ESOS · Reporting requirements
ESOS reporting requirements in the UK: what you report, notify and publish
The ESOS reporting requirements in the UK are set by the ESOS Regulations 2014 as amended in 2023 and 2026: an ESOS report, a notification of compliance, an action plan and three progress updates, most of which the Environment Agency then publishes.
Each output has its own contents list in the Regulations, and this page sets them out with the provision for each and the person who owes it.
The ring follows the reporting dates for Phase 4, from the 2026 amendments to the last progress update in 2031.
In one table
ESOS reporting requirements UK, one line each
The core requirements of Phase 4 in the order they fall, with the written output each one produces.
The Phase 4 compliance guide reads each one against its regulation in detail.
| Requirement | Who | When | Provision |
|---|---|---|---|
| Test every UK group member against the size test | Responsible undertaking | On 31 Dec 2026 | Sch 1; reg 15 |
| Measure total UK energy consumption over a 12-month reference period | Responsible undertaking | Period ending by 5 Dec 2027 | reg 22 |
| Identify significant consumption, if chosen: at least 95% of the total | Responsible undertaking | With the calculation | reg 25 |
| Calculate an intensity ratio for each organisational purpose | Responsible undertaking | With the calculation | reg 25C |
| Audit the significant or total consumption, or rely on ISO 50001 | Responsible undertaking | Within the period | regs 26–27, 33 |
| Appoint a lead assessor and have the assessment reviewed | Responsible undertaking; lead assessor | Before notifying | reg 21 |
| Notify the assessor’s approval body of completion | Lead assessor | Within 7 days of the review result | reg 21(2A) |
| Produce the ESOS report, with savings achieved and the plan review | Responsible undertaking | Before 5 Dec 2027 | regs 27A, 27D, 27E |
| Confirm the assessment | One or two responsible officers | With the notification | regs 30, 31 |
| Notify compliance through MESOS | Responsible undertaking | By 5 Dec 2027 | reg 29 |
| Keep the evidence pack | Responsible undertaking | To at least 5 Dec 2035 | reg 28 |
| Notify the action plan | Responsible undertaking; officer confirms | By 5 Dec 2028 | reg 34A |
| Notify three progress updates | Responsible undertaking; officer confirms | By 5 Dec 2029, 2030, 2031 | reg 34B |
| Publish the notified data, plans and updates | Environment Agency (scheme administrator) | Within six months; EA names 10 Jun 2028 | reg 10 |
Whether an organisation is in at all is a separate question, worked through on the ESOS qualification page.
Six written outputs
What ESOS makes you put in writing
ESOS is often described as an audit, but what the law asks a participant to hand over is a sequence of written outputs, each with its own contents list.
The ESOS report is the participant’s own record of the assessment, and the notification of compliance is the part of it the regulator receives.
The responsible officer’s confirmation travels with the notification, and with the action plan and each progress update.
The Environment Agency, as scheme administrator, then publishes the parts that Schedule 3 marks for publication, and every action plan and progress update.
The evidence pack under regulation 28 sits behind all of it and is kept, not filed, to at least 5 December 2035 for Phase 4.
The ESOS reporting guide follows the same outputs as filed, kept and published records, and the ESOS templates page gives a working shape for each.
- 1
ESOS report
Produced before 5 December 2027 under regulation 27A, with the savings achieved and the action plan review.
- 2
Officer’s confirmation
One or two responsible officers confirm scope, compliance and correct information under regulations 30 and 31.
- 3
Notification of compliance
The Schedule 3 column 2 items for the participant’s route, through MESOS by 5 December 2027, under regulation 29.
- 4
Publication
The column 3 items, the number of participants and the list of notifiers, published under regulation 10.
- 5
Action plan
Measures, dates and kWh savings, or a nil statement, notified by 5 December 2028 under regulation 34A.
- 6
Three progress updates
What was implemented and the savings achieved, by 5 December 2029, 2030 and 2031 under regulation 34B.
Regulation 27A
The ESOS report: what it must contain
Regulation 27A requires a responsible undertaking to produce an ESOS report for each ESOS assessment, before the compliance date for that period.
The report began with Phase 3: regulation 27A(2) disapplies it for assessments for compliance periods ending on or before 5 December 2019.
SI 2026/701 regulation 14 added a second carve-out: from Phase 4 no report is needed where the participant is deemed compliant through ISO 50001 over all its total or significant consumption, or has zero energy consumption.
The same regulation added the ESOS action plan review to the report’s core contents and pointed the savings estimate at new regulation 27D.
Where an audit was carried out, the report also records the site-visit details from regulation 26(9), the analysis of consumption, the opportunities identified, and the summed savings estimates for the whole participant, for each organisational purpose and for each energy saving category.
Where only part of the participant’s energy sits under ISO 50001, the report records which assets and activities that system covers, what share of consumption it is, and the measures and implementation programme it produced.
The consolidated text of regulation 27A on legislation.gov.uk still showed the pre-2026 wording on 11 October 2026 under a “no known outstanding effects” banner, so read it with SI 2026/701 regulation 14 beside it.
The ESOS assessment page covers how the figures behind the report are built, and the ESOS energy audit page what the audit itself must contain.
| Content | When it applies | Provision |
|---|---|---|
| Total energy consumption | Always | reg 27A(5)(a) |
| Significant energy consumption, in kWh and as a % of the total | Where the undertaking chose to identify it | reg 27A(5)(b) |
| Energy intensity ratios | Always, one per organisational purpose | regs 27A(5)(c), 25C |
| Estimate of energy savings achieved | Unless a new participant or zero kWh | regs 27A(5)(d), 27D |
| ESOS action plan review | Where a current action plan existed | regs 27A(5)(e), 27E |
| Site visits, analysis, opportunities and summed savings estimates | Where an energy audit was carried out | reg 27A(6) |
| Assets covered by ISO 50001, % covered, measures and programme | Where part of consumption is under ISO 50001 | reg 27A(7) |
| Schedule 3 column 1 items, Tables A, C and E | Always | reg 27A(4)(d) |
| Table B (group participants) and Table D (lead assessor) | Where they apply | reg 27A(4)(e), (f) |
New in Phase 4
Savings achieved and the action plan review
SI 2026/701 regulation 17 inserted a new Chapter 3B into Part 4, and it is the largest change to what an ESOS report says.
