Carbon, SECR, PPN and ESOS · one set of data
ESOS and UK SRS
ESOS and UK SRS, SECR and PPN 006 are four separate duties that a large UK group can meet at once, and they draw on the same energy and carbon data.
The ESOS assessment measures UK energy in kWh; the others ask for emissions, over different boundaries, on different dates.
This page maps what ESOS data can supply to each, and where the gaps are that no amount of reuse will close.
The map
Four duties, four tests
Each regime has its own instrument, its own test of who is in, its own boundary and its own date.
The first job is to know which of them binds you.
Module 01 / 04
ESOS
Module 02 / 04
SECR
Module 03 / 04
FCA rules on UK SRS
Module 04 / 04
PPN 006
Read the detailed guidance and evidence
| Regime | Source | Who is in | What is reported | When |
|---|---|---|---|---|
| ESOS | SI 2014/1643 | ≥ 250 persons, or > £44m and > £38m, and their groups | Energy consumed in the UK, audited; savings opportunities | Every four years; next by 5 Dec 2027 |
| SECR | SI 2008/410 Sch 7 | Quoted companies; large unquoted companies and LLPs | Energy and Scope 1 and 2 emissions, one intensity ratio | Annually, in the directors’ report |
| FCA rules on UK SRS | PS26/19 | Listed in UKLR 6, 14, 15, 16 and 22 | UK SRS S1 and S2, or an explanation | Annually, periods from 1 Jan 2027 |
| PPN 006 | Cabinet Office | Bidders for in-scope contracts over £5m a year | A Carbon Reduction Plan: Scope 1, 2, five Scope 3 categories | Per procurement |
Only ESOS and SECR are law with penalties behind them.
The FCA’s final rules make UK SRS a comply-or-explain obligation for listed companies in scope, across both standards; the consultation had proposed making UK SRS S2 mandatory, and the final rules do not.
PPN 006 binds contracting authorities, not companies: a company needs a Carbon Reduction Plan only when it bids for a contract to which an in-scope authority has applied the note.
Whether ESOS binds you is on ESOS Phase 4 thresholds, and SECR on SECR thresholds.
What ESOS measures
ESOS data: UK energy, not emissions
Module 01 / 04
UK energy consumption in kWh or £
Module 02 / 04
A split across four organisational purposes
Module 03 / 04
Transport fuel you are supplied with
Module 04 / 04
Costed savings opportunities
| ESOS gives you | ESOS does not give you |
|---|---|
| UK energy consumption in kWh or £ | Emissions in tonnes of CO₂e |
| A split across four organisational purposes | Overseas operations |
| Transport fuel you are supplied with | Most of Scope 3 |
| Costed savings opportunities | A target or a transition plan |
Read the detailed guidance and evidence
An ESOS assessment calculates total energy consumption in a common unit, which the guidance says may be kWh or energy spend, and states plainly that CO₂ is not an energy unit.
It counts energy consumed in the UK and its offshore area, under the Environment Agency’s guidance, with international travel optional.
It splits that energy across transport, industrial processes, buildings and other purposes, each with its own intensity ratio.
And it produces costed savings opportunities with payback periods, which none of the other three regimes asks for.
So ESOS data is a strong base for the energy lines of the other duties, and says nothing on its own about emissions, overseas sites or the value chain.
Into SECR
ESOS and SECR: the closest fit, with two traps
Module 01 / 04
Scope 1
Module 02 / 04
Oversight
Module 03 / 04
Reporting period
Module 04 / 04
Key point 04
ESOS: no lead assessor if total consumption is less than 40,000 kWh.
SECR unquoted relief: 40,000 kWh or less, in the UK.
At exactly 40,000 kWh the two answers differ.
Read the detailed guidance and evidence
SECR asks a large unquoted company for UK energy use, including transport fuel, and the emissions from it, under Schedule 7 Part 7A; a quoted company reports global Scope 1 and 2 emissions and at least its UK energy use.
ESOS energy data covers much of the unquoted company’s SECR energy line, once converted to emissions with the government conversion factors.
