On the former Cambrai-Épinoy air base 103, converted into the e-Valley business park, Data4, backed by Brookfield, is preparing one of the largest data center projects announced in France. The local authority has just approved the land sale a second time, as changes to the project required a new vote. But the most telling detail is about power: to get started, the campus does not go through an extra-high-voltage line first.
DOES YOUR SITUATION LOOK LIKE ONE OF THESE?
1. WHAT HAS BEEN ANNOUNCED
Capacity of up to 1 GW in the long run, with at least 300 MW in the near term according to the 2025 trajectory
In June 2026, development on around 23 hectares, with three buildings over three to five years
A first commissioning envisaged as early as 2027 according to 2025 announcements
2. A TWO-STEP GRID CONNECTION
A tender published in April 2026 covers an extension of the medium-voltage (HTA) distribution network to supply four customer substations on the future site. The works include around 29 km of underground cable, fed from two source substations, Haplincourt and Prémy. Works are scheduled for 2027.
In other words, the first phase relies on existing distribution substations, without waiting for a direct connection to RTE's transmission grid, which is essential to reach several hundred megawatts. It is an approach increasingly studied: start small on what exists, while the large connection follows its course.
3. WHAT TO CHECK BEFORE CHOOSING THIS APPROACH
Real substation capacity. A substation that shows capacity may lose it to other requests. What counts is the margin available at connection time, not the one on the map.
Works schedule. In Cambrai, commissioning announced for 2027 with grid works scheduled the same year leaves little slack. Every kilometre of underground cable is a construction project, with its own permits and risks.
Compatibility with what comes next. Delivery substations, switchboards and protections installed for the first phase must be able to evolve towards the main connection without starting over.
Redundancy. Two different source substations, as here, allow a dual supply. Future data center customers look at this closely.
Cost. Extending the grid for a customer is largely paid by that customer. It has to be weighed against the cost of waiting for a heavier connection.
4. WHAT IT SAYS ABOUT THE MARKET
Public or semi-public land is becoming a strategic resource, secured early for projects whose technical outline is still changing. But, as DCmag points out, success will not be judged by the megawatts announced but by the ability to deliver megawatts that are actually connected. That is the difference between compute ordered and compute installed.
The Hauts-de-France region already concentrates several gigawatts of data center connection requests. For a developer in the region, a phased start on the distribution grid is an option to study from the outset, alongside the main request to RTE. See our support for RTE PTF requests and exploratory study, PTF or connection agreement.
Sources: DCmag, "Cambrai : le méga data center e-Valley de Data4 et Brookfield reçoit un second feu vert foncier" (19 October 2026), citing La Voix du Nord; public project announcements (2025-2026). Figures are those published by the developer and the press; GridReadiness has not verified them. This article is general information.
FREQUENTLY ASKED QUESTIONS
Can a large data center be connected to the medium-voltage grid?
For a limited first phase, yes, provided nearby source substations have available capacity. For several hundred megawatts, a connection to RTE's transmission grid remains necessary.
Why start a data center in stages?
To bring a first tranche online earlier on the existing grid, while the main connection, which takes longer to obtain and build, follows its course.
What should be checked before a phased connection?
Real source substation capacity, the grid works schedule, compatibility with the main connection, redundancy and the cost of the extension.
Where does the Cambrai data center project stand?
In mid-October 2026, the local authority approved the land sale a second time, and medium-voltage grid extension works are scheduled for 2027, according to DCmag.