micro hydro summary

7/28/2019 Micro Hydro Summary

1/9

MicrohydroSummary

September2011

PreparedbyLukeHutchinson,LinkdEnvironmentalServices


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TableofContents

MicrohydroSummary ................................................................................................................................. 11. Introduction ........................................................................................................................................... 32. TechnicalOverview ................................................................................................................................ 32.1 ConfigurationOptions ......................................................................................................................................... 43. LocalPotential ....................................................................................................................................... 64. RegulatoryFramework .......................................................................................................................... 75. BarrierstoImplementation ................................................................................................................... 8


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1.IntroductionHydropoweristhemeansofusingtheflowofwater,whichismovingduetogravitationalforcetodriveturbinesthat

generate electricity. Thescaleof installation canvaryfrom aslittle asa few kilowatts to hundredsof megawatts.

Hydropowermayincludetidalandwavetechnologies,howeverthiswillnotbecoveredinthistechnologyreview.

Today, the development of large scale hydro operations is not preferred and resisted due to the potential for

upstream flooding which can destroy agricultural areas, animal habitats and displace communities in the affected

areas1. Microhydro presents an alternative option with environmental impact on a far minimal scale because

implementationispossiblecoupledtootherusesofwater(e.g.bulkwatersupply,irrigation,floodcontrol,etc)2.

Microhydro power plants, involving small dams, pumps or water mills, can provide a means of electricity to

communitiesthatcannotbeconnectedtothenationalgrid.Withcapacityof10kWto10MWthetechnologycan

provide electricityin remote areas in a very effective way with a lifespan of 30 years or more. Furthermore, it is

estimatedthatforevery1MWofhydropowerinstalled,twopermanentjobsarecreatedinthehydropowerindustry2.

Internationallynosizeterminologyisstandardised,thefollowingisanindication2:

Pico le ssthan20k W Micro 20kWto100kW Min i 100k Wto1 MW Small 1MWto10MW

Macrohydroconventionalinstallations:greaterthan10MW.Forgeneralpurposesmicrohydrowillbeusedtorefer

togenerationlessthan10MW.

2.TechnicalOverviewA fundamental design requirement for economic sustainability isthe efficient use of thewater resource. Modern

turbinetechnologywillallowupto95%oftheenergyavailablefromwatertobeconvertedintoelectricity3

.

Thepoweroutput of a hydropower plant isproportionalto thewaterflowrate andthe head (the height through

whichthewatermustdescendbeforegoingthroughtheturbine).Theflowrateisthequantityofwaterflowingpasta

point ina given time typicallymeasured inlitres persecondor cubic metres persecond. Thehead isthevertical

height,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, energyis alwayslost whenit isconvertedfromoneform toanother. Power will be lost inthe penstock

carryingthewatertotheturbine,duetofrictionallosses.Withcarefuldesign,thislosscanbereducedtoonlyasmall

percentage.

Example:Aturbinegeneratorsetoperatingataheadof10metreswithflowof0.3cubicmetrespersecond

willdeliverapproximately,(9.81x0.5x0.3x10=)18kW.

1DepartmentofEnergyPhilippineshttp://www.doe.gov.ph/ER/Hydropower.htm

2

BaselineStudy:HydropowerinSouthAfrica,DepartmentofMineralsandEnergy,CapacityBuildinginEnergyEfficiencyandRenewableEnergy(CaBEERE)2002

3HErdmannsdrfer,SmallDecentralizedHydropowerStationsAFutureforRuralAreaswithoutDieselPower,GermanyEnergyPartnerforAfrica


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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 while

reactionturbinesconvertthepressureenergyintomechanicalenergy.Reactionturbinesworkbyfullyimmersingthe

turbinebladesinwaterandmustbebuilttowithstandtheoperatingpressure,turbineexamplesincludeFrancisand

Kaplanturbines.Impulseturbinesmakeuseofahighspeedjetofwaterstrikingthebucketsmakinguseofthewaters

motion,turbineexamplesinclude:Pelton,Turgo,crossflowturbines4

.

Figure1Typesofturbines,reactionatleft,impulseatright.

2.1 ConfigurationOptionsRunofriver

Themajorityof microhydropower plantsarerunofriverschemes.Thistypeofhydropowerplantoperatesunder

lowheadandismainlybuiltinrivervalleys.Electricityisonlygeneratedwhenwaterisavailableandwillstopifthe

flowfallsbelowacertainlevel.Asaresultsmallindependentschemesmaynotalwaysbeabletosupplyelectricity,

unlesstheyaresizedsothatthereisalwayssufficientwater.

Themaincomponentsofarunoftherivermicro

hydroschemeareshownintheillustrationbelow.

This typeof setup requiresno waterstoragebut

instead diverts some water from the river along

the side of a valley to be dropped into the

turbineviathepenstock.Therearevariousotherconfigurations which can be used depending on

thetopographicalandhydrologicalconditions,but

all adopt similar general principles and

methodologies.