Regulation 27D requires an estimate of the energy savings the participant achieved in the compliance period, in kWh, with the share relating to each organisational purpose.
It also requires the measures that produced those savings to be identified, each with its energy saving category and its own estimated saving in kWh.
A participant that was not a participant in the previous compliance period need not make the estimate, and the zero-consumption route is excluded.
Regulation 27E requires an ESOS action plan review: the measures in any current action plan that have not been implemented and are not expected to be before the end of the compliance period, and the reasons why.
Where none of the members that were required to produce an action plan for the previous period did so, the review confirms that instead.
The review does not apply to a participant whose members had no action plan duty last time, or to a zero-consumption participant.
Both items go into the ESOS report and the notification, but only the combined kWh saving is published: Schedule 3 Table J marks every other row, including the reasons for unimplemented measures, as notified and not published.
The Explanatory Memorandum says the reasons are withheld to avoid releasing commercially sensitive information, and that including them in the notification gives DESNZ information for policy development.
The 27D estimate is a quantified list of the year’s efficiency measures in kWh.
The SECR reporting requirements ask for a description of the principal measures taken, so one dataset can serve both, though the two duties stay separate.
Regulation 29 and Schedule 3
The ESOS reporting requirements in MESOS: what you notify
Regulation 29(1) requires the responsible undertaking to notify the scheme administrator, through the Notification System, whether the participant has complied, after the qualification date and by the compliance date.
The Regulations call it the Notification System; MESOS is the Environment Agency’s service that implements it, launched in April 2024 for Phase 3.
What is notified depends on the route: an audit notifies column 2 of Tables A, C, E, F, G, H and J; a participant with part of its energy under ISO 50001 adds Table I.
A participant deemed compliant through ISO 50001 over all its total or significant consumption notifies Tables A, C, F, G, J and K, under limb (ad) inserted by SI 2026/701 regulation 20.
A zero-consumption participant notifies only Tables A and C, under limb (ae); a group participant adds Table B, and a participant that needed a lead assessor adds Table D.
Every notification also carries the confirmation in regulation 31, given by the responsible officer.
Schedule 3 is the contents list: each row says whether an item goes in the report, is notified, and is published, and the tool beside this text filters the rows.
The contact details of the undertaking, the names of the responsible officer and the lead assessor, and anything in Table K are notified but never published.
The ESOS notification guide walks the MESOS filing screen by screen, and the Environment Agency says on its ESOS page that MESOS sign-in is moving to GOV.UK One Login.
Schedule 3 · report, notified, published
59 of 59 rows · 31 of 59 are published
Table AName
Report: yesNotified: yesPublished: yes
Table AEmail address and telephone number
Report: noNotified: yesPublished: no
Table ARegistered office
Report: noNotified: yesPublished: yes
Table APrincipal place of activity, where there is no registered office
Report: noNotified: yesPublished: yes
Table ACompany registration number
Report: noNotified: yesPublished: yes
Table ATrading or other name commonly used
Report: noNotified: yesPublished: yes
Table AAt least two contacts, one of them the responsible officer
Report: noNotified: yesPublished: no
Table AName of a global parent the Regulations do not extend to, and its group’s name
Report: noNotified: yesPublished: yes
Table AStandard industrial classification code
Report: noNotified: yesPublished: yes
Table AWhy the undertaking is classed as large, or small or medium, under Schedule 1
Report: noNotified: yesPublished: yes
Table AName and registration number of the highest parent, if different
Report: yesNotified: yesPublished: yes
Inserted by SI 2026/701 reg 31(2)(b).
Table BNumber of relevant undertakings in the participant
Report: yesNotified: yesPublished: yes
Table BNames and registration numbers of those undertakings
Report: noNotified: yesPublished: yes
Table BA written aggregation agreement under Schedule 2, and the highest parents’ names
Report: noNotified: yesPublished: yes
Table BAny undertaking that left the participant after the qualification date
Report: noNotified: yesPublished: yes
Table BHow the undertakings in the participant relate to each other
Report: yesNotified: yesPublished: yes
Table BWhether the highest parent is in the participant, where it is not the responsible undertaking
Report: yesNotified: yesPublished: no
Inserted by SI 2026/701 reg 31(3)(b).
Table CName
Report: yesNotified: yesPublished: no
Table CFull title or position
Report: yesNotified: yesPublished: yes
Table CContact details
Report: noNotified: yesPublished: no
Table CDate the officer considered the audit recommendations
Report: noNotified: yesPublished: yes
Table DName
Report: yesNotified: yesPublished: no
Table DThe approved register
Report: yesNotified: yesPublished: yes
Table DWhether employed by the participant or a group undertaking
Report: noNotified: yesPublished: yes
Table EName of each person who did a significant share of site visits, data gathering or report drafting
Report: if recordedNotified: if recordedPublished: no
Table EWhether that person is employed by the participant or a group undertaking
Report: noNotified: if recordedPublished: no
Table FWhether, and how far, Part 6 (deemed compliance) was relied on
Report: —Notified: yesPublished: yes
Table FEstimates made under Part 4 and notified under reg 21A
Report: —Notified: yesPublished: yes
Table FSite visit details recorded under reg 26(9)(d), (e) and (f)
Report: —Notified: yesPublished: yes
“26(9)(d), (e)” substituted by SI 2026/701 reg 31(4).
Table FThat the audit has no analysis based on consumption profiles
Report: —Notified: yesPublished: no
Table FNon-disclosure to a group undertaking under reg 27C(3)(b)
Report: —Notified: yesPublished: no
Table FWhere 12 months’ verifiable data was not used, how far and why
Report: —Notified: yesPublished: no
Table GTotal energy consumption, in kWh
Report: —Notified: yesPublished: yes
Table GTotal consumption by organisational purpose
Report: —Notified: yesPublished: yes
Published from 22 July 2026: SI 2026/701 reg 31(5)(a).
