A Quick Guide to ESOS – Energy Savings Opportunity Scheme

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What is ESOS? 

The Energy Savings Opportunity Scheme (ESOS) requires all large businesses in the UK to undertake mandatory assessments looking at energy use and energy efficiency opportunities at least once every four years.

Who is affected by ESOS?
An organisation is considered a large undertaking if it employs at least 250 people, or employs fewer than 250 people but has an annual turnover in excess of €50 million and annual balance sheet in excess of €43 million. It is estimated that the regulations will apply to approximately 7,300 businesses.

What to do next?
To comply with ESOS regulations most businesses will need to undertake an ESOS Assessment, which will include the following:

• Measure your total energy consumption across transport, buildings and industrial processes.
• Ensure at least 90% of your total energy consumption is subject to an ESOS compliant energy audit
• Identify areas of significant energy consumption
• Identify cost-effective energy efficiency recommendations for those areas of significant energy consumption
• Appoint an Energy Assessor to oversee the ESOS Assessment

Once you have had the Assessment reviewed by a Board-level Director and approved by a Lead Energy Assessor you need to report compliance to the Environment Agency.

You must report compliance by 5 December 2015   

NB. Organisations will not need to undertake an ESOS assessment if an organisation is fully covered by ISO 50001. If that is the case then it is merely necessary to notify the Environment Agency of compliance with ESOS.


Energy reporting software is the most straightforward way to collect data and identify cost savings. 

Optimal Monitoring can help you to do this by:

• Collecting data from a range of hardware, systems and devices into one central platform
• Upload historical data for retrospective analysis
• Create consumption profiles for buildings, industrial processes and transport
• Keep a full audit of your consumption
• Identify where savings can be made through various analysis techniques

Savings have been identified, now what? 

Optimal can help you to:

• Work out where you achieve the greatest returns and we can also help you prove return on investment.
• Ensure continued best practice and efficiency. ·

Help you realise ongoing non-capital expenditure e.g. improved behaviour and correct plant operation.

What if I do nothing? ·

• You will continue to waste energy and money
• The regulator may issue financial penalties if an organisation does not meet the scheme’s obligations, for instance by failing to do the required audits or notify compliance

For full details please see DECC’s Guide to ESOS