ESOS · the law

ESOS legislation: one Act, three instruments

The ESOS legislation is the Energy Savings Opportunity Scheme Regulations 2014, as amended in 2023 and 2026, made and now amended under Part 11 of the Energy Act 2023.

The 2014 Regulations were made under the European Communities Act 1972, but section 254(9)(a) of the 2023 Act treats the scheme as if it had been made under the new power, which is why it can now be changed by statutory instrument alone.

The finder below locates any provision by subject and shows what has amended it.

Find a provision The Energy Act powers

The instruments

Three instruments, made under two different powers

Sources: the introductory text of SI 2014/1643, SI 2023/1182 and SI 2026/701
Instrument	Made	Laid	In force	Power	What it did
SI 2014/1643	24 June 2014	26 June 2014	17 July 2014	European Communities Act 1972, s.2(2)	Created ESOS: qualification, the four-year cycle, audits, lead assessors, notification, enforcement
SI 2023/1182	7 November 2023	7 November 2023	29 November 2023	Energy Act 2023, ss.254–260 and 263	The 95% floor, intensity ratios, the ESOS report, the 40,000 kWh limb, action plans and progress updates
SI 2026/701	23 June 2026	1 July 2026	22 July 2026	Energy Act 2023, ss.254–260 and 263	Phase 4: routes, savings achieved, the action plan review, the assessor’s notice, a third update, publication

There is no second set of ESOS regulations: every change since 2014 has been an amendment to the one instrument.

Both amending instruments recite that the Secretary of State consulted, as section 263(1) of the 2023 Act requires, and consulted the Department for the Economy in Northern Ireland under section 263(8)(b)(iii).

SI 2026/701 extends to England and Wales, Scotland and Northern Ireland, and its Explanatory Note was corrected by a slip on 3 July 2026 that touched no operative provision.

The 2014 instrument is read regulation by regulation on its own page.

Where the authority comes from

From the 1972 Act to the Energy Act 2023

The 2014 Regulations open by saying they are made under section 2(2) of the European Communities Act 1972, the general power to implement EU obligations.

The obligation was Article 8 of the Energy Efficiency Directive 2012/27/EU, on energy audits for large enterprises.

The 1972 Act was repealed on 31 January 2020 by the European Union (Withdrawal) Act 2018, with savings for the implementation period that ended on 31 December 2020.

The Regulations themselves continued in force, and the Energy Act 2023 gave the scheme a domestic home: section 254(9)(a) provides that the scheme established by SI 2014/1643 is to be treated as having been established under section 254(1).

That one subsection is why the 2023 and 2026 amendments could be made by statutory instrument under the 2023 Act, and why a further reform needs no new primary legislation.

The EU has since recast the Directive as Directive (EU) 2023/1791, which is EU law and does not apply in the UK; the 2023 and 2026 changes to ESOS were domestic decisions, not transposition.

Some older GOV.UK text still explained ESOS as implementing Article 8; that describes where the scheme came from, not the power it rests on now.

Energy Act 2023, Part 11

The powers, section by section

Part 11 of the Energy Act 2023, headed “Energy Savings Opportunity Schemes”, runs from section 254 to section 266; sections 254 to 263 and 266 came into force at Royal Assent, and sections 264 and 265 on 26 December 2023.

Source: Energy Act 2023, Part 11, read at source 1 October 2026. The last column is our reading of where each power is visible in SI 2014/1643; it is not stated in either instrument.
Section	Heading	What it allows	Where the Regulations use it, for example
254	Energy savings opportunity schemes	Regulations establishing schemes for six ESOS purposes, from assessing and publishing consumption to requiring savings; s.254(9) treats the 2014 scheme as made under it	The scheme as a whole
255	Application	Which undertakings are in or excluded; treating participants as one; energy in the UK, offshore and, where provided, elsewhere	Sch 1; regs 15–17
256	Requirement for assessment	ESOS assessments, their frequency, method and records; assessors; recommendations and cost-benefit analysis; reports; notification and publication; deemed compliance	Part 4; regs 29, 33, 33A
257	Assessors	Restricting appointment to a designated list or register; duties on register holders; quality checks	regs 12, 21
258	ESOS action plans	Plans of proposed action or targets, their timing, content and publication	Part 6A
259	Action to achieve savings	Encouraging or requiring specified action or savings, and reporting on them	Reporting on plans and savings achieved
260	Scheme administration	Appointing administrators, information, records, publication, guidance and fees	regs 5, 6, 10
261	Enforcement, penalties and offences	Information and entry powers, notices, financial and publication penalties, and offences	Parts 7 and 8
262	Appeals	A right of appeal against any financial penalty	Part 9
263	Procedure	Consultation, notice to devolved authorities, and the affirmative or negative procedure	The recitals of SI 2023/1182 and SI 2026/701
264–265	Directions; financial assistance	Directions to administrators; grants or loans to administrators or participants	—
266	Interpretation	Defines the Part’s terms, including “ESOS assessment” and “ESOS action plan”	—