Table GSignificant energy consumption, in kWh
Report: —Notified: yesPublished: yes
Table GSignificant consumption by organisational purpose
Report: —Notified: yesPublished: yes
Published from 22 July 2026: SI 2026/701 reg 31(5)(b).
Table GPercentage of total consumption that is significant
Report: —Notified: yesPublished: yes
Table GEnergy intensity ratios
Report: —Notified: yesPublished: yes
Table HSum of all estimated annual reductions in energy spend and consumption
Report: —Notified: yesPublished: yes
Table HThose estimates summed by organisational purpose
Report: —Notified: yesPublished: no
Table HThose estimates summed by energy saving category
Report: —Notified: yesPublished: no
Table IWhich assets or activities the certified system covers, and its share of total consumption
Report: —Notified: yesPublished: yes
Table ISavings measures from the certified system, summed by organisational purpose
Report: —Notified: yesPublished: no
Table ISavings measures from the certified system, summed in total
Report: —Notified: yesPublished: yes
Table ISavings measures from the certified system, summed by energy saving category
Report: —Notified: yesPublished: no
Table IISO 50001 certificate number and validity dates
Report: —Notified: yesPublished: no
Inserted by SI 2026/701 reg 31(7)(d).
Table JEnergy savings achieved in the period, in kWh (reg 27D(1))
Report: —Notified: yesPublished: yes
Table JShare of those savings by organisational purpose
Report: —Notified: yesPublished: no
Table JThe measures implemented
Report: —Notified: yesPublished: no
Table JEnergy saving category of each measure
Report: —Notified: yesPublished: no
Table JSavings in kWh from each measure
Report: —Notified: yesPublished: no
Table JMeasures in the current action plan not implemented
Report: —Notified: yesPublished: no
Table JWhy those measures were not implemented
Report: —Notified: yesPublished: no
Table JConfirmation that no undertaking required to produce a current plan did so
Report: —Notified: yesPublished: no
Table KConfirmation that all total or significant consumption is under the certified system
Report: —Notified: yesPublished: no
Table KISO 50001 certificate number and validity dates
Report: —Notified: yesPublished: no
Table KWhich assets or activities the certified system covers
Report: —Notified: yesPublished: no
Table KPercentage of total consumption under the certified system
Report: —Notified: yesPublished: no
Table KEstimated reductions from the certified system, by purpose, in total and by category
Report: —Notified: yesPublished: no
SI 2014/1643 Schedule 3 as substituted by SI 2023/1182 and amended by SI 2026/701 reg 31, read 1 October 2026.
Publication duty: reg 10(1)(c).
“—” means the statute leaves the report column blank for that table.
Nothing you type is saved.
Tables A to K
Schedule 3, table by table
| Table | Covers | Who notifies it | What is published |
|---|---|---|---|
| A | The responsible undertaking, contacts, SIC code, size reasons and, new in 2026, the highest parent | Every route | Name, registered office, registration number, trading name, global parent, SIC code, size reasons, highest parent |
| B | A participant of two or more undertakings, and the group relationship | Group participants | All rows except the new highest-parent confirmation |
| C | The responsible officer | Every route | Title or position and the date recommendations were considered; not the name or contacts |
| D | The lead assessor | Where one was required | Approved register and whether employed in the group; not the name |
| E | Others who did site visits, data gathering or drafting | Audit and part-ISO routes, where recorded | Nothing |
| F | The assessment: reliance on deemed compliance, estimates, site visits | Audit and ISO routes | The first three rows |
| G | Energy consumption: total, by purpose, significant, %, intensity ratios | Audit and ISO routes | Every row, since 22 July 2026 |
| H | Savings opportunities from the audit | Audit route | The total only, not by purpose or category |
| I | Part coverage by ISO 50001, with certificate number and dates | Part-ISO participants | Not the certificate details |
| J | Savings achieved since the last compliance date, and the action plan review | Audit and ISO routes | The combined kWh saving only |
| K | Deemed compliance through ISO 50001 over total or significant consumption | Full-ISO participants | Nothing |
Phase 4 publishes more than Phase 3 did: regulation 31(5) moved the split of total and significant consumption by organisational purpose in Table G from “not published” to “published”.
The same regulation re-headed Table I to regulation 33(2) and removed three of its rows, removed two rows from Table H, and added the highest-parent rows to Tables A and B.
Who owes what
Requirements by role, with the provision for each
The Regulations name each actor and give each its own duties, so the clearest way to read them is by person.
The responsible undertaking is the relevant undertaking that complies for the participant: the highest parent by default, or another member chosen in writing.
It carries almost every duty, from the assessment to the last progress update.
Responsible officers are directors, or people exercising management control where there are no directors, and their role is to confirm.
The lead assessor reviews, and since 22 July 2026 also reports completion to their approval body.
Other group members comply inside the participant, with rights to information and choices if they leave.
The approval bodies, the Environment Agency and the other regulators have duties too, and those shape what a participant can ask of them.
Who owes what · SI 2014/1643
The relevant undertaking that complies for the participant: the highest parent by default, or another member chosen in writing (regs 18, 19; Sch 2).
- Carry out an ESOS assessment in the compliance periodreg 20Deemed done at zero kWh (reg 33A)
- Appoint at least one lead assessor, give them the previous evidence pack, and have the assessment reviewedreg 21(1)Not under 40,000 kWh (reg 21(3)); deemed under reg 33(3) or 33A
- Calculate total energy consumption over a 12-month reference period that begins no more than 12 months before the qualification date and ends by the compliance datereg 22(2), (5)
- If it chooses, identify the areas making up at least 95% of consumptionreg 25(1), (2)
- Calculate at least one energy intensity ratio for each organisational purpose with consumptionreg 25C
- Carry out an energy audit of the significant or total consumption, with representative site visitsregs 26, 27Not for what ISO 50001 covers (reg 33)
- Produce the ESOS report before the compliance datereg 27ANot required for Phase 4 on the reg 33(3) or 33A routes (reg 27A(2)(b))
- Estimate savings achieved in the period, in kWh, per measure and per purposereg 27DNot for a participant new to the scheme (reg 27D(3))
- Review the previous action plan: measures not implemented, and whyreg 27E
- Disclose the relevant parts of the report to each group undertakingreg 27C
- Keep an evidence pack for at least two further compliance periodsreg 28
- Notify compliance through the Notification System, after the qualification date and by the compliance datereg 29
- Produce and notify an action plan, then three progress updatesregs 34A, 34BNot at zero kWh (regs 34A(11), 34B(9))
- Tell the scheme administrator if it becomes aware of a breachreg 37(1)
- Answer a compliance notice from the regulatorreg 35
SI 2014/1643 as amended by SI 2023/1182 and SI 2026/701, read at legislation.gov.uk on 1 October 2026.
