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

ESOS-Energy will appoint one of our 3 ESOS lead assessors to carry out and oversee your overall ESOS assessment, and/or varying aspects of ESOS compliance.

What is 'ESOS'?

ISO 50001

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


You are likely to be in scope of ESOS if, on the qualification date (31 December 2014 for the first phase of ESOS), you are:

1. An undertaking which has 250 or more employees


2. An undertaking which has fewer than 250 employees, but has:

o an annual turnover exceeding £38m and

o a balance sheet exceeding £33m


3. Part of a corporate group which includes an undertaking which meets criteria (1) or (2) above

ESOS-Energy provides ISO 50001, helping organisations to address and measure energy consumption. It’s a voluntary International standard providing organisations with a framework which will manage and improve energy performance. This framework allows the organisation to set and persue its own goals for improving performance.

Complying with


Ensuring full compliance.


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


Measure  >  Conduct  >  Report


1. Measure your total energy consumption

You must measure your total energy consumption across your buildings, transport and industrial activities.


2. Conduct energy audits to identify cost-effective energy efficiency recommendations

You must ensure that at least 90% of your total energy consumption is subject to an ESOS compliant energy audit, a Display Energy Certificate, a Green Deal Assessment or a certified

ISO 50001 Energy Management System during each phase of the scheme. For the first phase of the scheme, you can use any energy auditing activity dating back to December 2011 to support compliance provided that it meets the minimum standards required of ESOS Energy Audits.


3. Report compliance to the Environment Agency (as the scheme administrator)

By 5 December 2015, you must notify the Environment Agency (as the scheme administrator) that you have complied with the scheme.

Prior to notifying the Environment Agency, you must ensure that your ESOS Assessment has been reviewed by a Board-level Director and approved by an ESOS Lead Assessor.

Participants are not required to implement energy efficiency recommendations identified by their ESOS Assessments. However, they will only achieve the financial benefits that arise from avoiding energy waste if they do implement cost-effective recommendations identified.

What if I am an SME or public body?

Although SMEs or public sector bodies are not required to participate in ESOS, they could still benefit from voluntarily meeting the ESOS requirements. ESOS provides a framework you may wish to use to help you identify energy efficiency opportunities, e.g. you may wish to use a qualified ESOS Lead Assessor to undertake energy audits of your operations. 

Completing an audit.


ESOS-Energy will help at every step of the way to ensure your compliance. An assessment or audit will include:


1. Measuring energy consumption

We will measure what the organisation's total energy spend or consumption is over 12 months.


2. Create Audit schedule

This is based on the overall review from measuring total energy consumption in step 1.


3. Use established Methodology

Data is collected to follow a methodology such as BS EN, ISO etc.


4. Site audits carried out

The lead assessor will use discretion to decide on the number of site audits, but we suggest a minimum or at least one site visit per every different business area/operation type AND per enterprise.


5. Create profile and generate measures

We create a load or consumption profile which details energy use across the business. Once this is done, we generate a report or practicle measures, which can be implemented for reducing the business' energy consumption.



Undergoing an ESOS Audit.

We aim to make the whole process as easy as possible, with as little affect to your usual working operations as possible - allowing your business can run smoothly as normal. One of our Lead Assessors will oversee your overall ESOS assessment.

To play, press and hold the enter key. To stop, release the enter key.