Pillar sub-scores
A pillar mixes what is endured and what is chosen; a grade is not the average of the pillars. Energy ●●●●
EnergyE
Missing: PUE (announced energy efficiency), Waste-heat recovery — commitment.
Water ●●●●
WaterC
Missing: Cooling technology + announced water volume.
Land & biodiversity ●●●○
Land & biodiversityB
Missing: Ecological corridors (TVB), Site ground footprint, Avoid-reduce-offset (ERC) measures, Designated for urbanisation in a supra-municipal plan, Planning-document compatibility procedure under way.
Local impact ●●○○
Local impactB
Missing: Announced jobs, Announced tax revenue, Observed level of opposition, Elected officials' position (voted facts only).
Transparency & governance
Transparency & governance–
“Rated C on site, but E on “Energy”.”
This site is among the 80% of the fleet connected to an already-saturated substation. Fleet figures →
This site is in France — the country's site index: C (55.9). See the country index →
What the environmental case file states
2023-05-11 · 29 pages · read the opinion (PDF)
Energy and heat
Announced PUE1.8p.15
Concernant le site actuel TH3, le PUE est passé de 1,8 en 2018 à 1,67 en 2021 principalement en raison de l ’optimisation des installations.
Waste heat recoveryunder_studyp.16
12 L’étude de faisabilité jointe au dossier mentionne p.11 la « capacité de pouvoir élever la température de 70 à 80°C de l’eau d’un réseau de chaleur urbain et ceux à hauteur de 3880 kW soit 334 m3/h (eau claire) soit 33 988 MWh par an ce qui serait équivalent à l’alimentation en chauffage annuel de 645 logements en considérant un besoin moyen de 6 kW/logement ».
Generators and fuel
Backup generators (count)11 groupesp.2
À l’échelle du site, l’alimentation de secours repose sur 11 groupes électrogènes, alimentés par 140 m3 de fioul stockés dans 5 cuves enterrées.
Backup generator fuelfuel_oil_or_dieselp.2
À l’échelle du site, l’alimentation de secours repose sur 11 groupes électrogènes, alimentés par 140 m3 de fioul stockés dans 5 cuves enterrées.
Fuel tanks (count)4 values
5 cuvesp.2À l’échelle du site, l’alimentation de secours repose sur 11 groupes électrogènes, alimentés par 140 m3 de fioul stockés dans 5 cuves enterrées.
1 cuves · 4 cuvesp.2Le projet nécessite l’installation d’une cuve de fioul enterrée d’une capacité de 80 m3 en supplément des quatre cuves existantes, afin d’alimenter les trois nouveaux groupes électrogènes de secours.
2 cuvesp.8Actuellement, le site comporte également quatre cuves enterrées de fioul (deux cuves de 60 m3 sur la partie sud et deux cuves de 80 m3 seront installées sur la partie nord).
Fuel tank unit volume2 values
60 m³ · 80 m³p.8Actuellement, le site comporte également quatre cuves enterrées de fioul (deux cuves de 60 m3 sur la partie sud et deux cuves de 80 m3 seront installées sur la partie nord).
Backup autonomy72 hp.11
Avec 11 groupes électrogènes au total, dont trois pour le nouveau bâtiment P2, développant une puissance électrique totale de 23,1 MW, le maître d’ouvrage prévoit une autonomie électrique de 72 heures (p. 208), ce qui nécessite un total de cinq cuves enterrées (dont une nouvelle pour le nouveau bâtiment) d’une capacité totale de 360 m3 pour stocker la quantité nécessaire de fioul (p. 250).
Neighbourhood
Distance to nearest dwellings30 mp.7
Les premières habitations sont situées à 30 m des limites sud de propriété du site (p. 44).
Distance to nearest sensitive site300 mp.7
L’établissement scolaire le plus proche du site est une école primaire et élémentaire, à environ 300 m au sud du site (p. 52).
Footprint and buildings
Plot area6.5 hap.2
Le projet s’implante dans la zone d’activité de Gomberville sur une parcelle d’environ 6,5 hectares à moins de 100 m d’habitations et d’un site Natura 2000.
Building footprint1,520 m²p.2
Le projet consiste à construire, sur la partie nord de la parcelle, un nouveau bâtiment (P2) dédié au stockage de données informatiques (datacenter), d’une emprise au sol d’environ 1 520 m2, d’une hauteur R+2 et reposant sur un niveau semi-enterré (p.28).
Emissions
Refrigerant leakage53.5 tp.17
L’ensemble des fuites de fluide frigorigène sont évaluées à environ 53,5 t CO 2.
