On 21 September 2026, the European Commission adopted a common rating scheme for data centres. Each site will receive two letters from A to G, one for energy efficiency and one for water use. The label creates no ban and no mandatory works. But it makes sites publicly comparable, and it lays the ground for binding minimum performance standards.
For developers and the investors and lenders behind them, this matters more than it first appears.
WHAT THE REGULATION SAYS
The text is a delegated regulation, C(2026) 3472, supplementing the Energy Efficiency Directive (EU) 2023/1791. It builds on data that data centres with at least 500 kW of installed IT power already report each year to the European database. Ratings are calculated automatically from those reports.
| Class | Energy (PUE) | Water (WUE, litres per IT kWh) |
|---|---|---|
| A | ≤ 1.15 | ≤ 0.1 |
| B | 1.15 to 1.25 | 0.1 to 0.2 |
| C | 1.25 to 1.35 | 0.2 to 0.4 |
| D | 1.35 to 1.5 | 0.4 to 0.6 |
| E | 1.5 to 1.7 | 0.6 to 0.8 |
| F | 1.7 to 1.9 | 0.8 to 1.0 |
| G | > 1.9 | > 1.0 |
Source: Annex I to Commission Delegated Regulation C(2026) 3472, 21 September 2026. WUE is based on freshwater entering the site.
The label will also show:
The share of electricity bought from assets built or refurbished within the last 10 years
Whether the site provides flexibility to the grid: yes or no
Whether it is ready to supply waste heat: yes or no
A climate indicator for the location, which does not change the letters
Actual energy and water volumes remain confidential.
TIMELINE
The European Parliament and Council can still object to the text, but cannot amend it. In parallel, the Commission opened a consultation on binding minimum performance standards for new or retrofitted data centres (energy, water, waste heat, grid services), closing on 14 December 2026. A legislative proposal is expected in Q2 2027. The rating will also serve as a reference in other EU legislation, including the upcoming Cloud and AI Development Act.
WHAT IT CHANGES FOR COMMUNITY ACCEPTANCE
Until now, developers could stay general about water and energy. With a public, comparable letter, that will no longer be possible. An E, F or G rating will hand opponents a ready-made argument in public meetings and local press. An A or B rating, especially on water, will become one of the strongest arguments in a consultation file. See our guide to data center crisis management and 7 levers of community acceptance.
WHAT IT CHANGES FOR LENDERS AND FUNDS
A new due diligence item. A project's design, especially its cooling system, largely determines its future letters. A site designed today for a mediocre rating may need upgrading if minimum standards become binding from 2027. For a lender, that means additional capex risk, or even impairment.
Trade-offs to understand. Saving water often costs electricity, and vice versa. And the rating does not adjust for climate: a site in southern Europe is more exposed than one in the Nordics. These trade-offs should be made deliberately, at design stage.
A French advantage. The label explicitly identifies nuclear power among low-emission sources. For sites supplied by the French grid, that is a favourable point in how electricity origin is presented.
Grid flexibility becomes visible. The grid flexibility box ties directly into grid connection: a site that can modulate demand is a better neighbour for the grid operator.
QUESTIONS TO ASK ON ANY PROJECT
Which cooling technology, and what trade-off between water and power?
Is the site waste-heat ready, with an offtaker nearby?
Can it offer grid flexibility?
What happens to the project if minimum thresholds are imposed in 2027?
These questions are now part of our due diligence for lenders and funds.
FREQUENTLY ASKED QUESTIONS
What is the EU data centre A–G rating?
A common rating scheme adopted by the European Commission on 21 September 2026. Each data centre of at least 500 kW receives one letter for energy efficiency (PUE) and one for water use (WUE), calculated from data it already reports.
Does the rating create obligations?
Not directly: no ban and no mandatory works. But the Commission is consulting until 14 December 2026 on binding minimum performance standards, with a legislative proposal expected in Q2 2027.
What PUE is needed for an A energy rating?
A PUE of 1.15 or less. A G rating corresponds to a PUE above 1.9.
Why should lenders care?
A project's design determines its future ratings, and a poorly rated site could need upgrading if minimum thresholds become binding.