The 2026 Vattenfall Prize for best thesis

Adrian Ulfberg, a former doctoral student in structural engineering at Luleå University of Technology, is awarded the 2026 Vattenfall Prize for the best doctoral thesis.

“The phone call informing me that I had been awarded the prize came as a complete surprise. To receive such recognition for something I’ve been working on and pondering for several years feels both exciting and very honoring. I don’t see the award solely as a result of my own work, but also as a recognition of all the advisors, colleagues, family, and friends who have supported me along the way. I hope this award will help draw attention to research on dams and dam safety, an important field where there is still a great need for new knowledge,” says Adrian Ulfberg.

Adrian’s research focused on the safety of concrete dams against failure. Using scale model tests and numerical simulations conducted during his doctoral studies, he investigated an alternative failure behavior that concrete dams may potentially exhibit, compared to the failure mechanisms on which current practices and regulations are based. A simplified model to describe the load capacity for this alternative failure behavior was developed and compared with established calculation models. The influence of various variables on failure safety was also studied to identify which factors are most important. The research results indicate that concrete dams may have a higher load-carrying capacity and safety margin than current practice suggests. The results thus contribute knowledge and guidance to dam safety efforts and, when applied in the future, can lead to cost and material savings in the design of new dams as well as in the management and maintenance of existing dams.

“Through his research on the safety and long-term reliability of hydroelectric dams, Adrian Ulfberg is helping to further strengthen our understanding of dam behavior. The new insights Adrian has presented will be of great significance for future work on dam safety.” “We are very proud that Vattenfall’s prize of 75,000 kronor is being awarded to Adrian Ulfberg for his impressive research,” says Lovisa Fricot Norén, CEO of Vattenfall Vattenkraft AB.

The jury’s statement:

Vattenfall’s Prize for Best Doctoral Thesis 2026 is awarded to Adrian Ulfberg for his doctoral dissertation in structural engineering, “Reliability-based assessment of concrete dams considering combined sliding and overturning.” The dissertation addresses the safety and long-term reliability of hydroelectric dams. Adrian Ulfberg demonstrates that conventional deterministic analyses, in which sliding and overturning are considered separately, can provide a significantly misleading picture of the structural behavior and safety margins of dams with large-scale irregularities in the foundation. He therefore introduces and validates a failure mechanism for combined sliding and overturning, and integrates analytical modeling, probabilistic reliability methods, nonlinear finite element analyses, and experimental validation into a unified framework for assessing dam stability. The central scientific contribution is an analytical model that integrates probabilistic methods with structural mechanics analysis, thereby enabling more rational safety assessments.

The results are of great significance for the management of our aging hydropower infrastructure and thereby strengthen both the reliability and resilience of the renewable energy system.