The first trap is the period: SECR follows the financial year, ESOS a 12-month reference period set around 31 December 2026, and the two rarely coincide.
The second is the ratio: SECR needs one intensity ratio of the company’s choosing, ESOS one for each organisational purpose used.
The Environment Agency is explicit that SECR participation does not count as ESOS compliance, and the SECR Environmental Reporting Guidelines are a separate method.
The head-to-head comparison is on ESOS vs SECR, the SECR dates on the SECR deadline, and SECR against the standards on SECR and UK SRS.
Into UK SRS
ESOS and UK SRS S2: a different boundary
Module 01 / 04
Boundary
Module 02 / 04
Measure
Module 03 / 04
Scope 3
Module 04 / 04
Method
| ESOS | UK SRS S2 | |
|---|---|---|
| Boundary | Energy consumed in the UK | The reporting entity, worldwide |
| Measure | kWh or energy spend | Tonnes CO₂e, gross |
| Scope 3 | Only fuel you are supplied with | All 15 categories considered |
| Method | The ESOS Regulations | GHG Protocol Corporate Standard |
| Dates | Reference period around 31 Dec 2026 | The financial reporting period |
Read the detailed guidance and evidence
UK SRS S2 paragraph 29(a) asks for absolute gross Scope 1, 2 and 3 emissions, measured on the GHG Protocol Corporate Standard, for the same reporting entity as the financial statements.
ESOS energy data, converted to emissions, supplies part of Scope 1 and Scope 2 for UK operations, and no more.
Scope 3 is measured on the Corporate Value Chain Standard, and the FCA’s rules give a listed company one year’s relief from disclosing it, during which it states that it is using the relief.
The standards themselves are voluntary for any entity, and the government’s consultation response confirms UK SRS S2 is a national framework for section 414CB(6) of the Companies Act 2006.
An ESOS audit’s costed opportunities can inform what a company says about its transition, but the FCA’s rules ask only whether it has a transition plan and where to find it.
The Scope 3 detail is on Scope 3 under UK SRS, and transition plans on transition plans under UK SRS.
Into PPN 006
Carbon Reduction Plans: the procurement duty
Module 01 / 04
Targets
Module 02 / 04
Key point 02
Module 03 / 04
Oversight
Module 04 / 04
Scope 3
Read the detailed guidance and evidence
PPN 006, the Cabinet Office note in force for procurements from 24 February 2025, asks bidders for a Carbon Reduction Plan as a condition of participation.
It applies to contracts an in-scope authority values at more than £5 million a year, including VAT, averaged over the contract, and the test is per contract.
In-scope authorities are central government departments, their executive agencies and non-departmental public bodies.
The plan reports Scope 1 and Scope 2 in full and five Scope 3 categories: upstream and downstream transport and distribution, waste, business travel and employee commuting.
It must also confirm a commitment to net zero by 2050 in the UK.
ESOS energy data feeds the Scope 1 and 2 lines; the five Scope 3 categories need data ESOS never collects.
Worked scenarios
Which duties apply, organisation by organisation
Illustrative profiles, not real companies.
Each answer reads the tests above; group structure and listing category change them.
Module 01 / 03
Separate tests
Module 02 / 03
Listing matters
Module 03 / 03
Procurement
| Profile | ESOS | SECR | FCA rules on UK SRS |
|---|---|---|---|
| UK company listed in UKLR 6, 2,000 UK employees | In — employee limb | In — quoted company | Comply or explain from periods beginning 1 Jan 2027 |
| Overseas company with a UK secondary listing (UKLR 14), UK subsidiaries under 250 employees and under the money limbs | In only if a UK group member is large, or a UK establishment employs 250 | Depends on each UK company | Comply or explain — UKLR 14 is in scope of the final rules |
| Private UK company, 400 employees, £60m turnover | In — employee limb | In — exceeds two of the three limits | Not in scope; UK SRS voluntary |
| Private UK company, 260 employees, £30m turnover, £15m balance sheet | In — at least 250 persons | Exempt if unquoted — within two of the three limits | Not in scope |
| Private UK company, 200 employees, £50m turnover, £40m balance sheet | In — both money limbs exceeded | In — exceeds two of the three limits | Not in scope |
| UK subsidiary of an EU parent, 350 UK employees | In — employee limb | Depends on its own size | Not in scope; the parent may report under the CSRD |
The fourth row is the one that surprises people: ESOS counts at least 250 persons on its own, while SECR lets an unquoted company off if it stays within two of three limits.
