Solar Water Pumps- Technical, Systems, And …cite.mit.edu/system/files/reports/Solar Water...
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1 SOLAR WATER PUMPS: TECHNICAL, SYSTEMS, AND BUSINESS MODEL APPROACHES TO EVALUATION Massachusetts Institute of Technology, Cambridge, Massachusetts
Transcript of Solar Water Pumps- Technical, Systems, And …cite.mit.edu/system/files/reports/Solar Water...
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SOLAR WATER PUMPS: TECHNICAL, SYSTEMS, AND BUSINESS MODEL APPROACHES TO EVALUATION MassachusettsInstituteofTechnology,Cambridge,Massachusetts
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Introduction.................................................................................................................................................4
WhySolarPumps?...................................................................................................................................4
DesignofSolarPumpSystems.................................................................................................................5
SolarPumpUseCases..............................................................................................................................7
OverviewofCITEEvaluationCriteria........................................................................................................8
MethodologyataGlance.......................................................................................................................10
FindingsataGlance...............................................................................................................................11
Case1:SolarWaterPumpsforIrrigation...................................................................................................12
Approach&MethodologyforSolarPumpsforIrrigation......................................................................12
FindingsfortheIrrigationCase:UserSurveys........................................................................................13
EaseofUse.........................................................................................................................................13
Affordability.......................................................................................................................................13
Availability..........................................................................................................................................14
Demand..............................................................................................................................................14
Safety..................................................................................................................................................14
EnvironmentalImpact........................................................................................................................15
FindingsfortheIrrigationCase:WaterEnergyFoodNexus...................................................................15
ModelStructure.................................................................................................................................16
Approach............................................................................................................................................17
SelectedFindings................................................................................................................................17
Summary............................................................................................................................................18
FindingsfortheIrrigationCase:PumpSizingTool.................................................................................19
Case2:SolarWaterPumpsforSaltProduction.........................................................................................22
Approach&MethodologyforSaltProductionCase..............................................................................22
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UserSurveysandFarmerInterviews..................................................................................................22
TechnicalPerformanceintheField....................................................................................................23
TechnicalPerformanceintheLab......................................................................................................24
FindingsfortheSaltProductionCase....................................................................................................25
UserSurveysandInterviews..............................................................................................................25
TechnicalPerformanceintheField–MeasuredData.......................................................................26
TechnicalPerformanceintheField-Sensors....................................................................................27
TechnicalPerformanceintheLab......................................................................................................28
ConclusionsforBothCases........................................................................................................................29
Authors&Acknowledgements...................................................................................................................31
SelectedReferences...................................................................................................................................32
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INTRODUCTIONTheComprehensiveInitiativeonTechnologyEvaluation(CITE)atMassachusettsInstituteofTechnology(MIT)isdedicatedtodevelopingmethodsforproductevaluationinglobaldevelopment.CITEisledbyaninterdisciplinaryteamatMIT,anddrawsupondiverseexpertisetoevaluateproductsanddevelopadeepunderstandingofwhatmakesdifferentproductssuccessfulinemergingmarkets.Ourevaluationsprovideevidencefordata-drivendecision-makingbydevelopmentworkers,donors,manufacturers,suppliers,andconsumersthemselves.
FromSeptember2015toMarch2017,CITEresearchersevaluatedsolar-poweredwaterpumpsystems.ThesearethemosttechnicallycomplexproductsyettobeconsideredunderCITE’s“3-S”evaluationframeworkofSuitability(doesaproductperformitsintendedpurpose?),Scalability(canthesupplychaineffectivelyreachconsumers?),andSustainability(isaproductusedcorrectly,consistently&continuouslyovertime?).
WhileotherproductsevaluatedbyCITEhavebeenrelativelysimple,asinwaterfiltersandfoodstoragetechnologies,solarpumpsincludecomponentsofpowergeneration,powerelectronics,andpumpcomponents.InadditiontopartnersintheUnitedStates,theteamworkedcloselywithpartnersinthreelocationsinIndiaandtwolocationsinMyanmar.Thesepartnershavebeeninstrumentalinchoosingthesolarpumptechnologyusedbyfarmersintheircommunities.
WHYSOLARPUMPS?Acrosstheagriculturalsectorindevelopingcountries,accesstoirrigationisanimportantstepinimprovingfarmerlivelihoodsandproductivityasitincreasesproductiveyields.Thevalueofirrigationisdependentonrainfallpatterns.Forexample,inaclimatelikeIndia’swhereafour-monthlongmonsoonseasonisfollowedbyeightmonthsoflittleornorain,irrigationmakesthefarmer’slandavailableforcultivationforthreeseasonsinsteadoftwo,significantlyimprovingtheirproductivityandincome.Manyothercountriesmayexperienceaseasonthatisdrierthanothersandwhiletheirrainfallpatternsallowthemtocultivateyear-round,irrigationcansignificantlyimproveyields,andprovideawidervarietyofcropoptions.
Pumpingwaterfromeithersurfacesourcessuchasponds,lakes,andcanals,orfromundergroundthroughopenwellsordeeperborewells,istheprimarydriverforirrigation.Thesepumpscomeinavarietyofpowersources,includinghandpumps,dieselpumps,grid-tiedelectricpumps,andsolarpumps.
InIndia,accesstoirrigationisseenasapolicypriorityformeetingimportantdevelopmentobjectives.Yet,significantroadblocksexist—forexample,weakwatermarketsandfragmentedinstitutionalcoordinationandimplementation(Varma2016).Further,theenvironmentalimpactsofexpandingirrigationhaveraisedconcernsaboutover-extractionofgroundwater,whichhasbecomethedominantirrigationsource,especiallyinthepresenceofalackofpoliticalandsocialincentivestoinstituteefficient
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irrigationpractices—namely,pricingwatertoreflectitstruevalue(AgriculturalCensus2011;ShahandKishor2012).
Inthiscontext,solarpumpinghasbeenidentifiedasadesirabletechnologicalsolution.Forinstance,oneresearchgroupfoundthat,outoffourrenewableenergytechnologiesforirrigation,solar-poweredpumpsseemedtohavethehighestutilizationpotentialacrossIndiaasawhole(KumarandKandpal2007).Fromapolicyperspective,theMinistryofNewandRenewableEnergy(MNRE)haspromotedsolarpumpsforirrigationunderanationalsolarmission,theJNNSM,whichprovideslargecapitalsubsidies(generally80percentto90percent)tomakesuchsystemsaffordabletofarmers.State-levelgovernmentshavefollowedsuitandprovidedsimilarandcomplementarypolicies.Also,whilesolarpumpshaveahighup-frontcost,theiroperatingcostsareverylowcomparedtowidelyuseddieselpumps,reducingriskofpricefluctuationstofarmers.
