EPI Calculation

Contents Energy Performance Index Aggregate output selection Weighted output example EPI calculation EPI report

Energy Performance Index A company’s Energy Performance Index (EPI) is based on the ratio of annual primary energy consumption to aggregate product output This output is developed individually by each company to reflect their unique mix of products and processes For a member’s first year of joining the LIEN, their EPI is normalised to 100 Subsequent improvements or deteriorations in energy performance are reflected in a decrease or increase of EPI

Aggregate Output Selection For a single commodity manufacturer, the output unit is simply their base production unit However, most firms have more than one product therefore an aggregate output must be selected It is necessary to look at the relative energy intensity of each product and assign a weighting if appropriate Must be a measure which can be meaningfully compared year-on-year

Weighted Output Example – Company XYZ Product AProduct B Product C Total Tonnes GWh Tonnes GWh

Energy per unit output If tonnes is used as output measure: Energy/output 2001 = 60/1110 = GWh/tonne = 54 MWh/tonne Energy/output 2002= 90/1170 = GWh/tonne = 77 MWh/tonne

Weighted Output Example It would not be representative to simply add the various quantities of Products A, B and C due to their different energy intensities A more representative approach is to assign a weighting to each output relative to the amount of energy it takes to produce In order to do this it must be possible to monitor the varying energy consumptions of each product e.g. meter each product line separately

Weighted Output Example – Company XYZ Product AProduct BProduct CTotal Tonnes GWh Weighting Weighted output 2001 (output x weighting) Tonnes GWh Weighting Weighted output 2002 (output x weighting)

Energy per unit output If weighted output is used as output measure: Energy/output 2001 = 60/3000 = 0.02 GWh/wt output = 20 MWh/wt output Energy/output 2002= 90/4500 = 0.02 GWh/wt output = 20 MWh/wt output

Output selection Consider; Weighted output may give a more representative indication if appropriate e.g. varying product mix and concentration Value chosen much be comparable year-on- year e.g. is product line constantly changing

EPI calculation Information is provided annually and must be reported in a manner that is confidential LIEN members come from 13 different sectors with thousands or varying products It is not possible to compare varying energy intensity units e.g. kWh/gallon, GWh/tonne, MWh/weighted production unit Need to make comparison in energy intensity trends Energy Performance Index developed

EPI calculation EPI = EnergyxF Output where F is a factor used to set the EPI to 100 for a firm’s base year (i.e. the year they joined the LIEN or started reporting) F then is fixed for subsequent years

EPI example

EPI Report EPI report contains 5 pages of information specific to your site Details trends in primary energy per unit of output since a company joined the LIEN Gives information on estimated CO 2 emissions as a result of energy use Estimates how these specific emissions have changed from the previous year as a result of a firm’s energy performance

EPI Calculation Fiona Murray LIEN Project Manager