Transcript EPI calculation - Fiona Murray SEI

EPI Calculation
Contents
• Energy Performance Index
• Aggregate output selection
• Weighted output example
• EPI calculation
• EPI report
Energy Performance Index
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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
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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 A
Tonnes
2001
GWh
2001
Tonnes
2002
GWh
2002
Product
C
10
Total
1000
Product
B
100
20
20
20
60
1000
150
20
1170
20
30
40
90
1110
Energy per unit output
If tonnes is used as output measure:
• Energy/output 2001
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= 60/1110
= 0.054 GWh/tonne
= 54 MWh/tonne
Energy/output 2002 = 90/1170
= 0.077 GWh/tonne
= 77 MWh/tonne
Weighted Output Example
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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 A Product B Product C
Tonnes 2001
Total
1000
100
10
1110
GWh 2001
20
20
20
60
Weighting
1
10
100
Weighted output 2001
(output x weighting)
1000
1000
1000
3000
Tonnes 2002
1000
150
20
1170
GWh 2002
20
30
40
90
Weighting
1
10
100
1000
1500
2000
Weighted output 2002
(output x weighting)
4500
Energy per unit output
If weighted output is used as output measure:
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Energy/output 2001
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Energy/output 2002
= 60/3000
= 0.02 GWh/wt output
= 20 MWh/wt output
= 90/4500
= 0.02 GWh/wt output
= 20 MWh/wt output
Output selection
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Consider;
Weighted output may give a more
representative indication if appropriate e.g.
varying product mix and concentration
Value chosen much be comparable year-onyear e.g. is product line constantly changing
EPI calculation
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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 =
Energy
Output
x
F
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 example
EPI Report
• EPI report contains 5 pages of information
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specific to your site
Details trends in primary energy per unit of
output since a company joined the LIEN
Gives information on estimated CO2
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