Measured noise
| Measure | Day | Night |
|---|---|---|
| Recorded levelsp.19 | — | — |
| Recorded levelsp.19 | — | — |
Il apparaît que les niveaux acoustiques sont compris entre 36,9 et 47,4 dB(A) de jour, et entre 35,2 et 45,1 dB(A) de nuit (p. 154).
Toutefois, afin de confirmer les résultats de la modélisation, les campagnes de mesures seront à poursuivre et étendre aux futures ZER potentielles afin de s’assurer que le site TH3, avec l’ajout des activités des P0, P1 et P2, respectera les valeurs réglementaires en limite de propriété et en ZER (valeur maximale de 50 dB(A) en période diurne et de 47 dB(A) en période nocturne).
State recorded in the impact assessment, before operation.
ICPE classificationICPE — the French regime that authorises, frames and inspects an activity liable to create a risk or a nuisance. Each number designates the activity concerned in the national nomenclature. Being classified does not mean being dangerous: it means being regulated, and therefore inspected.
- 3110Combustion — plants with a total thermal input ≥ 50 MW (IED directive)
- 2910Combustion — plants below that threshold
- 4734Storage of petroleum products (the generators' fuel)
- 1185Fluorinated greenhouse gases (cooling refrigerants)
Tracked indicators
| Indicator | Value | Reading | State | Source |
|---|---|---|---|---|
| Energy | ||||
| Local grid carbon intensity How much CO₂ is emitted to produce the electricity the site will consume, based on the regional grid. The lower the value, the better. | 17.6 gCO2e/kWh | Measured | RTE eCO2mix (données définitives) — France national CO2 intensity, 12-month mean 2025-07-30..2026-04-30 (17.6 gCO2/kWh, n=13196 half-hourly) — accessed 2026-07-30 | |
| Grid connection capacity / proximity How easily the site can be connected to the power grid: available capacity and distance to the nearest substation. | grid saturated at the connection point | Measured | Caparéseau (RTE S3REnR) — poste MERANTAIS at 2.4 km: 0.0 MW available hosting capacity (updated 13/06/2026) — accessed 2026-07-14 | |
| Grid congestion / connection queue How congested the local grid is: the more saturated, the more the connection competes with other users. | moderate local grid congestion | Measured | Caparéseau (RTE S3REnR) — poste MERANTAIS at 2.4 km: 67.0% reserved-capacity fill rate (updated 13/06/2026) — accessed 2026-07-14 | |
| PUE (announced energy efficiency) The announced energy efficiency: total electricity used versus what actually powers computing. Closer to 1 is better. The lower the value, the better. | — | — | Not looked for yet We have not looked for this yet. It is dropped from the calculation and does not penalise the site. | — |
| Heat-network connectability Whether the site can valorise its waste heat via a district-heating network: distance to the nearest network and presence of a connection obligation (priority development perimeter). | no heat network nearby | Measured | France Chaleur Urbaine (data.gouv, lov2) — réseau de chaleur le plus proche : aucun réseau dans ~1,5 km (point→segment, Lambert 93) ; dans un PDP : non ; réseau classé : non → eloigne (>1000 m) — accessed 2026-09-30 | |
| Waste-heat recovery — commitment Operator commitment level to valorise the site's waste heat (delivered / signed contract / study / intention / none). | — | — | Not looked for yet We have not looked for this yet. It is dropped from the calculation and does not penalise the site. | — |
| Water | ||||
| Local water stress Water tension in the area: in an already water-scarce region, withdrawals weigh more heavily. | moderate water stress | Measured | VigiEau — drought-restriction status at point (accessed 2026-07-14) — accessed 2026-07-14 | |
| Water body status The ecological health of the affected river or aquifer, per the EU classification (from 'high' to 'bad'). | water body in poor status | Measured | EEA WISE (WFD 2022) — water body FRHR99A-F4656000 'ruisseau le rhodon': ecological status class 4/5 — accessed 2026-07-14 | |
| Basin withdrawal pressure How intensively water is already withdrawn from the basin: a heavily-tapped basin ill affords a new user. | low abstraction in the basin | Measured | Hub'Eau BNPE — commune 78356: 0.003 Mm3 withdrawn in 2023 (all uses, provisional pressure band) — accessed 2026-07-14 | |
| Cooling technology + announced water volume The cooling technology chosen and the water volume it will consume, as announced by the operator. | — | — | Not looked for yet We have not looked for this yet. It is dropped from the calculation and does not penalise the site. | — |
| Land & biodiversity | ||||
| Overlap / distance to protected areas How close the project is to protected natural areas (Natura 2000, nature reserves…). | protected natural area within 1 km | Measured | INPN / IGN API Carto — Natura 2000 & ZNIEFF overlap by distance ring — accessed 2026-07-14 | |
| Soil status (artificialized / natural / agricultural) What the land was before: already built (brownfield), natural, or farmland — sealing farmland or nature weighs most. | previously developed land | Measured | IGN API Carto GPU — PLU zoning 'UAi7c16' — accessed 2026-07-14 | |
