A First Step up the Energy Ladder? - [PDF Document] (2024)

Policy Research Working Paper 7859

A First Step up the Energy Ladder?

Low Cost Solar Kits and Household’s Welfare in Rural Rwanda

Michael GrimmAnicet Munyehirwe

Jörg PetersMaximiliane Sievert

Development Economics Vice PresidencyOperations and Strategy TeamOctober 2016

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Abstract

The Policy Research Working Paper Series disseminates the findings of work in progress to encourage the exchange of ideas about development issues. An objective of the series is to get the findings out quickly, even if the presentations are less than fully polished. The papers carry the names of the authors and should be cited accordingly. The findings, interpretations, and conclusions expressed in this paper are entirely those of the authors. They do not necessarily represent the views of the International Bank for Reconstruction and Development/World Bank and its affiliated organizations, or those of the Executive Directors of the World Bank or the governments they represent.

Policy Research Working Paper 7859

This paper is a product of the Operations and Strategy Team, Development Economics Vice Presidency. It is part of a larger effort by the World Bank to provide open access to its research and make a contribution to development policy discussions around the world. Policy Research Working Papers are also posted on the Web at http://econ.worldbank.org. The authors may be contacted at [emailprotected], [emailprotected], and [emailprotected].

More than 1.1 billion people in developing countries are lacking access to electricity. Based on the assumption that electricity is a prerequisite for human development, the United Nations has proclaimed the goal of providing elec-tricity to all by 2030. In recent years, Pico-Photovoltaic kits have become a low-cost alternative to investment intensive grid electrification. Using a randomized controlled trial, the paper examines uptake and impacts of a simple Pico-Photovoltaic kit that barely exceeds the modern energy

benchmark defined by the United Nations. The authors find significant positive effects on household energy expen-ditures and some indication for effects on health, domestic productivity, and on the environment. Since only parts of these effects are internalized, underinvestment into the technology is likely. In addition, our data show that adop-tion will be impeded by affordability, suggesting that policy would have to consider more direct promotion strategies such as subsidies or financing schemes to reach the UN goal.

AFirstStepuptheEnergyLadder?LowCostSolarKitsand

Household’sWelfareinRuralRwanda

MichaelGrimm,AnicetMunyehirwe,JörgPeters,andMaximilianeSievert

JELcodes:D13,H23, H43, I31,O13,O18,Q41.Keywords:SustainableEnergyforAll(SE4All),householdwelfare,householdtechnology

adoption,Sub‐SaharanAfrica,RandomizedControlledTrial.

Michael Grimm is a Professor of Development Economics at University of Passau. He is also affiliated with Erasmus University Rotterdam and IZA, Bonn; [emailprotected]. Anicet Munyehirwe is director of IB&C Rwanda; [emailprotected]. Jörg Peters is heading the research group “Climate Change in Developing Countries” at RWI, Germany. He is Visiting Associate Professor at the University of the Witwatersrand, Johannesburg, South Africa; [emailprotected]. Maximiliane Sievert (corresponding author) is Research Fellow at RWI, Germany; [emailprotected]. We thank two anonymous referees and the editor for very valuable comments. We also thank conference participants in Münster (VfS 2015), in Oxford (CSAE 2015), in Kiel (VfS Development Economics 2015), Copenhagen (PEGNET 2013) and Düsseldorf (IAEE 2013) as well as participants at research seminars at the University of Bonn (ZEF), the Kiel Institute for the World Economy, and the University of Groningen. The data underlying this research was collected for an impact evaluation commissioned by the Policy and Evaluation Department of the Ministry of Foreign Affairs of the Netherlands (IOB). This work was supported by the German Federal Ministry for Economic Affairs and Energy and the Ministry of Innovation, Science, and Research of the State of North Rhine-Westphalia [Sondertatbestand – special grant] to JP and MS. Please cite the version of this paper published in the World Bank Economic Review (http://wber.oxfordjournals.org/).

Morethan1.1billionpeopleindevelopingcountrieslackaccesstoelectricity.Some

590millionofthemliveinAfrica,wheretheruralelectrificationrateisonly14percent

(SE4All 2015). Providing access to electricity is an explicit goal of the sustainable

developmentgoals(SDGs)andfrequentlyconsideredapreconditionforeconomicand

socialdevelopment(UN2005).Basedonsuchassumptions,theUnitedNationsaims

foruniversalaccesstoelectricityby2030viaitsinitiativeSustainableEnergyforAll

(SE4All; seealsoUN2010).The investment requirements toachieve this targetare

enormous,estimatedbytheInternationalEnergyAgency(IEA)(2011)tobeabout640

billionUSDollars.

In recent years, so‐calledPico‐Photovoltaic (Pico‐PV) kits have become a low‐cost

alternativetoexistingelectrificationtechnologiesthankstoasubstantialcostdecrease

ofphotovoltaicandbatterysystemsaswellasenergysavingLED lamps.Different

Pico‐PV kits exist that provide basic energy services like lighting,mobile phone

charging,andradiousage. In theSE4All initiative’smulti‐tierdefinitionofwhat is

consideredasmodernenergy,thePico‐PVtechnologyconstitutestheTier1andthus

thefirststeponthemetaphoricenergyladder.InvestmentcostsforPico‐PVkitsare

farlowerthanfortheprovisionofon‐gridelectricityorhighertierPVsystems.

Thispaperinvestigatesusagebehaviorandthechangesinpeople’slivingconditions

whenhouseholdsmakethisfirststeptowardmodernenergybasedonarandomized

controlled trial (RCT) thatwe implemented in rural Rwanda. The kit,whichwe

randomlyassignedfreeofchargeto150outof300householdsin15remotevillages,

consistsofa1Wattsolarpanel,a40lumenlamp,atelephonecharger,andaradio—

and thereby justbarelyreaches thebenchmarkofwhatqualifiesasmodernenergy

accessintheSE4Allframework.ThemarketpriceofthefullPico‐PVkitisataround

30USD.OurstudypopulationisthemaintargetgroupofthePico‐PVtechnology,that

is,thebottom‐of‐the‐pyramidlivinginacountry’speripherywhowillnotbereached

bytheelectricitygridintheyearstocomeandwhowillhaveproblemstoaffordhigher

tierPVsystems.

