SECR and ESOS · The hub
ESOS and SECR: two energy regimes, one table
ESOS and SECR are the UK’s two energy regimes for large organisations, and they are routinely confused: different tests, different cycles, different regulators (SI 2014/1643; SI 2018/1155).
ESOS measures and plans every four years; SECR publishes every year.
This page puts them side by side and links to every guide on this site for each.
ESOS vs SECR
The two regimes in one table
| ESOS | SECR | |
|---|---|---|
| What it is | An energy assessment and notification scheme | An annual disclosure in the annual report |
| Law | SI 2014/1643, amended by SI 2023/1182 and SI 2026/701 | SI 2018/1155, amending SI 2008/410 Sch 7 and SI 2008/1911 |
| Who | Large undertakings: at least 250 persons, or turnover over £44m and balance sheet over £38m; groups together | Quoted companies of any size; unquoted companies and LLPs exceeding two of £36m / £18m / 250 |
| When tested | On the qualification date: 31 December 2026 for Phase 4 | Each financial year, with a two-year rule for changes of size |
| Cycle | Four-year phases; Phase 4 ends 5 December 2027 | Every financial year since 1 April 2019 |
| Output | An ESOS report (kept) and a notification of compliance (submitted), then an action plan and progress updates | Energy, emissions, an intensity ratio, methodology and efficiency measures in the directors’ report |
| Unit | Energy, in kWh or £ — "CO2 is not an energy unit" | kWh and tCO2e |
| Intensity ratio | An energy ratio for each of four organisational purposes | At least one emissions ratio |
| Geography | UK energy | Quoted: worldwide. Unquoted and LLP: UK, overseas optional |
| Low-energy boundary | No lead assessor below 40,000 kWh | Disclosure relief at 40,000 kWh or less (UK, for unquoted) |
| Who checks | Environment Agency and the other UK regulators | Auditor’s consistency opinion; FRC reviews; no SECR regulator |
| Penalties | Up to £50,000 plus daily penalties; publication | None specific; Companies Act offences and late filing penalties |
The two tests are different logic, not only different numbers: ESOS is “250 persons, or both money limbs”, SECR is “two of three”.
At exactly 40,000 kWh the regimes point opposite ways: ESOS still needs a lead assessor, while SECR’s relief is available.
The Environment Agency’s Phase 4 guidance lists SECR among the schemes whose participation does not count as ESOS compliance.
Who is in which
In one, the other, or both
Most large organisations are in both, but the edges are wide.
An undertaking with 250 or more staff is in ESOS even with modest turnover, while SECR needs two of its three limbs.
A lean, high-turnover company can be in SECR and outside ESOS, because ESOS needs both money limbs.
Since April 2025 neither test moves with the Companies Act: the Explanatory Memorandum to the size uplift says it does “not affect” SECR, and ESOS has its own schedule.
The SECR thresholds page has a checker for the SECR side and ESOS Phase 4 one for ESOS.
| Illustrative organisation | SECR | ESOS |
|---|---|---|
| 300 staff, £20m turnover, £10m balance sheet | Exempt — exceeds one | In — headcount |
| 90 staff, £40m turnover, £20m balance sheet | In — exceeds two | Out — both money limbs needed |
| 260 staff, £50m turnover, £45m balance sheet | In | In |
| AIM company, 40 staff, £10m turnover | Out — unquoted, under the figures | Out |
The calendar
Where the two regimes’ dates fall
SECR has no deadline of its own: it goes in with the accounts, nine months after the year end for a private company or LLP and six for a public company.
ESOS runs on its own calendar, set by regulation 4 of the ESOS Regulations.
For a calendar-year company, the Phase 4 ESOS notification falls about two months after its 2026 accounts, and SECR report, are due.
Our read: planning the two together is cheaper than running them apart, because the energy measurement is shared; that is a view, not a requirement.
- 5 Dec 2026ESOS Phase 3 second progress update
- 31 Dec 2026ESOS Phase 4 qualification date
- 30 Sep 2027Example: SECR filed with accounts
A private company with a 31 December 2026 year end has nine months.
- 5 Dec 2027ESOS Phase 4 compliance date
- 5 Dec 2028ESOS Phase 4 action plan
- 2029 – 2031Three ESOS progress updates
By 5 December each year.
Shared data
One measurement, several uses
An ESOS assessment measures energy across four organisational purposes: transport, industrial processes, buildings, and any other purpose.
That is the activity data SECR converts into emissions, and the energy-efficiency measures an ESOS action plan commits to are the ones a SECR narrative reports on.
DESNZ’s 2026 review of SECR found businesses reusing SECR data for other schemes and the reverse, with varying ease.
ESOS reporting shows the conversion from kWh to tCO2e, and the SECR reporting template shows where the result goes.
ESOS covers one year in four, UK only, with a de minimis.
SECR wants every year and, for quoted companies, the whole world.
What is changing
Both regimes are under review
The 2026 SECR review recommends keeping SECR with amendments, none of them decided; the Modernising corporate reporting consultation proposes moving the SECR disclosures out of the directors’ report without changing the duty.
ESOS Phase 4 is settled law, in force since 22 July 2026, and an evaluation of ESOS is under way.
At ¶150 of that consultation document, DESNZ says it intends to consult on SECR and ESOS together later in 2026.
