar, wind, geothermal, and water technologies, and to compare and evaluate their competitiveness across leading nations. To this end, we performed trend analyses and both patent and technology portfolio assessments employing indicators such as the number of patents granted, claim count ratio, citation ratio, and patent family ratio on 194,485 granted patents collected from 1975 to 2024, according to International Patent Classification (IPC) codes, for the five major energy powers—the United States, European Union, Japan, China, and Korea. Trend analysis revealed a sharp increase in energy-related patents from 2010, with solar technologies accounting for over 60 percent of the total. Patent portfolio results positioned the United States as the Technology Leader, leading in both activity and quality; China stood out for its quantitative expansion and Europe for its qualitative strengths. Technology portfolio findings show that, although core technologies are shared globally, application-level technologies vary by country, reflecting each nation’s industrial base, policy orientation, and technological maturity. This study delineates priority technology domains, identifies optimal R&D collaboration pathways, and recommends policy levers that accelerate commercialization—enabling policymakers and industry stakeholders to allocate resources strategically and construct balanced technology portfolios aligned with global initiatives such as carbon-neutrality targets and the RE100 commitment.
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