Preface: SolarPACES 2025, 31st International Conference on Concentrating Solar Power and Chemical Energy Systems

Abstract

Achieving full decarbonization of the energy sector — in which approximately two thirds of total demand corresponds to thermal energy and one third to electricity — constitutes one of the most complex yet imperative challenges facing contemporary society. Concentrated Solar Thermal (CST) technologies have demonstrated a well-established capacity to deliver both clean thermal energy and electricity with high efficiency, while also showing considerable potential to complement other renewable energy sources in a cost-effective manner. In light of this, a sustainable energy future that does not incorporate a substantial contribution from CST systems appears highly unlikely.

The application of CST systems to supply the industrial sector with clean thermal energy — internationally referred to as Solar Heat for Industrial Processes (SHIP) — has already reached a competitive standing relative to conventional energy sources in numerous regions worldwide. This growing competitiveness is driving significant expansion of SHIP installations, particularly in countries endowed with favorable solar resources.

SolarPACES international conferences stand as the foremost global forums for the dissemination and discussion of advances in CST- related research and technology. A community that I am proud to belong to because we have a long-standing tradition of fostering excellent relationships among its members, regardless of culture, politics, or religion. With 43 years of activity since its inauguration in 1982, the conference has become the world's reference event for the CST community, consistently proving highly effective in convening stakeholders from across the sector — including researchers, industry representatives, and policy makers — to share experiences, exchange knowledge, showcase cutting-edge innovations, and foster collaborative research initiatives aimed at enhancing the competitiveness and broader deployment of CST technologies. In view of the current state of CST commercialization, this year's edition proved to be of considerable relevance to the field, as participants gathered in Almería to contribute innovative perspectives on cost reduction strategies, performance optimization, and the extension of operational lifespans.

The SolarPACES 2025 International Conference took place from 23 to 26 September 2025 in Almería, Spain. On this occasion, more than 520 experts and delegates from 40 countries convened at the Palacio de Congresos y Exposiciones of Almería. The Conference featured a rich and diverse technical programme comprising 4 plenary sessions with 10 keynote presentations and 3 roundtable discussions, 44 technical sessions encompassing 215 oral presentations, and 292 poster contributions. The scientific programme was further complemented by two technical visits: one to the commercial CSP plant Andasol-3 (Marquesado Solar) and another to the facilities of the Plataforma Solar de Almería, the world's largest public research and development center dedicated to CST technologies. The participants were welcomed during the opening session by distinguished authorities, among whom were the Spanish Secretary General for Research of the Ministry of Science, Innovation and Universities, Eva Ortega Paíno, and the Policy Officer at the Directorate-General for Research and Innovation of the European Commission, Marina Montero Carrero, both of whom underscored the crucial role of CST among the key energy technologies identified by the European Union in pursuit of its ambitious climate objective of achieving carbon neutrality by 2050.

This volume compiles the full papers submitted upon being presented at the conference, and successfully completed the review process for the SolarPACES 2025 Conference Proceedings. The contributions span across all 17 conference topics, collectively addressing a broad and comprehensive range of current issues in the field of CST technologies. Among these, the topics that attracted the greatest number of contributions were, “Thermal Energy Storage Materials, Media, and Systems”, “Analysis and Simulation of CSP Systems”, and “Measurement Systems, Devices, and Procedures”. This distribution clearly reflects the primary research trajectories that the CST community has been pursuing in recent years, and points to the directions in which the technology is expected to evolve in the coming decades.

The papers gathered in this volume represent a meaningful step forward in advancing the technological and economic performance of CST technologies, and are expected to contribute actively to their further development and wider deployment across the energy sector. Each contribution reflects the dedication and expertise of its authors, whose work is essential to the continued progress of this field. I wish to extend my sincere and deepest appreciation to all of them, as well as to the members of the organizing committee, whose efforts and commitment were instrumental in bringing this Conference to fruition. My gratitude equally extends to all participants, whose engagement and valuable contributions made this event a truly enriching scientific and professional experience.