SWR Data Lab, the data team of the German public broadcaster SWR, published its investigation on tagesschau.de on 6 November. The technology site heise online summarised it two days later.

The Energy Efficiency Act (Energieeffizienzgesetz) requires operators to publish the electricity and water consumption of each larger data centre. SWR searched the websites of about 30 of Germany’s largest operators but found no figures for more than half of them. Many did not respond to SWR’s enquiries or refused to provide the information. These include the major industry players Equinix, NTT and CloudHQ.

The German Datacenter Association (GDA), the industry association, points out that an unanswered press enquiry is no evidence of a breach of the law. SWR, however, could not find the figures on most companies’ websites either.

Data centres use almost four per cent of Germany’s electricity, according to the digital industry association Bitkom. Bitkom says Germany has 100 data centres with a connected load of at least five megawatts. The federal government wants to double data centre capacity by 2030.

Register lists fewer than a quarter of the largest

Germany’s Federal Ministry for Economic Affairs and Energy (BMWE) confirms the publication obligation. In August the ministry launched a national data centre register, but it lists fewer than a quarter of the 100 largest data centres. The ministry said many operators submitted their data to it but refused to have it published in the register. Operators may decide for themselves where to publish the data.

The ministry does not consider monitoring necessary because the obligation is set out in law and applies to everyone. Bernhard Wegener, professor of public law and European law at the University of Erlangen-Nürnberg, considers this problematic for the rule of law. Wegener said the companies’ practice is incompatible with the law: ‘The public has a right to this data.’

Companies cite trade secrets

Equinix said figures for individual data centres could reveal to competitors where the company is growing and investing. The company says it meets all its legal obligations. NTT disclosed only its total consumption for 2025, equivalent to the annual consumption of about 450,000 households. NTT refused to give figures for individual data centres, citing the trade secrets exemption in the EU Energy Efficiency Directive.

German law contains no such exemption. The Federal Office for Economic Affairs and Export Control (BAFA), which collects the data, said it has not agreed with anyone to withhold data on trade secret grounds. The GDA justifies the companies’ reticence by saying that data centres are highly sensitive sites. A legal opinion commissioned by the organisation AlgorithmWatch finds that consumption data are protected trade secrets only in exceptional cases, SWR reported.

The government is also preparing an amendment that would exempt trade secrets from the publication obligation. The change would meet the wishes of Bitkom and the GDA. If the Bundestag passed it, companies could classify their consumption as a trade secret more easily than they can now, SWR said. The EU directive already contains a similar clause. SWR reported that Die Zeit had found the clause was taken almost word for word from a lobbying organisation. Zeit said the clause may breach the Aarhus Convention, which requires environmental information to be publicly available.