A map of duties, not advice on a particular case.
The duty holder
The duty stays with the undertaking
Every core ESOS requirement is written as a duty on the responsible undertaking, and none of it moves to an adviser.
The undertaking appoints the lead assessor, must give them the evidence pack from any previous assessment, and must ensure the assessment is reviewed, under regulation 21(1).
The Environment Agency’s Phase 4 guidance says the lead assessor will not be held responsible for compliance by the compliance bodies.
A consultant can do much of the work, but the notification is the undertaking’s, the confirmation is its directors’, and a penalty notice is served on it.
The undertaking must also tell the scheme administrator if it becomes aware it is in breach of any requirement, under regulation 37(1).
How the assessment is put together, step by step, is on the ESOS assessment page; buyers weighing outside help can read how to check an ESOS consultant, or what decarbonisation consultancy covers once the measures are chosen.
Directors
One responsible officer or two, and what they confirm
A responsible officer is a director within section 250 of the Companies Act 2006 or, where the participant has none, a person exercising management control, under regulation 30(2).
One is enough where the lead assessor is independent of the participant; two are needed in any other case.
Independence is defined exhaustively: in the last 12 months the assessor must not have been an employee, a director, partner or person exercising management control, or a shareholder of the participant, or the spouse or civil partner of one.
The confirmation under regulation 31 covers scope, compliance with Parts 4 to 6, the accuracy of the notified information, and, since 22 July 2026, that the officer has seen and considered the audit recommendations and any certified energy management system relied on.
The action plan and each progress update carry a further confirmation by the responsible officer under regulations 34A(8) and 34B(7).
The Regulations fix no number of officers for those two confirmations, while the Environment Agency’s guidance asks for the same number of directors as for the notification.
The independence test, and how to check an assessor against it, is on the ESOS lead assessor page.
| Case | Responsible officers | Provision |
|---|---|---|
| Lead assessor independent of the participant | 1 | reg 30(3) |
| Lead assessor not independent | 2 | reg 30(3) |
| No lead assessor: under 40,000 kWh | 2 | reg 30(3A) |
| Zero consumption | 2 | reg 30(3), residual limb |
Regulation 34A
The action plan: contents, window and sign-off
After notifying compliance, the responsible undertaking must produce an ESOS action plan under regulation 34A(1), whatever route it used, unless it relied on the zero-consumption route.
The plan looks forward over the next compliance period: for Phase 4 that is 6 December 2027 to 5 December 2031.
It is notified through the Notification System between the first day of that period and the day before its first anniversary, so by 5 December 2028.
Each estimate must say whether it comes from the energy audit, from a deemed-compliance route, or from another reasonable method, and the last must be described and justified in the evidence pack.
The Environment Agency’s guidance says the savings estimates are expected to be indicative and must be stated in kWh.
There is no statutory line for investment or cost, and a plan that proposes nothing is lawful if it says so.
The responsible officer confirms that the plan complies and that they have seen and considered it, under regulation 34A(8).
Templates and a builder are on the ESOS action plan page.
| Limb | What it records | Provision |
|---|---|---|
| (i) | Each energy efficiency measure the participant proposes to implement before the end of the next compliance period | reg 34A(3)(a)(i) |
| (ii) | Whether an energy audit recommended it | reg 34A(3)(a)(ii) |
| (iii) | The date by which it will be implemented | reg 34A(3)(a)(iii) |
| (iv) | Estimated total savings over that period, in kWh | reg 34A(3)(a)(iv) |
| (v) | The share of those savings for each organisational purpose, in kWh | reg 34A(3)(a)(v) |
| (vi) | The method used to make the estimate | reg 34A(3)(a)(vi), (4)–(5) |
| or | A statement that no measure is proposed | reg 34A(3)(b) |
Regulation 34B
Three progress updates, each one a year
Regulation 34B requires a progress update in each year of the action plan’s period, each one notified in its own twelve-month window.
Each update records which measures from the latest action plan have been implemented, whether each met its planned date, and which have not.
It gives an estimate, in kWh, of the reduction in energy consumption achieved or to be achieved in the reporting period, and the method behind it.
The method is one of three: the audit’s estimate, the action plan’s estimate, or another reasonable method recorded with its reasons in the evidence pack.
The Environment Agency’s guidance says the updates are owed even where the action plan proposed no measures, and may include measures that were not in the plan.
Phase 3 participants still owe one: the further progress update on the Phase 3 action plan is due by 5 December 2026.
The guidance contradicts itself on these windows in its introduction and §14.1, so take the dates from the amended regulation; the ESOS progress report page sets out each update’s fields.
- 6 Dec 2028 – 5 Dec 2029
Initial progress update
Due by 5 December 2029, under regulation 34B(1)(a). - 6 Dec 2029 – 5 Dec 2030
Further progress update
Due by 5 December 2030, under regulation 34B(1)(b). - 6 Dec 2030 – 5 Dec 2031
Final progress update
Due by 5 December 2031, under regulation 34B(1)(c), inserted by SI 2026/701.
Regulation 10
What becomes public, and when
Regulation 10 makes the Environment Agency publish what the Notification System holds, within six months of the deadline or of a later notification.
The Environment Agency’s Phase 4 guidance names 10 June 2028 as the publication date for Phase 4 notifications.