The core power in section 254 lets the Secretary of State make provision for one or more schemes imposing obligations for six purposes, from assessing and publishing energy consumption and the resulting emissions to requiring energy savings or emissions reductions.

Section 255 allows ESOS to reach energy consumed outside the UK where regulations provide for it; the current Regulations and guidance count UK and offshore consumption only.

Section 266 takes “undertaking” and “group undertaking” from section 1161 of the Companies Act 2006, which is why ESOS groups follow company law.

How ESOS can change

What the Act allows that the Regulations do not yet do

The 2023 Act is wider than the scheme built on it, and the gap shows how ESOS could change without a new Act.

Section 259 allows regulations requiring participants to take specified action or achieve specified savings, including acting on audit recommendations or meeting targets in their action plans; the current Regulations require reporting, not action.

Section 254 covers greenhouse gas emissions as well as energy, and section 261(6) allows ESOS regulations to create criminal offences; the Regulations use neither.

Section 260(8) allows fees to be charged to participants; the Environment Agency says there is no charge for submitting a notification.

Section 263 sets the procedure: before making ESOS regulations the Secretary of State must consult those likely to be affected, and give devolved authorities at least 28 days’ notice of provisions within their competence.

Regulations that extend ESOS to new kinds of undertaking, require action under section 259(1)(b) for the first time, give new enforcement powers, create penalties, raise penalties beyond inflation, create offences or introduce a new fee need the affirmative procedure; anything else follows the negative procedure.

The government has said it intends to consult on SECR and ESOS later in 2026; what is and is not decided for the next period is set out on ESOS Phase 5.

The 2014 Regulations

Find a provision, and what has amended it

SI 2014/1643 is arranged in Parts that run in the order a participant meets them — administration, qualification, the ESOS assessment, notification, deemed compliance, action plans in Part 6A, enforcement, penalties and appeals — with five Schedules.

The finder beside this text lists the provisions a participant is most likely to need, by subject, with the regulation of each amending instrument that changed it.

The penalties in Part 8 are the provisions with the most direct consequences, set out on the ESOS penalties page with the Environment Agency’s Annex 2 method.

The duties in the order a participant meets them are in the Phase 4 compliance guide, and summarised on ESOS requirements.

