micro‐hydro summary - sa citiesreee.sacities.net/sites/default/files/tech...
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TableofContentsMicro‐hydroSummary ................................................................................................................................. 1
1. Introduction........................................................................................................................................... 3
2. TechnicalOverview................................................................................................................................ 3 2.1 ConfigurationOptions ......................................................................................................................................... 4
3. LocalPotential ....................................................................................................................................... 6
4. RegulatoryFramework .......................................................................................................................... 7
5. BarrierstoImplementation ................................................................................................................... 8
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1. IntroductionHydropoweristhemeansofusingtheflowofwater,whichismovingduetogravitationalforcetodriveturbinesthat
generate electricity. The scale of installation can vary from as little as a few kilowatts to hundreds ofmegawatts.Hydropowermayincludetidalandwavetechnologies,howeverthiswillnotbecoveredinthistechnologyreview.
Today, the development of large scale hydro operations is not preferred and resisted due to the potential forupstream flooding which can destroy agricultural areas, animal habitats and displace communities in the affectedareas1. Micro‐hydro presents an alternative option with environmental impact on a far minimal scale because
implementationispossiblecoupledtootherusesofwater(e.g.bulkwatersupply,irrigation,floodcontrol,etc)2.
Micro‐hydro power plants, involving small dams, pumps or water mills, can provide a means of electricity tocommunities that cannotbeconnected to thenational grid.With capacityof10kWto10MWthe technology can
provide electricity in remote areas in a very effective way with a lifespan of 30 years ormore. Furthermore, it isestimatedthatforevery1MWofhydropowerinstalled,twopermanentjobsarecreatedinthehydropowerindustry2.
Internationallynosizeterminologyisstandardised,thefollowingisanindication2:
• Pico lessthan20kW• Micro 20kWto100kW• Mini 100kWto1MW
• Small 1MWto10MW
Macrohydroconventionalinstallations:greaterthan10MW.Forgeneralpurposesmicro‐hydrowillbeusedtorefertogenerationlessthan10MW.
2. TechnicalOverviewA fundamental design requirement for economic sustainability is the efficient use of the water resource.Modern
turbinetechnologywillallowupto95%oftheenergyavailablefromwatertobeconvertedintoelectricity3.
The power output of a hydropower plant is proportional to thewater flow rate and the head (the height throughwhichthewatermustdescendbeforegoingthroughtheturbine).Theflowrateisthequantityofwaterflowingpasta
point inagiven time ‐ typicallymeasured in litresper secondor cubicmetresper second.Thehead is theverticalheight,inmetres,fromtheturbinetothepointwherethewaterenterstheintakepipeorpenstock.
Thepotentialpowercanbecalculated4asfollows:
Theoreticalpower(P)=Flowrate(Q)xHead(H)xGravity(g)=9.81m/s2
WhenQisincubicmetrespersecond,Hinmetresandg=9.81m/s2)then,P=9.81xQxH(kW)
However, energy is always lostwhen it is converted fromone form toanother.Powerwillbe lost in thepenstock
carryingthewatertotheturbine,duetofrictionallosses.Withcarefuldesign,thislosscanbereducedtoonlyasmallpercentage.
Example:Aturbinegeneratorsetoperatingataheadof10metreswithflowof0.3cubicmetrespersecond
willdeliverapproximately,(9.81x0.5x0.3x10=)18kW.
1DepartmentofEnergyPhilippines‐http://www.doe.gov.ph/ER/Hydropower.htm
2BaselineStudy:Hydropower inSouthAfrica,Department ofMineralsandEnergy,CapacityBuilding inEnergyEfficiencyandRenewableEnergy(CaBEERE)‐2002
3HErdmannsdörfer,SmallDecentralizedHydropowerStations‐AFutureforRuralAreaswithoutDieselPower,Germany‐EnergyPartnerforAfrica
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The type of energy conversion technology required is related to the head classification. Hydro power conversion
occurs through the use of either impulse or reaction turbines. Impulse turbines convert the kinetic energy whilereactionturbinesconvertthepressureenergyintomechanicalenergy.Reactionturbinesworkbyfullyimmersingtheturbineblades inwaterandmustbebuilttowithstandtheoperatingpressure,turbineexamplesincludeFrancisand
Kaplanturbines.Impulseturbinesmakeuseofahigh‐speedjetofwaterstrikingthebucketsmakinguseofthewatersmotion,turbineexamplesinclude:Pelton,Turgo,cross‐flowturbines4.
Figure1–Typesofturbines,reactionatleft,impulseatright.