WeinvestigatetheadoptionofthePico‐PVkitatboththeextensiveandtheintensive

margin.At theextensivemargin,weexaminewhetherhouseholdsactuallyuse the

Pico‐PV kit. This is not obvious given thatwe distribute the kit for free and the

technologyisnewforthehouseholds.Thereisanintensedebateinthedevelopment

communityaboutusageintensityoffreelydistributedgoods(see,e.g.,Dupas2014).

Attheintensivemargin,soconditionalonhouseholdsusingthekit,weexaminethe

effectsofPico‐PVusageonthreetypesofoutcomes:energyexpenditures,healthand

environment,andproductivity indomesticwork.Theamplitudeofeffectsheavily

dependsonusagebehavior:isthekitusedinadditionorasasubstitutetotraditional

lightingsourceslikekerosene?Whichhouseholdmemberusesthekitandforwhich

purposes?Dohouseholdsexpand theiractivities that require lighting into evening

hours,ordotheyjustshiftactivitiesfromdaytimetonighttime?Doesthetotaltime

awakeofhouseholdmemberschange?NonelectrifiedruralhouseholdsinAfricaare

increasinglyusingLEDlampsthatrunondry‐cellbatteries.Sincethesebatteriesare

notdisposedofappropriatelyandpotentiallyharm the localenvironment,Pico‐PV

usagemightalsoinduceenvironmentalbenefits.Wealsoanalyzewhetherpotential

productivitygainsindomesticworkreleasetimethatcannowbededicatedtoincome

generatingactivities.

OurpapercomplementstheseminalworkofFurukawa(2014)whostudiestheeffects

ofPico‐PV lampson children’s learningoutcomes in ruralUganda.Weextend the

scopebyexamining theeffectsofPico‐PVkitsonvarious in‐houseactivitiesofall

householdmembers,notonlythoseofschoolchildren.Wefindthathouseholdsuse

the kits intensively in spite of the zero price and the novelty of the product.

Furthermore,thekitconsiderablyreducesconsumptionofkerosene,candles,anddry‐

cellbatteriesand, in consequence,energy expenditures.The reductionofkerosene

improveshousehold airquality and the reductionofdry‐cellbattery consumption

plausiblyleadstoenvironmentalbenefits.Moreover,wefindthatchildrenshiftpart

of theirhomework into theeveninghours.Primaryschoolboyseven increase their

totalstudy time.Whilepartsof theseeffectsareclearly internalizedbenefits,other

partsareimportantexternalities,whichmayprovidethecauseforpublicsubsidies,in

particularifitturnsoutthathouseholdsaresimplytoopoortoraisetheupfrontcosts

alone.

TheroleofpublicpolicyinthepromotionofPico‐PVtechnologyisnotdefinedsofar.

TheexpectationoftheWorldBank’sLightingGlobalprogram,forexample,aswellas

otherdonorsisthatPico‐PVkitsmakeinroadstoAfricanhouseholdsviacommercial

markets,implyingthatenduserspaycost‐coveringprices(seeLightingGlobal2016).

Thismightinfactworkoutfortherelativelywell‐offstratainruralareasbutismuch

moreuncertainfortheruralpoor.Infact,themajortargetgroupofPico‐PVkitswithin

theSE4Allendeavorislocatedbeyondthereachofthegridinremoterareas.These

households are short on cash, credit constrained, andmight havemore essential

prioritiestospendtheirmoneyon.Ifthesegroupsintheperipheryofthedeveloping

world shall be reached by the SE4All initiative, direct subsidies or even a free

distributionmightberequired.Thisisindeedthepolicyinterventionwemimicinour

study.Fromawelfareeconomicspointofviewthiswouldbejustifiediftheusageof

Pico‐PVkitsgeneratesprivateandsocialreturnsthatoutweightheinvestmentcost.

Ourpaperprovidesempiricalsubstancetothisdebate.

Sofar,onlyverylittleevidenceexistsonthetake‐upandimpactsofPico‐PVlamps.To

ourknowledge, theonlypublishedstudy isFurukawa (2014),whoconcentrateson

educational outcomes alone. Furukawa randomized Pico‐PV lamps among 155

primaryschoolstudentsinUgandawhoatbaselineusedkerosenewicklampsasthe

mainlightingsourceathome.AlthoughFurukawa(2014)findsthatchildren’sstudy

hours clearly increased among Pico‐PV lamp owners, he curiously observes

decreasing test scores. Furukawa tests different explanations of this “unexpected

result”.Withouthavingthedataathandtoobtainarobustanswer,hehypothesizes

thatthelowpowerofthelampsandtheinadequaterechargingbehaviorcouldhave

ledtoflickeringlight,whicheventuallyworsenedstudyingconditions.Basedonthis

experience,wewillthereforecarefullycheckthelightingqualityandusers’satisfaction

inourexperiment.

Much more evidence exists on the socioeconomic effects of classical rural

electrificationprogramsusinghigher tier technologies,mostly theextensionof the

electricitygrid.Theseinterventionsdifferfromourrandomizedsolarkittotheextent

thatmuchhighereffectsizescanbeexpected,butalsomuchhighercostsareincurred.

Nonetheless, this literature constitutes an important background of ourwork, in

particular those studies that explore the effects of electricity usage on similar

outcomes.VandeWalleetal.(2016)forinstancefindthatinruralIndiaelectrification

led to a significant increase in households’ expenditures. For the case of a grid

extensionprograminElSalvador,BarronandTorero(2014,2015)findreductionsin

kerosene consumption, in particulate matter exposure, and respiratory disease

prevalenceaswellasanincreaseinstudyhoursamongchildren.Thelatterfindingis

confirmedinagridextensionprograminBangladesh(Khandkeretal.2012)butnotin

apreviousstudy inRwandaon theeffectsofmini‐gridelectrification (Benschetal.

2011).ForSouthAfricaandNicaragua,respectively,Dinkelman (2011)andGrogan

andSadanand(2013)provideevidencethattheuseofelectricitysaveswomen’stime

inhouseholdchoresandleadstoincreasedlaborsupplyofwomen.1

In SE4All’s multi‐tier framework solar home systems are the intermediate step

betweenPico‐PVandgridelectricity.Samadetal.(2013)evaluateasolarhomesystem

programinBangladeshandfindincreasesineveningstudyhoursofschoolchildren,

TV usage, and female decision‐making power. They also find reduced kerosene

consumptionand somemoderateevidence forpositivehealtheffects.Benschetal.