Withthiscontextinmind,thesolarwaterpumpprojecthasthefollowingobjectives:
● Tocreateatechnicalcomparativeevaluationofthepumpsusedinconjunctionwithsolarpanels
● Tounderstandthesocio-economicdriversandgrassrootslevelinsightsassociatedwithsolarpumpuse
● Toanalyzethecomplexinteractionbetweenwater,energy,andfoodthroughsystemdynamicsmodeling
● Toanalyzethebusinessmodelsusedbyfarmerstoaccessandusesolarpumps
● Tocreateatooltoenablefarmersandinstitutionssupportingfarmerstocorrectlysizethepumpneededfortheirparticularapplication
DESIGNOFSOLARPUMPSYSTEMSSolarpumpsystemscomeinmanyformsformanydifferentapplications,butarebroadlydividedintothreecomponents:thesolarpanels,theelectronics,andthepumpitself.Figure1showsthebasicdesignofthesolarpumpsystemsincludedinthisevaluation.
Figure1:SketchofSolarPumpDesign
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PANELS
Solarpanelsarebyfarthemostexpensivecomponentofthesolarpumpsystem.Thesizeofthearrayisdependentonthepowerneededforthepump,soevenasmallchangeinthepumphorsepowercanhaveanoutsizedimpactontheoverallcostofthesystem.Panelscanbeeitherfixedorhavemanualsingle-axistrackingtoensurethehighestlevelsofsunlightarehittingthepanelsduringbothmorningandafternoonhours.
Figure2:SolarPanelintheLittleRannofKutch
ELECTRONICS
Mostpumpsusedforagriculturearealternatingcurrent(AC)pumps,butsolarpanelsproducedirectcurrent(DC)power.Theelectronics,usuallyhousedinaweatherproofboxunderthepanels,convertthatDCpowerintoACthatcanbeusedwiththepumps.Theon/offswitchisusuallyapartoftheelectronicsboxaswell.Theamountofaccessfarmershavetotheelectronicsvariesfromprojecttoproject.InGujarat,India,saltfarmersusingsolarpumpshadfullaccesstotheelectronicsandoftenmadesmalladjustmentstomaximizetheiruseofthesystemincludingattachingadditionalpumps,andevendivertingelectricityforhome-lightingandtelevision.
Figure3:SolarPumpSystemElectronics
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PUMPS
Thepumpsarethesystemcomponentmostunderstoodbythefarmers,becauseinalmostallcases,theyhavealreadybeenusingpumpsofsomekind.Inseveralcases,wesawfarmersusetheirexistingelectricpumpswiththenewpanelsandthemajorityofsaltfarmersinterviewedpumpusingthesolarpanelsduringthedayandusingdieselgeneratorsatnight.
Figure4:SolarPump
SOLARPUMPUSECASESInordertofocusourresearch,theCITEteamconductedascopingstudyduringthefirstseveralmonthsoftheproject.ThisincludedfieldworkinJanuaryandApril2016inordertogatherprimarydatafromuserswhohaveadoptedasolar-poweredpumpsystem.Thiswascomplementedbyinformationgatheredfrominterviewsandmeetingswithprojectimplementerstaffandotherrelevantstakeholderssuchassuppliersandmanufacturers.
Specifically,wedevelopedourresearchunderstandingofseveraldifferentusecases,includingthreecasesinIndia(shallowopenwellirrigationinUttarPradesh,deepborewellpumpsforirrigationinKarnataka,andsurfacepumpsforpumpingbrineforsaltfarminginGujarat),asitevisittoMercyCorpsinMyanmarwherethemarketisverynascent,anddiscussionswithUSAIDandOxfamregardingtheirworkusingsolarpumpsfordrinkingwatersupplytoInternallyDisplacedPerson(IDP)campsinDarfur,Sudan.
TheprocesstheteamusedtodownselecttotwoUseCasesforfurtheranalysisisillustratedinFigure5.
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Figure5:DownselectProcess
OVERVIEWOFCITEEVALUATIONCRITERIAIn past evaluations, the CITE team has defined six primary criteria to be used in our comparativeevaluations,asshowninFigure5.ForboththeIrrigationCaseandtheSaltProductionCase,weattemptedto stay as consistent as possiblewith this six criteria comparative system; however,wemodified theapproachinseveralways:
IrrigationCase
First,fortheIrrigationCase,thepumpsbeingpilotedinintheareaswherefieldworkwasconductedwerelarge(e.g.,5ormoreHp)anditwasinfeasibletopurchaseandtestthepumpsintheMITlabduetotheircost, size and power requirements. Therefore, in this Case, the “Technical Performance” criteriawascombinedwithEaseofUseand isbased solelyon theperceivedperformanceof the largerpumpsasreportedbytheusersurveys.Also,sincethepumpsusedintheSaltProductionCasewereconsiderablysmaller(~1Hp)thanthoseobservedinthefieldintheIrrigationCase,wethoughtthatanyattempttocomparethetwosetsofpumpsagainsteachotherwouldproveimbalanced.GiventhattherewereonlyafewfarmersusingthelargersystemsinUtterPradeshandalimitednumberinKarnataka,fewerthan30 surveys were administered in the irrigation case and therefore the sample size was too small toproducerobustresults.Forthisreason,wedonotpresenta“Scorecard”summaryofresultsinthisCase.
SaltProductionCase
FortheevaluationofthepumpssizedfortheSaltProductionUseCase(~1Hp),weconductedinterviewsinApril2016usingthefullsurveywithonly21saltfarmers.Fromthoseresultsanddiscussionswithourpartner the Self-EmployedWomen’s Association (SEWA), we decided to focus this evaluation on thetechnicalperformanceofthepumpsinthefieldandtheMITlab,theperformanceofthesolarpanelsin
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thefield,thereportedandobservedusabilityofthesolarpumpsystem,andadetailedanalysisofthecostadvantage of replacing or combining solar pumpswith diesel pumps. For the Technical Performancecriteria,wedopresenta“Scorecard”stylecomparativetableofpumpperformanceintheMITLab.InthisUseCaseevaluation,wedidnot address the supply chain (Availability) aspects, thedemand for solarpumpswithusersotherthanSEWAmembers,ortheEnvironmentalimpactsofthesaltproduction.
Figure6:CITEEvaluationCriteria
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METHODOLOGYATAGLANCE
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FINDINGSATAGLANCE
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CASE1:SOLARWATERPUMPSFORIRRIGATION NumerousprogramsexistinIndiatoencouragesmallholderfarmerstoirrigatetheirfieldstoincreaseself-relianceandfoodproduction.Theseincludefreeorlow-costelectricityinsomeregionsand,morerecently,capitalsubsidiesforpurchasingsolarwaterpumps.InSeptember2014,theGovernmentofIndia’sMinistryofNewandRenewableEnergy(MNRE)setatargettodeploy1Millionsolarpumpsforirrigationanddrinkingwateruseinthecountry1.However,pumpingwaterforagricultureuseinIndiahasasignificantimpactonthewatertableandlong-termwaterresources.
