Offer · Regulatory diagnostic and energy trade-offs
Your data center exceeds 500 kW, or your project exceeds 1 MW. You must report your indicators every year and, above 1 MW, reuse your waste heat or show that it is impossible. We help you report accurately and decide before technical choices are locked in.
You receive:
- a statement of your obligations given your capacity and permit date
- PUE, WUE and ERF calculated consistently, with their assumptions
- the waste heat cost-benefit analysis, or a review of it
- for a project, a comparison of cooling options on all three indicators
First conversation confidential and with no commitment. Fixed fees proposed in writing before any assignment. Best-efforts obligation.
The problem. Three indicators are now looked at together: energy (PUE), water (WUE) and reused heat (ERF). They do not always point the same way. Cooling that improves PUE can raise water use, and heat rejected at low temperature is hard to reuse. These trade-offs are made at the concept stage: once the site is delivered, there is little room left.
THREE INDICATORS, THREE QUESTIONS
WUE (Water Usage Effectiveness): water used by the site relative to IT energy, in litres per kWh
ERF (Energy Reuse Factor): the share of energy consumed that is reused outside the data center, for example in a heat network. An ERF of 0.20 means the equivalent of 20% of the energy consumed is reused
WHAT YOU MUST DO, BY CAPACITY
| Threshold | Obligation | Deadline |
|---|---|---|
| 500 kW and above installed capacity, per site registration | Report administrative, environmental and energy information each year on a digital platform, and publish part of it on a dedicated web page whose address is sent to ADEME | Before 15 May, for the previous calendar year. New sites: within two months of commissioning |
| 500 kW and above | Submit sustainability indicators, including PUE, WUE and ERF, to the European data center database | Each year, before 15 May |
| 1 MW and above | Reuse waste heat: the site is deemed compliant if its ERF is at least 0.20. This threshold can be raised to 0.40 by ministerial order | Since 1 January 2026 |
| 1 MW and above, impossibility shown | Exemption possible if a cost-benefit analysis shows technical or economic impossibility. The operator must still reuse the feasible share | Permits filed before 1 January 2026: analysis due before 1 October 2027 |
Non-compliance: formal notice with up to a year to comply, then an administrative fine of up to €50,000 per data center. The sanction may be published. Several points are still to be set by ministerial order: the detailed reporting fields, how impossibility is assessed, and a distance threshold beyond which the absence of a heat user exempts the site.
HOW TECHNICAL CHOICES AFFECT THE THREE INDICATORS
| Choice | PUE | WUE | ERF |
|---|---|---|---|
| Dry air free cooling | Good in a temperate climate | Low | Low: low-temperature heat, hard to reuse |
| Adiabatic or evaporative cooling | Very good | Higher, especially in summer | Low |
| Direct liquid cooling | Good | Depends on heat rejection: dry coolers or towers | More favourable: warmer water is easier to reuse if a heat user exists |
| Heat pump to raise temperature | May worsen depending on metering boundary | Neutral | Higher |
These trends are indicative: results depend on climate, density, setpoints and metering. Two points often decide everything: a heat user nearby (heat network, industrial site, greenhouses), which is a siting question, and metering quality, without which no indicator can be defended. See waste heat and district heating in France.
WHAT WE DO
For an operating site: check metering and data, calculate the three indicators consistently year on year, prepare the report, and if an ERF of 0.20 cannot be reached, build or review the cost-benefit analysis. For a project: build the three indicators into the brief, compare cooling options, and look for a heat user from site selection onwards.
Geoffrey Garriga
Energy compliance & building services
Building services and energy engineer, 15+ years: tertiary decree, regulatory energy audits, building automation and control systems, HVAC and electrical design. Read his profile →
HOW IT WORKS
WHAT WE COMMIT TO
Review of connection documents and the announced energisation date for a European data center developer, ahead of its investment decision. Audit of high-voltage equipment sourcing for a petrochemical group.
We do not design, build or sell equipment. No commission, no brokerage. Never on both sides of the same project.
Confidentiality agreement before any document. Professional liability insurance. Best-efforts obligation: only RTE and Enedis commit to capacity and a date.
Sources: French law no. 2025-391 of 30 April 2025 (DDADUE); decree no. 2025-1382 of 29 December 2025, Energy Code articles D. 236-1 to D. 236-7 and R. 237-1 to R. 237-7, as analysed by Gide Loyrette Nouel and DCmag (in French); Delegated Regulation (EU) 2024/1364. General information, to be checked against the official text for a specific file.
FREQUENTLY ASKED QUESTIONS
My data center is 600 kW: am I concerned?
Yes for annual reporting, before 15 May. The waste heat reuse obligation only applies from 1 MW of installed capacity.
What if my ERF does not reach 0.20?
You may be exempted if a cost-benefit analysis shows technical or economic impossibility. You must still reuse the feasible share.
Is a good PUE enough?
No. A very low PUE achieved with evaporative cooling can come with high water use, and low-temperature heat is hard to reuse. The three indicators must be traded off together.