Mathias Days: AI and simulation at the heart of energy challenges

In December 2025, the latest edition of Mathias Days brought together over 230 participants, including nearly 100 external partners from more than a dozen countries to explore advances in artificial intelligence, applied mathematics, scientific computing and energy optimisation. All in all, a key moment for the TotalEnergies digital community, marked by innovative demonstrations and high-level discussions.

Organised by TotalEnergies’ R&D digital platforms, Mathias Days were held in Marne-la-Vallée on 2 and 3 December 2025. This event brought together 120 of the Company’s employees and nearly one hundred academic, research and technological partners.

Among them were 18 employees from CSTJF and PERL who attended presentations, workshops and demonstrations over four days, according to a tightly-packed agenda! We asked two of our employees from the Pau site to share their impressions and what they learned.

Feedback on an unprecedented international event by Margaux Raguenel, a Reservoir Engineer specialising in CO₂storage/Simulation and Stefano Frambati, a Specialist in Numerical Methods for scientific computing.
 

A cross-disciplinary event promoting progress in digital R&D

Over the years, Mathias Days have become a key  moment of cohesion, curiosity and open-mindedness. This event offers the opportunity to compare approaches, receive constructive feedback on research presented and benefit from a rich and comprehensive overview of digital R&D. The large number of external partners present plays an essential role, offering a clear insight into the state of the art and the latest trends, and opening up unexpected bridges between disciplines, professions and energies.

"It is a key moment where the Company’s digital community can meet, identify common interests and gain an overview of what our colleagues, students and partners do", explained Stefano Frambati, who has participated in the event since 2014. "Taking part in Mathias Days allows us to present our work and obtain constructive feedback, as well as a cross-functional vision of all digital R&D at TotalEnergies", Margaux Raguenel added.

People get involved on both the collective and individual level to contribute to the various scientific activities taking place at the event:

"I presented my work and was ‘Chair’ of my session, which involved introducing the authors and leading discussions on their presentations", Margaux Raguenel explained. Stefano Frambati has been a long-standing participant: "Over the years I have presented research, chaired sessions and led communities of interest. Above all, I have encouraged significant contributions from our academic partners."

This edition confirmed a fundamental shift: the growing importance of AI in research projects. Large Language Models (LLM) are emerging as accelerators to test ideas, rapidly generate high-quality code and streamline otherwise costly iteration loops. This development also facilitates “traditional” scientific computing activities, with a large number of very high-quality presentations shown this year focusing on traditional approaches to digital modelling in high-performance computing (HPC).

At the heart of energy challenges, the value of digital technology – particularly AI and simulation – lies in its ability to anticipate, predict and analyse with scientific rigour. Mathias Days offer this essential opportunity to "decompartmentalise, take a step back and look at the bigger picture", Stefano Frambati explained.

"Digital technology in the broadest sense of the term, whether with AI or with more traditional simulation methods, is a necessary tool to tackle current energy challenges", Margaux Raguenel reiterated. Discussions showed the importance of cross-functional methods. "With a few adjustments, many numerical methods can be applied to various fields and thus various energy types. It is therefore crucial that we continue to discuss and share these new methodologies and tools to meet the latest challenges and ambitions", she added. "This effectively creates deeper, more effective and proactive responses. This is a strength in an ever-changing and uncertain world", Stefano Frambati confirmed.

For both of them, the benefits can really be felt in their daily lives: a renewed sense of momentum, new ideas and encounters that lead to further discussions and which are transformed into projects.

"It boosts motivation and energy, and offers new topics and contacts to further the exchange of ideas", Margaux Raguenel explained. Stefano Frambati confirmed this: "I left Mathias with a renewed enthusiasm for digital topics and AI, a notebook brimming with new project proposals, potential collaborations and new ties formed between colleagues and partners which I couldn’t have imagined before."

How would you sum up Mathias Days in three words?

"At the forefront", Stefano Frambati summed up. "Innovation, research, community", Margaux Raguenel concluded.

And these six words together perfectly describe the spirit of Mathias Days: a dedicated research community at the forefront of innovation.