TheirrigationportionoftheCITEevaluationfocusedontwomainsites:JhansiinUttarPradeshandBangaloreinKarnataka.Bothsiteshaveanumberofsolarwaterpumpsthatarebeingusedbylocalfarmersforirrigationpurposes,buttheimplementationanddemographicsofthefarmersdiffergreatly.
InJhansi,thepumpswestudiedwerepartofaprojectimplementedbyDevelopmentAlternatives,andwereinstalledbyPunchlineinabatchofsix.Punchlineisasystemaggregatoranddoesnotmanufacturethecomponentsthemselves.Fromstakeholderinterviews,itwasdeterminedthatlittle-to-nositesurveyingwasdonepriortoinstallation.Additionally,allsixsystemswereidenticalandnottailoredtoindividuallocations.
InKarnataka,thepumpswerebothinstalledandtheprogramimplementedbySunEdison,thesystemmanufacturer.Consequently,SunEdisonhadateamembeddedinthecommunitytoensurecorrectandefficientinstallationofthesystems.
Threeresearchtopicswereaddressedinthesolarpumpingforirrigationportionofthisstudy:a)aqualitativeevaluationoftheCITEcriteriashowninFigure6;b)theappropriatechoiceofpumpsizeandc)theimpactofsolarpumpingonthewater,energy,foodnexus.
APPROACH&METHODOLOGYFORSOLARPUMPSFORIRRIGATIONTheirrigationusecaseevaluationwasdividedintothreemainactivities:
• Administrationofusersurveystogathersocialandeconomicdata• Developmentofapumpsizingtool(detailedinthe“CorrectSizingforPumps”sectionofthis
report)• DevelopmentofaSystemDynamicsmodeloftheeffectofsolarwaterpumpimplementation
policies(detailedintheWater,Energy,FoodNexussectionofthisreport)Surveys were developed to gather data to calculate indicator and criterion scores for ease of use,availability,affordabilityanddemand.Separatesurveysweregiventotheend-userfarmers,landowners,facilitatingNGOs,systeminstallers,andindustryexperts.
1MNREDirectiveNo.42/25/2014-15/PVSE,Dated22ndSeptember,2014http://mnre.gov.in/file-manager/UserFiles/Scheme-for-Solar-Pumping-Programme-for-Irrigation-and-Drinking-Water-under-Offgrid-and-Decentralised-Solar-applications.pdf[downloadedAugust2,2017]
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Fortheend-userfarmersurveys,asmallconveniencesampleapproachwasusedandatotalof25farmerswere interviewed, with the majority being in Karnataka State. An average demographic profile wasdeveloped,asshowninTable1.
Table1:DemographicDataofSurveyGroup
AverageAgeofRespondents 39.6GenderofRespondents
Male 12Female 13
AverageHouseholdSize 6.6EducationLevel
Noschoolorilliterate 15Primary,MiddleorSecondary 9
HigherSecondary 1Averageincomefromfarming(Rps) 81,240Averageincomefromfarming(USD) $1,200
FINDINGSFORTHEIRRIGATIONCASE:USERSURVEYSBasedontheusersurveysadministeredtothesamplegroup,welearnedthefollowing:
EASEOFUSEDespitethetechnicalcomplexityofthesolarpumpsystems,usersoverallfoundthemoverwhelminglyeasytouseandmaintainonaday-to-daybasis,whichconsistsprimarilyofcleaningthepanelswhentheybecomedusty.Somerespondentsnotedadesiretolearnhowtotroubleshootmorecomplexproblems,expressingconcernthattheywereexclusivelyreliantonhavingtocalltechnicalstafftocomeinspectandfixtheproblems.Basedontheseresults,theimportanceofsystem-levelsupportability2becomesevident:aslongasthesystemdoesn’tbreak,itiseasytouse,butifitbreaks,itmaybealongtimebeforeit’sfixedandcouldbeanexpensiverepairdependingonthewarrantyand/orservicecontract.AfullsupportabilityanalysisofsolarpumpsystemsinIndiawouldbeaninterestingareaforfutureresearch.
AFFORDABILITYThoughthecostofsolarsystemshavecomedownsignificantlyoverthepastdecadethankstoadropintheperunitcostofphotovoltaic(PV)cells,theycontinuetorepresentasignificantcapitalinvestmentforsmallholderfarmers.Asacostof190,000Rps.(~$2,800),thecheapestsystemwesawwasnearlydoubletheaverageannualincomefromfarming—approximately105,000Rps.(~$1,500)—ofour
2“Supportability” isasystemsengineeringdisciplinethatreferstothecombinationofReliability(i.e.,howoftendoesitfail),Availability(percentageoftimeit’sreadytouse),Maintainability(howquicklyandeasilycanitbefixedifitdoesbreak)andIntegratedLogisticsSupport(i.e.,ifitneedsasparepart,canIgetit).
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respondentsample.Asaresult,96percentofrespondentssaidthattheywouldnothaveboughttheirsolarsystemhadafinancingorinstallmentoptionnotbeenoffered.
Withsuchanexpensiveproduct,itisperhapsnotsurprisingthathowlongitwouldtaketoowntheentiresystemwasnotaconsiderationthatdrovepurchasingdecisions—eitherbetweenbuyingornotbuying,orbetweenonesystemandanother.Thisisinkeepingwithdevelopmentliteraturethatsuggests,giventhehighrisksanduncertaintiesassociatedwithpoverty,thetimevalueofmoney(netpresentvalue,orNPV)ishighlyskewedtowardthepresentwithlessregardforlong-termfinancialconsiderations.
AVAILABILITYAkeydimensionofavailabilitythatemergedduringinterviewswithimplementingpartnerswastheimportanceofskilledtechniciansatthelocallevel.Thiswouldbecriticalassolarpumpsystemsscaleinaregion,andwouldbecomemoreimportantasthesystemsageandrequiregreatermaintenanceandincreaseintheirlikelihoodofneedingrepairs.Intheabsenceofaskilled,localworkforce,solarpumpsystemsmayscaleandyetmayunderperformorfallintodisrepair,misuse,ordisuse.Unfortunately,thisisacommonthemewiththeintroductionoftechnicallycomplexproductsinremote,impoverishedareas.Therequiredskillsandcredentialstorepairthesolarpumpsystemswithoutjeopardizingmanufacturerwarrantiescanonlybeobtainedinlargerurbanareas,andoncefullytrained,techniciansmaybeunwillingorunabletorelocatetoruralareaswherethemarketismuchsmaller.