Listed companies in scope of the FCA’s final rules report against UK SRS on a comply-or-explain basis for accounting periods beginning on or after 1 January 2027; that is a third duty, not a replacement for either; the UK SRS hub covers it.
The wider map is on ESG reporting requirements in the UK and UK carbon reporting requirements.
The SECR hub and the ESOS hub
Every SECR and ESOS guide on this site
| Guide | What it answers |
|---|---|
| Streamlined energy and carbon reporting | What SECR is, who reports, when it is due, and why there is no SECR certification |
| SECR thresholds | The two-of-three test, the two-year rule, groups, AIM, and the 2025 uplift |
| SECR requirements | Every disclosure, paragraph by paragraph, and the three reliefs |
| SECR carbon reporting | Factors, Scope 2 methods and the intensity ratio |
| SECR reporting template | A blank working sheet and an illustrative worked example |
| ESOS Phase 4 | Qualification, dates, changes from Phase 3, penalties |
| ESOS compliance | The eight steps from qualification to notification |
| ESOS action plans and progress updates | What follows the notification, and when |
| ISO 50001 and ESOS | When certification replaces the energy audit |
| ESOS reporting | The ESOS report, what is published, and kWh to tCO2e |
| ESOS for energy and industry | CHP, UK ETS and CCA data, and multi-site estates |
For implementation help across regimes, carbon compliance consultancy explains what that kind of engagement involves, and emissions compliance consultants covers choosing one.
The government’s own SECR guidance is the Environmental Reporting Guidelines, and the ESOS penalties are in Part 8 of the ESOS Regulations.
Frequently asked
ESOS and SECR: questions people ask
What is the difference between ESOS and SECR?
ESOS is an energy assessment scheme: large undertakings measure their energy use, audit the significant part and notify the Environment Agency once every four years, then produce an action plan. SECR is an annual disclosure: quoted companies and large unquoted companies and LLPs publish energy use, emissions, an intensity ratio and efficiency measures in their annual report. One measures and plans; the other publishes.
Can a company be in SECR but not ESOS, or the other way round?
Yes. ESOS catches an undertaking with at least 250 persons, or with both turnover above £44 million and balance sheet total above £38 million; SECR catches an unquoted company exceeding two of £36 million turnover, £18 million balance sheet and 250 employees, and every quoted company. A company with 300 staff and £20 million turnover is in ESOS but not SECR; one with 90 staff, £40 million turnover and £20 million balance sheet is in SECR but not ESOS.
Are ESOS and SECR thresholds being aligned?
Not for Phase 4. A change to align the ESOS qualification thresholds with SECR was dropped for Phase 4, and no Phase 5 commitment to it has been published. DESNZ has said it intends to consult on SECR and ESOS later in 2026, which may revisit both.
Can ESOS data be used for SECR?
The energy data can. An ESOS assessment measures energy use across transport, industrial processes, buildings and any other purpose, which is SECR’s activity data. But ESOS is four-yearly, UK-only and allows a de minimis, while SECR is annual and, for quoted companies, worldwide, so ESOS data needs extending before it can be reported under SECR.
Which carries penalties, ESOS or SECR?
ESOS has its own civil penalties: up to £50,000 plus a daily penalty for failing to undertake an assessment, and up to £5,000 plus a daily penalty for failing to notify, with publication. SECR has none of its own; a deficient directors’ report is caught by the general Companies Act offences, and late accounts by the Companies House late filing penalty.
Did the 2025 company size changes affect ESOS or SECR?
Neither. The April 2025 rise in the Companies Act size thresholds did not change SECR, whose figures are written into its own regulations; the Explanatory Memorandum to the uplift says it does not affect SECR. ESOS has its own test in Schedule 1 to the ESOS Regulations, which the 2026 amendments also left unchanged.
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)
ESOS: qualification, the assessment, notification, penalties.
- legislation.gov.ukSI 2014/1643, Schedule 1 — large undertaking
At least 250 persons, or both money limbs over £44m and £38m.
- legislation.gov.ukSI 2018/1155 — the SECR Regulations
SECR, for financial years beginning on or after 1 April 2019.
- legislation.gov.ukSI 2008/410, Schedule 7 Part 7A — SECR for unquoted companies
The ¶20B test and the disclosures.
- legislation.gov.ukSI 2024/1303 — the 2025 company size uplift
Raised the Companies Act limits; did not touch SECR.
- legislation.gov.ukExplanatory Memorandum to SI 2024/1303, ¶6.7
"These Regulations do not affect the … SECR requirements".
- legislation.gov.ukSI 2014/1643, Part 8 — ESOS civil penalties
Regs 43–47.
- Environment AgencyHow to comply with ESOS phase 4 (30 July 2026)
Phase 4 dates; SECR and other schemes do not count as ESOS compliance.
- GOV.UKEnvironmental Reporting Guidelines, including SECR guidance (March 2019)
The government’s SECR guidance.
- Department for Energy Security and Net Zero2026 post-implementation review of the SECR Regulations
Retain SECR with amendments; reuse of SECR data across schemes.
- Department for Business, Innovation, Science and TradeModernising corporate reporting — consultation document
¶150: DESNZ intends to consult on SECR and ESOS later in 2026.
- Department for Business and TradeUK Sustainability Reporting Standards — guidance
The standards both regimes’ data feeds.