EnvisionCharlotte:BilledElectric-EnergySavingsandCorrespondingEmissionsReductions
FinalReport
PreparedbyRobertCox,UNCCharlotte
ReviewedbyEnvisionCharlotteMeasurementCommittee
ExecutiveSummary
Between2010and2016,61commercialbuildingsinuptownCharlotteparticipatedinEnvision
Charlotte.Asapartofthiseffort,allparticipatingbuildingsreceivedshadowelectricmetersthat
wereinstalledinparallelwiththeiractualrevenuemeters.Datawasprovidedtokiosksineach
buildingaswellastoanonlineportal.EnvisionCharlottestartedtotrackbilledenergy1savings
afterDukeEnergyhadcompletelyinstalledtheseshadowmetersjustpriortothestartofQ3
2012. Figure 1 shows the trend in aggregate billed energy from mid-2012 through the
culmination of the program at the end of 2016. This graph shows the aggregate energy
consumption based entirely on actual site electricity usage as read from the meters. No
normalizationsoradjustmentshavebeenapplied.Thisdataiscomparedtoabaselineenergy
consumptionvaluecomputedin2010.Table1summarizestheoverallchangeinbilledenergy
consumption, and Tables 2 and 3 present corresponding information about the equivalent
numberofhomespoweredandtheestimatedcumulativereductioninenergybills.Tables4
through6summarizethecorrespondingemissionsreductions.
EnergyConsumption(MMkWh)
RollingAnnualizedEnergyConsumptionSinceQ32012
540
520
500
480
460
440
420
Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4
2012 2012 2013 2013 2013 2013 2014 2014 2014 2014 2015 2015 2015 2015 2016 2016 2016 2016
Quarters(July2012- December2016)
Figure1:Annualizedenergyconsumptiontrendforthe61participatingEnvisionCharlottebuildingsthroughouttheentireprogram.
Thedotshownforeachquarterreflectstheannualizedenergyconsumptionintheyearendingonthelastdataofthatquarter.Thus,
forinstance,thevalueshownforQ32012correspondstotheaggregateenergyconsumedbetweenOctober1,2011andSeptember
30,2012.
1
Throughout this document, the term “energy” refers entirely to site electric energy consumption.
1
Table1:BilledEnergySavings
Baseline:Billedenergyconsumption
estimatedforthe12-monthperiodending
562.18MMkWh
December31,2010
Final:Billedenergyconsumption
estimatedforthe12-monthperiodending
454.45MMkWh
December31,2016
Percentreduction
19%
Table2:EquivalentNumberofHomesPowered2
EquivalentNumberofHomesPowered
9,964homes
Annually
Table3:EstimatedCumulativeReductioninEnergyBills3
EstimatedCumulativeBillingReduction
$25.74MM
SinceQ32012
Table4:EstimatedCO2EmissionsReductionSummary
Baseline:CO2emissionsestimatedforthe
12-monthperiodendingDecember31,
296,830tons
2010
Final:CO2emissionsestimatedforthe12239,949tons
monthperiodendingDecember31,2016
Percentreduction
19%
Equivalentnumberofelephants
12,928
Equivalentnumberofcarsremovedfrom
11,003
theroad
Table5:EstimatedNOxEmissions-SavingsSummary
Baseline:NOxemissionsestimatedforthe
12-monthperiodendingDecember31,
469,154lbs
2010
Final:NOxemissionsestimatedforthe12379,250lbs
monthperiodendingDecember31,2016
Percentreduction
19%
Equivalentnumberofelephants
10
2
Thisisthenumberofhomesthatcouldhavebeenpoweredbytheaggregatesavingsin2016alone.
Notethatthesavingsreflectedinthisanalysisresultedfromavarietyofmeasuresundertakenwithinthe61buildings,andthussignificant
investmentwaslikelyrequiredinmanycases.Giventhenatureofthisactivity,informationaboutsuchinvestmentsisconfidentialandthusa
return-on-investmentcannotbecomputed.Informationinthepublicdomain,however,suggeststhatanumberofthe61buildingsinvested
significantlyinenergysavingsprojectsduringthemeasurementperiod.