DEMANDWhilethereexistsstronginterestinsolarsystemsforuseinagricultureandbeyond(householdlighting,forexample)amongfarmerhouseholds,demandisrelativelyweakandrequiresa“push”strategy.”Thisispartlyduetothesystems’costbutisalsoafunctionofhowtheyarepromotedmoregenerally.Solarsystemsarerarelyfoundasanoff-the-shelfproductthatresidentscanpurchaseontheirown.Rather,most systems are made available only through participation in specific programs, often governmentinitiativesundertheaegisoftheMinistryofNewandRenewableEnergy(MNRE).
Moreover,demandforpumpsystemsisskewedtowardthosethat includehigherhorsepowerpumps.This is because many farmers use horsepower as a proxy for system performance: the higher thehorsepower,thebetterthesystem.Severalorganizationsweinterviewednotedthechallengingnatureofconvincingfarmerstousealowerhorsepowerpumpwiththeirsystems.Thispointstotheimportanceofaddressing“soft”issuessuchassocialnormsandingrainedperceptionsinthepromotionoftechnologies.
SAFETYIntermsofsafety,beyondthethreatofpossibleshockfromwires,norealperceiveddangerwascommunicatedtoresearchersbyrespondents.Thereseemedtobeageneralconsensusthatsolarpumpsystemsaresaferthanbothdiesel-andelectric-poweredpumps.
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ENVIRONMENTALIMPACTWhilesolarwater-pumpingsystemshavebeenheraldedastheenvironmentally-friendlyalternativetogridorfossilfuelpoweredpumps,cautionneedstobetakenwhenimplementingthistechnologyifitistobetrulyenvironmentallysustainable.
Theeconomicadvantageofasolarpoweredsystemresultsinapotentialincreaseingroundwaterextraction.Whenconvertingfromfossilfuelpoweredsystems,thefarmersdonotpayforincrementalpumping(i.e.noongoingfuelcosts)andthereforeincurnoadditionalfinancialburdenforincreasingthehoursspentpumpingwater.Thisincrease,whileadvantageousinnumerouscases,resultsinadangerousprecedentandcanresultinover-pumpinganddamagingthelocalwatertable.
Incombinationwithsolarwaterpumping,theuseofdripirrigationasaprimaryirrigationmethodshouldbeconsidered.Itreducestherequiredamountofwaterand,whenpumpingtoastoragetank,providesthefreedomtoirrigateatanytime,evenoncloudydays.
MoreinformationontheusersurveysandfindingscanbefoundintheFullReportatcite.mit.edu.
FINDINGSFORTHEIRRIGATIONCASE:WATERENERGYFOODNEXUSInordertoexpandtheunderstandingoffuturetrendsintheadoptionofsolarpumpsystemsinIndia,theteamdevelopedaSystemDynamicsmodel.SystemDynamics(SD)isaquantitativemodelingtoolthatemploysmacro-levelthinkingtoanalyzetheimpactofcomplexfeedbacksindynamicsystems,suchasagriculturalprocessesandgroundwatermanagement.Itisbuiltonthebeliefthatthestructureofasystemdeterminessubsequentbehaviors,andcapturestwoessentialfeaturesofmanysystems:thattheyareself-regulatingandexhibitnon-linearityovertime.Suchsystemsarecommoninbothenvironmentalandsocialsystems.
Agriculturecanbeconsideredacoupledsocial-environmentalsystem,wherefarmersrelyonenvironmentalinputs—namelywater,butalsoseeds,fertilizerandsunshine—publicpoliciesthatdeterminetheiraccesstotheseinputs(e.g.,capitalintheformofpumps)andmarketconditionsthatgovernhowmuchincomecanbemade.Feedbackswithinthissystemareabundant:poorrainsinoneyearmayservetoincreasegovernmentsupporttofarmersinthenextyear;subsidiesfornewirrigationpumpsmayleadtoincreasesincultivatedland;cashincentivesforfarmerstouseefficientamountsofwaterfortheircropscanhelpstymiegroundwaterover-extraction.Assuch,SDmodelingprovessuitableasameanstoinvestigatethedynamicissuesinherentinagriculture.
ToensuretheSDmodelisasaccurateaspossible,datawasincorporatedfromseveralsources,including:primarydataforCITE’sfieldworkinKarnatakaandGujaratinIndia;rainfalldatafromtheIndiaMeteorologicalDepartment;agriculturaldatafromvariouscentralandstateministries;andwateravailabilityandusedatafromMinistryofWaterResources,CentralGroundwaterBoard,andstateagriculturalpolicydocuments.
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MODELSTRUCTUREThemodel’sstructuredrawsfromSDmodelsdevelopedbyotherscholarsinvestigatingtherelationshipbetween agricultural production, natural (especially water) systems and policy environments (Sohofi,Melkonyan,KarlandKrumme2015;Zhuang2014;Wang2011;AhmadandPrashar2010)andispremisedontheexistenceofaWEFnexus.Figure7showsthekeyrelationshipscapturedbythismodel.
Onekeyaspectofthemodelisthefeedbackloopbetweenirrigatedagriculturalland,solarpumpadoptionandwater-and-energyuse. In theabsenceofdemand-side incentivesandpolicies,greatersolarpumptechnologytranslatestogreaterpotentialwatersupply,whichleadstogreaterwaterdemandedandused,whichthenleadsfarmerstofurtherexpandtheareaoflandtheyareabletocultivate,and/ortoirrigateforalongerperiodoftime(day-to-day,orduringthedryseason).
Themodelissimulatedovera10-yearperiod,beginninginJanuary2017,withamonthlytimestep(120timestepstotal).
Figure7:SchematicofSDmodelstructure(blue:policyinterventions)
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APPROACHTheCITEteamdevelopedaseriesofScenariostounderstandtheimpactofdifferentpolicyinitiativesandtechnologydecisionsovertime.Theseinclude:aBaselineScenario,whichreflectsthecurrentsituationinKarnatakaandGujaratandprojectsgroundwaterdepletionovertime;aPolicyInterventionScenario,includingexaminationofpossiblecapitalsubsidies,mechanismstofeedintotheelectricalgrid,andvaryinglevelsofirrigationefficiency;aBanDieselPumpsScenario,whicheliminatesdieselpumpswhileaddingsubsidiesforelectricalpumppurchase;andaCombinedScenariosstudywhichlooksatinteractionsoftheotherscenariosatdifferentlevelsofimplementation.
SELECTEDFINDINGSWhileinitiallythegroundwaterlevelsinGujaratbenefitfrompoliciessuchasadieselpumpban(Figure8),overthecourseof10yearstheeffectisnegatedbytheadoptionofalternativepumpingtechnologies.Additionally,thereductioningroundwaterusageinyears1-6hasadetrimentaleffectontheagriculturalindustryastheystruggletosupplyenoughwatertomaintainthecurrentfoodproductionlevels.
