WP#94 - IT Work Capacity (ITWC) v1 Metric - A Methodology
The Green Grid · TGG ITE Metrics Work Group
A Green Grid white paper describing a methodology for computing the total server work capacity (Cserv) of a data centre via PerfCPU for EU EED compliance.
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Overview
The Green Grid's WP#94 is dated 27 March 2025 and was prepared by The Green Grid ITE Metrics Work Group. The paper introduces the ITWC v1 metric: a methodology for calculating the total server work capacity (Cserv) of a data centre. The calculation serves requirements under the EU Energy Efficiency Directive (EED). The paper is available through a registration-based download, and this summary relies on the public library page.
The method uses a PerfCPU value for each processor. The paper includes an error analysis of estimating PerfCPU from a physical core-count trendline. Lookup tables are also given, with PerfCPU values by CPU SKU and by core count, manufacturer and generation. The two approaches allow a direct lookup when the exact SKU is known and an estimate based on core count when it is not.
Searchable PerfCPU Excel tables and an ITWC calculation tool, together with an online calculator, accompany the paper. This makes the method easy to use in practice and gives a repeatable calculation route for audits. The limit of the paper is that v1 covers servers only; future versions are stated to add storage and networking work capacity. Related documents include Delegated Regulation (EU) 2024/1364 and ETSI EN 303 470. This record rests on the abstract only; for the detailed coefficients and tables, the paper itself should be consulted.
Key points
- Dated 27 March 2025; prepared by The Green Grid ITE Metrics Work Group.
- ITWC v1 calculates total server work capacity (Cserv) for EU EED requirements.
- Includes error analysis of PerfCPU estimated from a physical core-count trendline.
- Provides lookup tables by CPU SKU and by core count, manufacturer and generation.
- Searchable PerfCPU Excel tables and an ITWC calculation tool accompany it.
- Future versions will cover storage and networking.
- Related documents: Delegated Regulation (EU) 2024/1364 and ETSI EN 303 470.
Using it in design
- In the server catalogue, add CPU SKU and PerfCPU fields.
- Compute Cserv per hall for EED reports.
- Fall back to core-count lookup tables when SKU information is missing.
- State the lookup method used (SKU or core count) in the report.
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Who should read it
Energy and sustainability engineers and compliance officers reporting data centre work capacity under the EU EED.
Related standards
- Delegated Regulation (EU) 2024/1364
- ETSI EN 303 470
Publication details
- Authors
- TGG ITE Metrics Work Group
- Publisher
- The Green Grid
- Year
- 2025
- Document number
- WP 94
- Document language
- English
- Source type
- Industry body
- Access
- Citation only
- Licence
- Copyright retained; citation only — the publisher’s terms apply to the original document
Original licence note
Download requires a free TGG account sign-in and is governed by The Green Grid Terms of Use; summary and facts from the public library landing page; full text not redistributed.
Citation
TGG ITE Metrics Work Group (2025). WP#94 - IT Work Capacity (ITWC) v1 Metric - A Methodology. The Green Grid. WP 94. https://www.thegreengrid.org/resources/library-and-tools/wp-94-itwc-methodology-calculate-server-work-capacity-cserv-data
Events on this subject
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Related sources
All sources on this topicThe Green Grid 2024
WP#92 - TGG's Position on the Metric to Calculate ICT Server Capacity (Cserv) Under the EU EED Delegated Regulation (2024/1364)
In the EED reporting export, include a Cserv field computed from PerfCPU per server SKU.
- Context: EU EED Delegated Regulation 2024/1364.
The Green Grid 2023
WP#90 - Assessment of the Use of SPEC SERT Suite Measured Data to Create a Data Center Work per Energy Metric
For EED reporting, prepare to compute work capacity from SERT-derived values (see WP#94).
- The white paper is dated 29 August 2023.
European Commission 2026
Report from the Commission to the European Parliament and the Council on the energy efficiency of data centres in the EU - COM(2026) 500 final
Set the PUE target for new designs against the bands in the report (below 1.2 excellent, above 1.5 needs improvement) and possible future minimum-standard thresholds, noting that the 500-1000 kW class averaged 1.64.
- EU data centres consumed 68 TWh of electricity in 2024, expected to reach 114 TWh by 2030 (3.2% of EU electricity).
European Commission 2026
Annexes 1 to 3 to Commission Delegated Regulation C(2026) 3472 - EU data centre energy (PUE) and water (WUE) efficiency classes, data centre label, and amendments to Delegated Regulation (EU) 2024/1364
Translate PUE and WUE targets into A-G classes: class A needs a design PUE of 1.15 or below and WUE of 0.1 or below; the class D boundary is 1.5 and 0.6. Write the class target into the design specification.
- WUE classes: A <= 0.1; B 0.1-0.2; C 0.2-0.4; D 0.4-0.6; E 0.6-0.8; F 0.8-1.0; G > 1.0.
European Commission 2026
Commission Delegated Regulation C(2026) 3472 of 21.9.2026 supplementing Directive (EU) 2023/1791 and amending Delegated Regulation (EU) 2024/1364 as regards the establishment of a common Union rating scheme for data centres (main act)
As labels will be issued every year from 15 August 2027, set PUE and WUE class targets (Annex I) at design stage for new and existing sites and build the metering infrastructure to the reporting requirements.
- Labels are generated automatically by the European database every year from 15 August 2027 and are publicly available electronically in all official Union languages.
European Commission, DG ENER (AIT, Borderstep Institute, EY) 2025
Assessment of next steps to promote the energy performance and sustainability of data centres in EU, including the establishment of an EU-wide rating scheme - Second technical report
Align the PUE target of new designs with the proposed MPS: design PUE below 1.3 and operational PUE below 1.4 in the first three years; for existing sites plan the path to below 1.5 by 2030.
- MPS feasibility was tested across 27 data centre archetypes with selected best available techniques (BAT).