3
2
Table6:EstimatedSO2Emissions-SavingsSummary
Baseline:SO2emissionsestimatedforthe
12-monthperiodendingDecember31,
586,092lbs
2010
Final:SO2emissionsestimatedforthe12473,780lbs
monthperiodendingDecember31,2016
Percentreduction
19%
Equivalentnumberofelephants
13
Energy-SavingsAnalysis
In May 2015, UNC Charlotte was requested to prepare energy-savings reports for Envision
Charlotte using data provided confidentially by Duke Energy under the terms of an existing
Master Research Agreement. With the approval of Envision Charlotte’s Measurement
Committee,theteamcomparedaggregatebilledenergyconsumptionwithoutusinganyweather
oroccupancynormalizationprocedures.UNCCharlotteusedthefollowingprocess:
1. Baseline Computation: UNC Charlotte computed the baseline energy-consumption
valuebysummingelectricmeterdatafromall61participatingbuildingsoveraoneyearperiod.ThisbaselinewascomputedusingthesamedatasetutilizedforDuke
Energy’sSmartEnergyNowprogram,withadditionalbillingdatafortwoDukeEnergy
buildingsthatwereexcludedfromtheSmartEnergyNowprogram.
2. ReductionComputation:Onaquarterlybasisbeginninginthethirdquarterof2012,
UNCCharlotteprovidedanaggregateenergy-consumptionvaluerecordedoverthe
previous12monthsforthe61participatingbuildings.PriortoQ32015,thisvalue
wascomputedusing15-minuteintervaldataprovidedbyEnvisionCharlotte’sshadow
meters.Duetocommunicationsissueswithsomeofthesemeters,allanalysisfrom
Q42015onwardwascompletedusingmonthlybillingdataprovideddirectlybyDuke
Energy.
Pleasenotethefollowingassumptions:
• BaselineDataSet:TheoriginalSmartEnergyNowdatasetcontains2010billingdata
for only 52 of 61 buildings. The remaining seven buildings have the following
anomalies:
o TwoDukebuildingswerenotincludedinSmartEnergyNow
o 3havedatasetsbeginninginFebruary2010
o 1hasadatasetbeginninginDecember2010
o 1hasadatasetbeginninginJanuary2011
o 1hasadatasetbeginninginSeptember2011
o 1hasadatasetbeginninginJanuary2012
3
•
Theseminorvariationsresultprimarilyfromfactorssuchasthedateuponwhichthe
buildings were initially occupied, e.g. the Duke Energy Center and 1 BAC. To
accommodateforthesevariations,UNCCharlottehascomputedanannualbaseline
valueusingthefirst12monthsofavailabledataforeachbuilding.Foreaseofpublic
communications,theEnvisionCharlotteMeasurementCommitteedecidedtorefer
tothisbaselineastheannualenergyconsumptionin2010.Thisannualizedbaseline
actuallycontainsvaluesrecordedoverthefollowingtimeintervals:
o 54buildingsusedatabeginninginJanuary2010(includestheadditionofthe
twoDukebuildingsnotintheoriginalSmartEnergyNowdataset)
o 3buildingsusedatabeginninginFebruary2010
o 1buildingusesdatabeginninginDecember2010
o 1buildingusesdatabeginninginJanuary2011
o 1buildingusesdatabeginninginSeptember2011
o 1buildingusesdatabeginninginJanuary2012
Figure2providesagraphicalsummary.
FirstComparisonofDatatoBaseline:UNCCharlottebegancomparingtothebaseline
inthethirdquarterof2012.ThisdecisionreflectsthefactthatQ32012wasthefirst
complete quarter in which all of the 61 buildings were officially participating in
EnvisionCharlotte.
BaselineCalculation
2010
2011
2012
J F M A M J J A S O N D J F M A M J J A S O N D J F M A M J J A S O N D
54of61buildings
3of61buildings
1 of61buildings
1of61buildings
1of61buildings
1of61buildings
Figure2:Thechartaboveshowsthetimeperiodforwhichdatawaspulledforeachofthe61buildings
whencomputingthebaseline.
4
CommentsontheSourcesofEnergyReduction
IntheyearssincetheEnvisionCharlotteprojectbegan,thecommercialreal-estatemarketinthe
uptown core has obviously undergone changes. Given the nature of Envision Charlotte, it is
impossiblefortheMeasurementCommitteetofullyunderstandthemultitudeofreasonswhy
energy consumption decreased. Certainly, some reduction can be attributed to changes in
behaviorsbybothbuildingoperatorsandoccupants,butitisimpossibletoquantifytheprecise
amount. Furthermore, it is also impossible to quantify the exact impact of various capital
improvements made within the Envision Charlotte buildings since confidentiality agreements
preventusfromobtainingsuchinformation.Asearchofdocumentsinthepublicdomainshows
thatseveralbuildings,suchasCharlotte’sOldCityHall,4investedsignificantlytoachievetheir
savings.InthecaseofOldCityHall,forinstance,theprojectwasfinancedatleastinpartusing
anEnergyEfficiency&ConservationBlockGrant.Itislikelythatmanybuildingsmadesimilar
investments,butinformationaboutprivate-sectorbuildingsismuchmoredifficulttoobtainin
thepublicdomain.
