ESOS reporting — the notification, what it contains, and who signs it
ESOS reporting is a private compliance notification to the Environment Agency once per four-year phase — not a public disclosure. Here is what the report must contain, the board sign-off it needs, how it is submitted through MESOS, and the evidence pack that has to stand behind it for eight years.
What ESOS reporting actually is — and is not
One private notification per phase, backed by a retained evidence pack. No annual filing, no publication.
Under the Energy Savings Opportunity Scheme, reporting means notifying the Environment Agency — once per four-year phase — that the organisation has completed a compliant assessment: total energy measured, at least 95% of consumption covered by energy audits or recognised alternatives, lead assessor review done, and board approval given, as required by the ESOS Regulations 2014 2 as amended in 2023 3.
What it is not: a public disclosure. Nothing from an ESOS report appears in the annual report or at Companies House. The public-facing counterpart is SECR — the two regimes are compared line by line in ESOS vs SECR — and the only route to publicity in ESOS is the enforcement register described in ESOS penalties.
The reporting rhythm
One compliance notification per four-year phase, submitted online via MESOS by the phase deadline — 5 December 2027 for Phase 4 — plus annual action-plan progress updates for organisations carrying Phase 4 obligations.
The evidence pack behind each notification is retained for two compliance periods.
What the ESOS report contains
The notification is a structured summary; the weight sits in the evidence pack behind it.
- Undertaking and qualification detailsWho is reporting
- The responsible undertaking, the corporate group it reports for, and the basis on which the group qualified at the 31 December 2026 qualification date.
- Compliance routes usedHow coverage was achieved
- Which parts of consumption were covered by ESOS energy audits or ISO 50001 certification — and confirmation the combined coverage reaches at least 95%. Display Energy Certificates and Green Deal Assessments are no longer permitted routes: regulation 26 of SI 2026/701 omits regulation 34 of the 2014 Regulations.
- Energy consumption and intensityThe numbers
- Total energy consumption, significant energy uses, energy-intensity metrics and an estimate of the savings opportunities identified.
- Energy savings actually achievedNew in Phase 4
- The measures implemented during the compliance period, the saving from each measure in kWh, and each measure's energy-saving category. Only the combined figure across all measures is published — per-measure savings are withheld as potentially commercially sensitive.
- Action plan reviewNew in Phase 4
- The measures proposed in the previous action plan that were not implemented, and why. Unlike action plans and progress updates, this review is not published.
- Sign-offsWho approved it
- The registered lead assessor who reviewed the assessment and the board-level director (or directors) who approved it — both identified in the notification, both dated before the deadline.
The filing mechanics — creating the account, the submission flow, common errors — are covered in ESOS notification, and structured field-by-field record formats are in ESOS templates.
The Phase 4 reporting cycle, step by step
Reporting is the last step of a chain that starts with twelve months of energy data.
Organisations that submitted Phase 3 action plans also carry annual progress-update reporting between notifications — the ongoing obligation most often missed, because it arrives in the quiet years of the cycle. Full date detail is in ESOS deadlines.
Much of this chain now runs through software — energy-data platforms that maintain the dataset continuously and assemble the evidence pack — covered in managing ESOS online.
ESOS reporting — frequently asked questions
Direct answers on contents, publication, deadlines and record-keeping.
What is ESOS reporting?
ESOS reporting is the compliance notification a qualifying organisation submits to the Environment Agency once per four-year phase, confirming it has measured its total energy consumption, audited at least 95% of it (or covered it through routes such as ISO 50001), obtained lead assessor review and board-level approval.
It is submitted online through the MESOS service.
Unlike SECR, nothing is published in the annual report — ESOS reporting is private to the regulator.
What must an ESOS report include?
The notification covers the responsible undertaking and group structure, qualification basis, the compliance route used for each part of consumption (ESOS energy audits or ISO 50001 — Display Energy Certificates and Green Deal Assessments were removed for Phase 4 by regulation 26 of SI 2026/701), total energy consumption and significant energy uses, the lead assessor's details, confirmation of board-director approval, energy-intensity metrics and estimated savings identified, and — new in Phase 4 — the energy savings actually achieved during the compliance period plus a review of the measures in the previous action plan that were not implemented.
The underlying detail sits in the retained evidence pack rather than the submission itself.
Is an ESOS report made public?
No.
The ESOS notification goes to the Environment Agency and is not a public disclosure — the public-facing counterpart in UK energy reporting is SECR, which is published in the directors' report.
The exception is enforcement: organisations penalised for non-compliance can be named on a public register.
When is the next ESOS report due?
The Phase 4 compliance notification is due by 5 December 2027, with qualification assessed at 31 December 2026.
Phase 4 participants who submitted action plans also carry annual progress-update obligations between notifications.
How long must ESOS records be kept?
The evidence pack supporting each notification must be retained for two compliance periods — in practice around eight years — and be capable of standing up to an Environment Agency compliance audit: consumption data, audit reports, sampling rationale, assessor review records and sign-off documentation.
Complete the chain
The stages on either side of the report.
Related guides & references
Energy Savings Opportunity Scheme (ESOS) — the hub
Qualification, phases, audits and penalties — the full ESOS picture
ESOS notification — submitting via MESOS
The where-and-how of the submission this page describes
ESOS vs SECR — how the two regimes differ
Private four-yearly notification vs annual public disclosure
ESOS templates — evidence pack structures
Field-by-field structures mapped to the regulations