A Comparison of Measure Avoided Cost Calculations

A Comparison of Measure Avoided Cost Calculations

using Utility TOU Load Shapes and DEER Hourly Measure Savings

14 March 2006

Measure Avoided Cost Calculations

For this analysis, we compared annual avoided costs for selected measures determined using IOU load shapes and using DEER hourly savings results.

This work does NOT examine or compare the magnitude of measure savings in the IOU filings vs. DEER savings for the same measure; this work only shows the relative avoided cost values when the SAME measure annual savings has an avoided cost calculated using the DEER hourly profile, or the IOU hourly or TOU profiles.

The components used for the analysis include:– cpucAvoided26.xls from E3

• levelized hourly avoided cost values were extracted from this spreadsheet for each utility/climate zone combination examined and for a range of measure expected life values.

• contains hourly TOU period definitions for each utility

– Utility specific “shape viewer” spreadsheets• “SCE-res2.xls”: SCE residential spreadsheet provides TOU values by end-

use and climate zone for new construction, and by end-use for retrofit.• “SCE-nonres2.xls”: SCE non-residential spreadsheet provided TOU values

by building type, end-use/measure-type and climate zone for new construction, and by building type and end-use for retrofit.

• “SDG&E3.xls”: SDG&E spreadsheet provides TOU values by building type and end-use for both residential and commercial building types.

• “ComViewer.xls” and “ResViewer.xls”: PG&E spreadsheets that provided TOU load shapes by end-use for building sector. These spreadsheets also contain the hourly load profiles by building type and end-use.

– Attachment II-T3 tables• For each of the utilities, these tables map the TOU load shapes used for

each of the measures.



The DEER version of eQUEST was used for this analysis, with minor modifications.– hourly whole-building electricity use for both the base

case run and the measure run is now written to a file. End-use hourly values are not yet available.

– some improvements were made to the DEER process to fix known problems:

• minor changes to schedules (open-closed hours)

• night-cycle control added for hot climates

• residential HVAC performance curves updated


Measures by Building TypeLarge Office Small Retail Grocery Single Family

Chiller efficiency Pkg AC efficiency Pkg AC efficiency AC efficiency

Indoor Lighting reduction Indoor Lighting reductionIndoor Lighting

reduction Refg Charge

Economizer Maintenance Reduce Over-Ventilation Reduce Over-Ventilation Duct Sealing

Side Daylighting Top Daylighting Top Daylighting Low-E Window

LowSC Window on West LowSC Window on WestLowSC Window on

West Indoor Lighting

LowSC Window on East LowSC Window on East LowSC Window on East Ceiling Insulation

Supply Fan Motor Eff.LowSC Window on

South Zero Heat Doors

CHW Loop Motor Eff. Night Covers

2-Speed Cooling Tower

Climate Zones by UtilityPG&E SCE SDG&E

CZ03 CZ09 CZ07

CZ13 CZ15 CZ15

Preliminary conclusions Use of TOU load shapes typically under-predicts the avoided cost of Commercial measures relative to hourly load shapes by up to 20% (or more)– For the commercial building cases examined, the average difference

between TOU avoided cost to Hourly Avoided cost is 12%

DEER TOU Avoided Cost / DEER Hourly Avoided Costfor Measures in Large Office

0.5

0.6

0.7

0.8

0.9

1.0

1.1

1.2

1.3

1.4

Retro NC Retro NC Retro NC Retro NC Retro NC

CZ03 CZ03 CZ07 CZ07 CZ09 CZ09 CZ13 CZ13 CZ15 CZ15

DE

ER

TO

U /

DE

ER

Ho

url

y av

oid

ed c

ost

Indoor Ltg reduction

Side Daylighting

LowSC Window on West

LowSC Window on East

Econo Maint. (retro only)

Chiller eff.

Supply Fan Motor Eff.

CHW Loop Motor Eff.



DEER TOU Avoided Cost / DEER Hourly Avoided Costfor Measures in Small Retail

0.5

0.6

0.7

0.8

0.9

1.0

1.1

1.2

1.3

1.4



DE

ER

TO

U /

DE

ER

Ho

url

y av

oid

ed c

ost

Ltg reduced

Pkg AC eff.

Reduce OverVent

Top Daylighting



LowSC Window on South



DEER TOU Avoided Cost / DEER Hourly Avoided Costfor Measures in Grocery

(0.2)

0.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4



DE

ER

TO

U /

DE

ER

Ho

url

y av

oid

ed c

ost

Ltg reduced

Pkg AC eff.

