EPI Calculation

ContentsEnergy Performance IndexAggregate output selectionWeighted output exampleEPI calculationEPI report

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

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

Weighted Output Example Company XYZ

Energy per unit outputIf tonnes is used as output measure:

Energy/output 2001 = 60/1110= 0.054 GWh/tonne= 54 MWh/tonneEnergy/output 2002= 90/1170= 0.077 GWh/tonne= 77 MWh/tonne

Weighted Output ExampleIt would not be representative to simply add the various quantities of Products A, B and C due to their different energy intensitiesA more representative approach is to assign a weighting to each output relative to the amount of energy it takes to produceIn 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

Energy per unit outputIf weighted output is used as output measure:

Energy/output 2001 = 60/3000= 0.02 GWh/wt output= 20 MWh/wt outputEnergy/output 2002= 90/4500= 0.02 GWh/wt output= 20 MWh/wt output

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

EPI calculationInformation is provided annually and must be reported in a manner that is confidentialLIEN members come from 13 different sectors with thousands or varying productsIt is not possible to compare varying energy intensity units e.g. kWh/gallon, GWh/tonne, MWh/weighted production unitNeed to make comparison in energy intensity trendsEnergy Performance Index developed

EPI calculationEPI = EnergyxFOutput

where F is a factor used to set the EPI to 100 for a firms base year (i.e. the year they joined the LIEN or started reporting)

F then is fixed for subsequent years

EPI example

EPI example

EPI ReportEPI report contains 5 pages of information specific to your siteDetails trends in primary energy per unit of output since a company joined the LIENGives information on estimated CO2 emissions as a result of energy useEstimates how these specific emissions have changed from the previous year as a result of a firms energy performance

EPI CalculationFiona MurrayLIEN Project Manager