1Furtherstudiesexistthatexaminewhetheron‐gridruralelectrificationprogramscanspurincomegenerationand

economicgrowth(see,e.g.,Benschetal.2011;Dinkelman2011;Bernard2012;Khandkeretal.2012,2013;Grogan

andSadanand2013;Lipscometal.2013;BarronandTorero2014;Lenzetal.2016;PetersandSievert2016).As

discussedabove,wedonotexpectthePico‐PVsystemstoaffectsuchoutcomes.

(2013) confirmpositive effects of solar home systemusage on children’s studying

hoursinSenegal.

Itistheaimofourpapertoextendthescopeofthisliteraturetothebottomstepofthe

energy ladder. Hence, these findings are important to classify our observations,

although of course the cost‐related and technological differences between on‐grid

electricity,50Wattsolarhomesystemsandour1WattPico‐PVkithavetobebornein

mind.

The remainderof thepaper isorganizedas follows:Section Igives thepolicyand

countrybackground.SectionIIprovidestheoreticalconsiderationsthatwillguideour

empiricalanalysis.SectionIIIpresentsourexperimentaldesign.SectionIVdiscusses

allresults,andSectionVconcludes.

Background

PolicyBackground

Intheabsenceofelectricity,peopleinruralSub‐SaharanAfricalighttheirhomesusing

traditional lighting sources—candlesorkerosenedrivenwick lampsandhurricane

lamps.Inrecentyears,dry‐cellbatterydrivenLED‐lampshavebecomeavailable in

almosteveryruralshopandareincreasinglyused(seeBenschetal.2015).Themost

common ones are small LED‐torches andmobile LED‐lamps that exist in various

versions (see Figure 1). In addition,many rural households use hand‐crafted LED

lamps,thatis,LED‐lampsthatareremovedfromtorchesandinstalledsomewherein

thehouseorona stick thatcanbecarriedaround.For ruralhouseholds inAfrica,

expenditures forboth traditional lightingsourcesanddry‐cellbatteriesconstitutea

considerablepartoftheirtotalexpenditures.Inveryremoteandpoorareas,people

whoarecashconstrainedgenerallyusevery littleartificial lightingand sometimes

evenonlyresorttothelightingthatthecookingfireemits.Forthisstratum,theday

inevitablyendsaftersunset.

Figure1:Traditionallightingdevices

Hurricane

lamp

Traditionaltin

lamp

Ready‐

madetorch

Hand‐crafted

LEDlamp

MobileLEDlamp

Source:Ownillustration

Obviously, this lightingconstraintrestrictspeople inmanyregards.Activitiesafter

nightfallareliterallyexpensivebutalsodifficultandtiringbecauseofthelowquality

ofthelighting(seeSectionIIformoreinformationonlightingquality).Atthesame

time,itbecomesevidentthatmodernenergyisnotabinarysituation.Rather,thereare

severalstepsbetweenacandleandanincandescentlightbulb.

Thiscontinuumhassometimesbeenreferredtoastheenergyladder.Infact,SE4Allhas

defineddifferenttiersofmodernenergyaccesswithinitsGlobalTrackingFramework

(SE4All2013)accordingtotheelectricitysupplythatismadeavailable.Forexample,

aregularconnectiontothenationalgridqualifiesasTier3,becauseitallowsforusing

generallighting,atelevision,andafanthewholeday.Asolarhomesystemwould

qualifyforTier1or2(dependingonitscapacity).Tier1requireshavingaccesstoa

peakcapacityofatleast1Wattandbasicenergyservicescomprisingatasklightand

aradiooraphonecharger for fourhoursperday.Thespreadbetween theservice

qualitiesof thedifferent tiers isalso reflected in the required investmentcosts: the

retailpriceofthePico‐PVkitusedinthisstudyisataround30USD.TheWorldBank

(2009)estimatesacostrangeforon‐gridelectrificationinruralareasof730to1450USD

perconnection.2

The promotion of Pico‐PV kits ismost prominently pursued by theWorld Bank

programLightingGlobal.BasedontheassumptionthatthemarketforPico‐PVsystems

is threatened by a lack of information and information asymmetries, it provides

technical assistance togovernments, conductsmarket research, facilitates access to

financetomarketplayers,andhasintroducedaqualitycertificateforPico‐PVsystems.

TheobjectiveofLightingGlobal’sinitiativeintheregion,LightingAfrica,istoprovide

accesstocertificatedPico‐PVkitsto250millionpeopleby2030.ThePico‐PVlantern

andthepanelusedforthepresentstudywerecertifiedbyLightingAfrica.3

2TheinvestmentrequirementscalculatedbyIEA(2011)ofadditional640billionUSDtoachieveuniversalaccess

toelectricityarebasedonelectricityconnectionsthatprovideaminimumlevelofelectricityof250kWhperyear.

ThisroughlycorrespondstoaTier2electricitysource.3At thepointof thePico‐PVkit’s certification,LightingAfricadidnotyet issue certificates formobilephone

chargingandotherservices.

CountryBackground

Rwanda’senergysectorisundergoinganextensivetransitionwithaccesstoelectricity

playing a dominating role. The Government of Rwanda’s goal is to increase the

electrificationrateto70percentofthepopulationby2017/2018andtofullcoverageby

2020. The key policy instrument clearly is the huge Electricity Access Roll‐Out

Program (EARP) that since 2009 quintuplicated the national connection rate to 24

percentcountrywide.Threefurtherprogramsexistthathavenotbeenimplemented

sofar,though.First,theGovernmentplanstoestablishamechanismtoprovidethe

pooresthouseholds(categorizedasUbudehe1accordingtothenationalpovertyscale)

with abasic solar system corresponding toTier 1 electricity access. Second, a risk

mitigationfacilityshallbeestablishedtoencouragetheprivatesectortoincreasesales

ofsolarproductsand services.Third,mini‐gridsshallbedevelopedby theprivate

sector(MININFRA2016).Theseprogramsarecomplementedbytheso‐calledByeBye

Agatadowa initiative that aims at eliminating kerosene lamps completely from the

country.

Intheabsenceofpublicpromotionschemes,fewprivatefirmsthatsellLightingAfrica

verified Pico‐PV kits were active in the country at the time of the study

implementation.TheyoperatemostlyintheRwandancapitalKigaliandothercities.

