What it is about
Part 4‑8 establishes CUE as the indicator for CO2 emissions in the operational phase, introduces measurement categories, and sets out the rules for calculation, emission factors, and reporting. It is aimed at data center managers, operations managers, ICT managers, and general contractors.
CUE does not assess staff, floor space, or water, nor the productivity of the data center; it applies only within the data center boundary, and the standard sets no limit or target value (EN 50600‑4‑8:2022, Introduction, Clauses 1 and 4).
Core requirements in our own words
CUE is an annual value in kilograms of CO₂ per kilowatt-hour of IT energy.
The ideal value is zero; there is no upper limit. Emissions and IT energy are recorded for the same twelve months; the measurement frequency determines the next rolling value. Clauses 5 and 6.2.1.
Two categories determine which sources count.
Category 1 considers only electrical energy from external and internal sources and only CO2; Category 2 also includes all other energy sources and emission sources as CO₂ equivalents, for example natural gas for combined heat and power, refrigerant losses, or insulating gases. Clause 6.2.2.
The emission factor comes from the supplier and must be approved.
The energy supplier determines the factors and conversions, approved by the regional authority; where regional values are not available, national or international reference values apply. Stating the source is mandatory. Annex C.1, Clause 8.1.2.1.
A report states the data center, the value, the category, and the end date.
The category appears as an index on the abbreviation, and the boundary conditions must match those of the PUE report; on request, the PUE value and PUE category form part of the evidence. Clauses 8.1.1 and 8.1.2.2.
Derived indicators follow the rules of PUE.
Interim values carry the prefix “i” with the time period, subsystems “p”, design values “d”; where a pPUE is reported, the pCUE must also be reported. Clauses 8.4.2 to 8.4.5.
Non-electrical energy is converted into kilowatt-hours.
Diesel, natural gas, hydrogen, or district cooling enter the balance with the supplier’s conversion factors; only where these are not available should the example values of the standard be used. Annex B.
From our seminars: two misconceptions
“CUE is our carbon footprint.”
The indicator covers the use phase within the data center boundary, that is, purchased electricity, on-site generation, and in Category 2 further operational emissions. From seminar practice: the large block of a greenhouse gas balance lies in the manufacture, transport, and disposal of the components, and CUE does not reflect it (Clauses 1 and 4).
“With green electricity, CUE is taken care of.”
The emission factor for purchased electricity must come from the supplier and be approved by the authority; certified renewable energy may then also come from abroad. From seminar practice: test runs of the standby generator and refrigerant losses are usually small, but in Category 2 they belong in the calculation as CO2 equivalents (Annex C.1, Clause 6.2.2.3).
Where Part 4‑8 applies in a project
Planning and site
The design CUE is derived before commissioning from the infrastructure specifications and the climate at the site, together with a plan for dCUE and dPUE across the target IT loads (Clause 8.4.5).
Reporting
If you report under the Greenhouse Gas Protocol, Category 1 corresponds to the emissions from purchased electricity, and Category 2 additionally to the direct operational emissions; this is the assessment of DCE academy, not a requirement of the standard.
Operation
The partial CUE for power distribution, air supply, and cooling shows which subsystem drives the emissions and whether a measure has had an effect (Clause 8.4.4).
This saves you a CO2 figure in the sustainability report whose factors nobody can substantiate in an audit (Annex C.1).
Status and revision
- Current edition
DIN EN 50600‑4‑8:2023‑08, German edition of EN 50600‑4‑8:2022 (December 2022); preceded by the draft E DIN EN 50600‑4‑8:2022‑04.
- International
ISO/IEC 30134‑8:2022; according to the European foreword, the European Standard is based on its content.
- Revision
no ongoing revision known. Committee CLC/TC 215, national mirror committee DKE/GK 719.
- Last reviewed
EN 50600‑4‑8
Frequently asked questions
The ratio of the CO2 emissions attributable to the data center over one year, in kilograms, to the annual energy consumption of the IT equipment, in kilowatt-hours (Clause 5).
In Category 1, only the CO2 from electrical energy, generated on site or purchased; in Category 2, all energy sources and further emission sources of operation as CO2 equivalents (Clause 6.2.2).
No. Neither the German Energy Efficiency Act (EnEfG) nor Commission Delegated Regulation (EU) 2024/1364 requires CUE. Both call for other indicators of the series, such as PUE, REF, ERF, and WUE (EnEfG Annex 3, as of 13 November 2023; Regulation, Annexes II and III).
From the energy supplier, approved by the competent regional authority; alternatively, national or international reference values apply. The source, values, and year of the factors must be stated in any publication (Annex C.1, Clause 8.1.2.1).
Both use the same boundaries and the same IT energy in the denominator; when CUE is reported, the corresponding PUE value should be reported as well, but the accuracy of the IT measurement may differ (Clauses 5, 6.1 and 7).
Seminars
Related seminars
- DC-21008
Data Center Sustainability & Efficiency
5 days · In person
Greenhouse gas accounting under Scopes 1 to 3, sustainability reporting, and the indicators of the 4-x series with their system boundaries; this saves you a CO₂ figure in the report that does not match the balance.
Next date: 7–11 Jun 2027, Munich · GermanPrice plus VAT: €6,990 Training path 1/4
DC-21001Data Center – General Principles
3 days · In person · Live webinar · Video course
Introduction to climate neutrality, the Greenhouse Gas Protocol, and the indicators according to EN 50600‑4-x.
Next date: 19–21 Oct 2026, onlinePrice plus VAT: €4,195
All prices plus VAT; the price is the same in every format.
- DIN EN 50600‑4‑8:2023‑08 (German edition of EN 50600‑4‑8:2022), national foreword of the German edition and European foreword, Introduction, Clauses 1, 3.1, 4, 5, 6.1, 6.2, 7, 8.1 to 8.4, Annexes A, B, C
- ISO/IEC 30134‑8:2022
- Commission Delegated Regulation (EU) 2024/1364 of 14 March 2024, Annexes II and III
- German Energy Efficiency Act (Energieeffizienzgesetz, EnEfG) of 13 November 2023, Annex 3
- DCE academy seminar practice: Data Center Sustainability & Efficiency (session November 2025), Data Center – General Principles (session April 2026)
Glossary terms
- Carbon Usage Effectiveness (CUE)
- CO₂ equivalent
- emission factor (EFC)
- CUE category
- partial CUE (pCUE)
- design CUE (dCUE)
- interim CUE (iCUE)
- greenhouse gas
- Greenhouse Gas Protocol (Scopes 1 to 3)