Figure8:EffectonWaterSupplyversusDemandofBanningDieselPumpsinGujarat.
Whenconsideringonlythereducedimpactongroundwaterlevels,apolicyofmoreefficientirrigationyieldsthebestresultsforbothKarnatakaandGujarat,inthelong-term.Theintroductionoftheothertwopolicies,thecapitalsubsidiesandthegridfeed-intariffs,whileassumedtoreducethepumpinghoursofsolarpumpsystemsbyhalfbecausefarmersareincentedtomaximizetheamountofenergytheycanfeedbackintothegrid,onlyhasaminoreffectongroundwaterstorage,asshownFigure9.However,theseinterventionsdohaveanimpactonothercriteria,suchasfarmerincome.
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Figure9:IntroductionofCapitalSubsidiesandGridFeed-in,Karnataka
Anextensivediscussionofthescenariosandmodelresultscanbefoundinthefullreportatcite.mit.edu.
SUMMARYThroughourmodel,wehavesoughttodemonstratetheinterconnectednessbetweenagriculturaltechnologiesintheformofsolar-poweredpumpsandtheirimpactonthenaturalsystem—namely,onwateruseandmorespecificallyongroundwaterextraction.Theroleofpolicyinshapingfarmers’actionsandbehaviorsprovespowerful.Importantly,thedisseminationofpumpingtechnologiesaloneseemstoexacerbateunsustainablewaterusage:itaugmentsfarmers’accesstosupplywithoutincentivizingdemand-siderestrictions.Inthissense,capitalsubsidiesalonetogetsolarpumpsintothehandsoffarmersmaynotbethemostenlightenedpolicy.Couplingsuchapolicywithtechnologicalandeconomicincentives,suchasbanningdieselpumpsandprovidingmechanismstofeedelectricitybackintothegrid,however,reducestheuseofgroundwater.
Takingcurrentwaterconsumptionfornon-agriculturalusesandlevelsoffoodproductionintoconsideration,eventhecouplingoftheseinterventionsonlytakesthestatesofGujaratandKarnatakahalfwaytowardscompletesustainablegroundwaterextraction.Severalpossibleextensionstothismodelexist.Chiefamongthemarethecostofthetechnologyandtheimpactonadoption,whichwouldrequirewillingnesstopay(WTP)data.Further,coordinationissuesbetweenimplementationagencieswarrantsfurtherscrutiny,thoughsuchaninvestigationmaylenditselftocasestudiesasopposedtoSDscenariomodeling.Regardless,institutionalfragmentationandoverlap3remainsachallengein
3 For instance, theMinistryofNewandRenewableEnergy (MNRE) is responsible for thenational solarmissionschemethatprovidescapitalsubsidiesforthesolarpumpsystems,buttheCentralGroundwaterBoard(CGWB)andtheMinistryofWaterResources(MOWR)areresponsibleforwaterresourcemanagement.Moreover,theMinistry
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developingameaningfulmodeloftheWEFnexus.Asourmodelseekstodemonstrate,thebenefitsofsuchaholisticapproachareconsiderable,especiallyforthesustainableuseofwaterresources.
MoreinformationontheSDmodelandfindings(andadownloadableVensimfile)canbefoundintheFullReportatcite.mit.edu.
FINDINGSFORTHEIRRIGATIONCASE:PUMPSIZINGTOOLInordertoallowuserstoselectanappropriatepumpsize,theCITEteamdevelopedasoftwaretooltoautomatetheprocess.Aspreviouslymentioned,theproperpumpselectionisessentialtoboththefinancialandenvironmentalsustainabilityofaproject.Thesetypesofsizingtoolsareroutinelyusedbypumpsystemmanufacturersandintegratorstorecommendpumpstopotentialcustomers;however,eachcompanyhasaproprietarytoolthatisnotavailabletothegeneralpublicandthereforetheusermustrelysolelyonthemanufacturerorintegrator’sadvice.Webelievehavinganindependenttooltocrosschecktherecommendationsishelpfulbothintermsofensuringapropermatchbetweenpumpsizeandtheuser’sspecificconditions,aswellasenablingtheusertobeamoreinformedbuyer.
TheExcel-basedtoolisavailablefordownloadontheCITEwebsiteatcite.mit.eduandaMatlabversionisalsoavailableuponrequest.ItshouldbenotedthatthesetoolsarestillindevelopmentandtheresultscannotbeguaranteedbyUSAIDorMIT.Wewelcomediscussionandimprovementstothetools.
Asanexampleofhowthepumpsizingtoolcanbeusedtomakepurchasedecisions,werevisitedthecaseinUttarPradeshwhereDevelopmentAlternativeshasreplacedafewdiesel-poweredpumpsystemswithsolarpumpsystems.Basedonthefieldresearchandinterviews,weknowthefollowing:
� Asinglesolarpumpwasinstalledateachsite,alongwithothernecessaryequipmenttooperateit(solarpanels,inverter,etc.),replacingthedieselpumppreviouslyatthesite.
� Themethodusedtodeterminewhichsizepumpstopurchaseandinstallwastosizethepumpsaccordingtotheaveragedepthofthewatertablefortheregion.
� Toourknowledge,therewasnoon-sitepumptestingcompletedpriortotheinstallationandsubsequentuseofthesolarpumpsattheseirrigationsites.
� Priortoinstallation,theselectedpumpwaspurchasedandtestedinafacilityalongwithothersystemcomponents.
� Groundwaterhydrologyandwelllimitationsfromthefieldwerenotconsideredwhenselectingthesizeofthepumpstobeinstalled.
Inordertotestthepumpsizingtool,wehypothesizedthatbecausethepumpselectionmethodwasinsufficient,thepumpsinstalledonthesesiteswereimproperlysizedfortheirrigationsystems.Thus,weexploredthepumpselectionprocessspecificallyforshallowwellirrigationsystemssuchastheonesinUttarPradesh,andextrapolatedourmethodforbroaderapplication.ThisprocessisshowninFigure10.
ofAgricultureandFarmerCooperation(MAFC)isresponsibleforagriculturalpolicy.Beyondnationalministrypoliciesandprograms,stateandprivatesectorschemescomplicatetheinstitutionallandscapeevenfurther.
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Figure10:OverviewofthePumpSelectionProcess
ThecalculationsforthisparticularcaseareshowninFigure11.Therecommendedpumpsizerangeshownin(#4)ontheuserinterfacevariesbetween0.7and1.5hP,whichissignificantlylessthanthecurrent3horsepower(HP)ACsubmersiblewaterpumpthatisbeingusedattheDevelopmentAlternativessite.
