From the First Reporting Period: The European Commission's Report on the Energy Efficiency of Data Centers in the EU

Data centers in the European Union with an installed IT power demand of at least 500 kW must make their energy and water figures public, and report them to a European database. The European Commission has now assessed the first round of those reports. Its report to the European Parliament and the Council is dated "Brussels, 21.9.2026," numbered "COM(2026) 500 final," and covers "the first reporting period (May-September 2024)." The copy read here is the one the Council of the European Union circulated to its delegations.

Who reported

"770 data centres reported their data in the first reporting period, representing around 36% of the estimated total of data centres in the EU falling under the reporting requirement," the report says. Six member states reported none, and five reported fewer than three, which the report says gives "a limited picture of the sector in those regions." The estimated total, a footnote explains, was built from several sources, among them commercial databases and inputs from national associations and industry. It includes data centers above 500 kW and those above national reporting thresholds, such as 300 kW in Germany.

More are coming. For the second reporting period the Commission "has already received preliminary data from at least 30% more data centres," which it will analyze in a later report. And not all of the first round was deemed reliable. Of the reported data, 70.1% are "deemed to be reliable," and because not every data center reported every indicator, "the number of data points differs per indicator."

An average built from part of the data centers that should report is a first reading, not a census. Whatever the averages below say, they say it of the data centers that reported in the first period.

Power use

The report calls PUE, or Power Usage Effectiveness, "a key measure of energy efficiency in data centres," and defines it as "the ratio of total facility energy consumption to IT equipment energy consumption." Lower is better, "with values typically ranging from 1.0 (the theoretical ideal where every single watt is utilised for IT equipment) to 2.0 or more in less efficient facilities."

In 2024, "the average reported PUE of data centres in the EU stood at 1.36," and national values ranged "from 1.15 to 1.66." The average is weighted by each facility's total energy consumption, and a footnote says "681 data centres reported PUE values deemed reliable," and that "In 5 Member States, less than 3 data centres submitted their data, potentially leading to non-representative figures." The report says the results "indicate substantial potential for improving PUE and energy efficiency in European data centres."

Water use

Water use, the report says, "depends primarily on the cooling technology employed." Water-based or evaporative systems "consume substantial amounts of water," while air-side or liquid-direct cooling operates with "minimal to no water use." WUE, or Water Usage Effectiveness, is "the ratio of total water input to IT equipment energy consumption," and here too lower is better.

In 2024, "the average reported WUE of data centres in the EU was 0.58," with national values "ranging from 0.07 to 1.28." The average counts only data centers that reported some water use. A footnote excludes those "relying on dry cooling technologies," and says "458 data centres reported WUE values deemed reliable." The report adds that "in some Member States, WUE figures are dominated by a few large operators with single facilities, that happen to report higher water input," and that "WUE tends to increase with facility size, likely due to the rare use of evaporative cooling in smaller facilities."

A water average that leaves out the dry-cooled sites describes the sites that use water, not the whole fleet.

What the Commission proposes

The report finds that "roughly half of reporting data centres in Europe exceed a recommended PUE baseline of 1.5 and/or a recommended WUE baseline of 0.4." It does not set standards yet. "The minimum performance standards could set thresholds for key performance indicators such as PUE, WUE, and REF, or a combination of them, ensuring a minimum level of performance is met by all data centres." The report also says that a second delegated regulation, concerning "the establishment of the common Union rating scheme," has been adopted. As a first step, the report says, the Commission is publishing a call for evidence and an open public consultation, "followed by an impact assessment to evaluate policy options."

A threshold set on these scores would turn a reported number into a design limit. A campus planned in Europe already has the recommended baselines to read its own figures against, before any standard is set.