In rural areas,Pico‐PV kits are sometimes available,but their retailprice ismuch

higher compared to lower quality dry‐cell battery driven LED‐lamps that can be

boughtinruralshopsalloverthecountry.Thesedevicesarenotqualityverified,but

costonlybetween500FRW(0.82USD4)forhand‐craftedLEDlampsand3000FRW

(4.95USD)foranLEDhurricanelamp.ThebatterycoststorunanLEDhurricanelamp

foronehourarearound0.01USD.Thisischeaperthanrunningakerosenedrivenwick

lamp(around0.03USDperhour)andthelightingqualityisslightlybetter,whichis

whymanyhouseholdsarenowusingsuchready‐madeorhand‐craftedLED‐lamps.

Compared to both battery‐driven LED lamps and kerosene lamps, Pico‐PV kits

providehigherquality lighting (dependingon thenumberofLEDdiodes)atzero

operatingcosts.Assumingthatahouseholdusesthelampforfourhoursperday,the

investmentintothePico‐PVlampusedforthisstudyamortizesafter10monthsifa

ready‐madeLEDlampisreplacedandafterlessthan5monthsifitreplacesakerosene

wicklamp.

TheoreticalConsiderations

Based on the literature on rural electrification presented in the Introduction,we

assumethatthePico‐PVtreatmentaffectsthreedimensionsoflivingconditions:First,

the budget effect which arises because households with access to a Pico‐PV kit

experienceachange in thepriceofenergy,whileno (substantial) investmentcosts

occuraslongasweassumethatthePico‐PVtreatmentissubsidizedordistributedfor

free. Second, health and environmental effects occurwhenever Pico‐PV kits replace

kerosene lamps,candles,anddry‐cellbatteries.Adecrease inkeroseneandcandles

4ExchangerateasofNovember2011:1USD=607FRW.

consumptionreduceshouseholdairpollutionwithpotentialeffectsonhealth(seeLam

etal.2012;WHO2016).Environmentalbenefitsarisedue to inappropriatedry‐cell

batterydisposal(seeBenschet.al2015)thatisreducedifdry‐cellbatteryconsumption

goes down. Third, we analyze the productivity of domestic production, that is,

productionnot intended tobe tradedon competitivemarkets.Thiswe refer to as

domesticproductivityeffectinwhatfollows.Thereasonforonlyfocusingondomestic

production is that income insuchremoteruralareas isvirtuallyonlygeneratedby

subsistence agriculture.ThePico‐PV kit, in turn, is too small to affect agricultural

production. For non‐agricultural products, access tomarkets is very limited and,

hence, localnonagricultural labormarketsarenonexistent.Atbaseline,only seven

percentofheadofhousehold’smainoccupationandonepercentof spouse’smain

occupationwasanon‐agriculturalactivity.Yet,sinceintheorythePico‐PVkitcould

liberatetimefromdomesticlaborandextendthetimeawakeofhouseholdmembers,

weexamineatleastthetimededicatedtoanyincomegeneratingactivity(agricultural

andnonagriculturalactivities).Labordemandinsuchruralregionsistoolow,though,

to absorb increases in labor supply, and therefore measurable effects on

nonagriculturalincomecannotbeexpected.

Themechanismleadingtothebudgetandhealthandenvironmentaleffectsarequite

intuitive,whereasthetransmissionchannelforthedomesticproductivityeffectmight

belessobvious.Productiveactivitiesathomeincludecooking,cleaning,andmaking

andrepairingofhouseholdgoodsaswellasstudyingandchargingacellphone.Since

thevisualperformanceofhumansstronglyincreaseswiththelightinglevel(Brainard

etal.2001),weassumethattheproductivityinperformingtheseactivitiesincreases

withthequantityandqualityoflight.Productivityinfineassemblyworkforinstance

hasbeenshowntoincreaseby28percentasthelightinglevelincreasesfrom500to

1500lumen(lm)(Lange1999).Butevenincreasingthelightinglevelfrommuchlower

levelscomeswithsignificantproductivityeffects.Evidencecomesforinstancefrom

weavingmills(Lange1999).5Theliteratureattributesgoodqualitylightingtodevices

that provide sufficient, nonglaring, nonflickering and uniform light, balanced

luminousdistribution throughout the room,good color renderingandappropriate

lightcolor(Lange1999).Alongallthesecriteria,thePico‐PVkitsperformbetterthan

other traditional lighting devices such as kerosene lamps and candles, but also

comparedtosmallerhand‐craftedLEDlamps.OurPico‐PVlampemits40lm,whilea

candleonlyemitsaround12lm,ahurricanelampusedatfullcapacityaround32lm

andlargemobileLEDlampscanreachlevelsaround100lm(O’SullivanandBarnes

2006). The LED lamps used in poor and remote areas are less luminous, though.

Lumenlevelsemittedbyhand‐craftedLEDlampsvarysubstantiallydependingonthe

numberandqualityofdiodesandbatteriesused.Twotothreediode‐lampsconnected

toabatterypackageemitabout10lm.6

5Moreevidenceexistsalsoonsofterimpactssuchasapositivelinkagebetweenlightingandworkmood(Kuller

andWetterberg1993;Boyceetal.1997;PartonenandLönnqvist2000),fatigue(Dauratetal.1993;Grunbergeret

al.1993;Begemannetal.1997),andeyestrainandheadache(Wilkinsetal.1989,KullerandLaike1998)thatcan

beassumedtoimproveworkingperformance.Foradetailedpresentationoftheevidenceforproductivityeffects

associatedwithlight,seethesupplementalappendix.

6Sincelumennumbersforthesehand‐craftedlampsdonotexist,wetestedthetwomostwidelyusedstructures(a

twodiode‐lampandathreediode‐lampstructure)inalaboratoryatUniversityofUlm,Germany,usingstandard

lumenemissiontestprocedures.Accordingtothesetests,thelevelofemittedlumensbyhand‐craftedLEDlamps

isataround10lm.

Oneadditionaleffectassociatedwithapossibleincreaseinradiousageisbetteraccess

toinformation,whichinturnmayhaveproductivityeffectsiftheinformationrelates

tomarketdataorcanaffectnorms,suchasgendernormsforinstance,andpreferences

(Bertrand et al. 2006; Jensen andOster 2009; La Ferrara et al. 2012; Sievert 2015).

