For a 100–200 MW AI campus in France, the building is rarely what sets the date. Four things do: the grid connection, high-voltage equipment, permits and local acceptance. Each runs on its own clock, measured in years or close to it, and most decisions that shorten them have to be taken before the design is final.
1. THE GRID CONNECTION: THE LONGEST CLOCK
At this size the site will almost certainly be connected by RTE at HTB, not by Enedis. The connection timeline depends on the document you hold (exploratory study, accepted PTF or signed connection agreement), the works RTE must build or reinforce, and their permits. RTE's fast-track HTB3 route, targeting three to four years, is designed for 400 MW to 1 GW on State-identified sites, so most 100–200 MW projects follow the standard procedure.
Decide early: secure land control (a promise to sell is often enough), request the exploratory study, then accept the PTF to enter the queue. Plan the capacity in steps that match your IT ramp-up, since unused capacity can later be reduced. See which grid document actually secures a site.
2. HIGH-VOLTAGE EQUIPMENT: ORDER BEFORE YOU FEEL READY
Your customer substation needs large power transformers and HV switchgear. In our 2026 tracking, second-tier European manufacturers quote around 20–32 months for power transformers and the major OEMs 48–60 months or more; HV and MV switchgear commonly runs 18–36 months. See our transformer lead time tracker.
Decide early: fix the substation architecture and reserve manufacturing slots as soon as the connection solution is known, rather than after full design freeze.
3. PERMITS: THE PARALLEL TRACK
A campus of this size usually needs a building permit and an environmental authorisation (classified installation rules for generators and cooling), sometimes a change to the local plan, with a public inquiry. RTE's own grid works have separate permits. At Rantigny, in the Oise, the inquiry for a large project ended in September 2026 with a favourable opinion subject to eight reservations, according to local press.
Decide early: start environmental studies while the grid process runs, not after.
4. LOCAL ACCEPTANCE: THE HIDDEN CLOCK
Water, noise, heat, the identity of the end customer and on-site generation are the questions residents ask. A challenge to a permit can freeze a project for years. Our observatory of challenges in France (in French) tracks the cases.
Decide early: engage the municipality before filing, publish verifiable commitments, and plan heat reuse and water use with local constraints in mind.
THE SEQUENCE THAT SAVES TIME
PTF accepted as soon as possible, capacity in steps matched to the IT ramp
Environmental studies and local engagement started during the grid process
Transformer and switchgear slots reserved once the connection solution is known
A bridge plan for the first phase if full grid power comes later
Not sure which of these clocks is driving your project? That is exactly what we check. Grid connection glossary · Lender due diligence.
FREQUENTLY ASKED QUESTIONS
What has the longest lead time for a 100–200 MW AI campus in France?
Usually the grid connection to RTE's network, which depends on the connection document obtained, the grid works required and their permits. High-voltage equipment and permits come close behind.
Can a 100–200 MW project use RTE's fast-track procedure?
The HTB3 fast-track route is designed for very large loads, typically 400 MW to 1 GW on the 400 kV network at State-identified sites, so most 100–200 MW projects follow the standard procedure.
When should power transformers be ordered?
As soon as the connection solution and substation architecture are known, without waiting for full design freeze, since manufacturer lead times commonly run from around 20 to 60 months or more.