A six-month period beginning with 5 December 2027 ends on 4 June 2028 on the usual reading, so the guidance date and the regulation are recorded side by side here rather than reconciled.
Action plans and progress updates are published as notified, while the action plan review, which names measures not done and why, is notified but not published.
The guidance also says the scheme administrator will publish any failure to submit an action plan or progress update, even though no penalty attaches to it.
The GOV.UK ESOS page says the published records have not been verified for compliance and carry no amendments unless requested or to remove personal data.
The Phase 3 records are on data.gov.uk, and DESNZ’s 2025 post-implementation review reports 8,581 Phase 3 notifications against the Environment Agency’s estimate of 9,871 qualifying groups, with 5,403 action plans from the 7,145 groups confirming they were required to comply.
| Published | Within | Provision |
|---|---|---|
| Number of undertakings that have complied | 6 months from the compliance date or later notification | reg 10(1)(a), (2)(a) |
| List of responsible undertakings that have notified | As above | reg 10(1)(b), (2)(a) |
| Schedule 3 column 3 items, Tables A to K | As above | reg 10(1)(c), (2)(a) |
| Each ESOS action plan | 6 months from the plan deadline or later notification | reg 10(1)(d), (2)(b) |
| Each ESOS progress update | 6 months from the update deadline or later notification | reg 10(1)(e), (2)(c) |
Phase 4 dates
When each report is due
| Date | Output | Provision |
|---|---|---|
| 6 December 2023 | Phase 4 compliance period begins | reg 4(2) |
| 22 July 2026 | SI 2026/701 in force: new report and notification content | SI 2026/701 reg 1 |
| 5 December 2026 | Phase 3 further progress update due | reg 34B(1)(b) |
| 31 December 2026 | Qualification date; notification possible after it | regs 4(3)(b), 29(1) |
| Before 5 December 2027 | ESOS report produced | reg 27A(3) |
| 5 December 2027 | Notification of compliance, with the officer’s confirmation | regs 4(4)(b), 29, 31 |
| 10 June 2028 | Phase 4 data published (Environment Agency’s announced date) | EA guidance §12.4; reg 10(2) |
| 5 December 2028 | Action plan notified | reg 34A(7)(b) |
| 5 December 2029, 2030, 2031 | Initial, further and final progress updates | reg 34B(1)(a)–(c) |
| 5 December 2035 | Phase 4 evidence pack may be discarded after this date | reg 28(2)(b) |
SI 2026/701 changed no compliance date: the dates come from regulation 4 and Part 6A, though the guidance’s §15.1 says otherwise.
Every date since 2014, with Phases 1 to 5 side by side, is on the ESOS deadlines page.
Your route
Which requirements apply on your route
Four facts change the list of requirements: how much energy the participant uses, whether ISO 50001 covers it, how much it covers, and whether the lead assessor is independent.
Under 40,000 kWh, no lead assessor is needed, but every other requirement stays.
With ISO 50001 over all total or all significant consumption, the lead assessor, audit and ESOS report are deemed done, and the notification, action plan and updates remain.
At zero consumption, the assessment duties and the action plan are deemed done, and the notification remains.
Display Energy Certificates and Green Deal Assessments stopped being routes on 22 July 2026, though their data may still be used inside an assessment.
Your route, duty by duty · Phase 4
Total energy consumption over the reference period
ISO 50001 certification, valid on 5 December 2027
Is the lead assessor independent of the participant?
Not independent if, in the last 12 months, they were an employee, director, person exercising management control or shareholder, or the spouse or civil partner of one (reg 30(4)).
- Measure total energy consumption (the ESOS assessment, reg 20)Requiredreg 20; Part 4 Ch 2
- Appoint a lead assessorRequiredreg 21(1)
- Carry out an ESOS energy auditRequiredreg 26; Part 4 Ch 3
- Produce the ESOS reportRequiredreg 27A
- Keep an evidence packRequiredreg 28
- Notify compliance through MESOS by 5 December 2027Requiredreg 29(1)
- Responsible officers who confirm1reg 30(3)–(4)
- Action plan and three progress updatesRequiredregs 34A, 34B
SI 2014/1643 regs 20, 21, 26–30, 33, 33A and Part 6A, as amended by SI 2026/701.
An orientation aid, not advice.
How much
Coverage, data and site visits
All energy the participant consumes in the UK is measured, in kWh or by spend, over a reference period that begins no more than 12 months before the qualification date and ends by the compliance date.
The audit then covers either the total, or the areas the participant elects to identify as significant, which must together account for at least 95% of total consumption, measured in energy units or by spend.
The remainder, up to 5%, needs no audit, and the participant chooses what goes in it.
So far as reasonably practicable the audit rests on verifiable data over 12 months, under regulation 26(3), and where that is not available it may rest on a shorter period or a reasonable estimate, with the reasons recorded.
It must include visits to sites the undertaking considers representative of how energy is used, and the undertaking records how many sites there are, how many were visited and why those were chosen.
For Phase 4 the audit’s data must begin no earlier than 6 December 2022 and no more than 24 months before the audit starts; the windows are set out on the ESOS deadlines page.
Consequences
Which requirements carry a penalty
| Requirement breached | Maximum | Provision |
|---|---|---|
| Notify compliance | £5,000, plus up to £500 a working day for up to 80 working days | reg 43 |
| Keep records (the evidence pack) | £5,000, plus the cost of confirming compliance | reg 44 |
| Undertake an ESOS assessment | £50,000, plus up to £500 a working day for up to 80 working days | reg 45 |
| Comply with a compliance, enforcement or penalty notice | £5,000, plus up to £500 a working day for up to 80 working days | reg 46 |
| Not make a false or misleading statement | £50,000 | reg 47 |
| Action plan and progress updates | No penalty in Part 8; non-submission is published | regs 34A, 34B |
Each penalty also carries publication, naming the undertaking for at least a year.
The gap for action plans and updates is in the statute, not only in regulator policy, but an enforcement notice requiring one would be enforceable under regulation 46.