AlthoughweanalyzewhetherradiosareusedwiththePico‐PVkitanddisplayradio

ownershipandusage in the supplementalappendix (seeAppendixS5),wedonot

furtherinvestigateanyoftheseeffectsasmosthouseholdsusethePico‐PVkitonlyfor

lighting.

ResearchApproachandData

OuridentificationstrategyreliesontherandomizedassignmentofPico‐PVkitsafter

thebaselinesurvey.Theintention‐to‐treateffect(ITT)inourcaseisalmostidenticalto

theaveragetreatmenteffectonthetreated(ATT)becauseofthehighcompliancerate

inthetreatmentgroupandnotreatmentcontaminationinthecontrolgroup.Sinceall

resultsarerobustwithregardtobothwaysofestimatingimpacts,weshowonlythe

moreconservativeITTresults.

Treatment

Therandomizedkits includea1Wattpanel,arechargeable4‐LED‐diodes lamp(40

lumenmaximum) including an installed battery, amobile phone charger, a radio

including a charger, and a back‐up batterypackage (see Figure 2)Error!Reference

sourcenotfound..7Therearedifferentoptionstousethepanel.First,itcanbeusedto

directlychargethelamp’sbattery.Afteronedayofsolarchargingitisfullycharged.

Thelampcanbeusedinthreedimminglevelsand—fullycharged—provideslighting

forbetween6and30hoursdependingonthechosenintensitylevel.Second,thekit

canbeconnecteddirectlytothemobilephoneconnectorplugandtheradioconnector

tochargemobilephonesortheradio.Third,thekitcanbeusedtochargetheback‐up

batterypackagethatcanthenbeusedtochargetheotherdeviceswithoutsunlight.

Thecompletekitcostsaround30USD,thesmallestversionwithonlythesolarpanel

andanLEDlampincludinganinstalledbatterycostsaround16.50USD.

Figure2:ThePico‐PVkit

Source:Ownillustration

ImpactIndicators

As a precondition for the three effects on budget, health, and environment, and

domesticproductivitythehouseholds’usagebehaviorisourfirstmatterofinterest.

WelookatusageandchargingpatternsofthePico‐PVkitandanalyzewhichofthe

7ThekitusedinourexperimentprovidesmoreenergyservicesthanthesolarlanternusedbyFurukawa(2014),

butthepanelisalsotwiceaslarge(1Wattcomparedto0.5Watt).

different energy services—lighting, radio operation, andmobilephone charging—

householdsusemost.Sincethekitismostlyusedforlighting(seebelow),wefocusin

particularonthisservice.

Forbudget effects,we first look at changes in thepriceof the energy service.We

calculatethepriceperlightinghourandpriceperlumenhourthehouseholdseffectively

pay. Second,we analyzewhether price effects translate into a change in lighting

consumption.Here,welookattheaverageamountoflightinghoursconsumedperday

andlumenhoursconsumedperday.Lightinghoursarecalculatedasthesumofusage

time of all lamps used during a typical day (including candles and ready‐made

torches).Thepriceperlightinghouriscalculatedbydividingexpendituresonlighting

fuelsby thenumberof lightinghours consumed.For calculating lumenhours,we

multiplythelampspecificlightinghourswiththeamountoflumenemittedperlamp.

Finally,welookatchangesintotalenergyexpendituresandintheexpendituresforthe

differentenergysourceskerosene,batteries,andcandles.

For health and environmental effects,we first explore reductions in kerosene and

candleconsumptionandtowhatextentthisleadstoaperceivedimprovementofair

quality,measuredbythesubjectiveassessmentoftherespondents.Alsoformeasuring

the household members’ health status, we rely on self‐reported information on

whetheranyhouseholdmembersuffersfromrespiratorydiseasesandeyeproblems.We

distinguishbetweenmaleandfemaleadultsaswellasprimary,andsecondaryschool

children.We did not measure air quality or undertake any medical exams. For

environmentaleffects,weanalyze reductions indry‐cellbatteryconsumptionand the

wayhowhouseholdsdisposeofdry‐cellbatteries.

In order to investigate domestic productivity effects,we look at themain users’

domesticlaboractivitiesexercisedwhenusingthePico‐PVlamp.Themaindomestic

laboractivityforadultsishousework;childrenusethelampmainlyforstudying.We

assesstheincreaseofdomesticproductivitybyanalyzingthelightingsourceusedfor

these respective activities. Based on the evidence from the literature presented in

SectionIIandthesupplementalappendix,weassumethathouseholdsbecomemore

productivewhen they switch from a lower quality lighting source or no artificial

lightingtothePico‐PVlamp.Thisseemsreasonablesinceevenatdaytime,thetypical

dwellinginruralRwandaisquitedark.Windowsaresmallinordertokeeptherain

and the heat out of the inner of the dwelling. To analyze lamp switching, we

enumeratedalllampsineachhouseholdinterviewandaskedrespondentstonameall

usersforeachlampandtherespectivepurposeofusingit.Theinformationontime

spentondifferentactivitieswaselicitedintheinterviewsthroughanactivityprofile

for eachhouseholdmember. If a certain activitypursuedby thehousehold isnot

associatedwithoneoftheemployedlamps,weassumethatnospecificlightingdevice

isused for thisactivity, and it is either exercisedusingdaylight,orusing indirect

lightingfromthefireplaceorlampsusedforotherhouseholdtasks.

Inordertoanalyzewhetherthehigherproductivityalsoleadstoanincreaseintotal

domesticlaborinput,weanalyzethetotalamountoftimededicatedtodomesticlaborper

day.Wefurthermoreexaminewhethertotaltimehouseholdmembersareawakechanges

dueto increased lightingavailabilityandwhethertimededicatedto incomegenerating

activitieschangesasaresultoftimesavingsindomesticproduction.

RCTImplementation

ThekeyfactsoftheimplementationarepresentedinTable1.Adetaileddescriptionof

theimplementation includingamapofthesurveyareaandafigureillustratingthe

participant flow can be found in the supplemental appendix.A discussion of the

externalvalidityofourresultsisalsopresentedinthesupplementalappendix.

Table1.KeyFactsonRCTImplementation

Baselinesurvey November2011

DeliveryofPico‐PVkits December2011

Follow‐upsurvey June2012

Studypopulation15nonadjoinedcommunitiesinfourruraldistrictsofRwanda

locatedintheNorthern,WesternandSouthernProvince.