| Ecological corridors (TVB) Whether the project severs a wildlife corridor (green-and-blue network). | Not disclosed | — | Absent from the file We read the public file and the information is not in it. It counts as a zero in the grade. | — |
| Site ground footprint The SITE's ground footprint in hectares — the land the project takes up (buildings, roads, parking, substation, retention basins), not the building print alone: the larger, the greater the land impact. The lower the value, the better. | — | — | Not looked for yet We have not looked for this yet. It is dropped from the calculation and does not penalise the site. | — |
| Avoid-reduce-offset (ERC) measures Measures to avoid, reduce or offset harm to soil artificialisation and biodiversity. (Heat recovery moved to E6/E7, Energy pillar.) | — | — | Not looked for yet We have not looked for this yet. It is dropped from the calculation and does not penalise the site. | — |
| Designated for urbanisation in a supra-municipal plan not scored · contextual fact Is the site designated for urbanisation in a planning document above the municipality? A contextual fact, published as such: it neither improves nor worsens the grade. | — | — | Not looked for yet We have not looked for this yet. It is dropped from the calculation and does not penalise the site. | — |
| Planning-document compatibility procedure under way not scored · contextual fact Is a procedure under way to make the planning document compatible with the project? A contextual fact: we follow the instrument, not the intention — the land status only changes the day the procedure completes. | — | — | Not looked for yet We have not looked for this yet. It is dropped from the calculation and does not penalise the site. | — |
| Local impact | ||||
| Municipality socio-economic profile The host town's social profile. A safeguard: a project must never improve its grade by locating in a vulnerable town. | municipality's social profile: favourable | Measured | INSEE Filosofi (via data.gouv) — commune 78356: median disposable income 28610 €/consumption unit — accessed 2026-07-14 | |
| Absorption capacity (project size vs municipality) The project's size relative to the town: a very large project in a small town disrupts more. The lower the value, the better. | 2.4611 MW per 1000 inhabitants | Announced | INSEE populations légales via geo.api.gouv.fr — Magny-les-Hameaux (9386 hab.) ; puissance 23.1 MW (DCWatch ODbL, export 7dd5b5e9). Ratio MW/1000 hab, calcul déterministe — accessed 2026-07-14 | |
| Technological hazard / nearby Seveso sites The presence of hazardous industrial sites (Seveso) nearby, adding risk to the surroundings. | no technological-risk site on record within 5 km, to our knowledge | Measured | Géorisques — registre des installations classées (statut Seveso) qui ÉNUMÈRE : aucun établissement Seveso (seuil haut/bas) dans 5 km (site-de-contrôle A1 validé). — accessed 2026-10-06 | |
| Announced jobs The number of permanent jobs announced, relative to project size. More is better. The higher the value, the better. | — | — | Not looked for yet We have not looked for this yet. It is dropped from the calculation and does not penalise the site. | — |
| Announced tax revenue The tax revenue the project would bring to the town, as announced. | — | — | Not looked for yet We have not looked for this yet. It is dropped from the calculation and does not penalise the site. | — |
| Observed level of opposition The scale of observed opposition: appeals, petitions, mobilizations reported by the press. | Not disclosed | — | Absent from the file We read the public file and the information is not in it. It counts as a zero in the grade. | — |
| Elected officials' position (voted facts only) Elected officials' position as expressed by official votes only (council decisions), with no personal judgment. | Not disclosed | — | Absent from the file We read the public file and the information is not in it. It counts as a zero in the grade. | — |
| Transparency & governance | ||||
| Consultation / consent / governance (procedural proxies) The quality of the democratic process: public inquiry held, environmental authority opinion, appeals, CNDP referral. | — | — | Not looked for yet We have not looked for this yet. It is dropped from the calculation and does not penalise the site. | — |
| Documentation transparency / file availability How genuinely accessible the project's file is to the public: published studies, figures and commitments. | — | — | Not looked for yet We have not looked for this yet. It is dropped from the calculation and does not penalise the site. | — |
Operator response
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State of the available data
26 indicators tracked · 11 measured · 1 announced (unverified) · 3 absent from the file · 11 not looked for yet.
Grade history
Methodology 0.3.0 scoremydatacenter.org