Energy Savings Opportunities Scheme (ESOS)

The ESOS regulations apply to any large undertaking or enterprise that carries out a trade or a business, which includes any corporate group where one or more members of the UK group meets the ESOS definition of a large undertaking. An organisation is considered a large undertaking if it:

  • Employs 250 or more people


  • Employs fewer than 250 people, but has an annual turnover in excess of €50 million and an annual balance sheet in excess of €43 million


  • Is a part of a group that includes at least one entity that meets either of the criteria above.


These are the basic qualification requirements. However, you may still fall under the scheme if you are part of a corporate group where one member qualifies. Please contact Eneco Consulting and our Accredited Lead Assessors can ensure you meet your ESOS obligations.

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ESOS Compliance Dates

ESOS operates in four-yearly compliance phases. Organisations in the UK must assess whether or not they are required to participate in ESOS on the qualification date of each phase. The qualification date for the Phase 3 is 31st December 2022.

The last day of each compliance phase (‘the compliance date’) is the date by which the Participant must have undertaken its ESOS Assessment and notified its compliance to the Environment Agency.

Qualification Date: Four-Year Compliance Phase: Compliance Date:
31st December 2022 6th December 2019 – 5th December 2023 5th December 2023
31st December 2026 6th December 2013 – 5th December 2027 5th December 2027
31st December 2030 6th December 2017 – 5th December 2031 5th December 2031

Basic Requirements of ESOS

In simple terms, an ESOS Assessment requires participants to do three things:

  1. Measure your total energy consumption.
  2. Conduct energy audits to identify cost-effective energy efficiency recommendations.
  3. Report compliance to the Environment Agency (as the scheme administrator).

Key Steps

  1. Consider if all your energy consumption is covered by an ISO50001 Energy Management System. If you have an ISO50001 Energy Management System (certified by an approved certification body) covering all your energy use this shall be sufficient to constitute an ESOS Assessment. However, you will still need to notify the Environment Agency of your compliance by the next compliance date.
  2. Measure your total energy consumption. You are required to measure your total energy (all fuels including gas, electricity, petrol, diesel, LPG, LNG etc) consumption across a 12-month period (‘the reference period’). The scope of ESOS includes energy consumed in:
    1. Buildings
    2. Transport
    3. Industrial processes
  3. Determine your areas of significant energy consumption. Once you have measured your total energy consumption you can then identify your ‘areas of significant energy consumption’. Your areas of significant energy consumption must account for at least 90% of your total energy consumption. Within a phase, all of your areas of significant energy consumption must be covered either by an ESOS Energy Audit or by an alternate route to compliance. You do not need to audit the remaining 10% of your total energy consumption (referred to as ‘de minimis’ energy use).
  4. Consider the routes to compliance available to cover your areas of significant energy consumption. You must conduct compliant energy auditing assessments or energy management activity in relation to all of your areas of significant energy consumption by the compliance date. There are four distinct types of routes to compliance that can be taken or you can use a combination of the following:
    1. ESOS Energy Audits:
    2. An ISO 50001 certified Energy Management System;
    3. Display Energy Certificates (DECs) and accompanying advisory reports; or
    4. Green Deal Assessments.
  5. Consider appointing an ESOS Lead Assessor & Audit areas of significant energy consumption. ESOS Energy Audits must be carried out by, or overseen/approved by, recognised Lead Assessors (members of professional registers approved by the Environment Agency). These can be either in-house experts or external providers. Energy saving opportunities and measures identified as part of an ESOS Energy Audit will then need to be presented to a board-level director for review and sign off.
  6. Report your ESOS compliance. You will need to make a notification to the ESOS Scheme Administrator (currently the Environment Agency) that you have completed an ESOS compliant assessment for your organisation on or before the Phase’s compliance date.

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