Guidance

Comply with the Energy Savings Opportunity Scheme (ESOS) phase 3

Qualification, compliance and notification requirements for ESOS phase 3.

• From: Environment Agency
• Published: 17 February 2015
• Last updated: 30 July 2026
  Show all updates

  1. 30 July 2026

     The ESOS guidance has been updated and split into 2 separate documents for phase 3 and phase 4. The remaining deadline for phase 3 is to submit the second progress update report by 5 December 2026. The phase 4 guidance provides information on the qualification, compliance and notification requirements for the fourth compliance period. It reflects the changes in the most recent amendment in the Energy Savings Opportunity Scheme Regulations 2014, as amended 2026. A link to the new phase 4 guidance has been added to the publication page.

  2. 14 August 2025

     Section 4 – ESOS assessment - added participant requirements checklist, expanded energy type definitions and exclusions, introduced new estimation methods, and confirmed all participants must report total energy consumption in kWh. Section 5 – Significant Energy Consumption - updated de minimis threshold, clarified exclusion options by group, site, asset, activity or fuel. Section 6 – Energy intensity ratios - made ratio calculations mandatory for buildings, transport, industrial processes and other uses, with recommended indicators and examples. Section 7 – Compliance routes - clarified lead assessor requirements Section 8 – Energy audits - expanded minimum audit requirements, added guidance on categorising energy saving opportunities and implementation considerations. Section 9 – Alternative compliance - removed DECs and GDAs as valid compliance routes for Phase 4. Section 10 – ESOS report - added requirement to estimate energy savings since previous compliance period with guidance on categorising and calculating savings. Section 11 – Evidence pack - detailed required contents including estimation methods and audit data. Confirmed retention period for two subsequent compliance periods. Section 12 – Notification - replaced smart survey with new MESOS system. Expanded notification requirements to include energy data, intensity ratios, and savings summaries. Updated director sign-off requirements. Section 13 – Action plans - introduced mandatory action plans for Phase 3 due 5 December 2024, requiring efficiency measures, expected savings, and breakdowns by organisational purpose. Section 14 – Progress updates - added two mandatory progress updates (December 2025 and 2026) reporting implemented measures and estimated savings. Section 15 – Enforcement - Clarified enforcement approach. Action plan and progress update submission failures do not currently result in any penalties but may be identified through public disclosure. Appendices - Expanded checklists, improved accessibility, new energy savings estimation requirements, updated sign-off processes, and improved consistency between reporting and notification requirements.

  3. 29 August 2024

     Section 11.1 The ESOS compliance notification system - provided information about the new digital system releases and how to use the compliance notification system. Section 11.3 After you’ve submitted – clarified that ‘You should keep a copy of your submitted notification of compliance as a record of your submission.’. 12.3.7 Sign off and action plan submission – clarified ‘If you do not intend to carry out any energy saving action you must notify the Environment Agency through the notification system by 5 December 2024’.

  4. 29 November 2023

     Updated the guidance to include the changes for phase 3.

  5. 1 February 2021

     Replaced the PDF with a HTML guide for accessibility reasons. This included adding text alternatives for graphics. Updated section 1.1 to add qualification dates and criteria for the third compliance period. Added table to section 1.7.4, as this was missing from the previous version. Edited section 1.8 to say copies of the written agreement should be kept in the evidence pack. Updated sections 3.1, 3.2 on carrying out an ESOS assessment. Added new section 3.3 on zero energy supplies. Updated section 3.6.2 on buildings to say you should keep copies of any notes or emails to support what you exclude from your total energy consumption in your evidence pack. Updated section 5.3 to correct the date that assessments can have been made for the second compliance period. Updated section 5.4.1 to correct when data used in ESOS energy audits must begin from for the second compliance period. Added section 5.8 on ISO 14001:2015. Updated section A3.1 to say where copies of ISO 50001:2018 can be obtained from. Updated section A3.2 on the use of ISO 14001. Updated section A7.4 to remove the section on enhanced capital allowances, as this is no longer applicable.

  6. 28 October 2019

     Updated Complying with the Energy Savings Opportunity Scheme (ESOS).

  7. 8 February 2019

     Updated Complying with the Energy Savings Opportunity Scheme (ESOS) to include phase 2.

  8. 21 March 2016

     The attachment about complying with the ESOS has been updated.

  9. 8 October 2015

     New version 4 of document: Inclusion of enforcement position and link to the Environment Agency's Enforcement and Sanctions Guidance in Section 9.1. Inclusion of references to this position in sections 2.1 and 8.1. Annex B - Clarification in Q18 of the notification that the number entered should only include 'active' entities. - Clarification of Q25 and additional answer added to reflect enforcement position.

  10. 14 July 2015

      Minor wording changes have been made and some additional paragraphs of text added to this guidance and these are referenced in the version control table in the document.

  11. 19 May 2015

      Minor changes have been made to the guidance document. The version control table in the document contains further information.

  12. 17 February 2015

      First published.

Documents

Comply with the Energy Savings Opportunity Scheme (ESOS): phase 3

Ref: LIT 10094

HTML

Appendices A1 and A2: Report checklists for participants

HTML

Appendix A3: Example template of phase 3 ESOS recommendations

ODT, 198 KB

This file is in an OpenDocument format

This file may not be suitable for users of assistive technology.

Request an accessible format

If you use assistive technology (such as a screen reader) and need a version of this document in a more accessible format, please email enquiries@environment-agency.gov.uk. Please tell us what format you need. It will help us if you say what assistive technology you use.

Appendix B: Information to provide through the ESOS notification system

ODT, 38.1 KB

This file is in an OpenDocument format

Appendix C: Advice for complying with ESOS

HTML

Appendix D: Useful contacts and information

HTML

Details

This guidance provides information on the qualification, compliance and notification requirements for the third compliance period (phase 3). The remaining deadline is to submit the second progress update report by 5 December 2026.

It details:

• which organisations qualify for this mandatory scheme
• what qualifying organisations need to do to comply
• how organisations should notify the Environment Agency that they are compliant
• when the compliance deadline is
• what the penalties are for not complying

Past versions of this guidance for the first and second compliance periods (phase 1 and phase 2) are on the National Archive. Alternatively, check the shorter overview of ESOS.

ESOS phase 4 guidance

See the Comply with ESOS phase 4 guidance for information on the qualification, compliance and notification requirements for Phase 4.

Phase 4 guidance reflects the changes in the most recent amendment in the Energy Savings Opportunity Scheme Regulations 2014, as amended 2026.