The EU parent in the last row reports under the Corporate Sustainability Reporting Directive, which Omnibus I narrowed to undertakings above €450 million net turnover and 1,000 employees, both, from financial years 2027.
How the EU and UK standards compare is on UK SRS vs CSRD.
What is changing
Reform: a consultation promised, nothing decided
Module 01 / 04
Oversight
Module 02 / 04
Proposal
Module 03 / 04
Proposal · 2
Module 04 / 04
Proposal · 3
Read the detailed guidance and evidence
The government’s modernising corporate reporting consultation of 7 September 2026 says DESNZ intends to consult on SECR and ESOS later in 2026.
It says that consultation will explore longer-term options to reform SECR, building on the SECR evaluation of 29 January 2026 and an evaluation of ESOS that is under way.
The SECR post-implementation review recommends keeping SECR with amendments, and lists alignment with other frameworks among the questions for that consultation, not as a decision.
SI 2026/701 did not change the ESOS thresholds, and no instrument proposes aligning them with SECR’s.
The same consultation says the government will consider how UK SRS should be reflected in the Companies Act 2006, with no proposal, mechanism or date.
Until something is made, the four regimes stand as they are; the FRC adds that new ISSB standards would not automatically apply in the UK.
Getting it right
Mistakes that cross the four regimes
Module 01 / 04
Method
Module 02 / 04
Reporting period
Module 03 / 04
Listed categories
Module 04 / 04
Key point 04
Read the detailed guidance and evidence
Treating ESOS as an emissions report: it measures energy, and the conversion to carbon is a separate step with its own factors.
Assuming one data year serves all four: ESOS’s reference period sits around 31 December 2026, SECR and UK SRS follow the financial year, and a Carbon Reduction Plan has its own reporting year.
Describing UK SRS as mandatory: the FCA’s final rules are comply or explain across S1 and S2, and UKLR 14 and 15 are in scope, not merely signposting.
Reading UK SRS as IFRS: UK SRS S2 is IFRS S2 endorsed and adapted, and the ISSB’s own IFRS S1 and IFRS S2 differ from it in places, set out on UK SRS vs IFRS S1 and S2.
Citing the TCFD as current: the Task Force disbanded on 12 October 2023, and its four pillars live on in UK SRS S2; see UK SRS vs TCFD.
Assuming section 463 protects everything: the government says only UK SRS disclosures inside the strategic report are covered by the directors’ liability regime, unless the section is widened.
Read next
The UK SRS side, in more depth
Module 01 / 04
Standard
Module 02 / 04
Deadline
Module 03 / 04
Assurance
Module 04 / 04
Oversight
Read the detailed guidance and evidence
The standards are introduced on the UK SRS hub, and each is explained on UK SRS S1 and UK SRS S2, with their shared structure on the four pillars.
Who is caught is on UK SRS scope, and when on the UK SRS timeline, the S1 and S2 timeline and UK SRS deadline.
Reporting without a duty is covered on voluntary reporting under UK SRS, and assurance, which no UK entity must obtain, on UK SRS assurance.
For implementation, see UK SRS compliance, UK SRS for boards, UK SRS for financial services and the UK SRS FAQ.
The activity as a whole is on sustainability reporting; on the ESOS side, whether the scheme compels you is on is ESOS mandatory.
The sister reference covers the ESOS route itself in its ESOS Phase 4 compliance guide, and the GOV.UK ESOS overview is the regulator’s own summary.
The ESOS instrument’s size test is in Schedule 1, and SECR’s origin is SI 2018/1155.
Frequently asked
ESOS, SECR and UK SRS: questions people ask
What is the difference between ESOS and SECR?
