Data centre pushback has been building for years. Complaints range from power bills to water for cooling to grids that cannot take another hall. Ireland is the most prominent example, with data centres already using 23% of the country’s electricity.
Yet Brussels still has to build compute if it wants to stay in the same AI race as the US and China. That means answering those complaints without stopping the buildout.
On 21 September the Commission adopted a delegated regulation that puts an A-to-G grade on how a site uses power and water. Energy Commissioner Dan Jørgensen told reporters that “we want AI, of course, we want data centers, we want Europe to be a place for investments, but it’s in the interest of them and of the European Union that we do it in a way that is sustainable.”
Will the new grading system reduce those complaints, or will operators spend the next year saying the letters measure the wrong thing?
What the EU A-to-G Data Centre Label Measures
The public face of the label is two letter grades.
The first is PUE, power usage effectiveness. It asks a simple question. Of all the electricity the building draws, how much reaches the servers, and how much is lost to cooling, lights and other kit? A perfect hall would score 1.0. Class A is 1.15 or better. Class G is worse than 1.9. Those bands are in Annex I of the act.
The second is WUE, water usage effectiveness. It asks how much water the site uses for each unit of IT energy. Class A is 0.1 or better. Class G is worse than 1.0.
There is no third letter for clean power. The label still shows a source breakdown: on-site generation, PPAs, guarantees of origin, and low-carbon power, including nuclear. That is leftover from a spring fight over nuclear. Ten member states, led by France, said a renewables-only box would treat nuclear as dirty. The draft that was meant to land with the June sovereignty package slipped. Monday’s text is what replaced it.
The scheme also notes what a site gives back. Waste heat reused in homes or industry. Extra clean generation on site. The ability to ease off when the grid is tight. The Commission’s headline number is that reusing about half of European data-centre waste heat would heat four million homes.
Reuters notes the scheme does not cap how much power a site can use, and does not force operators to publish their total load. The grade is a ratio, not a megawatt figure. A small efficient hall and a huge efficient hall can get the same letter.
Which Data Centres Must Display the EU Sustainability Label
A 2024 rule already made operators report into an EU database if their IT kit draws at least 500 kW. This new act takes those filings and turns them into a public label.
500 kW is a real hall, not a cupboard of office servers. If the computers inside need half a megawatt or more, the site is in. Below that, the label is optional. Jørgensen told reporters that smaller sites can join if they want but they do not have to.
The Commission also opened a consultation on Monday for minimum performance standards. Those would be actual limits, not a letter on a webpage and they have talked about presenting them in spring 2027. That rule, not this sticker, is what could decide whether a weak score becomes a problem for new builds.
When the First Sticker Appears
The database is supposed to generate the first labels by 15 August 2027, then every year after that. Parliament and the Council have two months to object to the delegated act as a whole.
August 2027 is also when several EU AI Factory and EuroHPC machines are due to come up, including Gaia in Krakow. Operators are reading the dates together, which is why this is being treated as a planning document rather than a communications exercise.
In the 2024 reporting cycle only about 36% of in-scope sites filed. The 2027 label is generated from whatever the database holds that year, so a weak filing rate still means a partial public picture.
What DIGITALEUROPE Already Said
DIGITALEUROPE represents European operators and the American hyperscalers with sites here, and it put its objections on paper well before September 21. The December 2025 position is still the one that matters.
The paper says a flat PUE and WUE scale punishes climate. A hall in southern Europe will post a worse PUE than an identical hall in Sweden because of cooling degree days, not because the kit is sloppy, and DIGITALEUROPE wants those figures climate-normalised before anyone prints a letter on them.
It also says that publishing WUE alongside total water use lets a competitor reverse-engineer IT load, which is the number operators treat as a trade secret. The Commission’s own recital claims the public fields were chosen to stay inside existing confidentiality rules. DIGITALEUROPE does not think the current pair manages that.
What the EU Data Centre Label Does Not Do
Monday’s act publishes a grade. It does not stop a site from connecting, cap how many megawatts it can draw, or set the minimum standard the Commission still wants next year.
The grade itself is split. A site can land A on water and E on power. The renewables box can look clean while the letters look poor, or the other way around.
For the companies pouring concrete, including Mistral’s Paris cluster, two questions matter now. Which year’s running data will the first grade use? And does a G in a hot country become a planning problem before the 2027 factories open? That fight starts this week.
Author: Grace Sharp
See Also:
EU AI Factories 2026: Europe’s 5 Sovereign Hubs