SI 2014/1643, provision by provision

SearchSubjectChanged by

36 of 36 provisions

reg 3The Secretary of State reviews the RegulationsSI 2023/1182: — · SI 2026/701: para (2) omitted (reg 4)
reg 4Compliance periods, qualification dates and compliance dates, as a rolling four-year formulaSI 2023/1182: — · SI 2026/701: —
reg 5The Environment Agency is the scheme administratorSI 2023/1182: — · SI 2026/701: —
reg 6The compliance bodies for England, Wales, Scotland, Northern Ireland and offshoreSI 2023/1182: — · SI 2026/701: —
reg 8The Notification System, which the Environment Agency runs as MESOSSI 2023/1182: — · SI 2026/701: —
reg 10What the scheme administrator publishes, and within six months of whenSI 2023/1182: para (2) inserted (reg 6(c)) · SI 2026/701: “Tables A to I” becomes “A to K” (reg 5)
reg 12Approved registers and approval bodies; the PAS 51215 competence requirementsSI 2023/1182: — · SI 2026/701: —
reg 15 and Sch 1Relevant undertakings and the large undertaking testSI 2023/1182: — · SI 2026/701: —
reg 16Public bodies and undertakings in insolvency proceedingsSI 2023/1182: — · SI 2026/701: insolvency widened; new (1)(c); Insolvency Act 1986 definition (reg 6) · “public body” re-defined by the Procurement Act 2023 (SI 2025/163)
reg 17Participants and the responsible undertakingSI 2023/1182: — · SI 2026/701: —
reg 20The duty to carry out an ESOS assessmentSI 2023/1182: — · SI 2026/701: “which includes an energy audit” omitted (reg 7)
reg 21Appointing a lead assessor and the reviewSI 2023/1182: para (3), the 40,000 kWh limb (reg 9) · SI 2026/701: para (2A), the assessor’s seven-day notice (reg 8)
reg 21AEstimates and the data behind themSI 2023/1182: — · SI 2026/701: para (1)(b), the data used (reg 9)
reg 22Total energy consumption over a 12-month reference periodSI 2023/1182: — · SI 2026/701: —
reg 25Significant energy consumption, not less than 95%SI 2023/1182: 90% becomes 95%; paras (3)–(4) inserted (reg 13) · SI 2026/701: —
regs 25A–25COrganisational purposes, subtotals and energy intensity ratiosSI 2023/1182: Chapter 2A inserted (reg 15) · SI 2026/701: reg 25C(4), verifiable data or a reasonable estimate (reg 11)
reg 26The duty to carry out energy auditsSI 2023/1182: — · SI 2026/701: “Subject to regulations 33(3) and 33A” (reg 12)
reg 27What an energy audit must doSI 2023/1182: — · SI 2026/701: savings estimates in kWh (reg 13)
reg 27AThe ESOS reportSI 2023/1182: — · SI 2026/701: must include the action plan review (reg 14)
reg 27BSavings since the previous compliance dateSI 2023/1182: — · SI 2026/701: omitted (reg 15), re-enacted as reg 27D
regs 27D–27ESavings achieved in kWh; the action plan reviewSI 2023/1182: — · SI 2026/701: Chapter 3B inserted (reg 17)
reg 28The evidence pack and how long it is keptSI 2023/1182: retention for two subsequent periods (reg 19(2)) · SI 2026/701: new limbs (a)(iv)–(ix), (j), (k) (reg 18)
reg 29The notification of compliance, by routeSI 2023/1182: limbs (a)–(ac) substituted (reg 21) · SI 2026/701: limbs (ad)–(af); para (2) omitted (reg 20)
reg 30Responsible officers: one or twoSI 2023/1182: para (3A), two where reg 21(3) applies (reg 22) · SI 2026/701: —
reg 31What the responsible officer confirmsSI 2023/1182: paras (a)(ii)–(iii) (reg 23) · SI 2026/701: certified energy management system relied on (reg 21)
reg 32Energy consumption not subject to auditSI 2023/1182: — · SI 2026/701: omitted (reg 23)
reg 33ISO 50001 deemed complianceSI 2023/1182: — · SI 2026/701: total or significant trigger; three duties deemed (reg 24)
reg 33AZero energy consumptionSI 2023/1182: — · SI 2026/701: inserted (reg 25)
reg 34Display Energy Certificates and Green Deal AssessmentsSI 2023/1182: — · SI 2026/701: omitted (reg 26)
reg 34AThe ESOS action planSI 2023/1182: Part 6A inserted (reg 26) · SI 2026/701: kWh; para (11) for zero consumption (reg 27)
reg 34BProgress updatesSI 2023/1182: Part 6A inserted (reg 26) · SI 2026/701: a third, final update; kWh; para (9) (reg 28)
regs 35–38Compliance notices, inspection, self-reporting a breach, enforcement noticesSI 2023/1182: — · SI 2026/701: —
regs 39–42Penalty notices, payment, publication and the discretion to waive or reduceSI 2023/1182: — · SI 2026/701: —
regs 43–47The five breaches and their maximum penaltiesSI 2023/1182: — · SI 2026/701: reg 45(1) reworded for deemed routes (reg 29)
regs 48–50Grounds, appeal bodies, suspension and outcomeSI 2023/1182: — · SI 2026/701: —
Sch 3The tables of information notified and publishedSI 2023/1182: — · SI 2026/701: Tables J and K added; Table G rows 2 and 4 now published (reg 31)

Amending regulation numbers in brackets. legislation.gov.uk applies these amendments provision by provision; read the amending instrument beside the consolidated text.

