Researcher at Bureau of Geological and Mining Research, BRGM, France
Bernard Sanjuan is a distinguished French scientist and recognized senior expert in geothermal energy and water geochemistry. Over the course of his career, he has dedicated himself to advancing scientific understanding and practical applications of geothermal systems, water–rock–gas interactions, and environmental geochemistry. His work spans continents, addressing both academic research and industrial development, with an emphasis on sustainable energy solutions. Through his leadership in numerous international collaborations, Sanjuan has built a global reputation as an authority on geothermal fluids, enhanced geothermal systems, and lithium-rich brines. His contributions to major European and global projects, alongside his editorial and advisory responsibilities, have significantly shaped the trajectory of geothermal science and technology. His influence is felt not only through research publications and technical reports but also through mentorship, training, and active participation in scientific committees, demonstrating his enduring commitment to advancing renewable energy resources.
Professional Profile
Scopus Profile | ORCID
Education
Bernard Sanjuan’s academic journey reflects his deep commitment to the geosciences, beginning with advanced studies in internal geophysics, geochemistry, and earth sciences at the University of Paris 7. His early training equipped him with a solid interdisciplinary foundation, which he later expanded into highly specialized expertise in water geochemistry. His PhD, completed at the University of Paris 7 – IPGP, was a landmark study focused on the behavior of dissolved aluminum in geothermal waters. This research not only advanced understanding of aluminum mobility in complex hydrothermal environments but also laid the groundwork for multiple peer-reviewed publications. The scientific rigor and methodological innovation demonstrated in his thesis positioned Sanjuan as a rising expert capable of addressing practical challenges in geothermal energy exploration and development. Combined with advanced academic diplomas and field training, his education established a strong base that would support his lifelong contributions to geochemistry, geothermal modeling, isotope studies, and tracer applications in fluid systems.
Experience
Sanjuan’s professional career demonstrates the integration of rigorous science with applied solutions in geothermal energy and environmental geochemistry. His first major assignment was in Djibouti, where he managed a hydrochemistry laboratory and gained extensive experience in geothermal exploration within basaltic environments. These early years were instrumental in developing his applied expertise in fluid geochemistry, aquifer monitoring, and hydrothermal systems. His career reached maturity at BRGM, where he worked for more than three decades, advancing from research scientist to senior expert and later holding leadership positions within units and departments. At BRGM, he played a pivotal role in developing the Bouillante geothermal field in Guadeloupe, contributing to its transformation into a significant energy producer. His research also extended to enhanced geothermal systems in the Rhine Graben, where he investigated geochemical monitoring, tracer applications, and lithium recovery from deep geothermal brines, projects that have direct implications for Europe’s energy transition. Alongside geothermal development, Sanjuan conducted environmental geochemistry studies, providing expertise in cases of water contamination and pollution control. His leadership roles within BRGM further demonstrate his capacity to combine management with high-level research, ensuring progress both scientifically and institutionally.
Research Focus
Sanjuan’s research has consistently bridged the gap between geochemical science and applied geothermal energy solutions. Central to his work are high-temperature geothermal systems, enhanced geothermal systems, and geothermal lithium extraction, with particular emphasis on the chemical, isotopic, and thermodynamic characterization of fluids. He has developed methodologies to improve geothermal exploration, including the use of isotopes and chemical tracers to monitor subsurface processes. His work in the Rhine Graben is especially influential, where his studies on geothermal brines not only expanded scientific understanding but also demonstrated the feasibility of lithium recovery, positioning geothermal energy as a dual source of renewable power and critical mineral resources. Sanjuan has also been deeply involved in projects addressing geothermal resources in overseas French territories, where his studies have guided national energy strategies and supported the development of sustainable infrastructure. His research continues to contribute to global efforts in mitigating climate change by advancing cleaner, more efficient, and resource-integrated energy systems.
Publication Top Notes
Title: One hydrothermal system may hide another: Insights from a geochemical exploration of Chaudes-Aigues and nearby springs (French Massif Central)
Authors: Emmy Penhoët; Bernard Sanjuan; Laurent Guillou-Frottier; Manuel Moreira; Laurent Arbaret
Summary: Geochemical exploration identified multiple hydrothermal systems at Chaudes-Aigues, enhancing understanding of reservoir interactions and geothermal energy potential.
Title: Atlas of lithium geothermal fluids in Europe
Authors: Blandine Gourcerol; Bernard Sanjuan; Romain Millot; Detlev Rettenmaier; Elodie Jeandel; Albert Genter; Clio Bosia; Aurélien Rombaut
Summary: Comprehensive atlas mapped lithium-rich geothermal fluids across Europe, providing essential geochemical data for sustainable energy and critical resource development.
Title: Reply to the Boschetti’s comments on the paper: “Lithium-rich geothermal brines in Europe: An up-date about geochemical characteristics and implications for potential Li resources”
Authors: Bernard Sanjuan; Romain Millot
Summary: Authors clarify methodological approaches and interpretations regarding lithium-rich geothermal brines, reinforcing reliability of geochemical data and resource implications.
Title: Auxiliary Chemical Geothermometers Applied to Waters from some East African Rift Areas (Djibouti, Ethiopia, Kenya) for Geothermal Exploration
Authors: Bernard Sanjuan
Summary: Study applied auxiliary geothermometers to East African Rift waters, improving geothermal exploration methods and revealing subsurface thermal conditions.
Title: Lithium-rich geothermal brines in Europe: An up-date about geochemical characteristics and implications for potential Li resources
Authors: Bernard Sanjuan; Blandine Gourcerol; Romain Millot; Detlev Rettenmaier; Elodie Jeandel; Aurélien Rombaut
Summary: Research updated geochemical understanding of European lithium-rich geothermal brines, assessing their potential as valuable resources for renewable energy transition.
Conclusion
Bernard Sanjuan’s career stands as a testament to the transformative role of geochemistry in advancing geothermal energy and sustainable development. From early work in Africa to leading research in Europe and French overseas regions, his contributions span exploration, field monitoring, resource assessment, and innovative integration of mineral recovery with energy production. His leadership in scientific committees, editorial responsibilities, and supervision of doctoral and master’s research further demonstrate his dedication to advancing both knowledge and practice. As a widely respected figure in geothermal science, his influence extends beyond academia into policymaking, industry applications, and international collaborations. By combining a strong educational foundation with decades of impactful professional experience, Sanjuan has become one of the foremost experts in his field, making him a highly deserving candidate for recognition in global scientific and energy communities.