>An ESOS assessment would undertake a review of the total energy use and energy efficiency of the organisation, including the measurement of an energy intensity ratio (e.g. energy use per employee or per unit of output) and, as appropriate, considering the variation in energy use over time within key buildings, key industrial operations, and key transport activities (exempting de minimis energy use).

The review would need to be proportionate and sufficiently representative “to permit the drawing of a reliable picture of overall energy performance” of the organisation and present clear information on potential savings, which identify and quantify cost-effective energy savings opportunities.

These should be, wherever practical, based on life cycle assessments (LCA) instead of simple payback periods (SPP), as the former are more realistic.

All procedures for doing this are outlined under the international standard for energy management, ISO 50001, with which all energy and facility managers are encouraged to become competent.

The Government has come under sustained criticism recently for failing to do enough to promote energy efficiency.<