ESOS is a four-yearly energy assessment notified to the Environment Agency, for undertakings with at least 250 persons or over £44 million turnover and over £38 million balance sheet, and their groups.
SECR is an annual energy and carbon disclosure in the directors' report, for quoted companies and for large unquoted companies and LLPs — a large unquoted company is exempt only if it stays within two or more of £36 million turnover, £18 million balance sheet and 250 employees.
Neither satisfies the other.
Can ESOS data be used for UK SRS reporting?
It can feed part of it.
ESOS measures energy consumed in the UK, in kWh or energy spend.
UK SRS S2 asks for absolute gross Scope 1, 2 and 3 greenhouse gas emissions for the whole reporting entity, measured on the GHG Protocol.
ESOS energy data, converted with emissions factors, supplies part of Scope 1 and 2 for UK operations; it does not supply overseas operations or most of Scope 3.
What does "carbon SECR PPN ESOS" cover?
Four separate UK duties that use the same energy and carbon data: ESOS (the four-yearly energy assessment), SECR (annual energy and carbon reporting in the directors' report), PPN 006 (a Carbon Reduction Plan required from bidders for major central government contracts), and, for listed companies, the FCA's comply-or-explain rules on UK SRS. Each has its own test, and none satisfies another.
Is a Carbon Reduction Plan under PPN 006 a legal requirement?
No. PPN 006 is procurement policy that binds in-scope contracting authorities.
A bidder needs a Carbon Reduction Plan only where an in-scope authority applies PPN 006 to a contract worth more than £5 million a year, including VAT.
The plan covers Scope 1, Scope 2 and five Scope 3 categories.
Is UK SRS mandatory for companies in ESOS?
No. Being in ESOS says nothing about UK SRS.
UK SRS S1 and S2 are voluntary standards; listed companies in UKLR 6, 14, 15, 16 and 22 report against them on a comply-or-explain basis for accounting periods beginning on or after 1 January 2027, under the FCA's final rules published on 30 September 2026.
No private-company threshold has been proposed.
Are ESOS and SECR being merged?
Not by any instrument.
The government's modernising corporate reporting consultation of 7 September 2026 says DESNZ intends to hold a consultation on SECR and ESOS later in 2026, building on an evaluation of SECR and an ESOS evaluation under way.
Until then both regimes stand as they are, with their different tests.
Does a company in ESOS also report under SECR?
Often, but not always.
An undertaking with 260 employees, £30 million turnover and a £15 million balance sheet is in ESOS on headcount but, if unquoted, exempt from SECR because it stays within two of the three SECR limits.
The tests have to be run separately.
Prepare the evidence
ESOS and UK SRS: from a requirement to a reporting pack
Use this preparation sequence alongside the detailed requirements on this page.
An editorial workflow, not a statutory schedule.
- Stage 0101
Qualification record
Resolve the undertaking and group position at the qualification date.
- Stage 0202
Energy period
Retain the chosen reference period and its source records.
- Stage 0303
Assessment coverage
Document the audit coverage, exclusions and compliance routes used.
- Stage 0404
Assessor review
Check whether a lead assessor is needed for the chosen compliance route.
- Stage 0505
Approval and notification
Retain the applicable director sign-off and notification evidence.
- Stage 0606
Action plan
Use the assessment findings to support the applicable action plan and progress record.
Read the applicable instrument: The Energy Savings Opportunity Scheme Regulations 2014 (SI 2014/1643), revised text
A practical brief
An evidence pack, with a clear review trail
Ask for a pack that lets the next reviewer retrace the scope decision, follow the evidence and understand the limitations.
This describes a useful handover; it does not certify compliance or establish that a vendor or adviser delivers it.
Module 01 / 04
Applicability record
Write down the entity, reporting route and relevant period, including why the route applies.
Module 02 / 04
Evidence register
Attach each reported figure or statement to its source, method, version and limitations.
Module 03 / 04
Review trail
Name the preparer, reviewer, open questions and decisions taken before publication.
Module 04 / 04
Usable handover
Retain the working files and unresolved actions so the next reporting cycle can reuse the evidence.
