We had the pleasure of participating in the HotCarbon’25 conference, held on July 10 and 11 at MIT in Cambridge — a flagship event dedicated to sustainable computing.

On this occasion, three colleagues from iCosys — David Bekri, Loïc Guibert, and Sébastien Rumley — presented a paper entitled: “Carbon Topography Representation: Improving Impacts of Data Center Lifecycle”, in collaboration with INSA Rennes, CNRS, and Resilio.

The goal: to better understand the carbon footprint of data centers. Does the biggest impact come from server manufacturing? From their usage? Or both?

To answer this, the team:

• Measured the actual power consumption of several servers under different usage conditions;
• Estimated the carbon footprint of their manufacturing using a Life Cycle Assessment (LCA) method;
• And proposed a simple way to visualize the results, to better see where and when emissions occur.

Key takeaways: Even when a server is barely used, it still consumes a lot of energy. And this “idle” consumption can sometimes have a greater carbon impact than manufacturing itself.

To truly reduce a data center’s footprint, we need to:

• Better utilize machines (avoid letting them run idle),
• Use low-carbon electricity,
• And extend hardware lifespan.

A big bravo to the team for this clear, useful, and concrete contribution — and for representing HEIA-FR and iCosys on an international stage.