2.1 ConfigurationOptions
Run‐of‐river
Themajorityofmicro‐hydropowerplantsarerun‐of‐river schemes.Thistypeofhydropowerplantoperatesunderlowheadand ismainlybuilt inrivervalleys.Electricity isonlygeneratedwhenwater isavailableandwillstop if the
flowfallsbelowacertain level.Asaresultsmall independentschemesmaynotalwaysbeabletosupplyelectricity,unlesstheyaresizedsothatthereisalwayssufficientwater.
Themaincomponentsofarun‐of‐the‐rivermicro‐
hydroschemeareshownintheillustrationbelow.This typeof setup requiresnowater storagebutinstead diverts some water from the river along
the side of a valley to be ‘dropped’ into theturbineviathepenstock.Therearevariousotherconfigurations which can be used depending on
thetopographicalandhydrologicalconditions,butall adopt similar general principles andmethodologies.
Figure2:Layoutofatypicalmicrohydroscheme5
4Onlineresource‐http://www.hydro‐turbines.com/id74.html
5Micro‐hydroPower,PracticalAction–TechnologyChallengingPoverty
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Damwalls
Damwall hydropower schemes are usually not implemented for small ormicro‐hydro due to financial constraints,however; this configuration is viable if such dams have already been constructed6. Themain issue is how to linkheadwaterandtailwaterbyawaterwayandhowtofit theturbine inthiswaterway.Thetwoconfigurations inthis
casearetoplacetheturbineatthebaseofthedamifachannelcanbeconstructed,thealternativeisasiphonintakeasshownbelow.
Figure3.Siphonintakeconfigurationwiththeturbineplacedattheapexofthesiphon.
WaterInfrastructure
Insomeinstancesthereistheopportunitytoharnesstheenergycontainedinthebulkwatersupplyanddistributionsystem,oneexample is constructingahydropower facilitywithin irrigation canals.Anotheroption is to integratea
turbineintothedrinkingwaterinfrastructurebetweenreservoirandthewatertreatmentplant.Insomecasesplantshavespecialvalvestodissipatethekineticenergyandthereisanopportunitytoconvertthisenergyintoelectricity.
6GuideonHowtoDevelopaSmallHydropowerPlan–ESHA2004
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3. LocalPotential
Figure4:AreaswithmicrohydropotentialinSouthAfrica(DME,Eskom,CSIR,2001)
Thehydropowerpotentialhasbeenshowninthe“BaselineStudyonHydropower inSouthAfrica”(CaBEERE,2002–anassessment conductedby theDME) that there existsa significantpotential fordevelopmentofall categoriesofhydropower in the shortandmedium‐term in specific areasof the country. The imagebelow showsall areaswith
hydropotentialand it isevidentthattheEasternCapeandKwaZulu‐Natalprovinceshold significant capacity–andnotably,withthebestpotentialforthedevelopmentofsmall,hydropower(lessthan10MW).
Furthermore, the Eastern Cape province (particularly in the area of Transkei) is identified as potentially themost
productiveareasforhydro‐electricdevelopmentinSouthAfrica.InvestigatingthepotentialintheLowerOrangeriverforhydropowersetup inseriesortandem,showsthatsome12hydro‐electricplantscanbe installed inseries,eachsitehavingapotentialoutputofbetween6MWand25MW7.TableXshowstheavailableandpotentialofhydropower
inSouthAfrica.
Another study indicates that there are 3500 – 5000 potential sites for mini/micro hydro electric power plantsidentifiedalongtheeasternpartsofthecountry8.
7Clackson,E.(2002).Refurbishmentandupgradingofexistinghydro‐powerinstallations.Personalcommunication,Nelspruit,Mpumalanga,July
8BBarta,HydropowerPotentialinSouthernAfrica,TradersIssue20,November2004‐February2005
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Table1:TotalformacroandsmallhydropowerinSA‐excludingpumpstorage(CaBEERE,2002).
JobCreation
Theshort‐tomedium‐termpossiblehydro‐electricityproduction isestimatedatsome450GWh/year,dependingontheloadfactoradopted.Themedium‐termpotentialforjobcreationonlyfromthedevelopmentofmicrohydropowerschemesisestimatedatabout3,000jobs,withsome1,100jobsonapermanentbasisintheoperation,manufacturing
andadministrationofhydropowerdevelopment9.
DuetothepresenceofsizableandestablishedminingindustryinSouthAfrica,thereisalargeindustrialsupportbasecapable of providing needed expertise for manufacture, servicing and refurbishment of essential hydropower
products for the development of small hydropower systems. It is estimated that for every 1 MW of hydropowerinstalled,twopermanentjobswillbecreatedinthehydropowerindustry8.
4. RegulatoryFrameworkIrrespective of the size of installation, any hydropower development will require authorisation10 in terms of theNationalWaterAct1998,Act36of1998. Theact stipulatesthenecessityto registeraWaterUseLicense,andthe
followingentitiesarerequiredtoregister:
• Individuals–suchasfarmers,small‐holders,land‐ownersorlessees.• Communities–suchascommunalenterprises,traditionalfarmersgroups.
