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The Joule Ledger Assessment

AAERL measures one system with you, at the meter points you choose, and reports a ledger graded Witnessed. $9,800 for one system.

Apply for an assessment See all prices

Reviewed 5 November 2026

What you get

  • Scoping: the system, the meter points (M1 to M4) and the task set
  • Measurement with AAERL present, using calibrated analyzers and the window rules
  • A closed ledger, or a not-closed result with its residual diagnosed
  • The five ratios that apply, each with meter point, label and direction
  • A written report graded Witnessed

Who it is for

AI labs, data-center operators, chip makers and device companies that need an energy figure a buyer, investor or regulator can check. One system per assessment; a whole facility may need a wider scope, agreed in writing.

How it works

  1. Send an application describing the system and the meter points you can reach.
  2. We agree the scope, task set and dates in writing.
  3. We measure together, run the closure check and calculate the ratios.
  4. You receive the report and the ledger.

Price and limit

  • $9,800, one payment.
  • At most 300 a year. The limit reflects what we can deliver well; we do not run countdowns.
  • Prices rise 10% each year. A price you have paid stays fixed for the period you paid for; the increase applies from your next purchase or renewal, and we tell you before it does.

What it is not

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. An audit grade (Declared, Witnessed or Replicated) says who checked a result and how. It is not a certification, an accreditation or a regulatory approval.

Questions

Can we publish the result?

Yes, as a Witnessed result under the edition and revision it cites, with the report available on request.

Does the assessment certify compliance with EU rules?

No. It measures and reports. The crosswalk shows how the ledger relates to EU indicators; compliance is a legal question.

Keep reading

Labels and gradesHow JL-26 labels every energy result (Measured, Estimated, Projected), grades who checked it (Declared, Witnessed, Replicated) and labels science claims.Meter points M1 to M4The four Joule Ledger meter points, from chip (M1) to facility (M4), what each includes, and why figures from different boundaries cannot be compared.AdvisoryEnergy advisory from AAERL: monthly access to the authors of the Joule Ledger for your measurement plans, reviews and reports.EU reporting crosswalkHow 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.

Take the next step.

The Joule Ledger Assessment: a Witnessed-grade energy audit of one system, rack or facility at declared meter points, with a report. $9,800.

Apply for an assessment See all prices