Summary
- Lighthouse Reports has filed an Aarhus Convention complaint over data centre environmental disclosure.
- The dispute concerns facility-level energy, water, emissions, and heat information collected by the Commission.
- The Commission’s new rating scheme publishes sustainability indicators while taking account of confidentiality requirements.
A legal complaint has challenged the European Commission’s approach to publishing data centre environmental information, opening a new dispute over how much facility-level energy, water, emissions, and heat data should be visible to the public.
Lighthouse Reports said on 30 September that it had submitted a communication to the Aarhus Convention Compliance Committee. The organisation alleges that the Commission is withholding environmental data collected from operators and that this restricts public access to information needed to assess the local effects of data centre development.
The filing is an allegation, not a finding that the Commission has breached the convention. The compliance process will determine how the complaint is handled and whether the Commission’s approach is considered consistent with its obligations.
The dispute follows the Commission’s 21 September publication of a common EU data centre rating scheme package. The system builds on reporting obligations established under the Energy Efficiency Directive and is intended to classify aspects of data centre sustainability using information submitted to the European database.
Reporting is moving closer to facility performance
The EU reporting regime covers data centres above the relevant power threshold and collects information intended to give policymakers a clearer picture of energy and water performance. The Commission has said the lack of consistent sector-wide information made it difficult to evaluate data centre efficiency or design further regulation.
The September package moves that system from data collection towards visible ratings and future performance policy. The Commission says the label draws on reported indicators while respecting confidentiality concerns, and it has also started work towards minimum performance standards intended to address inefficient technologies.
Lighthouse Reports argues that the published scheme does not go far enough. Its complaint focuses on underlying facility-level figures, including absolute resource use and emissions, rather than only ratios or labels derived from those figures. It argues that communities cannot properly assess the effects of individual sites if the absolute data remains unavailable.
That distinction is increasingly important because efficiency ratios and total resource consumption answer different questions. A large data centre can improve its power usage effectiveness while still consuming more electricity in absolute terms as IT load grows. Water efficiency can show how effectively water is used relative to computing output without, by itself, showing the scale of local abstraction or consumption.
For planning authorities and communities, those absolute figures can become relevant when multiple large facilities cluster around the same grid, water system, or heat network. For operators, however, facility-level information can also expose commercially sensitive details about load, utilisation, capacity, or customers. The Commission’s policy has attempted to balance those competing considerations.
Transparency pressure is increasing
The dispute arrives as Europe’s data centre sector becomes more visible to energy and environmental policy. The Commission’s 2026 package combines the rating scheme with an assessment of sector efficiency and consultation work around minimum performance standards. Its broader energy-system policy also treats data centres as potential participants in grid flexibility, power procurement, and waste-heat reuse.
Those measures require increasingly detailed information about what facilities consume and how they operate. Once regulators collect that data, the question of who else can see it becomes harder to separate from the reporting regime itself.
The Aarhus Convention centres on access to environmental information, public participation in environmental decision-making, and access to justice. Lighthouse Reports argues that environmental information held by the Commission should be disclosed more fully under those principles. The Commission’s published material, by contrast, explicitly refers to confidentiality considerations in determining which reported indicators appear on the sustainability label.
The compliance process will now put that interpretation under scrutiny. Whatever the outcome, operators should expect data centre environmental reporting to move towards more structured measurement and greater regulatory visibility. The unresolved question is how much of that visibility ultimately extends beyond authorities to customers, communities, and the wider public.
