ESOS Advice

What is ESOS?

ESOS (Energy Savings Opportunity Scheme) is a mandatory energy assessment and energy saving identification scheme for large undertakings and their corporate groups.

The aim is to increase business profitability and competitiveness by encouraging better monitoring of the business’ energy consumption, and identifying cost-effective savings.

The scheme is estimated to generate £1.6bn net benefits to the UK, with the majority of these benefits as a direct result of energy-saving measures.

What are my obligations?

Organisations that qualify for an ESOS Assessment are required to do three things:

  • Measure your total energy consumption
  • Conduct energy audits to identify cost-effective energy efficiency recommendations
  • Report compliance to the Environment Agency


What information do we need to provide?

At least 90% of your total energy consumption must be covered. This can be done through an ESOS compliant energy audit, Display Energy Certificate, Green Deal Assessment, or ISO 50001 certification.

This must be carried out across all aspects of your business, including:

  • Buildings (rented and owned)
  • Transport
  • Industrial processes
  • Electricity and heating

Unless your total energy consumption is covered by a certified ISO 50001 Energy Management System, you must ensure that your ESOS Assessment is conducted or reviewed by a qualified Lead Assessor.

Your ESOS Assessment must be signed off by an approved Lead Assessor and a board-level director before it is sent to the Environment Agency.

What are the time scales?

ESOS operates in four-year phases – we are now currently in Phase 2. Organisations must assess whether or not they are required to comply with ESOS before the qualification date of each phase.


Qualification date

Compliance phase

Compliance date


31st December 2014

6th December 2011 – 5th December 2015

5th December 2015


31st December 2018

6th December 2015 – 5th December 2019

5th December 2019


31st December 2022

6th December 2019 – 5th December 2023

5th December 2023

The ESOS Assessment can be conducted up to four years before the compliance date. This must be measured over a 12-month period, and must include the phase qualification date.

For example, if your selected 12-month period runs from 1st April 2014 to 31st March 2015, your 12-month period overlaps the Phase 1 qualification date of 31st December 2014.

Once completed, your ESOS Assessment must be signed off and submitted before the phase compliance date.

What are the penalties?

The penalty for failing to comply with any aspect of an ESOS Assessment is:

  • A fixed penalty of up to £5,000 and/or
  • An additional £500 penalty for each day, starting the day after the date of compliance and up to a maximum of 80 days and/or
  • Publication of details of non-compliance

Penalties have been more lenient during Phase 1, but this is likely to change in Phase 2. Instances of non-compliance can include:

  • Failure to report compliance by the required date
  • Failure to maintain adequate records demonstrating ESOS compliance
  • Failure to carry out an ESOS Assessment
  • Failure to employ an approved Lead Assessor
  • Failure to comply with enforcement or penalty notice
  • Making a false or misleading statement