Reading the text

The consolidated text is only partly up to date

legislation.gov.uk publishes SI 2014/1643 as revised, but its editors apply amendments provision by provision, and for SI 2026/701 that work was still in progress on 1 October 2026.

On that day the regulation 21, 16 and 29 pages showed their SI 2026/701 amendments in place, while the Part 8 page still listed regulation 21(2A), regulation 16(1)(c) and regulation 29(1)(ad)–(af) among changes “yet to be applied”.

The regulation 31 page carried a “no known outstanding effects” banner without the SI 2026/701 change to the officer’s confirmation, and the Part 8 page showed regulation 45 in its pre-2026 wording.

The safe way to read any Phase 4 provision is as a pair: the 2014 provision and the regulation of SI 2026/701 that amends it.

SI 2026/701 itself exists only as made, because an amending instrument is not consolidated into itself, and its HTML text carries the correction slip.

The regulator’s guidance is a restatement

The Environment Agency’s Phase 4 guidance, published on 30 July 2026, explains the amended Regulations and is the regulator’s own account of how it applies them.

Where the guidance and the Regulations differ, the Regulations govern; the guidance has, for example, used the word “third” for the fourth compliance period in places.

Who applies it

The scheme administrator and the regulators

Regulation 5 makes the Environment Agency the scheme administrator for the whole UK, and regulation 6 names the compliance bodies.

The regulator follows the registered office: the Environment Agency in England, the Natural Resources Body for Wales, the Scottish Environment Protection Agency, the Chief Inspector in Northern Ireland, whom the guidance calls the Northern Ireland Environment Agency, and the Secretary of State offshore.

The Department for Energy Security and Net Zero owns ESOS policy, a role the guidance states rather than the Regulations.

The GOV.UK ESOS page describes the law as the 2014 Regulations “as amended most recently by” the 2026 Regulations, which has been accurate since its rewrite on 2 September 2026.

Neighbouring law

ESOS beside SECR and UK SRS

ESOS is a standalone scheme in its own regulations, enforced by environmental regulators with civil penalties.

SECR sits in company law instead, in the Companies Act 2006 framework for directors’ reports, and is policed through the annual report; the SECR legislation page traces that footing, and SECR covers the duty itself.

The two use overlapping energy data but have different size tests, dates and enforcement, compared on ESOS and SECR and in the SECR reporting guide.

UK SRS S1 and S2 are voluntary standards published by the Department for Business and Trade on 25 February 2026; the FCA’s final rules require listed companies in scope to report against them on a comply-or-explain basis for periods beginning on or after 1 January 2027, set out on UK SRS and the FCA and UK SRS legislation.

None of these changes where ESOS gets its authority; where ESOS data can feed them is on ESOS and UK SRS integration.

The scheme as a whole is introduced in the plain-words ESOS overview and on the Energy Savings Opportunity Scheme page, and what is published under it on ESOS reporting.

The Act’s full contents are on legislation.gov.uk, including the rest of the Energy Act 2023.

True or false?

01The ESOS Regulations 2014 were made under the Energy Act 2023.
02SI 2026/701 changed the ESOS size thresholds.
03Extending ESOS to medium-sized businesses would need the affirmative procedure.
04The Energy Act 2023 allows ESOS regulations to require organisations to take action, not just audit.
05Directive (EU) 2023/1791 now governs ESOS.
06A legislation.gov.uk banner saying “no known outstanding effects” proves a provision is current.

6 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 legislation, answered

What is the ESOS legislation?

The Energy Savings Opportunity Scheme Regulations 2014 (SI 2014/1643), as amended by the Energy Savings Opportunity Scheme (Amendment) Regulations 2023 (SI 2023/1182) and 2026 (SI 2026/701).

The power to make and amend them is in Part 11 of the Energy Act 2023.

Under what Act are the ESOS Regulations made?

The 2014 Regulations were made under section 2(2) of the European Communities Act 1972.

That Act was repealed on 31 January 2020, and section 254(9)(a) of the Energy Act 2023 treats the 2014 scheme as if established under section 254(1).

