Become an EMA Registered ESOS Lead Assessor

How to become an EMA Registered ESOS Lead Assessor?

The four-step process through which a candidate is placed on the register is outlined below.

1. Application — The application form can be downloaded here.
   NB. As part of the application each candidate must submit a CV, copies of academic, vocational or professional qualification certificates and evidence of competence in the mandatory areas outlined in PAS 51215:2014 and as outlined in the Competence and Commitment section of the application form. In addition to the application form, CV and certificates, the initial pack should also include a signed copy of the EMA Code of Conduct (this can be done within the application form).
2. Become an ESOS Lead Assessor Course — This one day tutor-led virtual course (Zoom delivery) has been designed to ensure successful candidates are conversant in all aspects of ESOS. The next course will be delivered on 3 October 2025.
   NB. A place on the course is guaranteed only upon the EMA's review of the application pack, deemed all evidence satisfactory, reference checked and payment received.
3. Written Assessment — Each candidate will be asked to complete a post-course written assessment to progress to the Peer Review Interview stage.
4. Peer Review Interview — The candidate will then undergo a peer-review interview (conducted via Zoom) by two members of the EMA ESOS Scrutiny Panel to check the candidate's knowledge of the ESOS compliance requirements, knowledge gained through the process, professional energy management experience and technical skills gained throughout candidate's career, and also to check the validity of the evidence provided at the previous stages.

What is ESOS?

The Energy Savings Opportunity Scheme (ESOS), as an energy assessment and energy savings scheme, mandates that all large enterprises carry out an ESOS compliant energy assessment and identify energy efficiency opportunities at least ones every four years. ESOS was established through the Energy Savings Opportunity Scheme Regulations 2014 (ESOS Regulations) and significantly amended in 2023, through The Energy Savings Opportunity Scheme (Amendment) Regulations 2023.

We are now in the Phase 4 (fourth compliance period) of ESOS. For organisations qualifying for Phase 4 of ESOS (qualification date is 31 December 2026), the deadline for submitting a compliance notification will be the 5 December 2027 .

However, if an organisation qualified for Phase 3 of ESOS and completed the submission of the compliance notification by 6 August 2024 , this participating organisations is required to:

• complete an ESOS action plan and submit it using MESOS portal by 5 March 2025
• complete an Action Plan Progress update 1 by 5 December 2025
• complete an Action Plan Progress update 2 by 5 December 2026

Formal guidance relating to ESOS requirements is provided in the Comply with the Energy Savings Opportunity Scheme guidance document.

ESOS Phase 4 Changes

The government has decided to postpone some changes announced in the previous government’s response to the ESOS consultation. See below for full details of which changes will and will not go ahead in Phase 4 (compliance deadline 5 December 2027).

The following changes announced in the previous government’s response to the ESOS consultation will not go ahead for Phase 4:

• changes to refocus the scheme to cover net zero as well as energy efficiency (responses to questions 16, 17, 18 and 19)
• change to qualification thresholds to better align with Streamlined Energy and Carbon Reporting (SECR) (response to question 23)

Following delays to the introduction of Phase 3 legislation and guidance, and in order to give sufficient time for such a major change to ESOS, the new government has decided to postpone the introduction of net zero requirements until Phase 5.

The following changes announced in the previous government’s response to the ESOS consultation are intended to go ahead for Phase 4, subject to parliamentary time and scrutiny:

• removal of Display Energy Certificates (DECs) and Green Deal Assessments (GDAs) as compliance routes (response to question 10)
• progress against action plan commitments to be included in the ESOS assessment (response to question 20)
• where action plan commitments have not been met, participants must provide an explanation (response to question 20)

Further details of these changes will be provided in due course. These changes and full guidance, as well as the necessary changes to the Manage your ESOS reporting system are planned to be in place by early 2027 in advance of the notification of compliance deadline for Phase 4, which is 5 December 2027.

Publication of new PAS standards

On 7 February the British Standards Institution (BSI) published two new standards which were referenced in the government response to the ESOS consultation:

• PAS 51215-1:2025 Energy and decarbonization assessment – Part 1: Process – Specification
• PAS 51215-2:2025 Energy and decarbonization assessment – Part 2: Competencies of lead assessors and assessment teams – Specification

Participants will be able to use these standards on a voluntary basis for ESOS compliance. Further guidance on voluntary use of these standards will be published in due course.

The existing competency standard, PAS 51215:2014 Energy efficiency assessment: Competence of a lead energy assessor – Specification, will continue to be used as the competency standard for ESOS lead assessors for Phase 4.

