ESOS notification of compliance — the MESOS portal guide
Every qualifying organisation must submit its notification of compliance through the Environment Agency’s MESOS (Manage your ESOS reporting) portal — and organisations that do not qualify are advised to file a Do Not Qualify (DNQ) notification instead. Here is what each submission needs, and the Phase 4 deadline of 5 December 2027.
What is the MESOS portal?
Manage your ESOS reporting (MESOS) is the Environment Agency's online service for every ESOS submission — notifications, DNQs, action plans and progress updates.
MESOS — Manage your ESOS reporting 1— is the Environment Agency’s digital service under which the ESOS Regulations 2014 (SI 2014/1643) require large undertakings to notify the ESOS administrator that they have complied with the scheme. It is the sole channel for the compliance notification, the Do Not Qualify (DNQ) notification, and — since the ESOS (Amendment) Regulations 2023 — the Part 6A action plan and its annual progress updates. There is no paper or email route.
If you are new to ESOS entirely, start with the ESOS overview or the full compliance guide; this page focuses specifically on the notification submission itself — what it must contain, how DNQ differs, and the current Phase 4 deadline.
What the ESOS notification of compliance must include
Five components make up a compliant submission — from the audit findings through to a named director's sign-off.
- Total and significant energy consumptionRequired
- The organisation's total energy use for the 12-month reference period covering buildings, transport and industrial processes, plus the portion classified as significant (subject to audit or ISO 50001 coverage).
- Audit findings or ISO 50001 certification detailsRequired
- A summary of the energy audit results covering at least 95% of significant consumption, or the details of a UKAS-accredited ISO 50001 certificate where that route is used instead — see ISO 50001 vs ESOS.
- Energy intensity ratioRequired
- At least one intensity metric (e.g. energy per employee, per square metre, or per unit of output) that lets the Environment Agency and other readers compare consumption across reporting periods.
- Energy-saving opportunities identifiedRequired
- A summary of the cost-effective energy-saving measures the audit or ISO 50001 review identified — the basis for the action plan that follows the notification.
- Board-level director sign-offRequired
- A named board-level director confirms the organisation is compliant before the notification is submitted — a personal accountability step, not a formality.
DNQ — the Do Not Qualify notification
Organisations that expect to be asked about ESOS but do not meet the large undertaking test are advised to file a DNQ, not to do nothing.
A Do Not Qualify (DNQ)notification is for an organisation that has been told it may need to comply with ESOS, or reasonably expects to be asked, but has determined on assessment that it does not meet the large undertaking criteria for the current phase. GOV.UK guidance advises submitting the DNQ through MESOS by the compliance deadline so the Environment Agency’s records are accurate — an organisation that simply does nothing risks being chased for a notification it never owed, or being wrongly flagged as non-compliant on the public register.
Common DNQ scenarios include an organisation that qualified for a previous phase but has since shrunk below the 250-employee or turnover/balance-sheet thresholds, a group restructuring that removed the UK entity which previously triggered group-level qualification, or an organisation that was contacted in error. See ESOS exemptions for the full set of scope edge cases, including group aggregation and de-qualification rules.
File it, don't ignore it
A DNQ notification takes minutes to submit through MESOS and closes the compliance question formally.
Doing nothing leaves an open question mark against the organisation on the Environment Agency's records — the DNQ route exists specifically to avoid that.
How to file the ESOS notification
Five steps take a qualifying organisation from a completed assessment to a submitted notification on MESOS.
Registration on MESOS should not wait until the final weeks of a phase — account setup and evidence assembly both take longer than expected for organisations submitting for the first time. The Phase 4 compliance guide sets out a realistic countdown from the 31 December 2026 qualification date to the 5 December 2027 notification deadline.
ESOS notification — frequently asked questions
Direct answers on the MESOS portal, what to submit, DNQ notifications and the current deadline.
What is the ESOS notification of compliance?
The notification of compliance is the formal submission a qualifying organisation makes to the Environment Agency confirming it has met its ESOS obligations for the phase — the audit or ISO 50001 route, lead assessor review (where required), and board-level director sign-off.
It is submitted online through the Manage your ESOS reporting (MESOS) service, not by post or email.
What is the MESOS portal?
MESOS — Manage your ESOS reporting — is the Environment Agency's digital service for submitting ESOS notifications, action plans and progress updates.
It replaced the previous ESOS notification system ahead of the Phase 3 deadline and is the single route for all Phase 3 and Phase 4 submissions and for Do Not Qualify (DNQ) notifications.
What information does the ESOS notification need?
A compliant notification includes: total energy consumption for the 12-month reference period; the energy audit findings or ISO 50001 certificate details covering at least 95% of that consumption; at least one energy intensity ratio; a summary of energy-saving opportunities identified; confirmation of lead assessor review (unless exempt); and board-level director sign-off confirming the organisation is compliant.
What is a Do Not Qualify (DNQ) notification?
A DNQ notification is submitted by an organisation that was told (or expects) it needs to comply with ESOS but has determined, on assessment, that it does not meet the qualifying criteria for that phase.
GOV.UK guidance advises submitting a DNQ through the MESOS portal by the phase deadline so the Environment Agency's records are correct and the organisation is not chased for a missing notification it never owed.
What is the ESOS notification deadline for Phase 4?
5 December 2027, for organisations that qualify on the Phase 4 qualification date of 31 December 2026.
The notification — audit findings, energy intensity ratios, savings opportunities identified and board-level director sign-off — must be submitted through MESOS by that date.
Is there a public ESOS register?
The Environment Agency publishes ESOS compliance data, including notification status, action plans and progress updates, on a public register.
Non-submission is visible on that register, which is why organisations that genuinely do not qualify are advised to file a DNQ rather than simply doing nothing.
Explore the ESOS guides
Dedicated pages covering every stage of the compliance journey.
ESOS compliance — the full guide
Qualification, routes, sign-off and notification, step by step.
TemplatesESOS action plan and evidence templates
Structured templates mapped to the exact regulatory clause each satisfies.
Phase 4ESOS Phase 4 compliance guide
Qualification checker, what changed from Phase 3, and the 2027 deadline.
ScopeESOS exemptions
Public bodies, de-qualification and the group-structure edge cases.
Related guides & references
ESOS compliance — the full guide
Qualification, routes, sign-off and notification, step by step
ESOS Phase 4 compliance guide
Qualification on 31 Dec 2026 and the 5 Dec 2027 notification deadline
ESOS action plan and evidence templates
Structured templates mapped to the SI 2014/1643 requirements
ESOS exemptions
Who falls outside ESOS, and the DNQ edge cases in detail
ESOS deadlines — all phases
Every Phase 3 and Phase 4 date in one tracker