Both amending instruments since were made under sections 254 to 260 and 263 of the Energy Act 2023.

When did the ESOS Regulations come into force?

SI 2014/1643 was made on 24 June 2014, laid before Parliament on 26 June 2014 and came into force on 17 July 2014.

What did SI 2026/701 change?

In force 22 July 2026, it widened the insolvency exclusion, gave the lead assessor a seven-day notice duty, put estimates in kWh, added reports of savings achieved and an action plan review, widened the ISO 50001 route to total or significant consumption and three duties, added a zero-consumption route, removed Display Energy Certificates and Green Deal Assessments as routes, added a third progress update and rewrote the publication tables. It did not change the size test.

What did SI 2023/1182 change?

In force 29 November 2023, it raised the significant-consumption floor from 90% to 95%, added energy intensity ratios, the ESOS report, the 40,000 kWh limb for lead assessors, and Part 6A on action plans and progress updates.

Is ESOS still EU law?

No. ESOS was first made to implement Article 8 of Directive 2012/27/EU, but it is now domestic law resting on the Energy Act 2023.

The EU’s recast Directive (EU) 2023/1791 does not apply in the UK.

Can the government change ESOS without a new Act?

Yes.

Part 11 of the Energy Act 2023 lets the Secretary of State make ESOS regulations by statutory instrument after consultation.

Section 263 requires the affirmative procedure for some changes, such as extending ESOS to new kinds of undertaking or creating penalties, and the negative procedure for the rest.

Is the legislation.gov.uk text of the ESOS Regulations up to date?

Only partly.

Some SI 2026/701 amendments have been applied provision by provision, while other pages still list them as yet to be applied.

Read SI 2026/701 itself beside the consolidated text, and check each provision.

Does ESOS create criminal offences?

No. The Energy Act 2023 would allow ESOS regulations to create offences, but the Regulations use civil penalties only.

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.

Checked against 16 sources fromlegislation.gov.ukEUR-LexEnvironment AgencyGOV.UK (Environment Agency)

legislation.gov.uk
Energy Act 2023, Part 11 — Energy Savings Opportunity Schemes (sections 254–266)
The standing powers to make and amend ESOS regulations, read in full.
legislation.gov.uk
Energy Act 2023, section 254 — energy savings opportunity schemes
The core power, the ESOS purposes, and s.254(9)(a) on the 2014 scheme.
legislation.gov.uk
Energy Act 2023, section 263 — ESOS regulations: procedure
Consultation, devolved notice, and when the affirmative procedure applies.
legislation.gov.uk
Energy Act 2023 — contents
The Act as a whole.
legislation.gov.uk
The Energy Savings Opportunity Scheme Regulations 2014 (SI 2014/1643) — contents
The instrument, as consolidated.
legislation.gov.uk
SI 2014/1643 — the instrument page
Including the effects register and the as-made version.
legislation.gov.uk
SI 2014/1643, Part 8 — civil penalties
The five breaches, and a dated example of the consolidation lag.
legislation.gov.uk
The Energy Savings Opportunity Scheme (Amendment) Regulations 2023 (SI 2023/1182)
The first amendment made under the Energy Act 2023.
legislation.gov.uk
SI 2023/1182, as made
Made 7 November 2023, in force 29 November 2023.
legislation.gov.uk
The Energy Savings Opportunity Scheme (Amendment) Regulations 2026 (SI 2026/701)
Made 23 June 2026, laid 1 July, in force 22 July 2026.
legislation.gov.uk
European Communities Act 1972, section 2 (repealed)
The power under which the 2014 Regulations were first made.
EUR-Lex
Directive 2012/27/EU on energy efficiency
Article 8, which ESOS was first made to implement.
EUR-Lex
Directive (EU) 2023/1791 on energy efficiency (recast)
EU law that does not apply in the UK.
Environment Agency
Comply with ESOS phase 4
The regulator’s guidance on the amended Regulations, published 30 July 2026.
Environment Agency
Enforcement and sanctions policy, Annex 2
How the penalties set by the Regulations are applied.
GOV.UK (Environment Agency)
Energy savings opportunity scheme (ESOS): find out if you qualify and how to comply
Describes the 2014 Regulations as amended most recently by the 2026 Regulations.