Reduce OverVent

Top Daylighting



Zero Heat Doors

Night Covers

Preliminary conclusions Use of TOU load shapes typically under-predicts the avoided cost of Residential measures relative to hourly load shapes by up to 30%– For the residential cases examined, the average difference between TOU

avoided cost to Hourly Avoided cost is 19%

DEER TOU Avoided Cost / DEER Hourly Avoided Costfor Measures in Single-Family Residential

0.5

0.6

0.7

0.8

0.9

1.0

1.1

1.2

1.3

1.4



DE

ER

TO

U /

DE

ER

Ho

url

y av

oid

ed c

ost

Indoor Lighting

AC efficiency

Refg Charge

Duct Sealing

Low-E Window

Ceiling Insulation

Preliminary conclusions

Difference between DEER Hourly and TOU Avoided Cost

Measures Large Office Small Retail Grocery Single-Family

Lighting 2.7% 6.3% 2.9% 3.5%

HVAC 6.8% 17.5% 21.1% 20.2%

All Measures 6.5% 14.5% 37.3% 20.5%

The agreement between annual avoided costs calculated with hourly and with TOU load shapes varies by building type and measure


Use of a Super-TOU load shape for the DEER TOU Avoided Cost calculation improved the agreement between the hourly and the TOU annual avoided costs by about 20%

– For the cases examined, the average difference between Super-TOU avoided cost to Hourly Avoided cost is 11% (compared to 13% for the standard TOU).

– For commercial buildings, the use of a super TOU period improved the comparison of Lighting vs. HVAC measures only slightly (about 10%).

– For the single-family residential building, the use of a super TOU period did bring the Lighting and HVAC ratios closer together (by about 25%).

– For this analysis, Super-TOU is defined as a new TOU period containing the 100 highest levelized avoided cost hours in the Summer On-Peak period.


Difference between DEER Hourly and TOU Avoided Cost

Measures Large Office Small Retail Grocery Single-Family

Lighting 2.7% 6.3% 2.9% 3.5%

HVAC 6.8% 17.5% 21.1% 20.2%

All Measures 6.5% 14.5% 37.3% 20.5%

Difference between DEER Hourly and Super TOU Avoided CostMeasures Large Office Small Retail Grocery Single-Family

Lighting 2.3% 6.1% 2.9% 3.8%

HVAC 5.7% 14.7% 17.0% 16.5%

All Measures 5.4% 12.4% 35.8% 15.4%

Preliminary conclusions Use of IOU load shapes can under-predict and over-predict the avoided cost of measures relative to DEER hourly load shapes by up to 30% (or more)– For the cases examined, the average difference between the Utility TOU

avoided cost to DEER Hourly Avoided cost is 20%.

Utility TOU Avoided Cost / DEER Hourly Avoided Costfor Measures in Large Office

0.5

0.6

0.7

0.8

0.9

1.0

1.1

1.2

1.3

1.4

PG&E PG&E PG&E PG&E SCE SCE SCE SCE SDG&E SDG&E SDG&E SDG&E

Retro Retro NC NC Retro Retro NC NC Retro Retro NC NC

CZ03 CZ13 CZ03 CZ13 CZ09 CZ15 CZ09 CZ15 CZ07 CZ15 CZ07 CZ15

Uti

lity

TO

U /

DE

ER

Ho

url

y av

oid

ed c

ost

Indoor Ltg reduction

Side Daylighting



Econo Maint. (retro only)

Chiller eff.

Supply Fan Motor Eff.

CHW Loop Motor Eff.



Utility TOU Avoided Cost / DEER Hourly Avoided Costfor Measures in Small Retail

0.5

0.6

0.7

0.8

0.9

1.0

1.1

1.2

1.3

1.4




DE

ER

TO

U /

DE

ER

Ho

url

y av

oid

ed c

ost

Ltg reduced

Pkg AC eff.

Reduce OverVent

Top Daylighting



LowSC Window on South



Utility TOU Avoided Cost / DEER Hourly Avoided Costfor Measures in Grocery

(0.2)

0.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4




DE

ER

TO

U /

DE

ER

Ho

url

y av

oid

ed c

ost

Ltg reduced

Pkg AC eff.

Reduce OverVent

Top Daylighting



Zero Heat Doors

Night Covers



Utility TOU Avoided Cost / DEER Hourly Avoided Costfor Measures in Single-Family Residential

0.5

0.6

0.7

0.8

0.9

1.0

1.1

1.2

1.3

1.4




DE

ER

TO

U /

DE

ER

Ho

url

y av

oid

ed c

ost

Indoor Lighting

AC efficiency

Refg Charge

Duct Sealing

Low-E Window

Ceiling Insulation

Preliminary conclusions Use of the IOU load shapes under-predicts the avoided cost for HVAC measures by a wider margin than lighting measures

– For the cases examined, the average difference between the Utility TOU avoided cost and the DEER Hourly Avoided cost is 9% for the indoor lighting measure.