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Figure11:PumpSizingToolUserInterface
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CASE2:SOLARWATERPUMPSFORSALTPRODUCTIONInadditiontotheagriculturalirrigationcasespresentedintheprevioussection,theCITEteamalsoworkedwiththeSelfEmployedWomen’sAssociation(SEWA)inGujarat,Indiatoevaluatethe1-1.5horsepowersolarwaterpumpsthatarecurrentlybeingusedbyseasonalsaltfarmers.
Wechosetoevaluatethesesmallerscalesolarwaterpumpsystemsforthefollowingreasons:
• SEWAhasanextensivesolarpumpprogram;• TheharshenvironmentalconditionsintheLittleRann,Gujarat,Indiaaresomethingofa
“challengecase”scenarioforthetechnicalperformanceofthepumps;• Thesmallscalepumpsaremuchmoreaffordableandtheresultsoftheevaluationcouldbe
usedasaguideforindividualfarmersorotherorganizationsinterestedinusingsolarwaterpumpsforirrigationofsmallfarms
TheSelf-EmployedWomen’sAssociation(SEWA),anorganizationwhosemembershipconsistsofinformalworkersandwhosemissionistoensuretheirrights,isthedrivingforcebehindthesolarpumpprojectforthesaltfarmersintheLittleRannofKutch.Theyhavesecuredloansforthesaltfarmersandnegotiatedthepurchasingofthesolarwaterpumpingsystems.Additionally,SEWAhastakenanactiveroletodateinrelationtomaintenanceandaftersalessupport.Thisismotivatedbyadesiretocontinuetheprojectandencouragemorefarmerstoadoptthetechnology.
SEWAfirststartedinstallingthesolarpumpsfouryearsago.Asofourfirstvisitin2016,250ofthe286solarpumpsinstalledontheRannwereinstalledbySEWA.
APPROACH&METHODOLOGYFORSALTPRODUCTIONCASEThemethodologyforevaluationofsolarpumpsforsaltproductionusecasewasdividedintoseveralactivities:
● Usersurveysforsocialandeconomicfactors,includingperceivedtechnicalperformance● Farmerinterviewsforseasonalcashflowsofbothsolaranddieselpumpsystems● Technicalperformancemeasurementinthefield,bothin-personandthroughsensors● Labtestingofthepumpsusedinthesolarpumpsystems
USERSURVEYSANDFARMERINTERVIEWSForthepurposesoftheresearch,weinterviewedatotalof98solarpumpowners,ofwhich10usedonlythesolarpumpsystemsand88usedacombinationofsolarpumpsanddieselpumps.Wealsointerviewed10farmerswhousedonlydieselpumps.Theselectionoffarmerswasbasedonaconveniencesampleandalsoconsideredthegeographicdistributionofthefarmers.
Ourfirststepwastoconductfairlydetailedinterviewswiththefarmerswhohadagreedtohavesensorsinstalledontheirsolarpumpsystems, inordertoevaluatetheirtechnicalperformance.Thesefarmers
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alreadyhada relationshipwithour researchersandwereable togiveusaboutanhourof their time.Theselongerinterviewsallowedustounderstandthevocabulary,timing,andunitstheyusedtotalkabouttheircashflows,whilealsoprovidingmoredetailedinformationabouthowandwhentheyarepaidbythemerchants,andhowfuelistransportedtothesaltpans.Weconducted16oftheseinterviewsoverthecourseofthreedays.
Fromtheselongerinterviews,wewereabletoconstructamuchmoreconciseinterviewthatcouldobtainalmost all of the same information in amuch shorter period.Over the course of threemore days ofinterviews,wewereabletoconduct92moreinterviewsincluding72withfarmersthatusedbothdieselandsolarpumpsystems,tenwhousedonlydieselsystems,andtenwhousedonlysolarpumpsystems.
Theinterviewscollectedavarietyofinformationonthefarmers’cashflows,suchthatasimplefinancialstatementcouldbeconstructedforeachfarmer.
TECHNICALPERFORMANCEINTHEFIELDInApril2016,theCITEteamtraveledtoIndiaandvisitednumeroussitesandpartners,includingSEWAinGujarat.Duringthevisit,SolarWaterPumpusersweresurveyedontheirreactionsandopinionsofthesystems.Inparalleltogatheringsurveyresponses,theteamcollectedinstantaneoustechnicaldatafor28ofthesystems,inordertoinformthesubsequentdesignofsensors.
Forthe28systemsmeasured(ownedby25farmers),wewereabletogatherflowdatafor7pumps,dueprimarilytothefactthatwehadtwoteamsconductingsurveysinparallel,butonlyoneflowmeter.Alsosomeofthefarmersdidnotwantustochecktherateasitwouldinterferewiththeirpumping.Thesolarpanelvoltageandcurrentdatawasgatheredforsomealmostallofthesystems,butwewereunabletogatherallofthepumpvoltageandcurrentnumbersduetovariousreasons(e.g.,noopenwirestotakemeasurements,etc.).
Followingthefieldwork,wedevelopedspecializedremote-sensingprototypestocharacterizetheoutputandusageofthesystems.Theprototypedata-loggerswerebuiltusingtheParticleElectronplatformandinterfacedwithacustomcircuitboardthatallowedforlocalizeddatastoragetomicroSDcards.Thedata-loggersconnectedtothesystematthesolarpanelinputtothecontrollerandtheoutputtothemotors.Thedatawasuploadedtoacloud-basedserverusingcellularnetworksevery12hours.Figure12showstheinstallationofthesensorsinoneofthe17locationsintheLittleRannofKutchinJanuaryanddesignedtomeasureoutputofthesystemsuntilMay-June.
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Figure 12: Researchers Éadaoin Ilten (left), Amit Gandhi (middle) and Przemyslaw Pasich (right) testingperformanceandinstallingsensors
TECHNICALPERFORMANCEINTHELAB
Tomeasurethetechnicalperformanceofpumps,severaltestpumpswereusedthatcorrespondedtobothpumpsthatwerebeingusedatthefield-testingsiteandothersimilarlysizedcommerciallyavailablepumpsthatwereavailableinIndia.Thepumpsweremountedtothetestrig,showninFigure13andattachedtotheplumbingwithflowandpressuresensors.Afterprimingthepumps,weturnedthemonandslowlyrampeduppowertofullpower,asdefinedinthepowerpumpssection.Ifthepumpwasnotprimedproperlyandwenoticedthewaterhammereffect,powerwasimmediatelydisconnectedandthepumpwasdisconnectedfromtheplumbingandprimed.Thiswasprocesswasrepeateduntilthepumpwasabletoachievesteady-stateflowandperformance.
