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Prometheus Search

How to read a site in six steps.

You do not need to know planning law or the electricity grid. This guide walks through the map, then explains every term you will meet.

  1. Find a place

    Type a town or an address in the search box, or simply zoom on the map. France is shown first; Luxembourg, Belgium, the Netherlands and Germany follow.

  2. Read the territory before clicking

    Turn layers on and off in the Layers panel. Thick black lines are the 225 and 400 kV grid, small squares are substations, symbols mark power plants. Hover a department to see its grid and generation at a glance. Hatched areas are where a project would be blocked.

  3. Click a parcel

    Zoom until the parcel outlines appear, then click inside one. The site sheet opens and fills in source by source; a thin moving line means a source is still answering.

  4. Read the verdict

    The black block at the top is the finding: buildable, buildable with conditions (attention points), or not buildable. Red squares are blocking, ochre squares need attention, black squares are clear.

  5. See what can be built

    Four classes of data centre, from a small edge site to an AI training campus, are read against the parcel's size, zoning, grid connection and water. Open a class to see why it fits or not, and what it usually needs.

  6. Take the next step

    Each criterion ends with what it means for your project and who to contact next: the town's planning department, the grid operator (RTE or Enedis), or the authority in charge. Every line names its source and date.

Open the map →

From electricity to tokens

Every AI answer travels a long way. A power plant makes electricity; high-voltage lines carry it; a substation lowers the voltage for one site; inside the building it is conditioned and cooled away as heat; racks of accelerators compute; models turn that computing into words; and every word is counted in tokens, each with a small cost in energy. Prometheus Search shows where steps 1 to 4 can happen. Each step has a chapter in Prometheus Knowledge.

From electricity to tokens: power plant, high-voltage line, substation, data-centre building, racks of accelerators, AI models, tokens.1Generation

Power plants make electricity.

400 kV2Transmission

High-voltage lines carry it across the country.

 3Connection

A substation lowers the voltage for one site.

 UPS4The building

Inside, power is conditioned and the heat is removed.

2.2 m5Accelerators

Racks of GPUs and other chips do the computing.

6Models

Clusters train and run AI models.

Thegrid is ready.7Tokens

Every answer is counted in tokens, and each costs energy.

Sheet X-001 · From electricity to tokens · not to scale

The four kinds of data centre

KindPowerWhat runs insideGrid connectionLand
Edge siteunder 1 MWStandard servers (CPUs) and a few GPU servers for inference.Low or medium voltage from the distribution grid (Enedis, HTA ≤ 50 kV).From a few hundred m².
Enterprise or colocation1 to 10 MWMixed CPU and GPU servers, mostly air-cooled racks.Medium voltage (HTA, 20 kV), often a dedicated feeder.About 0.5 to 2 ha.
Cloud or hyperscale hall10 to 100 MWCloud CPU and GPU fleets at higher rack densities; liquid cooling appears.High voltage from RTE: HTB1 (63–90 kV) or HTB2 (150–225 kV), usually a dedicated substation.About 2 to 10 ha.
AI training campus100 MW to 1 GWDense GPU/accelerator clusters, liquid-cooled racks far above air-cooled densities.Very high voltage: HTB2 (225 kV) or HTB3 (400 kV), typically a new substation on the line.From about 10 ha, often several assembled parcels.
12 m5 m
Edge site — a container. A shipping-container room by a car park or telecom mast: a few racks, cooled by a rooftop unit, fed from the local grid.
GENTR≈ 60 m20 m
Enterprise or colocation — a building. A two- or three-storey building with chillers on the roof, diesel generators and a transformer in the yard.
≈ 250 m50 m
Cloud or hyperscale hall. Long single-storey halls side by side, a cooling plant, and a dedicated high-voltage substation on site.
400 kV≈ 1 km200 m
AI training campus. Several large buildings, a new substation on the 225–400 kV line, liquid-cooling plants and room to grow.

Indicative ranges used for prospection. Actual needs depend on the design, and connection capacity is only confirmed by the grid operator.

Glossary

Cadastral parcel
The official plot of land, with a national reference number.France divides all land into numbered parcels (section + number). The reference lets you find the owner through the land registry and the rules that apply to that exact plot. Prometheus never shows owners who are private individuals.
PLU — local urban plan
The town's rulebook saying what can be built where.The Plan Local d'Urbanisme (PLU, or PLUi when several towns share it) splits the territory into zones, each with its own rules on use, height, density and access. A data centre must fit the zone's rules or the plan must be modified, which takes months.
Zones U, AU, A, N
U built-up · AU to be built · A farmland · N natural.U zones are already urbanised and usually the easiest. AU zones are planned for future development, sometimes subject to a development plan. A zones protect farmland: building is restricted. N zones protect nature, forests or landscapes: building is generally prohibited. Sub-codes (UX, AUe…) refine the use; activity zones are the natural home of data centres.
RNU — national planning rules
Default national rules where a town has no local plan.Where no PLU exists, the Règlement National d'Urbanisme applies: building is generally limited to already built-up areas. The town hall is the first contact.
PSMV — safeguarded sector
Historic district where heritage rules apply to every project.A Plan de Sauvegarde et de Mise en Valeur protects historic centres. Works need the approval of the Architecte des Bâtiments de France. Possible for small sites, rarely realistic for a large data centre.
Natura 2000
EU network of protected natural sites.Sites designated under the EU Habitats (SIC/ZSC) and Birds (ZPS) directives. Any project likely to affect a site needs an impact assessment, and most industrial projects inside a site are refused.
Substation
Where the grid changes voltage and where large sites connect.A large data centre connects to the transmission grid at a substation, existing or built for it. The nearer the substation and the higher its voltage, the more power can be delivered and the faster. Only the grid operator (RTE) can confirm available capacity.
HTA, HTB1, HTB2, HTB3
French voltage levels: ≤ 50 kV, 63–90 kV, 150–225 kV, 400 kV.HTA (up to 50 kV) is the distribution grid run by Enedis: enough for small and medium sites. HTB1 (63–90 kV), HTB2 (150–225 kV) and HTB3 (400 kV) form the transmission grid run by RTE. Roughly: tens of megawatts need HTB1 or HTB2; hundreds of megawatts need 225 or 400 kV.
MW — megawatt
Unit of power: how much electricity a site draws at once.1 MW powers roughly a few hundred racks of ordinary servers. An enterprise data centre draws a few MW; a hyperscale hall tens of MW; an AI training campus hundreds of MW, as much as a mid-sized city.
ZRE — water deficit area
Area where water is chronically scarce.Zones de Répartition des Eaux are areas where demand exceeds the resource. Water withdrawals are tightly controlled there, which matters for evaporative and liquid cooling.
Seismic zone
From 1 (very low) to 5 (strong); construction rules tighten with the zone.France is divided into five seismic zones. From zone 2 upward, buildings of importance must follow earthquake-resistant design rules (Eurocode 8), which adds cost but rarely blocks a project in mainland France.
Natural and technological risks
Hazards listed for the town: floods, industrial sites, dams…The State lists the risks each town is exposed to (Géorisques). Flood and industrial risks matter most for data centres: they affect insurance, building rules and sometimes outright prohibitions in risk-prevention plans (PPR).