NoPico‐PVkitsavailableonthemarket

~5.5hoursofsunlightperday(whichissimilartocountryaverage)

Sample 300randomlysampledhouseholds

Randomization

Stratifiedrandomizationandadditionalre‐randomizationusing

minmaxt‐statmethodatthehouseholdlevel;randomassignmentof

150Pico‐PVkits

StratificationcriteriaConsumedlightinghoursperday,usageofmobilephones(binary),

radiousage(binary),anddistrict

Re‐randomization

BalancingcriteriaaremarkedinThesurveyedhouseholdsare

mainlysubsistencefarmersthatliveinvery

modestconditions.Theeducationallevelofthe

headofhouseholdislowandhouseholdsown

onlyafewdurableconsumptiongoods.The

householdsinoursamplehavecashexpenditures

ofonaverage0.45USD(1.12USDPPP)adayper

personwiththelower25%‐stratumhavingonly

0.07USD(0.18USDPPP).Eventheupperquartile

hascashexpendituresof1.14USD(2.86USDPPP)

only.Byanystandard,thesampledhouseholds

qualifyasextremelypoor.

Also energy consumption patterns illustrate the

precarioussituationofmosthouseholds(see

Table 3). They consume on average only around

threehours of artificial lightingperdaywhich is

mainlyprovided throughkerosenewick lampsor

battery‐driven small hand‐crafted LED lamps.

Around11percentofhouseholdsevendonotuse

any artificial lighting devices and rely only on

lighting from the fireplace after nightfall. For the

baselinevalues,wecalculate lightinghoursas the

sumoflightingusageperdayacrossallusedlamps,

excludingcandlesandtorches,forwhichwedidnot

elicitusagehoursat thebaselinestage.Almost65

percentof thehouseholdown a radio, around 40

percenthaveacellphone.

Table2and

Table3

Compensationforcontrolhouseholds Onebottleofpalmoilanda5kgsackofricewortharound7USD

Attritionrate <1%

Compliancerate 87%(18householdsdeclaredtheirPico‐PVkittobesold,lostor

stolen;Onehouseholdreceivedkitonlyduringfollow‐up)

Source:Householddataset2011/2012.

Results

BalanceofSocioeconomicCharacteristicsofParticipatingHouseholds

Thissectionexaminesthebalancingbetweentreatmentandcontrolgroupand,atthe

sametime,portraysthesocioeconomicconditionsinthestudyareas.Baselinevalues

ofthehouseholds’socioeconomiccharacteristicsshowthattherandomizationprocess

wassuccessfulinproducingtwobalancedgroups(seeThesurveyedhouseholdsare

mainlysubsistencefarmersthatliveinverymodestconditions.Theeducationallevel

oftheheadofhouseholdislowandhouseholdsownonlyafewdurableconsumption

goods.Thehouseholdsinoursamplehavecashexpendituresofonaverage0.45USD

(1.12USDPPP)adayperpersonwiththelower25%‐stratumhavingonly0.07USD

(0.18USDPPP).Eventheupperquartilehascashexpendituresof1.14USD(2.86USD

PPP)only.Byanystandard,thesampledhouseholdsqualifyasextremelypoor.

Also energy consumption patterns illustrate the precarious situation of most

households(see

Table3).Theyconsumeonaverageonlyaroundthreehoursofartificiallightingper

daywhichismainlyprovidedthroughkerosenewicklampsorbattery‐drivensmall

hand‐crafted LED lamps.Around 11 percent of households even do not use any

artificiallightingdevicesandrelyonlyonlightingfromthefireplaceafternightfall.

Forthebaselinevalues,wecalculatelightinghoursasthesumoflightingusageper

dayacrossallusedlamps,excludingcandlesandtorches,forwhichwedidnotelicit

usagehoursatthebaselinestage.Almost65percentofthehouseholdownaradio,

around40percenthaveacellphone.

Table2).

The surveyedhouseholds aremainly subsistence farmers that live inverymodest

conditions.Theeducationalleveloftheheadofhouseholdislowandhouseholdsown

only a fewdurable consumption goods.Thehouseholds in our samplehave cash

expendituresofonaverage0.45USD(1.12USDPPP)adayperpersonwiththelower

25%‐stratumhavingonly0.07USD(0.18USDPPP).Eventheupperquartilehascash

expenditures of 1.14 USD (2.86 USD PPP) only. By any standard, the sampled

householdsqualifyasextremelypoor.

Also energy consumption patterns illustrate the precarious situation of most

households(see

Table3).Theyconsumeonaverageonlyaroundthreehoursofartificiallightingper

daywhichismainlyprovidedthroughkerosenewicklampsorbattery‐drivensmall

hand‐crafted LED lamps.Around 11 percent of households even do not use any

artificiallightingdevicesandrelyonlyonlightingfromthefireplaceafternightfall.

Forthebaselinevalues,wecalculatelightinghoursasthesumoflightingusageper

dayacrossallusedlamps,excludingcandlesandtorches,forwhichwedidnotelicit

usagehoursatthebaselinestage.Almost65percentofthehouseholdownaradio,

around40percenthaveacellphone.

Table2.BalanceofSocioeconomicCharacteristicsbetweenTreatmentandControlGroup

(BaselineValues)

Treatment Control

t‐test/chi‐2‐test

(totaltreatedvs.control

p‐values)

total

(SD)

noncompliant

(SD)

total

(SD)

Householdsize1 4.85(2.0) 5.5(1.5) 5.0(2.0) .491

HH’scomposition(%)

Sharechildren0–15years 39(24) 51(16) 38(23) .680

Shareelderly65+ 7(20) 2(6) 5(16) .389

HH’sheadmale(%) 76 84 76 .892

AgeoftheHH’shead 47(15) 45(17) 48(15) .795

EducationofHHhead(%)1

None 35 53 35 .857

Primaryeducation 61 42 60

Secondaryeducationandmore 4 5 5

Cultivationofarableland(%)1 99 100 98 .314

Ownershipofarableland(%)1 95 90 95 .791

Ownershipofcows(%)1

Nocow 63 84 69 .542

Onecow 22 11 19

Morethanonecow 15 5 12

Ownershipofgoats(%)1

Nogoat 68 79 74 .476

Onegoat 16 5 12

Morethanonegoat 16 16 11

Materialofthewalls(%)1

Highervaluethanwood,mud,orclay 14 11 14 1.000

Materialofthefloor(%)1

Highervaluethanearthordung 12 5 11 .854

District(%)2

Gicumbi 19 16 20 .997

Gisagara 26 32 27

Huye 28 26 27

Rusizi 27 26 26

Numberofobservations 148 19 148

Note:1Usedforre‐randomization;2usedforstratification.

