Energy Savings Opportunity Scheme (ESOS)

ESOS is a mandatory energy assessment scheme for larger organisations in the UK that meet the qualification criteria.

The UK government established ESOS to implement Article 8 (4 to 6) of the EU Energy Efficiency Directive (2012/27/EU). The ESOS Regulations 2014 gave effect to the scheme. It is administered by the Environment Agency for organisations whose registered office is in England.

Organisations which qualify for ESOS must have their ESOS assessments carried out every 4 years. ESOS assessments are audits of the energy used by the organisation’s buildings, industrial processes and transport so cost-effective energy saving measures can be identified.

ESOS is applicable to large UK undertakings and their corporate groups, so it mainly applies to businesses. It can also apply to not-for-profit entities and any other undertakings which are not public sector and are large enough to meet the qualification criteria.

Corporate groups qualify if at least one UK group member meets the ESOS definition of a large undertaking.

For the qualification date for the third compliance period (31 December 2022) a large undertaking is any UK company that either:

employs 250 or more people

has an annual turnover in excess of £44 million, and an annual balance sheet total in excess of £38 million

UK registered establishments of an overseas company will also need to take part in ESOS (regardless of their size) if any other part of their global corporate group activities in the UK meet the ESOS qualifying criteria.

If you qualify for ESOS but your organisation is fully covered by ISO 50001, you do not need an ESOS assessment. You do however need to notify the Environment Agency that you are ESOS compliant.

If you qualify for ESOS, but your organisation is not fully covered by ISO 50001, you will need to have an ESOS assessment carried out. The assessment will help you work out what your organisation needs to do to comply with the ESOS regulations.

ESOS is about saving energy...
...and protecting the environment

For your assessment, you need to: 

  • Calculate your total energy consumption. This includes the energy consumed by buildings, industrial processes and transport.
  • Identify your areas of significant energy consumption, those that account for at least 90% of your total energy use.
  • Appoint a lead assessor who will carry out and oversee or review your energy audits and overall ESOS assessment. Lead assessors can be employees or external contractors as long as they are members of an approved professional body register.
  • Notify the Environment Agency when you have undertaken an ESOS assessment and are compliant with your obligations.
  • Keep records  of how you have complied with ESOS in an evidence pack.

When you have completed your ESOS submission you must submit a notification of compliance using the online system. The notification includes details about your organisation and how it has complied.

The next compliance deadline is 5th December 2023. It takes time to process the documents and year's data is needed so the best time to get started is the summer of 2022.

An ESOS compliant energy audit must:

  • Be based on 12 months’ verifiable data
  • Analyse the participant’s energy consumption and energy efficiency
  • Identify energy saving opportunities
  • Involve site visits to a proportion of locations

Use the Find A Member button at the top of the page to locate your nearest Proficiency member.