When ‘measuring’ the success of an energy efficiency project, there are several important considerations to ensure that the results are reported accurately and fairly – firstly, what do we mean by ‘measuring’ savings and why do we keep using inverted commas?
The section on how you can measure an energy saving clarifies this.
The source of energy data must be accurate and reliable. When the total consumption for a site is assessed, we are fortunately able to make use of the interval data recorded by the site’s fiscal meter - the same data used by the supplier to determine the site’s electricity bills. Meters for large sites will record the kWh consumption with a high level of resolution, for example every every half hour. This is particularly useful for analysing trends and consumption patterns - further details on the uses of interval data are in our section on half hourly data.
A further consideration is ‘variable’ data - information quantifying changes in conditions that are likely to have an effect on consumption. Common variables are external temperatures, footfall or production volumes. Whilst the latter are specific to each site, and may be recorded to varying levels of resolution and detail, information on changes in external temperature is widely available in the form of ‘degree days’ in standard formats.