Thepumpcurveforeachpumpwasgeneratedbycollecting3-5characterizationrunsoneachpump.Foreachrun,thepumpwasallowedtooperateunrestrictedforatleast5minutestoensurethatithadreachedsteadystate.Steadystateflowwasverifiedbycheckingthepressureandflow-ratesensorstomakesuretherewasnovariationinreadings.Aftertheinitialphaseofoperation,thepressurevalvewasincrementallyclosedtosimulateheadbyincreasingtheresistancetoflow.Aftertheflowstabilized,valuesforflowrateandpressurewererecorded.Thevalvewasprogressivelycloseduntilthepumpcouldnolongerpumpwater,atwhichpointthepumpswereswitchedoff.Powerinputtothesystemwasrecordedatvariouspoints.
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Figure13:PumpTestingExperimentalSetupatMIT
FINDINGSFORTHESALTPRODUCTIONCASE
USERSURVEYSANDINTERVIEWSThefocusonsolarpumpsforsaltproductionintheLittleRannofKutchin2017buildsonCITE’spreviousworkin2015-16byconsideringthefinancialimplicationstothefarmerofincorporatingasolarpumpintotheirsaltproduction.Unlikeagriculturalfarmerswhoonlyusepumpsforseveralhoursadayforirrigation,saltfarmersoftenpumparoundtheclock,leadingtomuchhigherdieselexpenses.Itfollowsthatthescopeforsavingsfromeitherswitchingsomeoftheirpumpingfromdieseltosolar,orincreasingproductionbyaddingasolarpumpingsystemisrelativelygreaterforsaltfarmersthanforagriculturalfarmers.
SEWAhas10,000membersactiveinsaltproductionintheLittleRannofKutch,ofwhichabout600haveinstalledsolarpumps.Forthepurposesoftheresearch,weinterviewedatotalof98solarpumpowners,ofwhich10usedonlythesolarpumpsystemsand88usedacombinationofsolarpumpsanddieselpumps.Wealsointerviewed10farmerswhousedonlydieselpumps.
Toanalyzethecashflowsofthefarmerswiththecombinedsystems,thecosts,revenues,andprofitfiguresareanalyzedpermetricton.TheaveragepricepertonthatthefarmersreceivedwasRps.159(USD2.37).ThemarginanalysisillustratedinTable2showshowthisRps.159issplitbetweenthedifferenttypesofexpenses,andthefarmer’sprofitmargin.Again,aswiththesolar-onlyfarmers,the
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mostimportanttake-awayisthatwhilethesolaranddieselelementsofthefarmer’sincomebothgaveverysimilarprofitmargins(of33percentand34percentrespectively)duringthepay-backperiod,oncetheloanwasrepaid,theprofitmarginforthesolarproductionincreaseddramatically.
Table2:VisualizingtheMarginAnalysis
AverageDiesel-PoweredProduction AverageSolar-PoweredProductionPre-Payback
AverageSolar-PoweredProductionPost-Payback
TECHNICALPERFORMANCEINTHEFIELD–MEASUREDDATA
TheCITEteamattemptedtogatherdataonasmanypumpsaspossibleinthefield,resultinginasamplesizeof28pumps,ownedby25farmers.ThemeasureddataincludedFlowrate(L/min),Pumprating(Hp),Welldepthfromsurface(ft),Waterlevelfrompump(ft),Distancetooutlet(ft),SuctionPipediameter(“),DischargePipediameter(“),Panelvoltage(V),Panelcurrent(A),Pumpvoltage(V),andPumpcurrent(A).Unfortunately,itwasnotpossibletorecordalloftheparametersforall28pumpsduetoanumberofreasons.
Figure14showstherecordedinstantaneousflowrateforeachFalcon1HPsystemwefoundintheLittleRannofKutch.Weselectedthissystembecauseitwasalsotestedinthelab.Aswiththelaboratorydata,thetotalheadandflowratedonotexceed24.3mand300L/min,respectively.Asexpected,theperformanceofthepumpsinthefieldissignificantlyreducedwhencomparedtothelabdata,thisisassumedtobeduetogeneralusageandexposuretothehighlevelsofsalinity(totaldissolvedsolids
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(TDS)=13,000-17,000mg/L).Theaverageefficiencywas35percent(s=16percent),againthislowefficiencyisattributedtotheharshnatureoftheenvironment.Onaverage,thesaltfarmersreportedtheexpectedpumplifetimetobe3.2yearsbeforeneedingreplacementduetorust.Notethatthelifetimeofstructuralcomponentsinaharshenvironmentisextremelydifficulttomeasureinalabandspeakstotheimportanceoffieldresearch.Thatsaid,withanextremelylimitedsamplesizeandnoavailableperformancedataonthesamepumpsusedindifferentenvironments,theseresultsmustbetakenwithagrainofsalt.
Figure14:HistogramofflowratesofFalcon1Hpseeninthefield.Mean120L/min(s=48L/min)
Fromtheelectricalmeasurementsofthe28pumps,currentandvoltageofboththepumpsandpanels,themeanACpowerintothepumpswascalculatedas0.91HP(+/-0.59)forthe1.5HPpumps,and0.53HP(+/-0.28)forthe1HPpumps,showingthattheywerenotbeingpoweredatoptimallevels.Thepanelsgeneratedameanof1.54HPand1.34HPforthe1.5HPand1HPpumpssystems,respectively,showingalossof40percentand60percentrespectivelywhenconvertingfromDCtoAC.4Thisisconsideredafairlylowefficiencybyindustrystandards,butgiventhecostofthesystemsandtheharshoperatingenvironmentitwasnotflaggedasamajorissue,especiallyconsideringthelimitedsamplesize.Alsonotethatthelabtestingresultscontainedinthenextsectionwerefairlyconsistentwiththesevalues.
Toreiterate,thesevalueswereinstantaneousandnottestedinalaboratorysetting,eachsolarpumpingsystemwaslocatedatadifferentlocationwithdifferingwaterlevelsandexposureratestotheenvironmentandthepanelsandpumpswereofvaryingsize,ageandmaintenancelevel.
TECHNICALPERFORMANCEINTHEFIELD-SENSORS
ThedatafromseveralpumpswasaggregatedfrominstallationinlateJanuary2017throughMarch31,2017tounderstandregularityofsystemusageandproduction.AsampleoftheoutputfromSP020isshowninFigure15.Thedatashowsconsistentusageofthepumpingsystems(indicatedbytheSolarPanelVoltage)withvaryinglevelsofpumpusage(indicatedbytheMotorCurrent).Themotorcurrent
4Electricalpowerisreportedhereinhorsepowertobetterconceptualizethevaluesforpumping.
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variationcouldbeattributedtosaltfarmersusingoneortwopumpsintheirsystemorbecauseofsolararraypowerlimits.ItwasdifficulttofindlocationswithgoodcellularavailabilityintheLittleRannofKutchandgapsindataarelikelyaresultofpoorcellcoverage.Wewillcontinuetoanalyzethedatatodetermineseasonvariabilityandtracklongertermadoptionratesforthedifferentsensorsystems.