Itshouldalsobenotedthatatleasttwoofthe61buildingsexperiencedmaterialreductionsin
their occupancy during the course of this study, and these reductions did contribute to the
reportedsavings.Confidentialityagreements,however,donotallowustodisclosetheirexact
contributiontotheoverallreduction.Itshouldbefurthernotedthatothersignificantchangesin
occupancy–ineitherdirection–mayhaveoccurredduringthetimeframeofthisstudy.Since
wecanonlyrelyondataavailableinthepublicdomain,itisimpossibleforustoaccountforall
ofthesechanges.Itisimportanttonote,however,thatmultiplesourcessitethesteadydropin
vacancyratesinCharlotte,whichwereapproximately7.5%inQ12016afterreachingahighof
approximately 15% in 20105,6. The consistent rise in occupancy is a trend that traditionally
accompanies a rise in energy consumption, and thus this result is extremely encouraging.
AnecdotalevidencealsosuggeststhatoccupantdensityhasincreasedinuptownCharlottesince
2010,buttheauthorwasunabletofindadocumentedsourcetocorroboratethisobservation.
CommentsontheEquivalentNumberofHomesPoweredAnnually
Wecomputedthenumberofhomesthatcouldhavebeenpoweredin2016bytheequivalent
savings recorded in that year. This was computed by dividing the annual reduction by the
electricityconsumptionintheaverageAmericanhome.AccordingtotheEIA7,theaveragehome
usedapproximately10,812kWhin2015.Thus,
4
http://www2.apwa.net/Documents/Advocacy/APWA%20CASE%20Study%20OCH%20(2).pdf
Cushman&WakefieldOfficeSnapshotQ12016,
http://www.cushmanwakefield.com/~/media/marketbeat/2016/04/Charlotte_Americas_MarketBeat_Office_Q12016.pdf
6
JLLSkyline,https://skyline.jll.com/
7
https://www.eia.gov/tools/faqs/faq.cfm?id=97&t=3
5
5
562.18 − 454.45 ×10< kWh
NumberofHomesPoweredin2016 = = 9,964homes
10,812kWh/home
CommentsontheEstimatedReductioninEnergyBills
We computed the estimated reduction in energy bills assuming a median utility rate of
$0.073/kWh8.Thebillingreductionsarecumulative,andwethusassumedthateachbuilding
continuedconsumingthesameamountofenergyithadinitsbaselineyear.Thus,wedetermined
thecumulativereductionin2013-2016aswellthereductioninthesecondhalfof2012.Asnoted
previously,thisvalueshouldbetreatedatfacevalue.Recallthatmanyofthe61buildingslikely
investedheavilytoachievetheirsavings,andthusamorecompleteeconomicanalysiswould
examineaweatherandoccupancyadjustedreturn-on-investment.Wedonothavesufficient
informationtocomputesuchavalue.Thedatadoessuggest,however,thatthecommercialrealestatecommunityinCharlottelikelydidfindgoodreasontoinvestinappropriateenergy-savings
measures.
Emissions-ReductionAnalysis
In May 2016, the Envision Charlotte Measurement Committee adopted a procedure for
calculatingemissionsreductionsfromtheenergy-savingseffortsinits61participatingbuildings.
Thissectiondescribestheprocessforcalculatingtheseemissionsreductions.
CalculationProcedure
1. BaselineComputation:Asdescribedpreviously,thebaselineenergyconsumptionforthe
61participatingbuildingswas562.18millionkWhin2010.Thecorrespondingemissions
of various gases and particulates can be calculated using rates published in the EPA’s
comprehensive Emissions & Generation Resource Integrated Database (eGRID).
AccordingtoeGRID,electricitygenerationinNorthCarolinaisresponsibleforproducing
emissionsofcarbondioxide(CO2),sulfurdioxide(SO2),andnitrogenoxides(NOx)atthe
followingrates:
a. CO2:1055.9975lb/MWh
b. SO2:1.0425lb/MWh
c. NOx:0.8345lb/MWh
Thus,energyconsumptioninthebaselineyearresultedinthefollowingtotalemissions:
a. CO2:1055.9975
b. SO2:1.0425
DE
FGH
DE
FGH
×562,180MWh×
JKLM
NOOODEP
= 296,830tons
×562,180MWh = 586,092lbs
8
ThisisthemedianratereportedtotheauthorbyDukeEnergyviaemailcorrespondenceonMarch27,2017.
