Data centre sustainability: what will you be able to declare on 15 May 2027?
10 min read
A data centre’s technical manager opens the draft specification for the plant-room extension planned for the autumn. The legal team asks a question that seems off-topic: “what do we declare on 15 May 2027?” It is not really a question about 2027: that reporting date covers the 2026 calendar year — the year now under way, of which seven months have already gone. If a meter that is missing today — on water, on waste heat, on renewable energy — does not come into service in the coming weeks, those seven months stay without data for good: a year of measurement cannot be recovered after the fact.
The obligation, the threshold, and why EN 50600-4 alone is no longer enough.
Article 12(1) of Directive (EU) 2023/1791 is precise on the threshold: “By 15 May 2024 and every year thereafter, Member States shall require owners and operators of data centres in their territory with a power demand of the installed information technology (IT) of at least 500kW, to make the information set out in Annex VII publicly available.” The same threshold returns, identical, in Article 1 of Delegated Regulation (EU) 2024/1364, which limits its scope to operators “with an installed information technology power demand of at least 500 kW” — the same regulation cited, for its definitions only and not for this threshold, by the operational guidance on the PUCD single authorisation.
Annex VII of the Directive, in setting out what to report, referred to “the CEN/CENELEC EN 50600-4 ‘Information technology – Data centre facilities and infrastructures’, until the entry into force of the delegated act adopted pursuant to Article 33(3).” That delegated act now exists: it is 2024/1364. Since it entered into force, the text to comply with is no longer the general technical standard alone, but Annexes I and II of the Regulation, with their own measurement methodology.
The exemption is not automatic: the word is “exclusively”.
Article 12(2) reads: “Paragraph 1 shall not apply to data centres used for, or providing their services exclusively with the final aim of, defence and civil protection.” The word that decides is “exclusively”: a data centre that also serves other functions — administrative, commercial, research — alongside defence or civil protection does not fall within the exemption, even where a substantial share of the load is dedicated to those two purposes. For mixed-use defence sites, the distinction has to be drawn at the level of the facility or group of facilities, not the department: it is the data centre as a whole, not the individual rack, that has to answer for its declared final aim.
The timetable, and the arithmetic of derogations that have already run out.
Article 3(1) of the Delegated Regulation sets the rhythm: “By 15 September 2024, then by 15 May 2025, and every year thereafter, reporting data centre operators shall communicate to the European database the information and key performance indicators set out in Annex I and Annex II regarding the data centre they operate.” Reporting takes place “via a national reporting scheme if the Member State where the reporting data centre is located has established such a scheme”; otherwise operators communicate “directly to the European database” — whether Italy has established one has not been verified against a primary source here. The information reported “shall cover the calendar year immediately preceding the reporting year”: the 15 May 2027 return covers 2026.
The Regulation allowed two shortcuts, each with its own expiry written into the text. Paragraph 2 applies “for the first reporting period”: an operator that “cannot monitor and gather” the indicators in Annex II, points 1(d), 1(e), 1(h)-(l) and 1(o)-(r) “for technical reasons” “may omit this information explaining the reasons for this omission”. Paragraph 3 applies “for the first two reporting periods”: a colocation operator unable to calculate the indicators in points 2(a) and 2(b) “shall estimate and indicate the percentage of the data centre computer room floor area that the information communicated to the European database covers”.
The periods, in sequence, are four: 15 September 2024, 15 May 2025, 15 May 2026, 15 May 2027. The first derogation covers only the first period, the second covers the first two. By the 15 May 2027 return neither remains — and that return is precisely the one covering 2026, the year running now.
The letters that could be left out are the ones with a real meter behind them.
That list is not arbitrary: these are the indicators that need a physical instrument in a precise location. Total energy consumption (E_DC) and energy consumption of IT equipment (E_IT); total water input (W_IN) and potable water input (W_IN-POT); reused waste heat (E_REUSE) and its average temperature (T_WH); average IT equipment intake air temperature set point (T_IN); and the four renewable-energy entries — total, with guarantees of origin, from power purchase agreements, from on-site sources. The rest of Annex II — floor area, installed power demand, IT capacity — can be drawn from datasheets and drawings already on file. These cannot: they need a meter, in service, at the right point, for twelve consecutive months.
The category of a measurement point is a plant design decision, not a figure to fill in.
