An ESOS assessment is an Energy Audit based on 12 month’s worth of data measuring total energy consumption across buildings, transport and industrial activities. Participating organisations must ensure that at least 90% of their total energy use is subject to an ESOS energy audit.

The Energy Audits should also provide participants with recommendations for any cost-effective energy efficiency measures that can be undertaken together with estimated costs and benefits quantified.

Compliance with ESOS requires participants to:

• Measure their energy use for a continuous twelve month period

• Undertake audits covering their main areas of energy consumption

• Report their compliance to the Environment Agency (the scheme administrator for ESOS) by the compliance date.

It should be noted that compliance with ESOS does not require a participant to undertake all, or any, of the recommended improvement measures, although clearly if there are financial benefits then it will be in the participant’s interests to do so.

Who does ESOS effect?

Participation in ESOS will be mandatory for: large undertakings operating in the UK; and undertakings which belong to a corporate group which includes a large undertaking operating in the UK.  A large undertaking is one which meets any one of the following criteria:

• It has 250 or more employees;

• It has fewer than 250 employees, but has an annual turnover exceeding 50m and a balance sheet exceeding 43m