6
c. NOx:0.8345lbperMWh×562,180MWh = 469,154lbs
2. Reduction Computation: At the end of the program on December 31, 2016, the
energyconsumptionintheprevious12monthshadbeen454.45millionkWh.Using
thesameemissionsratesprovidedabove,thisconsumptionresultedinthefollowing
emissions:
a. CO2:1055.9975
b. SO2:1.0425
c. NOx:0.8345
DE
FGH
DE
FGH
DE
FGH
×454,450MWh×
JKLM
NOOODEP
= 239,949tons
×454,450MWh = 473,780lbs
×454,450MWh = 379,250lbs
Thus,theemissionsreductionsbetweenthebaselineyearandthe12-monthperiod
endingDecember31,2016wereasfollows:
a. CO2:56,881tons
b. SO2:112,312lbs
c. NOx:89,903lbs
3. Number of Removed Cars: To help understand the impact of the avoided CO2
emissions, UNC Charlotte determined the number of cars that would need to be
removedfromtheroadinordertoachievethesameemissionsreductions.According
totheEPA,thetypicalpassengervehicleemitsabout5.17shorttonsofcarbondioxide
inoneyear.Giventhisfact,thetotalnumberofcarsthatwouldneedtoberemoved
from the road in order to achieve the same emissions reductions is calculated as
follows:
56,881𝑡𝑜𝑛𝑠
= 11,003𝑣𝑒ℎ𝑖𝑐𝑙𝑒𝑠
5.17𝑡𝑜𝑛𝑠/𝑣𝑒ℎ𝑖𝑐ℎ𝑙𝑒
4. Weight of Avoided Emissions: To help understand the impact of the avoided
emissions,UNCCharlottedeterminedthenumberofelephantshavinganequivalent
weight. In this case, we computed the number of elephants corresponding to the
reductions in CO2, NOx, and SO2, respectively. According to the interpretation of
multiple academic publications cited by Wikipedia, the weight of an average adult
maleAsianelephantis4.4shorttons(8,800pounds).Thiswasthevalueusedforour
computations.InthecaseofCO2reductions,forinstance,wecomputedasfollows:
7
NotesandAssumptions
56,881𝑡𝑜𝑛𝑠
= 12, 928elephants
4.4𝑡𝑜𝑛𝑠/elephant
Thereareseveralelementstonotefromtheabovecalculations:
1. Emissions rates were taken from the EPA’s comprehensive Emissions & Generation
ResourceIntegratedDatabase(eGRID).ThemostrecentlypublishedeGRID,whichuses
2012data,isavailableonlineathttps://www.epa.gov/energy/egrid.Forspecificdetails,
see ‘egrid2012_data.xlsx’, Tab ‘ST12’, row 33 for North Carolina specific power plant
emissionrates.
2. TheresourcemixforelectricitygenerationinNorthCarolina(andtheUnitedStatesin
general)continuestoevolve,withmostemissionsratesonthedecline.Newtechnologies
suchasscrubbersarealsohelpingtodecreaseemissionsrates.Toisolatetheeffectof
EnvisionCharlotte’sactivitiesandtoavoidanyadditionalconfusion,wehaveelectedto
usethe2012eGRIDemissionsratesinallpublishedreports.
3. Informationaboutaveragetailpipeemissionsfrompassengervehiclesisavailable
onlinefromtheEPAatthefollowinglocation:
https://www.epa.gov/sites/production/files/2016-02/documents/420f14040a.pdf
4. InformationabouttheaverageweightofanadultmaleAsianelephantcanbefound
here:
Disclaimer
All analysis presented herein was performed by researchers at UNC Charlotte using raw data
provided confidentially under the terms of a Master Research Agreement signed with Duke
Energy.Underthetermsofsaidagreement,DukeEnergyallowsonlypublicationofaggregate
energyinformationforallEnvisionCharlotteparticipants.DukeEnergydidnotparticipateinany
oftheanalysisandisnotresponsibleforanyresultspresentedherein.Furthermore,itshouldbe
notedthatEnvisionCharlotteandSmartEnergyNowarenotthesame.Asdescribedherein,
EnvisionCharlotteisaccountingforallbilledenergysavingswithinthe61participatingbuildings
betweenthemiddleof2012andtheendof2016.Thisencompassesfarmoresavingsthanthe
behavior-based savings encompassed by Smart Energy Now. Additionally, Smart Energy Now
included only data through August 2013 and thus Smart Energy Now entails a far shorter
evaluationperiod.Thisdocumentdoesnotintendtosuggestthattheenergysavingsreported
by Envision Charlotte resulted solely from energy efficiency or behavior change; rather, a
multitudeoffactorscontributed,andbehaviorchangewasoneportionofthesavingsreflected
inthisreport.
8