The Regulation does not simply ask for a value: it specifies where to take it. Total energy consumption (E_DC) “shall be measured at the input of the data centre system before the supply transfer switchgear”, with “measurement points … set at the primary and secondary supply of energy and at every additional supply” — back-up generation included, measured separately. Energy consumption of IT equipment (E_IT) is normally measured “in accordance with the category 1 methodology for the calculation of the PUE set out in the CEN/CENELEC EN 50600-4-2 standard”, at every uninterruptible power system (UPS) connected to the IT equipment. Where there is no UPS — direct-current data centres, for example — E_IT “can be measured at the power distribution unit (PDU) […], or in accordance with the category 2 methodology […], or at a measurement point that data centres will specify”: three alternatives, not interchangeable — declaring one in the specification and delivering another on site is the first thing an audit finds.
For water the hierarchy is explicit: total water input (W_IN) is measured “by using the methodology set out in the CEN/CENELEC EN 50600-4-9 standard WUE Category 2, or if not possible, the methodology set out in Category 1” — the same family of standards that governs availability classes and cabling in the data hall — while potable water input (W_IN-POT) always stays at “WUE Category 1”. Moving a measurement point from a general meter to a dedicated branch is an intervention on a switchboard, pipework or the electrical distribution: it has to be designed before ordering materials, not discovered when the reporting form arrives.
The register of points and devices: ten years, from day one.
Annex II opens with a line almost no specification repeats: “For all monitoring, data centre operators shall keep a record of the measurement points and measurement devices used, for a period of at least 10 years.” This is not a technical report to be written on the eve of reporting: it is instrument traceability — which meter, at which point, since when — built while the equipment is installed, and not something anyone can credibly reconstruct afterwards. The Commission, for its part, collects the data in a “European database on data centres” (Article 12(3)), “publicly available on an aggregated level”, and encourages — without obliging — operators with an installed IT power demand equal to or greater than 1 MW to take into account the best practices of the European Code of Conduct on Data Centre Energy Efficiency (Article 12(4)).
What to put in the specification.
- Measurement point and declared category, indicator by indicator — for E_IT and W_IN, which of the Regulation’s alternatives will be used (UPS or PDU, Category 1 or Category 2), not a generic “measured in accordance with the regulation”.
- Dedicated meters on the branches the Regulation treats as distinct: primary supply, secondary supply, every additional supply — back-up generation included, measured separately — and every uninterruptible power system connected to the IT equipment.
- Water measured at every entry point of the declared data centre boundary, not a single meter upstream: W_IN has to be summed source by source, environmental, power, security and IT functions included.
- A register of measurement points and devices opened at initial commissioning, updated at every replacement, never reconstructed at the time of the first useful return.
- Proof that the instrumentation delivered actually meets the declared category: a calibration certificate or verification report for each meter, not just the component’s datasheet.
How to check it at acceptance.
Acceptance testing does not end when the meters are switched on: it checks that every installed measurement point matches what the specification declared, at the right category — an E_IT measured at the PDU when the specification called for the UPS is a non-conformity, not an equivalent variant. It checks that the points on primary supply, secondary supply and every additional supply are genuinely distinct, not a single totaliser split after the fact by a calculation. On water, it checks that every entry point at the boundary has its own meter. Finally, it opens the register of points and devices and checks that it is already populated, with an installation date and a reference to the instrument — not a document left blank to be filled in “when needed”.
The point.
The Directive asks for information to be made public; the Delegated Regulation turns it into indicators measured at precise points, with a declared category and a register that has to withstand a ten-year inspection. This is exactly the work we bring to a specifications and compliance exercise: the 500 kW threshold, the category of each measurement, the points on distinct branches become verifiable clauses, and the acceptance testing that proves them arrives together with the as-built documentation — not a file written afterwards, but the same trail to produce at an inspection. Energy, water, temperatures, waste heat and IT capacity, together with the infrastructure’s traces and as-built records, stop being scattered files and become a single map of the site and the network: that is where an AI flags a branch consuming out of range, a meter that has stalled for weeks, a temperature off its set point, and a team closes the fault before it becomes a gap in the register — for a data centre, together with CSIDIA, the group’s other company. Where an AI is needed on plant data, it runs within the client’s perimeter: on autonomous on-premise machines that need no deep integration into the existing network, or on dedicated cloud with a data centre in Italy, with shared management between the two teams.
Do you need to instrument a data centre above 500 kW today, or check whether the meters already installed will meet the category you will declare in 2027? Talk to an engineer: the site visit is free, and the measurement point is designed before the switchboard is ordered, not at reporting time.