– All other measure categories had significantly higher differences between Utility TOU and DEER Hourly avoided costs.

Measure Category Average Difference

Indoor Lighting Reduction 9%

Cooling Efficiency Improvement 27%

Economizer / OA Reduction 53%

Daylighting 17%

Low SC Glass on West 13%

Low SC Glass on East 19%

Preliminary conclusions The agreement between annual avoided costs calculated with hourly

and with Utility TOU load shapes varies by building type and measure.

Large Office Small RetailAverage Average

Measure Difference Measure DifferenceIndoor Ltg reduction 0.11 Indoor Ltg reduction 0.10Side Daylighting 0.17 Top Daylighting 0.15LowSC Window on West 0.08 LowSC Window on West 0.16LowSC Window on East 0.19 LowSC Window on East 0.20Chiller eff. 0.21 LowSC Window on South 0.18Supply Fan Motor Eff. 0.15 Pkg AC eff. 0.24CHW Loop Motor Eff. 0.08 Reduce OverVent 0.502-Speed Tower 0.55Econo Maint. (retro only) 0.60

Grocery Single FamilyAverage Average

Measure Difference Measure DifferenceIndoor Ltg reduction 0.05 Indoor Ltg reduction 0.03Top Daylighting 0.18 Low-E Window 0.14LowSC Window on West 0.15 Ceiling Insulation 0.41LowSC Window on East 0.18 AC efficiency 0.21Pkg AC eff. 0.37 Refg Charge 0.15Reduce OverVent 0.48 Duct Sealing 0.17Zero Heat Doors 0.34Night Covers 6.87


Building and end use load shapes, as used by the current E3 calculators, do not well represent measure impact shapes in most cases

The use of older building and end use load shapes used for the current filings amplify this difference.

Preliminary conclusions IOU load shapes can work quite well …

DEER Measure Savings and Utility End-Use TOU Loadshapes

0.00

0.05

0.10

0.15

0.20

0.25

0.30

0.35

0.40

0.45

Smr-On Smr-Ptl Smr-Off Wtr-On Wtr-Ptl Wtr-Off

frac

tion

of e

nerg

y sa

ving

s/us

e du

ring

TO

U p

erio

d

DEER TOU Loadshape SCE TOU LoadshapeSCE TOU from Hourly Loadshape fraction of annual hours in TOU period

SCE, Office, CZ09 - Measure: Chiller Efficiency Improvement

when the IOU load shape follows the same trends as the measure load shape.

Ratio of Annual Avoided Cost to DEER Hourly Avoided Cost

0.910.95

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

1.1

hourly TOU TOU

DEER DEER SCE

An

nu

al A

void

ed $

DE

ER

Ho

url

y A

nn

ual

Avo

ided

$

SCE, Office, CZ09 - Measure: Chiller Efficiency Improvement

Preliminary conclusions But if the TOU load shape doesn’t match the Measure load shape …

then the annual avoided cost may be significantly under or over-estimated.


0.00

0.10

0.20

0.30

0.40

0.50

0.60


fra

cti

on

of

en

erg

y s

av

ing

s/u

se

du

rin

g T

OU

pe

rio

d

DEER TOU Loadshape SCE TOU LoadshapeSCE TOU from Hourly Loadshape fraction of annual hours in TOU period

SCE, Office, CZ09 - Measure: Perimeter Side Daylighting


0.97

0.79

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

1.1

hourly TOU TOU

DEER DEER SCEA

nn

ual

Avo

ided

$D

EE

R H

ou

rly

An

nu

al A

void

ed $

SCE, Office, CZ09 - Measure: Perimeter Side Daylighting

Preliminary conclusions But if the TOU load shape doesn’t match the Measure load shape …

then the annual avoided cost may be significantly under or over-estimated.

Ratio of TOU Avoided Cost to DEER Hourly Avoided Cost

-0.10

0.00

0.10

0.20

0.30

0.40

0.50

0.60

0.70

0.80

0.90

1.00


TOU

Avo

ided

$D

EER

Hou

rly A

nnua

l Avo

ided

$

DEER Hourly DEER TOU SCE TOU SCE Hourly

SCE, Office, CZ09 - Measure: Economizer Maintenance


1.05

1.21

0.30.40.50.60.70.80.91.01.11.21.3

hourly TOU TOU

DEER DEER SCE

An

nu

al A

void

ed $

DE

ER

Ho

url

y A

nn

ual

Avo

ided

$

SCE, Office, CZ09 - Measure: Economizer Maintenance

Preliminary conclusions And even a TOU load shape that is quite different from the measure load shape …

can lead to a “correct” answer due to compensating errors.


