The year 2023 was then the warmest on record, and in response to this, RD20 was formed as a platform for R&D leaders from G20 countries to collaborate on achieving carbon neutrality. It established an annual summer school to strengthen global collaboration in clean energy research. The 3rd RD20 Summer School was held from June 15-20, 2025 at the Colorado School of Mines in USA. The event brought together early-career and senior researchers from G20 countries, with talks from experts across various fields of green energy. The goal was to share ideas and accelerate innovation in renewable technologies. Representing India were senior PhD students from NCPRE: Mr. Jenson Joseph Attukadavil and Mr. Shoubhik De. Dr. Nancy Haegel, Director of the National Center for Photovoltaics at NREL discussed the rapid global rise of solar PV and its critical role in achieving net-zero. According to her, the world needs 60–75 TWp of solar installations by 2050 to ensure clean and affordable energy for all. Other key speakers included Dr. Ron Sinton and Dr. Randy Cortright. There were also insightful sessions on perovskite solar cells, hydrogen production and storage, and other emerging technologies. One of the highlights for early-career researchers was a group project, where teams proposed innovative business models to solve real-world energy challenges. A poster session allowed young researchers to present their work, interact with peers, and build international networks. Out of the 78 participants at the Summer School, around 35 were Ph.D. researchers from various G20 countries. The NCPRE students had the opportunity to interact with many of them. These included Dr. Rajesh Raju, from the National Research Council, Canada, about recent developments in AI and its growing application in renewable energy systems, and Dr. Lian Li, a research fellow at CSIRO, Australia, about the challenges of PV degradation and soiling in both India and Australia. Dr. Li was particularly interested in the work that Shoubhik De has done at NCPRE on PV soiling. As part of the group project, Shoubhik collaborated with Andras Keovas, a student at Densys, and Yunae Cho, a senior researcher at the Korea Institute of Energy Research. Beyond academic activities, participants enjoyed an excursion to Breckenridge, a scenic town nestled in the Rocky Mountains. A visit to the NREL campus was also organised, including lab tours and discussions with scientists. Overall, the RD20 Summer School was a deeply enriching experience. It gave NCPRE students the opportunity to engage with global leaders and peer researchers in renewable energy, share their work, and gain valuable insights into the future of clean energy.