5yearsinaNet-Zero-ElectricitySolarHome

VictorYakovenkoDepartmentofPhysics,UniversityofMaryland,CollegePark,USA

h?p://physics.umd.edu/~yakovenk/solar-home/

“Everythingyouwantedtoknowabouthomesolarenergy,butdidnotknowwhomtoask”

10PVpanels(2.15kW)installedJanuary25-26,2011withba?erybackup

ConTnuouslyoperatedsinceMar9,2011

Extra3PVpanels(2.8kWtotal)installedOct26,2011,area12.6/16.4m2

SanyoHIT215A;efficiency:cell19.3%,module17.1%;sameasonthewinningUMDSolarDecathlonHouse2011

Generated16MWhin5.5years=7.8kWh/day,>100%ofconsumpTon

CollegePark,nearMetroStaTonInstalledbyStandardSolar.com

25November2016

Novel HIT design by Sanyo

HITDoublecollectslightfromtwosides.

h?p://us.sanyo.com/Solar/

SanyosolarpanelsHIT215A215W,cellefficiency19.3%,moduleefficiency17.1%.

SunPowerandSanyomakeconsumermodulesofthehighestefficiency.

Weneededthehighestefficiencybecauseofourlimitedareaofexposure.

SolarTourinDCarea:1stweekendofOctobereveryyearSolarTour.org

Besidesphotovoltaic(PV)modules(solarpanels),invertersareneededtotransformdirectcurrent(dc)fromPVintoalternaTngcurrent(ac)intheelectricgrid.

Oldstyle:Onebiginverteronthewallforallroofpanelsconnectedinseries.Onepanelblocksall.

Newstyle:Individualmicroinvertersforeachpanelontheroof.Parallel,independentoperaTon,datacommunicaTon,scalability.

TooperatePVduringgridoutage,itisnecessarytohaveaba?erybackuptostabilizethesystem.Otherwise,PVshutsdownwhengridgoesdown.

Typically,aPVsystemisconnectedtothegrid,soenergyflowsoutonasunnydayandinatnight.TheelectricuTlitycompany(PEPCO)billsmonthlyforthedifference(netmetering).NegaTvebalance(creditforgeneraTon)carriesover,butonceayearPEPCOpayscashforthenetcredit.

Shadefromtreescanbemeasured.SeealsoSunNumberofzillow.com

SolarPathFinder.com

Sequenceofsteps(donebytheinstalla=oncompany):§ IniTale-mailcontactwithStandardSolar,checksatelliteviewofthehouseonGooglemaps,decideonfeasibility

§ HousevisitofarepresentaTve,discussparametersofacontract,payiniTaldeposit

§ Engineeringdesign,getbuildingandelectricpermits,procureparts

§ InstallaTon,usually<day.Be?erinacoolseasontoprotectroofshingles§ ElectricinspecTonbythecounty,changeofelectricmeter,approvalfromtheuTlitycompany,switchon

§ Applyforrebates(state,county,federal),signacontractwithaSRECaggregator(e.g.SolSystems),registerthesystemforSRECs,receivecash

§ WatchelectricmeterspinningbackwardsJ

AmersigningofthecontractandinpreparaTonforPVinstallaTon,wereplacedaleakyplywoodpanelandshinglesontheroof.WeinstalledSolarisbrandofshinglesfromCertainTeedwithenhancedreflecToncoefficienttokeeptheroofcooler.

OverheaTngoftheancisaseriousproblem:withtheairtemperature100F(38C),theanctemperaturewas137F/59C(2008),butdecreasedto110F/43C(2011)amerinstallingridgevent,reflecTvesheetsinside,Solarisshingles,PVpanels,andthickbatsoffiberglassinsulaTonbetweentheancandthe2ndfloor.

PV installation and snowstorm afterwards

Jan25,2011,PVdoneonthe1stday Jan28,2011,amerahugesnowstorm

InstallaTonandwiringoftheba?erybackupwasfinishedonthe2ndday,Jan26,at4pm.At8pm,ahugesnowstormarrived,andthegridwentdown.Wesurvivedthenightonba?erybackup,whichpoweredgasfurnace,kitchenfridge,sumppump,Internet,andsomelightsandoutlets.Nextday,wegenerated4kWhofPVenergyandrechargedba?eriesbacktofull.Onourblock,thegridwasrestoredamer20hours,butinsomeareasitwasdownupto5days!

Battery backup in the basement PV,criTcalloads

Grid,non-criTcalloads

Ba?eries,10kWh

PVdatadisplay/Webinterface

Charger/Inverterfortheba?eries

DatadisplayfortheCharger/Inverter

Amerthesnowstorm,ImeasuredourcriTcal-loadelectricconsumpTonusingKillAWa?.Ourkitchenfridgeconsumedabout2kWh/day.WeboughtanewfridgeofthesamesizebyGeneralElectric,whichconsumes1kWh/day.