A false or misleading statement in a notification is the reporting breach with the highest maximum, which is why the officer’s confirmation is worth reading line by line before it is given.
How a penalty is set in practice is on the ESOS penalties page.
Group members
What a group member is entitled to
Regulation 27C requires the responsible undertaking to disclose to each group undertaking the parts of the ESOS report that relate to it.
For an audit, those are the savings opportunities about its energy, assets or activities, their estimated costs and benefits, considerations for implementing them, and the analysis of its consumption.
Where the participant relied on deemed compliance, relevant parts of the evidence pack are disclosed too.
Where the law prohibits disclosure, the undertaking tells the scheme administrator which parts and why.
A member leaving the group before the compliance date may agree in writing to comply with its old group or its new one, or must comply on its own; the same choice runs for the action plan and updates under Schedule 2 paragraphs 7A and 7B.
SI 2026/701
What the 2026 amendments changed in reporting
SI 2026/701 was made on 23 June 2026 and came into force on 22 July 2026, eight days before the Environment Agency published its Phase 4 guidance.
Its Explanatory Memorandum says it takes forward changes consulted on in 2021 and postponed from the 2023 amendments, to increase participants’ accountability for acting on energy efficiency.
Most of its changes land on what is reported: what the report contains, what is notified, and what is published.
It did not change the qualification test in Schedule 1 or any compliance date.
legislation.gov.uk has applied some of these amendments to its consolidated text and not others, so cite the amending regulation beside the 2014 provision.
The instruments themselves, and the Energy Act 2023 powers behind them, are on the ESOS legislation page.
| SI 2026/701 | Effect on reporting |
|---|---|
| reg 5 | Publication extends to Schedule 3 Tables A to K |
| reg 8 | Lead assessor notifies their approval body within seven days |
| reg 13 | Audit savings estimates stated in kWh |
| reg 14 | ESOS report adds the action plan review; none needed on the full-ISO or zero-kWh routes |
| reg 17 | New regs 27D (savings achieved) and 27E (action plan review) |
| reg 20 | Notification limbs for the full-ISO and zero-kWh routes |
| reg 21 | Officer confirms any certified energy management system relied on |
| reg 26 | DECs and Green Deal Assessments removed as routes |
| regs 27, 28 | Action plan and updates in kWh; a third progress update |
| reg 31 | Schedule 3: Table G published in full, Tables J and K added |
After Phase 4
ESOS reporting requirements after Phase 4: Phase 5 and reform
Phase 5 is fixed by regulation 4: the Environment Agency’s guidance gives a qualification date of 31 December 2030, a compliance period of 6 December 2027 to 5 December 2031, and a compliance date of 5 December 2031.
On the current rules a Phase 5 participant reports in the same shape as Phase 4, and its report will review the Phase 4 action plan under regulation 27E.
The Explanatory Memorandum to SI 2026/701 says the government will consider introducing a net zero assessment after Phase 4, to fit it with other business reporting changes; that is an intention, not a rule.
For now a net zero or decarbonisation assessment is voluntary, and the GOV.UK ESOS page says MESOS cannot receive one, though DESNZ is considering that for future changes.
The Modernising corporate reporting consultation of 7 September 2026 says DESNZ intends to consult on SECR and ESOS later in 2026, building on an evaluation of ESOS then under way.
No such consultation had been published when this page was checked on 11 October 2026, so no reform proposal for ESOS reporting exists yet to describe.
DESNZ’s 2025 post-implementation review recommended keeping the Regulations without major change on an incomplete evidence base, pending that evaluation.
What Phase 5 will and will not ask is tracked on the ESOS Phase 5 page.
Beside the other regimes
ESOS among the UK’s energy and carbon reports
ESOS reporting goes to the Environment Agency every four years, while SECR is an annual disclosure in the directors’ report on a different size test; the SECR reporting requirements page sets that duty out paragraph by paragraph.
The Environment Agency’s guidance says participation in UK ETS, a climate change agreement, SECR, or a DEC or Green Deal Assessment does not automatically count as ESOS compliance, though their energy data can feed the ESOS calculation.
The monitoring and reporting duty for installations is covered on the UK ETS reporting requirements page, and emissions reporting across all the regimes on the GHG reporting requirements page.
Listed companies now also report against UK SRS on a comply-or-explain basis under the FCA’s final rules for periods from 1 January 2027, which is a separate duty set out on the UK SRS reporting requirements page.
The carbon reporting requirements page and the UK sustainability reporting requirements hub put every regime on one map, and the ESOS and SECR comparison runs the two size tests together.
Not in the Regulations
Requirements that do not exist
ESOS sets no energy reduction target and requires no measure to be implemented.
There is no ESOS certificate; the record of compliance is the notification and the published data.
There is no fee for notifying, the Environment Agency’s guidance says.
A net zero or decarbonisation assessment is voluntary: the GOV.UK ESOS page says participants may use PAS 51215-1 and -2:2025 for that, but PAS 51215:2014 remains the competence standard for lead assessors, and MESOS cannot receive a decarbonisation assessment.
ESOS is not an annual disclosure in the accounts; that is SECR, whose own requirements are on the SECR reporting guide, and whose size test is not the ESOS test, as the UK SRS thresholds page shows alongside the other statutory size tests.
ESOS reports energy, not emissions: the guidance says CO2 is not an energy unit, so a figure in tonnes of CO2e does not meet a kWh or spend requirement.
Display Energy Certificates and Green Deal Assessments as compliance routes — omitted on 22 July 2026.
ISO 50001 must cover 100% of energy — Phase 4 accepts total or significant consumption.
Two progress updates — Phase 4 has three.
Estimates in “energy measurement units” — kWh since 22 July 2026.
Savings estimates under “regulation 27B” — omitted and re-enacted as regulation 27D.
Check yourself
Eight statements about who reports what
Each answer names the provision it turns on.
The scheme’s structure — administrator, regulators and policy owner — is on the Energy Savings Opportunity Scheme page, and the instruments themselves on the ESOS legislation page.
