Advancing Heliostat Field Measurement and Characterization: Insights from International Collaboration and Workshop Outcomes

Accurate characterization of individual heliostats and full heliostat fields is essential to improve the performance and reducing the operation and maintenance (O&M) costs of Concentrated Solar Power (CSP) Tower Plants. In this context, an international collaboration was initiated with the Analyze Heliostat Field project, funded by the International Energy Agency's Technology Collaboration Program on Solar Power and Chemical Energy Systems (IEA-TCP SolarPACES), to develop standardized methodologies for heliostat metrology, characterization, and calibration. This initiative has now evolved into Analyze Heliostat Field Phase II: "Beam Characterization System (BCS) as a Calibration Reference System". Given the growing importance of the BCS in real CSP Tower plants for quality control of heliostats during commissioning and start-up phases, as well as its widespread use as a verification system for heliostat aiming during operation, this work aims as a first step to consolidate the BCS as a reliable reference for heliostat pointing calibration (heliostat calibration). Through this collaboration, leading global research institutions and industry stakeholders have benchmarked metrology tools, identified technological gaps, and proposed guidelines to enhance optical quality, pointing accuracy and reliability in heliostat fields. The recent workshop "Solar Towers Performance Enhancement and Cost Reduction by the Development and Implementation of Innovative On-Site Measurement & Characterization Tools," organized at IMDEA Energy, further reinforced these efforts by fostering discussions between academia and industry on cutting-edge measurement techniques. Key outcomes include the evaluation of state-of-the-art metrology methods, the importance of standardization, and the need for cost-effective and scalable calibration solutions to improve heliostat field performance. This work summarizes the key findings from both project phases, highlighting advancements in heliostat metrology tools and discussing the next steps toward implementing a unified calibration framework. The results of this collaboration will support the commercial deployment of more efficient and reliable solar tower technologies, ultimately strengthening the competitiveness of CSP Tower Plants.