The purpose of the energy baseline is to develop a starting point for measuring energy performance improvements. At the simplest level the baseline could be the total amount of electricity and other fuels used in the year ending before the EnMS is implemented. The advantage of this is that future use is simply compared with this baseline year. The disadvantage is that it ignores the effects of the driving factors. For example production output could have increased or decreased significantly and this could be the reason for the change in energy use rather than any actual change in energy performance.
NOTE: measure of specific energy consumption is not an appropriate choice for energy baseline. In a large number of organizations, there is a high energy base load or a complex mixture of products. In the case of the large base load the level of production activity has a large effect on this indicator, i.e. if production volumes increase the ratio decreases and appears to show an improvement in energy performance when none has occurred.
In this method the baseline is the best fit straight line on the regression chart of driver against energy use. As performance improves this line will move downwards.