The regulator’s documents are collected on the Environment Agency’s ESOS guidance collection and the GOV.UK ESOS page.
True or false?
01The lead assessor is legally responsible for the participant’s compliance.
02Two responsible officers confirm where no lead assessor was needed under 40,000 kWh.
03ESOS requires the measures in the action plan to be implemented.
04The 95% may be measured by energy spend.
05A group member is entitled to the parts of the ESOS report about its own energy.
06Failing to file an action plan carries a fixed fine.
07The reasons for not implementing last phase’s measures are published.
08An ISO 50001 participant that is deemed to have produced its ESOS report still notifies compliance.
8 statements.
Pick an answer to see the provision behind it.
Answers rest on the provisions named beside each one.
Nothing you pick is saved.
Frequently asked
ESOS reporting requirements, answered
What are the ESOS reporting requirements in the UK?
A participant in ESOS must produce an ESOS report before the compliance date, have one or two responsible officers confirm the assessment, and notify the Environment Agency through the Notification System (MESOS) by the compliance date with the information listed in Schedule 3 to the ESOS Regulations 2014.
After notifying it must produce and notify an ESOS action plan within the following year and then three annual progress updates.
For Phase 4 those dates are 5 December 2027, 5 December 2028 and 5 December 2029, 2030 and 2031.
What must an ESOS report contain?
Under regulation 27A as amended by SI 2026/701, the participant’s total energy consumption, its significant energy consumption in kWh and as a percentage of the total where it chose to identify one, the energy intensity ratios, an estimate of the energy savings achieved in the compliance period, and the action plan review.
Where an audit was carried out it also records the audit’s site visits, analysis, opportunities and summed savings estimates; and it carries the column 1 items of Schedule 3 Tables A to E.
Is the ESOS report itself sent to the Environment Agency?
The Regulations require the report to be produced, not filed as a document.
Regulation 29 requires the responsible undertaking to notify the information in column 2 of the relevant Schedule 3 tables through the Notification System, and much of that information also appears in the report.
The report stays with the undertaking, and group members are entitled to the parts that relate to them under regulation 27C.
What information goes in an ESOS notification of compliance?
The column 2 items of Schedule 3 for the participant’s route: details of the responsible undertaking and any group members, the responsible officer, the lead assessor, the assessment, the energy consumption figures and intensity ratios, the audit’s savings opportunities, any ISO 50001 certificate, and since Phase 4 the energy savings achieved and the action plan review. It must also carry the responsible officer’s confirmation under regulation 31.
When is the ESOS Phase 4 notification due?
After the qualification date of 31 December 2026 and by the compliance date of 5 December 2027, under regulations 4 and 29 of the ESOS Regulations.
The Environment Agency says notifying is free and that the regulators cannot amend the deadline.
What ESOS information is published?
Regulation 10 requires the Environment Agency to publish the number of undertakings that have complied, a list of responsible undertakings that have notified, the column 3 items of Schedule 3, and every action plan and progress update.
Contact details, the responsible officer’s name, the lead assessor’s name and the action plan review are notified but not published.
When will ESOS Phase 4 data be published?
The Environment Agency’s Phase 4 guidance names 10 June 2028.
Regulation 10(2) requires publication within six months beginning with the compliance date, or with the date of notification if later, so late notifications are published later.
What must an ESOS action plan contain?
Under regulation 34A(3), each energy efficiency measure the participant proposes to implement before the end of the next compliance period, whether an audit recommended it, the date by which it will be implemented, the estimated total savings in kWh and the share by organisational purpose, and the estimation method.
Alternatively it may state that no measure is proposed.
There is no statutory investment or cost line.
How many ESOS progress updates are there in Phase 4?
Three.
Regulation 34B(1)(c), inserted by SI 2026/701, added a final progress update for compliance periods ending on or after 5 December 2027, so the Phase 4 updates fall due by 5 December 2029, 2030 and 2031.
The Environment Agency says they are owed even where the action plan proposed no measures.
What is the ESOS action plan review?
A written record, new in Phase 4 under regulation 27E, identifying measures in the previous action plan that have not been and are not expected to be implemented before the end of the compliance period, and explaining why.
It goes into the ESOS report and the notification of compliance but is not published.
Do we have to report the energy savings we have achieved under ESOS?
Yes, from Phase 4, unless the participant was not a participant in the previous compliance period or relies on the zero-consumption route.
Regulation 27D requires an estimate of the savings achieved in the compliance period in kWh, split by organisational purpose, with each measure, its energy saving category and its own saving.
Only the combined kWh figure is published.
Does an ISO 50001 participant still have to notify ESOS compliance?
Yes.
Where ISO 50001 covers all of the total or significant energy consumption, the participant is deemed to have appointed a lead assessor, carried out the audit and produced the ESOS report, but regulation 29(1)(ad) still requires it to notify Tables A, C, F, G, J and K of Schedule 3, and the action plan and updates still follow.
What changed in ESOS reporting in 2026?
SI 2026/701, in force on 22 July 2026, added the energy savings achieved (reg 27D) and the action plan review (reg 27E) to the report and the notification, moved estimates to kWh, added a third progress update, published more of the consumption data in Schedule 3 Table G, added Tables J and K, and removed Display Energy Certificates and Green Deal Assessments as compliance routes.
It did not change the Phase 4 dates or the qualification test.
Is ESOS being reformed after Phase 4?
Nothing is decided.
The Explanatory Memorandum to SI 2026/701 says the government will consider introducing a net zero assessment after Phase 4, and the Modernising corporate reporting consultation says DESNZ intends to consult on SECR and ESOS later in 2026; no such ESOS consultation had been published when this page was checked on 11 October 2026.
Phase 5 runs from 6 December 2027 to 5 December 2031 under the current rules.
What are the ESOS requirements?
A qualifying participant must measure its total UK energy consumption over a 12-month reference period, have the significant part of it audited or covered by ISO 50001, have a lead assessor review the assessment unless an exemption applies, produce an ESOS report, have one or two responsible officers confirm it, notify the Environment Agency by the compliance date, keep an evidence pack, and then produce an action plan and annual progress updates.
