Measuring Sustainability at Large Research Infrastructures Insights From Research Facility 2.0

Sustainability has become a critical priority for large research infrastructures (RIs) in the face of global resource constraints, climate change, and increasing societal expectations. This article introduces a structured framework for assessing sustainability performance in large RIs, such as particle accelerators and synchrotron light sources, while emphasizing environmental integrity and embedding economic and social dimensions in a nested approach. The approach asserts that environmental sustainability must remain the foundation for long-term viability, rather than being conditional upon economic or social goals. The framework organizes sustainability into three main domains: resources, energy, and greenhouse gas (GHG) emissions, each subdivided into relevant subdomains and quantified through 22 high-level indicators. A distinctive feature of this approach is the integration of scientific output and operational time as weighting parameters, enabling case-sensitive evaluations and meaningful comparisons across facilities and technical solutions. The framework is validated through a case study on neodymium iron boron (NdFeB) dipole magnet designs, demonstrating its applicability in comparing alternative technical solutions using normalized metrics and composite sustainability scores. The results highlight the potential of this approach to support evidence-based decision making, enhance transparency in sustainability reporting, and guide resource allocation toward environmentally responsible solutions. Further, this article highlights the international assessment of the Horizon Europe project Research Facility 2.0 (RF2.0) on energy efficiency at large RIs, engaging several facilities worldwide. Surveys conducted in 2024–2025 identified key energy-saving technologies, such as radio-frequency (RF) systems, magnets, and digital twins, and, at the same time, defined sustainability goals sought by different users and outlined practical methods to achieve them.