• NationalorProvincialGovernment.• Companiesandbusinesses–includingpartnerships,publiccompanies,privatecompanies,companiesnot
forgain,guaranteecompanies,foreigncompanies,incorporatedprivatecompanies,closedcorporations
etc.• WaterUserAssociations.• WaterServicesProviders,includingWaterBoardsandLocalGovernment.
9BaselineStudy:Hydropower inSouthAfrica,Department ofMineralsandEnergy,CapacityBuilding inEnergyEfficiencyandRenewableEnergy(CaBEERE)‐2002
10DepartmentofEnergyWebsite‐http://www.energy.gov.za/files/renewables_frame.html
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Registrationdoesnotsetupentitlementtousethewater, thewateruse licenseauthorisesproponenttousewater.
Registration should be seen as the first step in establishing a relationship as a water userwith theDepartment.FormstoregisterareobtainablefromanyofficeoftheDepartment.Registrationcannotbeturneddownordenied,ifthewateruseisofalegitimatemeans.
Thefollowingisabasicoutlineoftheprocessestoobtainawateruselicense11:
• ApplicationsareobtainedandsubmittedtoDWAFregionaloffices.• The regional office will assess the applications and advise on the requirements. The Regional office will
furthermakearecommendationtothedelegatedofficial.• The regional office will thensubmitthe application to the Head Office:Chief Directorate: Water Use for
furtherhandling.
• TheChiefDirectorate:WaterUsewillreviewthelicenseapplicationforcompliancewiththePolicy• TheChiefDirector:WaterUsewillthenmakerecommendationsfortheMinistertomakeadecision.• ApplicantsmayappealthedecisionstotheWaterTribunal.
Formoredetailedinformationreferto“AGuidetotheRegistrationofWaterUseUndertheNationalWaterAct(Act36of1998)”andseetheinstructionsatwww.dwaf.gov.za/Projects/WARMS
5. BarrierstoImplementationThemanychallengesfacingsmallhydropowerexploitationaregenerallysharedbarriersofrenewableenergyindustry
and independentpowerproducers.Thesebarriersarethe lackofclearandconsistentpoliciesonrenewableenergyand associated requisite budgetary allocations to create an enabling environment for mobilising resources and
encouraginginvestment.Furthermore,theabsenceoflow‐cost,long‐termfinancingmodelstoproviderenewablestocustomersataffordablepriceswhileensuringthattheindustryremainssustainableexasperatesdevelopment.
Micro‐hydrofacesthefollowingspecificissues12:
• Limitedaccesstoappropriatetechnologies,withspecialtechnicalchallengesduetothelocalcontextofsmallheadsandhighvolumesorveryhighheadsandlowvolumes.
• Limitedinfrastructureinthefield’sofmanufacturing,installationandoperation.Eventhemostrudimentary
turbinesorpartsthatare criticaltomaintenancehave limitedmanufacturing supportonthecontinent.Anexample is the un‐available capacity to manufacture high‐density polyvinyl pipes that can serve as goodpenstocks ‐ few countries have these products and as a result implementation at simple sites has been
hampered. (However,duetothepresenceofthemining industry inSouthAfrica,there isa large industrialsupport base in existence, capable of providing the needed expertise for manufacture, servicing andrefurbishmentofessentialhydropowerproducts,whichisprimarilymining‐typeequipment.)13
• Limitedcapacitytodesignanddevelopmicro‐hydroforareassometimesconsideredtooremote.Generally,SouthAfricahaslimitedcapacityofexpertstoundertakemicro‐hydrofeasibilitystudies.
• TheregulatoryadministrationissuesrequiredfortheWaterUseLicense.(TheDepartmentofWaterAffairsis
saidtohaveastrategytoguidetheprojectdevelopmentofhydropower).
Themicro‐hydroexperienceinthePhilippinesisthatoff‐gridelectrificationishinderedbyhighupfrontcostsandtheneedforgovernmentinterventionandsubsidy14.
11GuidelinefortheDevelopmentofRenewableEnergyProjects,2008–EthekwiniMunicipalityKnowledgeRepository
12SmallhydropowerforruralelectrificationinSouthAfrica‐usingexperiencesfromotherAfricancountries,Klunne‐CSIR2009
13BaselineStudy:HydropowerinSouthAfrica,DepartmentofMineralsandEnergy,CapacityBuildinginEnergyEfficiencyandRenewableEnergy(CaBEERE)‐2002
14DepartmentofEnergy,Philippines‐www.doe.gov.ph/ER/Hydropower.htm