Free guide: Germany's Energy Efficiency Act explained for data centres (Energieeffizienzgesetz, EnEfG)
- 4 days ago
- 4 min read
Updated: 1 day ago
Germany's Energieeffizienzgesetz (EnEfG) sets the strictest data-centre efficiency targets in Europe — and the deadlines start in 2025. This 25-page guide walks through every obligation that applies to data centre operators, with direct paragraph references to the Act as published (BGBl. 2023 I Nr. 309), the exact PUE and ERF targets you need to hit, the energy management system rules taking effect on 1 July 2025, and the Anlage 3 reporting deadlines.
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What's inside the Energieeffizienzgesetz (EnEfG) guide
Scope and applicability
• Who EnEfG applies to: the 300 kW “data centre” definition under § 3 Nr. 24
• Capacity and energy thresholds that trigger each obligation
• Obligations for IT operators with at least 50 kW capacity under § 12 Abs. 5
Core obligations
• Binding PUE targets
• Binding ERF targets
• Annual public reporting by 31 March each year
• Waste heat avoidance, notification, and reuse obligations
• Penalties for non-compliance
Practical sections
• A complete compliance timeline through 2030
• Worked ERF calculation with realistic data centre numbers
• ERF exemptions
• How EnEfG aligns with the EU's upcoming Minimum Performance Standards
• A section-by-section compliance checklist (Sections A–G)
Written by Markus Wråke who is the CEO of Calentix Energy. He spent nine years as CEO of Energiforsk, Sweden's leading energy research organisation, before joining Calentix to lead its work on turning data-centre waste heat into a low-carbon energy source for district heating networks across Europe.
He holds a PhD in economics from the Stockholm School of Economics and has built his career at the intersection of energy policy, research, and commercial development.
FAQ : Common questions about EnEFG (Energieeffzienzgesetz)
What is the EnEfG (Energieeffizienzgesetz)?
The Energieeffizienzgesetz (EnEfG) is Germany's Energy Efficiency Act, published in BGBl. 2023 I Nr. 309 and in force since 18 November 2023. It transposes the EU Energy Efficiency Directive (2012/27/EU) into German law and goes further by imposing binding energy efficiency and waste heat reuse targets specifically on data centre operators.
Which data centres does EnEfG apply to?
EnEfG applies to any structure or group of structures whose primary purpose is the centralised hosting, connection, and operation of IT and telecommunications equipment, with a non-redundant installed electrical capacity of at least 300 kW (§ 3 Nr. 24 EnEfG). Network nodes that don't perform substantial data processing are excluded.
What are the PUE targets under EnEfG?
Data centres operational before 1 July 2026 must achieve an annual-average PUE of ≤ 1.5 from 1 July 2027 and ≤ 1.3 from 1 July 2030 (§ 11 Abs. 1). Data centres commissioned on or after 1 July 2026 must achieve a PUE of ≤ 1.2 from day one (§ 11 Abs. 2).
What is the ERF target under EnEfG?
The Energy Reuse Factor (ERF, Anteil wiederverwendeter Energie per DIN EN 50600-4-6) applies to data centres commissioned on or after 1 July 2026. The targets are ≥ 10 % from 1 July 2026, ≥ 15 % from 1 July 2027, and ≥ 20 % from 1 July 2028 (§ 11 Abs. 2). Existing data centres have no ERF target under § 11, but §§ 16 and 17 still impose general waste heat obligations.
When do data centres need an energy management system under EnEfG?
All data centre operators must implement an ISO 50001 or EMAS energy management system by 1 July 2025 (§ 12 Abs. 1). Data centres with ≥ 1 MW non-redundant capacity (and publicly owned or operated DCs ≥ 300 kW) must have the system validated or certified by 1 January 2026 (§ 12 Abs. 3). Exemption applies where ≥ 50 % of waste heat is fed into a district heating network and annual energy use is below 7.5 GWh (§ 12 Abs. 4).
What are the EnEfG reporting deadlines?
By 31 March each year, all data centre operators must publish and submit Anlage 3 data for the previous calendar year using the electronic template provided by the Federal Government (§ 13 Abs. 1). Required data includes total electricity consumption, share of renewables, PUE, ERF, cooling system efficiency, water usage effectiveness, and the quantity and temperature of waste heat discharged.
What are the penalties for non-compliance with EnEfG?
Penalties are set out in § 19 EnEfG. Fines can be imposed for failing to meet PUE or ERF targets, failing to implement or certify the required energy management system, failing to submit Anlage 3 reports, or failing to comply with waste heat obligations under §§ 16 and 17. The guide covers each fine category and reference.
Are there exemptions from the ERF target?
Yes. § 11 Abs. 3 lists three grounds: (1) exceptional events outside the operator's control; (2) a binding agreement with a district heating network operator or municipality to accept the heat and build or extend the network within ten years; (3) refusal by the heat network operator to accept a waste heat offer at cost price within six months, provided the DC has the necessary heat delivery infrastructure in place.
How can data centres meet the ERF target without capital expenditure?
Under an Independent Heat Producer (IHP) arrangement, a third party such as Calentix Energy finances, builds, owns, and operates the heat recovery infrastructure and sells the recovered heat to a district heating network. The data centre signs a Heat Access Agreement (HAA) and a Heat Purchase Agreement (HPA) and achieves ERF compliance at zero capex.
Does EnEfG align with EU law?
Yes — and it leads it. In October 2025, the European Commission's Second Technical Assessment under Delegated Regulation (EU) 2024/1364 recommended binding Minimum Performance Standards for all EU data centres. The proposed thresholds align directly with EnEfG § 11, meaning operators complying with German law today are already positioned for the coming EU-wide framework