Energy-saving measures

Then,ImeasuredelectricconsumpTonofallpluggableelectricdevicesinthehouseandputallsleepingelectronicdevicesonswitches.Ireplaceda300Whalogenfloorlampbya13Wcompactfluorescentbulb,etc.ThismeasureshavereducedthebaseloadelectricconsumpTonbyabout30%.AlllightsinthehousearefluorescentandLED.

Howtobalanceenergybudget:increaseproducTonandreduceconsumpTon!

Better insulation of the house with poured-in foam

LiquidphenolicfoamispumpedbetweenexteriorandinteriorwallsandfillsallcaviTes,thenturnsintosolidclosed-cellfoam.DonebyUSAinsulaTon.net

The most efficient dehumidifier on the market

EnergyconsumpTonofallelectricappliancesislistedatEnergyStar.govbyDOE.

SantaFeImpactXT,seasonalconsumpTon~200kWh,dehumidifiesthewholebasementandhouse(usingcentralfan).ItomensubsTtutesaircondiTonerandcanbeoperatedduringoutage.WeusedaircondiTonerfor47daysin2011and31dayin2012.

CumulaTve5years8months,9March2011–9November2016

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ProducTon

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Netmeter

AnnualPV2.87MWh,usage2.5MWhnowvs.6MWhin2010,typicalhome14MWh

UMD people who have residential PV installations

ReinhardRadermacherProfessorofMechanicalEngineering,DirectorofCenterforEnvironmentalEnergyEngineering

MarlaMcIntosh,ProfessorofPlantSciencesh?ps://enlighten.enphaseenergy.com/public/systems/drUs9509

JeffreyLynn,NISTFellowandTeamLeader,AdjunctProfessorofPhysics

TheyallhavemuchbiggerPVinstallaTons(x3)thanmine

PeterShawhanAssociateProfessorofPhysics

§  Technologyismature:PVefficiencypushingto20%,PVwarranty20years,slickmicroinverters,warranty15years

§  Service:well-establishedinstallaToncompanieswithlongrecordandexperience

§  Cost:affordable,unprecedentedsubsidies,30%Federaltaxcredit+MDstate+PGcounty+SRECs(solarrenewableenergycredits)–totaldiscount>50%

§  PVmodulepricesaredecreasing:overcapacityduetocollapseofEuropeansubsidies,ramped-upSiproducTonforPVinsteadofelectronicslemovers

§  Wewantedabackupsystem.GridoutagesinDCareabecameendemic(4lastyear):winter(noheat),summer(foodspoils),rain(waterinbuckets,nosumppump),justtoohot(chainexplosionsofoverloadedtransformers)

§  Yet,abackupwouldbeusedonly1%ofTme.PV+ba?erybackuplookslikeagoodcombinaTon:generatespowerallyear,butalsoinemergency.

§  Ba?erybackupvs.generators:nofuel,nomovingparts,nomaintenance,indoorinstallaTon,easyelectricconnecTons,butafinitenumberofchargecycles.

§  Weblinkh?p://physics.umd.edu/~yakovenk/solar-home/

Nowisthe=metodoit!The=meformassiveadop=onofsolarpowerhasarrived.

Conclusions

UMD installed PV system on the former Washington Post printing plant in College Park (August 2011)

SevernBuildingUMD:2,600solarpanels631kWpower792MWhannualStandardSolarinstaller

h?p://newsdesk.umd.edu/scitech/release.cfm?ArTcleID=2341

AmericanUniversity:532kWpower,637MWhannual,onKatzenArtsCenter,BenderLibrary,etc.,StandardSolarinstaller,WashingtonGasEnergyServicesowner&operatorh?p://www.standardsolar.com/node/1292

h?p://datareadings.com/client/moduleSystem/Kiosk/site/bin/kiosk.cfm?k=5QJba0pN

SevernBuildingUMD,alsoLowe’s,IKEA,etc.

UniversityParkCommunitySolarLLC,ChurchoftheBrethern,22kW,May2010,StandardSolarinstaller

FraunhoferInsTtuteforSolarEnergyreport,17November2016

Canphotovoltaicssavetheworld?

•  GlobaltotalenergyconsumpTonisabout15TW=15,000GW•  CurrentglobalannualPVinstallaTonrateisabout50GW/year•  Atthecurrentrate,itwouldtake300yearstoswitchglobalenergytoPV•  PVinstallaTonratehastoincreasebyx10toreducetheTmeto30years