Brussels Proposes A-to-G Energy Labels for Large Data Centres

The European Commission proposed on 21 September 2026 a common EU rating scheme that would give every data centre above 500 kW of capacity an electronic label grading its energy efficiency, its water efficiency, where its electricity comes from and how it behaves towards the grid. The scheme arrives as a delegated regulation supplementing the recast Energy Efficiency Directive and amending the Commission's 2024 regulation that created the European database on data centres.

It is one of three pieces published the same day as the Data Centre Energy Efficiency Package. The others are a report to the European Parliament and the Council assessing what operators have reported so far, and a call for evidence on minimum performance standards, which the Commission's Directorate-General for Energy says runs 12 weeks and closes on 14 December 2026.

The database writes the label, not the operator

No new filing is involved. Under the regulation, the European database generates an electronic label automatically for each data centre that has submitted its information and key performance indicators, by 15 August 2027 and every year after that. Each label runs from 15 August of its issue year to 15 August of the next and is published in all official EU languages. Because the indicators come from reporting operators already do under the 2024 scheme, the Commission says the system creates no additional administrative burden. The database has been running since September 2024, with reporting rounds completed in 2024 and 2025.

Energy efficiency is graded A to G on Power Usage Effectiveness, the ratio of a facility's total electricity draw to the electricity reaching the computing equipment itself. Class A means a PUE of 1.15 or less; class G means anything above 1.9. Water efficiency is graded the same way on Water Usage Effectiveness, from class A at 0.1 or below to class G above 1.0. Alongside the two grades, each label carries the site's name, operator, location, size category and date of entry into operation, a QR code linking to its database entry, a breakdown of energy sourcing across on-site renewable and nuclear generation, power purchase agreements, guarantees of origin and unspecified sources, cooling degree days, whether the facility offers flexibility to the grid, and whether it is "waste heat reuse ready".

One definition will do more work than either grade. A data centre counts as contributing new clean generating capacity only where its power purchase agreements are with renewable or nuclear plants no more than ten years old, or substantially refurbished within the past ten years. That is the line between paying for electricity that already existed and paying for electricity that would not exist otherwise.

The rules with teeth are still a year away

A label describes; it does not forbid. The Energy Efficiency Directive gives the Commission power to propose minimum performance standards for data centres, and the consultation launched the same day is the preparatory work for exactly that, with a legislative proposal planned for the second quarter of 2027. The Commission has not said what those standards would require or which technologies they would phase out.

Getting even this far took longer than Brussels wanted. The Register reported on 22 September that the original A-to-G plan was delayed after industry criticism, that Moody's had warned grades could affect financing and collateral requirements rather than merely embarrass operators, and that a provision requiring clean-energy certificates to come from the same region as the data centre was loosened in a revised draft to allow sourcing from anywhere in the EU. A certificate bought in one member state does nothing for a strained grid in another.

The honest reading is that transparency will move money before it moves a single cooling system. Operators facing a public class F on water in a water-stressed region will hear about it from lenders and enterprise buyers well before any minimum standard exists to force a change. The strongest argument against reading too much into the grades is one the Commission concedes by shipping a contextualising document with every label: PUE tracks local climate, and WUE means something different in Ireland than in Spain, so a poor letter is not always a poorly run building.