Hubadviser is a tech intelligence company specializing in IT trends. We regularly conduct interviews with industry leaders in France to offer expert insights on key technological topics.
About Guillaume YVON
This time, we had the pleasure of speaking with Guillaume Yvon, Head of IT at Engie, who leads a team of 90 people.
He shared with us Engie’s « Move to Cloud » journey, aimed at achieving two major goals : Increasing operational efficiency across the energy group and supporting the launch of new customer offers.
This article explores key questions IT leaders face when leading a cloud migration.
Hello Guillaume, could you please introduce yourself ?
Hello Ismail, I’m Guillaume Yvon, in charge of IT infrastructure for Engie Retail France. I currently lead a team of 90 people working across support, cloud, testing, and digital platforms. Before that, I held positions at major companies such as Saint-Gobain and Storengy, where I worked on cloud strategy.
Why did Engie adopt a “Cloud First” strategy?
In my opinion, choosing the cloud is almost inevitable today, for several reasons:
- Flexibility needs : The energy market is highly unpredictable especially with the war in Ukraine. Prices fluctuate rapidly, and we must adapt quickly to regulatory constraints.
- Business needs : Engie must provide personalized, responsive offers to customers. Whether it’s during a cold wave or energy crisis, we need to deliver the right offers quickly and tailored to individual needs.
- Financial & technical reasoning : Innovation and performance gains are essential. We need AI capabilities, but these are inaccessible without the cloud.
At AWS Summit 2023, I met the CEO of Nvidia, the top supplier of AI chips. He made it clear that these chips are only sold to cloud providers meaning the only way to access this computing power is through the cloud.
So adopting the cloud is more of a business decision than a technical one ?
Yes and no. It’s true that it’s driven by business needs, but in the case of Storengy (an Engie subsidiary specializing in gas storage), the decision was also deeply technical.
At Storengy, we were facing:
Obsolete applications
Complex IT landscape with overlapping functionalities
Unmaintained internal developments
Heterogeneous hosting environments
Exploding maintenance costs
Recurring major incidents
Moving to the cloud allowed us to modernize our IT systems, rationalize applications, focus on value-added activities, and boost performance.
Can you tell us how you went about successfully moving to the cloud at Engie ?
We began by mapping the entire application landscape, evaluating Total Cost of Ownership (TCO) over 1 and 3 years. Then, we applied the 7R methodology from AWS to define a migration strategy for each app :
- Rehosting : Lift and shift move apps to the cloud without modification
- Replatforming : Light adjustments to optimize for the cloud
- Repurchasing : Replace with a SaaS/cloud-native solution
- Refactoring / Rearchitecting : Redesign for native cloud scalability
- Retiring : Remove unnecessary apps or components
- Retaining : Keep some systems on-premises
- Relocating : Move containers to AWS without major changes
This audit allowed us to build tailored strategies per application and cut IT operational costs by 40%.
Looking back, can you tell us what you have learned about the different move to cloud strategies you have adopted, the famous 7Rs ?
Let me start with what doesn’t work :
Pure lift & shift (Rehosting), without any adaptation, is costly and brings little value. It just moves problems from on-prem to cloud. However, cloud migration becomes an opportunity to rethink your application strategy. For example, we saw excellent ROI on :
Changing runtimes : Migrating apps to open-source frameworks to unify skills
Architectural changes : Using containers and managed services
Serverless adoption : Rewriting apps to leverage fully managed services
It is often said that the cloud is causing IT costs to explode. Do you agree with this idea ?
Regarding this point, I can simply share my experience; this wasn’t the case for us. For our part, we managed to reduce IT operational costs by 40%. Above all, there’s one extremely important point to emphasize: we drastically reduced the number of incidents, with all the costs that entails. After all, moving to the cloud isn’t magic; you have to prepare well to succeed.
La formation c’est le nerf de la guerre.
How did Engie prepare for its move to the cloud ?
There were three critical pillars:
Governance : We started with a centralized governance body to define standards (vendors, architecture, methodology). Later, we moved to a federated model, appointing cloud leads in each business unit to roll out the strategy and provide local flexibility.
Training : This is the heart of success. We invested heavily in training on methodologies (like FinOps) and technical tools at scale.
Vendor relationships : Cloud vendor management is strategic. We invested time and resources to negotiate contracts effectively. It’s crucial to dedicate staff to this topic to make informed, cost-effective decisions.
What impact has the cloud had on Engie ?
The cloud has transformed the way we work. It’s allowed us to be more agile, significantly reduce our operational costs, and accelerate the development of new offerings. Moreover, it has changed our role as IT professionals. I believe that thanks to the cloud, I no longer have the same job I had 10 years ago. Today, my teams and I can focus on higher-value projects.
In conclusion, what advice would you give to organizations considering a move to cloud ?
My main advice is: never underestimate preparation and training. Understand the full implications technical and business and make sure your entire organization is aligned on the shift. The cloud is not just a tech project; it’s a cultural transformation that requires full buy-in from everyone involved.