Source:Householddataset2011.

Ifwelookatthesmallgroupofnon‐compliers,whodeclaredtheirkittobesold,lost

orstolen,weseethattheyaregenerallypoorerthancomplyinghouseholds:Theyhave

morechildren,ownlessland,havelesscowsandgoats,andhavelessradiosandcell

phones.

Table3.BalanceofOutcomeRelatedCharacteristicbetweenTreatmentandControlGroup

(BaselineValues)

Treatment Controlt‐test/chi‐2‐

test

(totaltreated

vs.control

p‐values)

total

(SD)

non‐

compliant

(SD)

total

(SD)

Lightinghours,categorized(%)2

Nolampsorcandles 19 26 19

Lessorequal3h/day 51 42 51

Morethan3h/day 30 32 30 1.000

Lightinghoursperday,continuous1 3.1 2.7 3.2 .910

Usageofhand‐craftedLED1(%) 37 26 35 .628

UsageofmobileLED1(%) 4 5 3 .520

Consumptionofcandles1(piecespermonth) 1.25 2.32 1.76 .356

Usageofwicklamps(%) 49 47 47 .727

Usageofnoartificiallighting(%) 12 16 11 .715

Consumptionofkeroseneforlighting1(inliterpermonth) .46 .35 .54 .372

Radioownership2(%) 64 32 64 1.000

Mobilephoneownership2(%) 36 32 36 1.000

Numberofmobilephones1 .49 .21 .47 .876

Numberofobservations 148 19 148

Note:1usedforre‐randomization;2usedforstratification.

Source:Householddataset2011.

ImpactAssessment

Take‐UpandLightingUsage

Among the 131 households that still have a Pico‐PV kitwhen interviewed in the

follow‐upsurvey,usageratesareveryhigh(seeTable4).Insum,86percentusethe

kit at least once per day, primarily for lighting. Radio and especially cell phone

chargingusageratesareratherlow.Mosthouseholdsreportthatboththeradioand

thecellphonechargerwereverydifficulttousewiththekit,whichwasconfirmedby

technicalinspectorsinvolvedintestingthekitforLightingAfrica.Themajorreason

forthisseemstobethelowcapacityofthepanel,whichonlyallowsforchargingall

devicescompletelywithinonedayifthedailysunlightisexploitedatamaximum.In

practice,householdsusedthechargingcapacitiesmainlyforthelightingdevice.Given

thispreferenceforlighting,toolittlecapacityisleftfortheothertwoservices.Forcell

phonecharging,noncompatibilityofthesolarchargerwithsomeofthewidelyused

cell phone types in rural Rwanda posed additional problems. In linewith these

technicaldeficienciesandthehouseholds’expressedprioritiesforlighting,charging

patternsaredominatedbythelamp:mostofthetime,thekitisusedtochargethelamp

(26hoursperweek),followedbyoperatingtheradio(20hours).Itishardlyusedto

chargeacellphone(onlytwohours8).

DuetothetechnicaldrawbacksofthePico‐PVkit,wewillconcentrateinthefollowing

oneffectsrelatedtotheusageofimprovedlightingservice.Virtuallyallkitowning

8Theshareofhouseholdsusingthekitforcellphonechargingisverylowatlessthantenpercent.Thosehouseholds

thatdochargetheirphonewiththekitchargeit19hoursperweek.

householdspredominantlyuseitforlighting.9Somedetailsonradiousage,preferred

programsandotherinformationsourcesareshowninthesupplementalappendix.10

ThePico‐PV lampsaremainlyusedby femaleadults, followedbymaleadults (see

Table4).Childrenusethelampslessfrequently.

Traditional lampusagegoesdown substantially,with 47percent of the treatment

groupusingexclusively thePico‐PV lamp for lightingpurposes.11While treatment

grouphouseholdsuseonaverage0.8traditionallamps(anytype,includingcandles),

controlgrouphouseholdsuse1.4traditionallampsimplyingthatthePico‐PVlamps

havereplacedhalfofthetraditionallightingsources.Treatmenthouseholdsuseabove

allsignificantlylesswicklampsandhand‐craftedLEDlamps,butalsolessready‐made

torches,hurricanelamps,andmobileLEDlamps.Theshareofhouseholdsthatdonot

useanyartificiallightingsource,amountingtoninepercentinthecontrolgroup,still

reachesfivepercentamongtreatmenthouseholds.Theyeitherbelongtothegroupof

non‐compliersortothehouseholdswithtechnicalproblemswiththePico‐PVlamp.

Table4.UsageofPico‐PVKits(ShareofTreatmentHouseholdsinPercent)

9Theonlyexceptionsarefourhouseholdsthatreportedtohavetechnicalproblemswiththelampandcannotuse

itforthisreason.10Itcanbeseenthatradiousagesignificantlyincreasedinthetreatmentgroup,onaverageandacrossalltypesof

householdmembers.Adultslistenabovealltonewsontheradio,whilechildrenlistentomusic.Consequently,

radioissubstantiallymoreoftenthemainsourceofinformationfortreatmenthouseholds.Inthecontrolgroup

communitygatheringsconstitutetypicallyamoreimportantsourceofinformation.

11TableS6.1inthesupplementalappendixshowsacomprehensivepresentationoflampusageinthetreatment

andthecontrolgroup.

Shareoftreatmenthouseholds…

(inparentheses:onlycomplianthouseholds) %

Pico‐PVlampismainlyusedby… %

usingthekitatleastonceaday 86(95) Femaleadult>17yearsold 49

…usingthekitforlighting 85(97) Maleadult>17yearsold 23

…usingthekitforlisteningtotheradio 68(79) Femalebetween12and17yearsold 10

…usingthekitforchargingmobilephones 10(11) Malebetween12and17yearsold 7

…usethebatterypack 65(71) Collectivelyusedbywholefamily 6

Childrenbetweensixand11yearsold 5

Source:Householddataset2012.

