EU reporting crosswalk
How the Joule Ledger relates to what EU data centers must report and how they will be rated. It shows what the ledger covers and, as plainly, what it does not. As of 3 November 2026; not legal advice.
Rating criteria and the ledger
| EU criterion | Joule Ledger equivalent | Account or meter point | Coverage |
|---|---|---|---|
| Energy grade (PUE) | Overhead Ratio, OR(M4/M3), from 12 months of energy | Intake at M4; energy at M3 | Covered |
| Water grade (WUE) | — | — | Not covered: the ledger meters energy, not water |
| Energy sourcing (new clean generation, guarantees of origin) | Intake records energy in, by meter | Intake | Partial: the source attributes and certificates sit outside the ledger |
| Grid flexibility | Reserve records changes in stored energy over time | Reserve | Partial: the ledger records storage, not grid services |
| Waste heat reuse readiness | Waste and Overhead quantify heat leaving the system | Waste, Overhead | Partial: readiness is an infrastructure status the ledger does not assess |
| Cooling degree days | — | — | Not covered: a climate statistic |
Criteria as summarized in Latham & Watkins, 25 September 2026 and Freshfields, 24 September 2026, updated 8 October 2026.
The yearly reporting indicators
Under Delegated Regulation (EU) 2024/1364, data centers of 500 kW or more report 24 indicators each year by 15 May, grouped as energy and sustainability, information and communication technology, and data traffic (DLA Piper, 9 September 2024). The energy indicators draw on facility and IT energy, which the ledger records at M4 and M3. ICT capacity and data-traffic indicators are outside the ledger. Check each field against Annex II of the regulation on EUR-Lex before you rely on any mapping.
What the ledger adds
- Attribution below the rack, at M1 and M2, which the EU rules do not require
- A closure check that shows whether the energy figures are consistent
- Decision Yield: energy per useful decision, not just per unit of IT energy
- Labels and grades that say how each number was obtained and who checked it
Careful wording
JL-26, the Joule Ledger, is a proprietary measurement method published by AAERL. It is not a consensus standard and has not been adopted by any standards body or regulator. JL-26 reports PUE consistent with the definitions of ISO/IEC 30134-2:2026 and relates its accounts to the EU indicators above. It does not make anyone compliant; that depends on the official text and your own reporting.
Questions
Can a Joule Ledger Assessment replace our EU report?
No. Your report goes to the European database in the required format. An assessment can give you checked energy figures to report from.
Sources
Keep reading
Take the next step.
How Joule Ledger accounts and meter points relate to EU data-center rating criteria and reporting indicators: what JL-26 covers and what it does not.