0.00

0.10

0.20

0.30

0.40

0.50

0.60


fra

cti

on

of

en

erg

y s

av

ing

s/u

se

du

rin

g T

OU

pe

rio

d

DEER TOU Loadshape PG&E TOU Loadshape fraction of annual hours in TOU period

PG&E, Office, CZ03 - Measure: Economizer Maintenance


1.071.02

0.3

0.40.5

0.60.7

0.80.9

1.01.1

1.2

hourly TOU TOU

DEER DEER PG&E

An

nu

al A

void

ed $

DE

ER

Ho

url

y A

nn

ual

Avo

ided

$


Preliminary conclusions Some measures do not lend themselves to be summarized by any TOU end-use load shape:

Measures that save energy during some TOU periods but use more energy during other TOU periods

cannot be approximated by an end-use load shape.

Ratio of TOU Avoided Cost to DEER Hourly Avoided Cost

-3.00

-2.00

-1.00

0.00

1.00

2.00

3.00

4.00

5.00

6.00


TO

U A

void

ed $

DE

ER

Ho

url

y A

nn

ual

Avo

ided

$

DEER Hourly DEER TOU SCE TOU SCE Hourly

SCE, Grocery, CZ15 - Measure: Night Covers for Display Cases (medium temp)

This measure saves over 5000 kWh per

year in a typical sized grocery store, but increases demand during the summer

on-peak period.

Hourly Load Shape Comparison

PG&E Enduse Load Shape

0

0.0001

0.0002

0.0003

0.0004

0.0005

0.0006

0.0007

0.0008

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24

Weekday Hour

frac

tio

n o

f an

nu

al t

ota

l

Jan

Feb

Mar

Apr

May

Jun

Jul

Aug

Sep

Oct

Nov

Dec

Office, Cooling, CZ13, Weekdays

DEER Measure Load Shape

-0.0004

-0.0002

0

0.0002

0.0004

0.0006

0.0008

0.001

0.0012

0.0014

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24

Weekday Hour

frac

tio

n o

f an

nu

al t

ota

l kW

h s

avin

gs Jan

Feb

Mar

Apr

May

Jun

Jul

Aug

Sep

Oct

Nov

Dec


The hourly impact of economizer maintenance

has little in common with the hourly cooling profile.



0

0.0001

0.0002

0.0003

0.0004

0.0005

0.0006

0.0007

0.0008

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24

Weekday Hour

frac

tio

n o

f an

nu

al t

ota

l

Jan

Feb

Mar

Apr

May

Jun

Jul

Aug

Sep

Oct

Nov

Dec



-0.0005

0

0.0005

0.001

0.0015

0.002

0.0025

0.003

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24

Weekday Hour

frac

tio

n o

f an

nu

al t

ota

l kW

h s

avin

gs Jan

Feb

Mar

Apr

May

Jun

Jul

Aug

Sep

Oct

Nov

Dec

PG&E, Office, CZ13 - Measure: LowSC Glass on East

The impact of low shading coefficient glass on the

East has a much different load shape than cooling in

general.



0

0.0001

0.0002

0.0003

0.0004

0.0005

0.0006

0.0007

0.0008

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24

Weekday Hour

frac

tio

n o

f an

nu

al t

ota

l

Jan

Feb

Mar

Apr

May

Jun

Jul

Aug

Sep

Oct

Nov

Dec



-0.0005

0

0.0005

0.001

0.0015

0.002

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24

Weekday Hour

frac

tio

n o

f an

nu

al t

ota

l kW

h s

avin

gs Jan

Feb

Mar

Apr

May

Jun

Jul

Aug

Sep

Oct

Nov

Dec

PG&E, Office, CZ13 - Measure: LowSC Glass on West

The impact of low shading coefficient glass on the West has a much different load shape than

cooling in general.

demand definition

Demand Savings - kW

Demand PeriodChiller

EfficiencyLighting

ReductionAC

EfficiencyLighting

Reduction

Peak Hour 156.1 183.4 1.23 0.072Peak 9-Hour Window 121.9 140.9 0.97 0.049Super-TOU period 112.6 128.0 0.85 0.050Summer On-Peak Period 89.6 115.6 0.56 0.049

PG&E, CZ13Large Office Single Family

Demand Savingsfraction of peak hour

Chiller Efficiency

Lighting Reduction

AC Efficiency

Lighting Reduction

Peak Hour 1.00 1.00 1.00 1.00Peak 9-Hour Window 0.78 0.77 0.78 0.68Super-TOU period 0.72 0.70 0.69 0.69Summer On-Peak Period 0.57 0.63 0.46 0.68

Large Office Single FamilyPG&E, CZ13

Documents

A Comparison of Measure Avoided Cost Calculations