Figure15:PlotofMotorCurrentand
TECHNICALPERFORMANCEINTHELABThecomparativetestresultsforthe5pumpstestedintheMITlaboratoryareshowninTable3andFigure16. TheHarbor Freight pumpwas purchased locally andwas used primarily to test the experimentalprocedureandtestrig;however,theresultsareincludedforreference.
Table3:ResultsfromLabTesting
Pump
MaxHead(m)
MaxFlowRate(LPM)
ElectricPower
Input(W)
HydraulicPower
Output(W)
PeakEfficiency(%)
Flowrateat10m(LPM)
Dailymaxoutput(L)
Falcon 24.3 300 1200 561 46.75% 215 103,200HarborFreight 32.2 81 750 267 35.60% 21 10,080Kirloskar 22.9 291 1200 534 44.50% 207 99,360Rotomag 20.2 295 750 434 57.87% 178 85,440Shakti 32.0 162 1400 445 31.79% 134 64,320
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Figure16:PumpComparisonChart
Basedonourresults,wecanseethattheFalcon,Kirloskar,andRotomagpumpsprovidesufficientflowwhenthewellisfull(theintersectionofthepumpcurvesandthepurplesystemcurvearewithinourshadedregion).However,attimeswhenthewelllevelisatitslowest,theRotomagpumpisinsufficienttomeetourneedsandonlytheKirloskarandRotomagpumpsprovidesufficientflow(theintersectionofonlytwopumpcurvesandtheorangesystemcurvearewithinourshadedregion).Asaresult,ourfarmerislefttochoosebetweentheFalconandKirloskarpumps.
Todeterminewhichofthepumpstouse,wewouldfurtherconsiderthepumpefficiencieswithintheoperatingregionaswellasthecostofthepumps.Fromourresults,weseethattheFalconFCM115isslightlymoreefficientthantheKirloskarSKDS116++pump,butthedifferenceinminimal.Wecanalsofurtherconsidertheeaseofuseofthepumps–theFalconpumpreceivedahigherscoreintheprimingcategorysoinstallationandmaintenanceofthepumpisbetterthantheKirloskar.Costirrespective,wewouldrecommendtheFalconFCM115forthisusecase.
CONCLUSIONSFORBOTHCASES Asasustainableandscalabletechnology,solarwaterpumpsresideatthewater-energy-foodnexus.Theirimplementationinregionsheavilyreliantonfossilfuelsorgridelectricity(poweredprimarilybycoal)isoftenhailedasavitalstepinbattlingclimatechangeandincreasingfoodsecurity.
Thecasesstudiedwereapproachedfromaprogrammaticstandpointandrevolvedaroundcommunityintegration.Througharesearchapproachthatincludedcasestudydevelopment,directend-usersurveys,andstakeholderinterviews,fivekeyfactorstoconsiderbeforeimplementationwereidentified:
● End-usersatisfactionwiththetechnology● Systemsizing● Wateravailability● Technicalcapacityandlocalservicing● Financingavailability
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Theyarelistedasaformativefirststagechecklistwhenchoosingtoimplementanagricultural-based,community-widesolarwaterpumpingprogram.Thoughthefactorslistedarisespecificallyfromtheintroductionofsolarpumpingsystems,theymayofferlessonsgermanetoalternativetechnologiesmorebroadly.Beyondthechecklist,topicssuchassupplychainmappinginruralareasandalternativeassetproductivityusesforthesolarpanels,arehighlightedasofinteresttothoseprocuringsolarpumpingsystemsatscalebutbeyondthescopeofthisinitialinvestigation.
Oneofourfindingsfromthisresearchwasthatmanypartnersjumpedstraightintosolarpumpingdeploymentwithoutfullyinvestigatingtheotherelementsofanintegratedirrigationsystem,orunderstandingwhethersuchasystemisfinanciallyorenvironmentallysustainable.Whenconsideringtechnologyapplicationsforirrigation,itwouldbehooveprojectimplementersandfunderstofirstconsiderthesuitabilityofefficientirrigationsystems,thenconsidersolarenergytopowerthepump.Dripirrigationsystemsarelowercostthansolar,soasaninitialinvestmentforafarmer,thefinancialburdenwillbelessofabarrier.Ifthefarmerlaterchoosestopurchaseasolararraytopowerthepump,thepumpwillalsobeoftherightsizeandthesolarsystemoverallwillcostless.
Becausethesolarpumpsystemsarequitetechnologicallycomplex,weweresurprisedtofindthatallusersconsideredthesolarsystemsveryeasytouse.Respondentsreportedthatcomparedtodieselpumps,whichcanbedifficulttostartandrequiretheprocurementoffuelfromsometimesremotelocations,andelectricpumps,whichoftenrequirenighttimeoperationandsometimesdangeroustraveltoagriculturalfieldsawayfromthefarmer’shome,thesolarpumpsareturnedonandoffwithasimpleflickofaswitch.Somefarmershadtheirchildrenoperatethepumps.Thisdemonstrates,thatinadditiontothefinancialbenefitsofsolarpumps,thesolarsystemsprovideadditionalbenefitsintermsofincreasedsafety,easeofuse,andcomfort.
Wealsofoundthatfarmershaveahighcapacitytoacceptincreasesinmonthlypaymentsuptoandmaybejustslightlymorethantheircurrentpaymentsfordiesel.Itfollowsthatthefarmersarenotatallsensitivetothetotalcostofthesystem,aslongastheirmonthlypaymentsaremanageable.However,inasmuchastheyhaveachoiceintechnology,thefarmersarehighlysensitivetothetechnologytypeanddeploymentinaparticularproject.Thelessonlearnedisthatinvolvingfarmersinthetechnologychoiceisanimportantelementintheongoingsuccessofsolarpumpprojects.
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AUTHORS&ACKNOWLEDGEMENTSThisresearchwouldnothavebeenpossiblewithouttheguidanceandsupportoffaculty,staff,andstudentsattheMassachusettsInstituteofTechnologyaswellaspartnersattheSelf-EmployedWomen’sAssociation(SEWA),DevelopmentAlternatives(DA)andSunEdison.
ReportAuthors
JenniferGreen(TeamLead)AmitGandhiÉadaoinIlten(TechnologyExchangeLab)
BrennanLake(TechnologyExchangeLab)VandanaPandyaSaraLynnPesek
JonarsB.SpielbergChristinaSung
Partners
SEWAAnuragBhatnagarReemaNanavatiHeenabenMilindPauChandubhaiPankajbhaiMercyCorpsShantiKleiman
DevelopmentAlternativesDr.S.N.PandeySakshamPushpenderSunEdisonParameshwarHegdeSwarup
SELCOSandeshAnilkumarOtherNavyaN.ChuriPoojthiaN.PankajSmitaShah
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