GreenDays@Rennes: Beyond efficiency, how can we imagine a more sober digital world?
On March 25 and 26, 2025, Rennes hosted GreenDays, a must-attend event for eco-responsible digital professionals and enthusiasts. Organized by the GDR GPL, IASIS, MADICS, RSD, ROD, SOC2 and the GDRS EcoInfo, with the support of the PEPR Cloud and Réseaux du futur, these days, which brought together more than 150 people, were an opportunity to discuss the theme of eco-responsible computing. The CARECloud project, which aims to drastically reduce the environmental impact of cloud infrastructures, played a central role in the organization of this event.
An event to share ideas on green digital technology
GreenDays@Rennes provided an opportunity for participants to exchange views on issues related to environmentally responsible digital technology. With keynote speakers and proposals submitted by participants, the event looked at different angles for a more sustainable digital world. The days focused on environmental issues related to digital, with a particular emphasis on digital sobriety, energy efficiency and sustainable infrastructures.
Themes and speakers
Tuesday, March 25 :
- Opening and Introduction: Anne-Cécile Orgerie and Laurent Lefèvre opened the 13th edition of GreenDays. Matthieu Simonin presented the GreenDays carbon footprint, followed by a keynote by David Maenda Kithoko on infrastructure and extractivism in the Democratic Republic of Congo.
- AI session: this session looked at the energy efficiency of machine learning models.
- Measurement session: this session looked at methods for measuring and managing digital sobriety.
- Institutional session: Presentations of GDRs and other institutional initiatives.
Wednesday, March 26 :
- Keynote: Christine Solnon discussed the links between operational research and planetary limits, while Françoise Berthoud and Laurent Lefèvre addressed the locks and levers of digital sobriety.
- Teachings session: this session explored university training courses on digital sobriety.
- Industrial session: this session presented industrial feedback on life-cycle analysis and energy consumption.
- Software session: this session looked at the software aspects of sustainability.
- Data Centers session: this session explored ways of improving the energy efficiency of data centers.
- Posters session: over the course of the two days, 16 posters were presented by different teams, providing an opportunity to interact with participants on the issues surrounding eco-responsible digital design.
For more information about GreenDays, visit their website
To find out more about the CARECloud project, visit their dedicated page.
To find out more about PEPR Cloud and PEPR Networks of the Future, visit the PEPR Cloud website and the PEPR Networks of the Future website.