Most lampusers are satisfiedwith the lightingqualityof the lamp.More than 70

percentofalllampusersreporttheyare“always”or“often”satisfiedwiththelighting

quality.Only22percentreporttobesatisfiedonlyseldomandsixpercentarenever

satisfied.Satisfaction levelswithtraditional lampsaresubstantially lower.Forwick

lampsandhand‐craftedLEDlamps,94percentand91percent,respectively,reportto

besatisfiedseldomornever.

Sincebothtreatmentandcontrolhouseholdsarelocatedwithinthesamecommunities,

spill‐overeffectsmightoccur.Especiallychildrenoftenmeetandplaywithfriendsand

theremightbepositivespill‐overeffectsonotherhouseholds’children.Ifamongthese

‘other’householdsarehouseholds fromourcontrolgroup, itmayevendownward

bias our impact estimates. Yetwe did not find any evidence for spill‐overs. For

instance,inthecontrolgrouptheshareofchildrenstudyingoutsidetheirhomedid

notincreaseandisnegligibleatlessthanonepercent.Moregenerally,thequalitative

interviewsweconducteddidnotprovideanyindicationforjointactivitiesusingthe

kitsandhencespill‐oversofthatsort.

BudgetEffectsandKeroseneConsumption

Lookingatthepriceperconsumed lightinghourandthepriceperconsumed lumenhour

(Table5),householdsinthecontrolgrouppayapproximatelyfivetimesasmuchper

lightinghourashouseholdsinthetreatmentgroup(950FRWvs.180FRW;1.56USD

vs.0.30USD).Thedifference isobviouslyevenmorepronounced for thepriceper

lumenhour:Ahouseholdinthecontrolgrouppaysseventimesmoreperlumenhour

thanahouseholdinthetreatmentgroup(70FRWvs.9FRW;0.12USDvs.0.02USD).

This reduction in lighting costs effectively translates into a strong increase in the

amountoflumenhoursconsumedperdayintreatedhouseholds,whichismorethantwo

timesashighasincontrol‐grouphouseholds(seeTable5)—reflectingtheverypoor

lightingqualityof traditional lightingsources.Yet,alsowithoutaccounting for the

improved quality of lighting, the Pico‐PV kit leads to an increase in lighting

consumption.Theamountoflightinghoursconsumedperdayissignificantlyhigherin

thetreatmentgroupafterhavingreceivedthePico‐PVlamp.

Table5.PriceandConsumptionofLightingEnergy

Treatment Control ITT p‐value

Costperlightinghour(inFRWper100hours) 176 950 ‐702 .000

Costperlumenhour(inFRWper100hours) 9 70 ‐57 .000

Lightinghoursconsumedperday 4.43 3.85 0.59 .074

Lumenhoursconsumedperday 142 61 78 .000

Note:TheITTdepictsthedifferenceinmeansatthefollow‐upstagebetweenthewholetreatmentandcontrolgroup,

includingalsonon‐complyinghouseholds.Wecontrolforallstratificationandre‐randomizationcharacteristics.

Detailedestimationresultscanbefoundinthesupplementalappendix.ExchangerateasofNovember2011:1USD

=607FRW.

Source:Householddataset2011/2012.

Lookingattotalenergyexpenditure(Table6.ExpendituresperMonthperCategory(inFRW)

Treatment Control ITT

p‐

value

Candles 42 109 ‐20 .339

Keroseneforlighting 155 609 ‐418 .000

Bigbatteries(TypeD) 358 352 ‐9 .750

Smallbatteries(TypeAA) 30 72 ‐43 .003

Mobilephonecharging 407 520 ‐68 .407

Totaltraditionalenergysources(withoutcookingenergy) 993 1,662 ‐557 .000

Totalexpenditures 37,971 31,334 7,249 .276

Shareofenergyexpenditureontotalexpenditures 0.04 0.07 ‐0.03 .001

Note:TheITTdepictsthedifferenceinmeansatthefollow‐upstagebetweenthewholetreatmentandcontrolgroup,

includingalsonon‐complyinghouseholds.Wecontrolforallstratificationandre‐randomizationcharacteristics.

Detailedestimationresultscanbefoundinthesupplementalappendix.ExchangerateasofNovember2011:1USD

=607FRW).

Source:Householddataset2011/2012.

As a consequence, we observe a significant reduction in expenditures for small

batteries, but not for the larger batteries since households use their Pico‐PV kit

predominantlyforlightingbutonlyveryseldomtoruntheirradio.Theconsumption

ofcandlesisalsosignificantlyreduced.Inaddition,wefindamoderatereductionin

expenditures on cell phone charging, although the difference is not significant.

Estimating an ATT only among mobile phone users by employing the random

treatmentassignmentasan instrumentshowsastatisticallysignificantreductionof

costsforphonechargingof1,662FRW(2.74USD).Theaveragehouseholdthatpays

forchargingthemobilephonepays1,400FRWpermonth(2.31USD).

In total,energyexpenditureswithoutcookingenergyare557FRW (0.92USDPPP)

lowerinthetreatmentgroup.Thisdifferenceisstatisticallysignificant.Ifwecompare

this to the total household expenditures it shows the importance of energy

expenditures for thehouseholdbudget:The shareof energy expenditureswithout

cookingdecreasesbythreepercentagepointsfromsevenpercenttofourpercent.

),weobservethathouseholdsspendaroundfivepercentoftheiroverallexpenditures

on kerosene, candles, and dry‐cell batteries. In treated households we expect a

significantdecreaseofexpenditures forkerosene,candlesanddry‐cellbatteries. In

fact,we observe a significant and considerable drop of kerosene expenditures by

almost70percent.Twotypesofdry‐cellbatteriesareusedinoursample,big(TypeD)

andsmall(TypeAA)batteries.Whilemorethan90percentofsmallbatteriesareused

forlighting,morethanthree‐fourthsofbigbatteriesareusedforradios.

Table6.ExpendituresperMonthperCategory(inFRW)

Treatment Control ITT

p‐

value

Candles 42 109 ‐20 .339

Keroseneforlighting 155 609 ‐418 .000

Bigbatteries(TypeD) 358 352 ‐9 .750

Smallbatteries(TypeAA) 30 72 ‐43 .003

Mobilephonecharging 407 520 ‐68 .407

Totaltraditionalenergysources(withoutcookingenergy) 993 1,662 ‐557 .000

Totalexpenditures12 37,971 31,334 7,249 .276