The new PAS 51215-2:2025 competency standard can be used on a voluntary basis by organisations wanting to determine whether an assessor is suitable to carry out an assessment according to PAS 51215-1:2025.

Stay up to date with the Environment Agency's Newsletters:

ESOS NEWSLETTER -> MAY 2025 (ISSUE 36)

ESOS NEWSLETTER -> MARCH 2025 (ISSUE 35)

ESOS NEWSLETTER -> FEBRUARY 2025 (ISSUE 34)

ESOS NEWSLETTER -> FEBRUARY 2025 (ISSUE 33)

ESOS Phase 3 Changes

Changes brought in by the SI enact the following:

• Strengthening requirements for audits / standardisation
• Requires participants to audit at least 95% of total energy consumption – this was previously at least 90%. •
• Requires responsible undertakings to lay out more detail in respect of the calculation of participants’ energy consumption, including energy intensity ratios.
• Requires participants to explain how the site visits that are carried out for energy audits are considered to be representative of energy use covered by the audit.
• Requires all participants to produce an ESOS report, including those using alternative compliance routes such as the ISO 50001 energy management system, and requires specific data to be included. This includes information on energy savings made since the previous compliance date.
• Requires the responsible undertaking to disclose to all members of the corporate group certain relevant information from the ESOS report and relevant supporting information relating to alternative compliance routes.

Improve the quality of ESOS audits

• Specifies information that must be identified in relation to energy saving opportunities, including their costs, benefits and a programme for implementing them.

Require public disclosure of high-level recommendations by participants

• Requires additional information to be notified to the scheme administrator in relation to the participant’s energy consumption and other information to support compliance monitoring and enforcement.
• Following the submission of the compliance notification, requires participants, including those relying wholly or partly on alternative compliance routes, to produce and notify an ESOS action plan to the scheme administrator setting out any commitments to implement energy efficiency measures, and requires them to provide annual progress updates against actions they have committed to.
• Requires some of the additional information that is required to be notified to the scheme administrator, as well as action plans and progress updates, to be publicly disclosed.

Other provisions

• Extends the deadline for compliance with phase 3 of ESOS, including extending the dates in relation to most of the supporting data used, to allow participants more time to comply with phase 3 of ESOS, given the change made by these regulations.
• Puts into legislation an exemption from appointing a lead assessor for participants whose energy consumption is less than 40,000 kWh, but adds a requirement for two directors to sign off the compliance notification in this case.
• Sets out responsibilities for the action plan and subsequent progress updates where there are changes to a corporate group.
• Introduces specific requirements where estimates are made under the regulations.
• Applies the legislative changes to relevant trust assets.

If you have any queries in relation to the new requirements for Phase 3 please email Department of Energy Security and Net Zero (DESNZ) at [email protected].

Stay up to date with the Environment Agency's Newsletters:

ESOS NEWSLETTER -> JULY 2024 (ISSUE 26) 

ESOS NEWSLETTER -> JULY 2024 (ISSUE 25)

ESOS NEWSLETTER -> JUNE 2024 (ISSUE 24) + Guidance on Organisational Purpose document that represents guidance on how to determine energy consumption by organisational purpose

ESOS NEWSLETTER -> JUNE 2024 (ISSUE 23) + MESOS data requirements template, and Appendix B: Information to provide through the ESOS notification system document that is part of the Comply with the Energy Savings Opportunity Scheme (ESOS) Guidance

Which organisations qualify for ESOS?

1. Any UK organisation must comply with the Energy Saving Opportunities Scheme (ESOS) if it is a large undertaking, or is part of a corporate group which includes another UK undertaking, and meet either one or both of the conditions below:

– has 250 or more employees, or
– has a turnover of more than £44 million annually,  and an annual balance sheet total of more than £38 million

2. Any overseas (non-UK registered) company with a UK registered establishment which has 250 or more UK employees

Organisations qualify for the third ESOS compliance period if, on 31 December 2022, they met the ESOS definition of a large undertaking. Whilst ESOS compliance predominantly applies to businesses,  not-for-profit organisations and any other non public sector undertakings that meet the criteria must also comply.

For more information about ESOS, and to find out if your organisation will need to take part, refer to the Comply with the Energy Savings Opportunity Scheme guidance

The EMA offers opportunities for your company to train one of your staff member to undertake your ESOS compliance, or to appoint one of the EMA Registered Lead Assessors. If you have any questions regarding the training to become a registered ESOS Lead Assessor or appointing an ESOS Lead Assessor, please email [email protected].

Find a Lead Assessor

• Graeme Johnson
• Katie Elmer
• Neil Fright

View our entire list of ESOS Lead Assessors