The requirements are in the ESOS Regulations 2014 as amended in 2023 and 2026.
Who is responsible for ESOS compliance?
The responsible undertaking: the highest parent of the qualifying group by default, or another member chosen by written agreement.
It carries the duties to assess, appoint a lead assessor, produce the report, keep the evidence pack, notify, and produce the action plan and updates.
Directors confirm the work as responsible officers, and the lead assessor reviews it, but the duty stays with the undertaking.
Do directors have ESOS duties?
Yes, as responsible officers.
One or two are nominated under regulation 30, and the notification must include their confirmation that the participant is in scope, the undertaking has complied and the information is correct, and that they have seen and considered the audit recommendations and any certified energy management system relied on.
They also confirm the action plan and each progress update.
Is there an ESOS requirement to implement the recommendations?
No. ESOS requires an assessment, a notification, an action plan and progress updates, but no saving to be made and no measure to be implemented.
An action plan may state that no measure is proposed, though from Phase 4 the next report must review the last plan and explain any measure not implemented.
Which ESOS requirements carry a fine?
Five breaches in Part 8: failing to notify, failing to keep records, failing to undertake an assessment, failing to comply with a notice, and making a false or misleading statement.
No penalty attaches directly to the action plan or progress updates, though their non-submission is published and an enforcement notice requiring one would be enforceable.
What does the lead assessor have to do?
Review whether the ESOS assessment meets the Regulations and tell the responsible undertaking, and, since 22 July 2026, notify their own approval body within seven days that the assessment is complete, with two contacts for the undertaking, one of them the responsible officer.
The Environment Agency’s guidance says the lead assessor is not held responsible for the participant’s compliance.
What is the minimum coverage ESOS requires?
All of the participant’s UK energy is measured.
The audit then covers either total consumption or the areas the participant elects to identify as significant, which must account for at least 95% of total consumption, measured in energy units or by spend.
The rest, up to 5%, needs no audit.
Do group members have ESOS requirements of their own?
They comply as part of the participant, usually under the highest parent, and they are entitled to see the parts of the ESOS report about their own energy and assets.
If a member leaves the group, Schedule 2 lets it agree where it complies, or it complies on its own.
Sources
Primary sources
Every figure, date and status on this page traces to the instrument’s owner.
Secondary commentary is never the source for a number.
- legislation.gov.ukThe Energy Savings Opportunity Scheme Regulations 2014 (SI 2014/1643)
Every requirement on this page, as amended.
- legislation.gov.ukSI 2014/1643, regulation 27A — the ESOS report
What the written report must contain; read with SI 2026/701 reg 14, which the consolidated page does not yet show.
- legislation.gov.ukSI 2014/1643, regulation 29 — notification of compliance
Which Schedule 3 tables each route notifies, as amended by SI 2026/701 reg 20.
- legislation.gov.ukSI 2014/1643, regulation 31 — the responsible officer’s confirmation
Scope, compliance, correct information, and the recommendations seen and considered.
- legislation.gov.ukSI 2014/1643, Schedule 3 — information in the report, notified and published
Tables A to K, each row with its three columns.
- legislation.gov.ukSI 2014/1643, regulation 10 — publication of information
What the scheme administrator publishes, and within what period.
- legislation.gov.ukSI 2014/1643, Part 6A — action plans and progress updates
Regs 34A and 34B in their consolidated, kWh form.
- legislation.gov.ukSI 2014/1643, regulation 21 — the lead assessor
Appointment, review, the previous pack and the seven-day notice.
- legislation.gov.ukSI 2014/1643, regulation 26 — the energy audit
Coverage, verifiable data, site visits and the record of how the audit was done.
- legislation.gov.ukSI 2014/1643, regulation 27C — disclosure to group undertakings
What each group member is entitled to see.
- legislation.gov.ukSI 2014/1643, regulation 30 — responsible officers
Who may be one, and when one or two are needed.
- legislation.gov.ukSI 2014/1643, Part 8 — civil penalties
The five breaches that carry a penalty.
- legislation.gov.ukThe Energy Savings Opportunity Scheme (Amendment) Regulations 2023 (SI 2023/1182)
The report, ratios, action plans, updates and the 40,000 kWh limb.
- legislation.gov.ukThe Energy Savings Opportunity Scheme (Amendment) Regulations 2026 (SI 2026/701)
The Phase 4 requirements in force from 22 July 2026.
- legislation.gov.ukSI 2026/701, regulation 14 — amendments to the ESOS report
Adds the action plan review to the report and switches the savings estimate to reg 27D.
- legislation.gov.ukSI 2026/701, regulation 17 — energy savings achieved and the action plan review
New regs 27D and 27E, in kWh.
- legislation.gov.ukSI 2026/701, regulation 31 — amendments to Schedule 3
Tables G, J and K: what is now notified and published.
- legislation.gov.ukSI 2026/701, Explanatory Memorandum
Why the changes were made, and that a net zero assessment is to be considered after Phase 4.
- Environment AgencyHow to comply with the Energy Savings Opportunity Scheme (ESOS) phase 4
The regulator’s reading, including the publication date and what the lead assessor is not responsible for.
- Environment AgencyComply with the Energy Savings Opportunity Scheme (ESOS) — guidance collection
Where the Phase 3 guidance and its documents sit.
- GOV.UK (Environment Agency)Energy savings opportunity scheme (ESOS): find out if you qualify and how to comply
Last updated 2 September 2026: registers, PAS 51215, net zero and the published data.
- Environment AgencyAnnex 2: Climate change schemes — civil penalties
How a penalty is set in practice.
- data.gov.uk (Environment Agency)Energy Savings Opportunity Scheme — published Phase 3 data
The published action plans, progress updates and compliance notifications.
- DESNZThe ESOS Regulations 2014 — second post-implementation review (2025)
Recommendation “Keep”, and the Phase 3 notification and action-plan counts.
- GOV.UK (DBIST)Modernising corporate reporting — consultation
Published 7 September 2026; ¶150 says DESNZ intends to consult on SECR and ESOS later in 2026.