View the preparation diagram
- Prepare01
Create the traceable pack
Keep the input records, calculation files and narrative together.
- Challenge02
Resolve questions before publication
Record the assumptions challenged and any limitations still unresolved.
- Retain03
Make the next cycle reproducible
Keep the approved version and the actions carried forward.
Continue your research
Related guides, one question at a time
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), revised text
In force 17 July 2014. Consolidation of the 2026 amendments is partial — read with SI 2026/701.
- legislation.gov.ukESOS Regulations 2014, Schedule 1 ¶¶1, 1A, 5, 9–11 — the large undertaking test
At least 250 persons, or turnover in excess of £44m and balance sheet in excess of £38m; monthly-average headcount (¶10); two-period status rule (¶11).
- Environment AgencyHow to comply with the Energy Savings Opportunity Scheme (ESOS) phase 4
Published 30 July 2026. A restatement of the Regulations, never the source over them; where it and the SI differ, the SI governs.
- Environment Agency / GOV.UKEnergy savings opportunity scheme (ESOS): find out if you qualify and how to comply
Rewritten for Phase 4 on 2 September 2026; seven approved lead assessor registers; PAS 51215-1 and -2:2025 voluntary.
- legislation.gov.ukSI 2018/1155 — the instrument that created SECR
In force 1 April 2019.
- legislation.gov.ukSI 2008/410 Schedule 7 Part 7A ¶¶20B–20D — SECR for large unquoted companies
Exempt on two or more of not more than £36m, £18m and 250; UK energy; the 40,000 kWh relief.
- Department for Energy Security and Net ZeroEnvironmental Reporting Guidelines, including SECR guidance
- Department for Energy Security and Net Zero2026 Post-Implementation Review of the SECR Regulations 2018 (PDF)
Retain with amendments; a consultation on streamlining is planned.
- Financial Conduct AuthorityPS26/19: Aligning listed issuers’ sustainability disclosures with international standards
30 September 2026: comply or explain against UK SRS for UKLR 6, 14, 15, 16 and 22; accounting periods from 1 January 2027; one year’s Scope 3 relief.
- Financial Conduct AuthorityCP26/5 — the consultation PS26/19 finalised (PDF)
Proposed mandatory UK SRS S2; the final rules did not adopt it.
- Department for Business and TradeUK Sustainability Reporting Standards: UK SRS S1 and UK SRS S2
Published 25 February 2026; voluntary for any entity.
- Department for Business and TradeUK SRS S2 — Climate-related disclosures (PDF), ¶29(a)
Absolute gross Scope 1, 2 and 3 emissions on the GHG Protocol Corporate Standard.
- Department for Business and TradeExposure drafts of UK SRS: government response, Chapter 3
UK SRS S2 is a national framework for Companies Act 2006 s.414CB(6).
- Department for Business, Innovation, Science and TradeModernising corporate reporting — consultation, 7 September 2026
¶150: DESNZ to consult on SECR and ESOS later in 2026; ¶¶154–155: how UK SRS is reflected in the Companies Act is still to be considered.
- legislation.gov.ukCompanies Act 2006
Section 414CB (climate-related financial disclosures) and section 463 (liability for reports).
- Cabinet OfficePPN 006: Taking account of Carbon Reduction Plans in the procurement of major government contracts
A condition of participation above £5m a year (including VAT), per contract; Scope 1, 2 and five Scope 3 categories.
- Financial Reporting CouncilSustainability reporting developments: frequently asked questions
New ISSB standards would not automatically apply in the UK.
- IFRS FoundationIFRS S1 General Requirements
- IFRS FoundationIFRS S2 Climate-related Disclosures
- GHG ProtocolCorporate Accounting and Reporting Standard
- GHG ProtocolCorporate Value Chain (Scope 3) Standard
- TCFDTCFD recommendations (archive)
The Task Force disbanded on 12 October 2023; the site is no longer updated.
- EUR-LexDirective (EU) 2022/2464 — the Corporate Sustainability Reporting Directive
- EUR-LexDirective (EU) 2026/470 (Omnibus I)
€450m net turnover and 1,000 employees, both, from financial years 2027.