Figure2:Layoutofatypicalmicrohydroscheme5

4Onlineresourcehttp://www.hydroturbines.com/id74.html

5MicrohydroPower,PracticalActionTechnologyChallengingPoverty


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Damwalls

Dam wall hydropower schemesare usuallynot implemented forsmallor microhydrodue to financial constraints,

however;this configuration is viable if suchdams have already been constructed6. The main issueis how to link

headwaterandtailwaterby awaterwayand howtofittheturbineinthiswaterway.Thetwo configurationsinthis

casearetoplacetheturbineatthebaseofthedamifachannelcanbeconstructed,thealternativeisasiphonintake

asshownbelow.

Figure3.Siphonintakeconfigurationwiththeturbineplacedattheapexofthesiphon.

WaterInfrastructure

Insomeinstancesthereistheopportunitytoharnesstheenergycontainedinthebulkwatersupplyanddistribution

system,oneexampleis constructing ahydropower facilitywithin irrigationcanals.Anotheroptionis tointegratea

turbineintothedrinkingwaterinfrastructurebetweenreservoirandthewatertreatmentplant.Insomecasesplants

havespecialvalvestodissipatethekineticenergyandthereisanopportunitytoconvertthisenergyintoelectricity.

6GuideonHowtoDevelopaSmallHydropowerPlanESHA2004


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3.LocalPotential

Figure4:AreaswithmicrohydropotentialinSouthAfrica(DME,Eskom,CSIR,2001)

ThehydropowerpotentialhasbeenshownintheBaselineStudyonHydropowerinSouthAfrica(CaBEERE,2002

anassessmentconductedby theDME) that there existsa significantpotentialfordevelopmentof all categoriesof

hydropower inthe short andmediumtermin specific areas ofthe country. Theimagebelowshowsall areas with

hydropotentialandit isevidentthattheEasternCapeand KwaZuluNatalprovincesholdsignificantcapacityand

notably,withthebestpotentialforthedevelopmentofsmall,hydropower(lessthan10MW).

Furthermore,the EasternCape province (particularly in the area of Transkei) is identified as potentially the most

productiveareasforhydroelectricdevelopmentinSouthAfrica.InvestigatingthepotentialintheLowerOrangeriver

forhydropowersetupinseriesortandem,showsthatsome12hydroelectricplantscanbeinstalledinseries,each

sitehavingapotentialoutputofbetween6MWand25MW7.TableXshowstheavailableandpotentialofhydropower

inSouthAfrica.

Another study indicates that there are 3500 5000 potential sites for mini/micro hydro electric power plants

identifiedalongtheeasternpartsofthecountry8.

7Clackson,E.(2002).Refurbishmentandupgradingofexistinghydropowerinstallations.Personalcommunication,Nelspruit,Mpumalanga,July

8BBarta,HydropowerPotentialinSouthernAfrica,TradersIssue20,November2004February2005


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Table1:TotalformacroandsmallhydropowerinSAexcludingpumpstorage(CaBEERE,2002).

JobCreation

Theshorttomediumtermpossiblehydroelectricityproductionisestimatedatsome450GWh/year,dependingon

theloadfactoradopted.Themediumtermpotentialforjobcreationonlyfromthedevelopmentofmicrohydropower

schemesisestimatedatabout3,000jobs,withsome1,100jobsonapermanentbasisintheoperation,manufacturing

andadministrationofhydropowerdevelopment9.

DuetothepresenceofsizableandestablishedminingindustryinSouthAfrica,thereisalargeindustrialsupportbase

capable of providing needed expertise for manufacture, servicing and refurbishment of essential hydropower

products for the development ofsmall hydropower systems. It is estimated that for every 1 MWof hydropower

installed,twopermanentjobswillbecreatedinthehydropowerindustry8

.

4.RegulatoryFrameworkIrrespective of the size of installation, any hydropower development will require authorisation

10 in terms of the

National WaterAct1998,A ct36of1998. Theactstipulatesthenecessityto registera WaterUseLicense,and the

followingentitiesarerequiredtoregister:

Individualssuchasfarmers,smallholders,landownersorlessees. Communitiessuchascommunalenterprises,traditionalfarmersgroups. NationalorProvincialGovernment. Companiesandbusinessesincludingpartnerships,publiccompanies,privatecompanies,companiesnot

forgain,guaranteecompanies,foreigncompanies,incorporatedprivatecompanies,closedcorporations

etc.

WaterUserAssociations. WaterServicesProviders,includingWaterBoardsandLocalGovernment.

9

BaselineStudy:HydropowerinSouthAfrica,Department ofMineralsandEnergy,CapacityBuildinginEnergyEfficiencyandRenewableEnergy(CaBEERE)2002

10DepartmentofEnergyWebsitehttp://www.energy.gov.za/files/renewables_frame.html


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Registrationdoesnotsetupentitlementtousethewater,thewateruselicenseauthorisesproponenttousewater.

Registrationshouldbe seenas thefirststep in establishinga relationshipas a water userwith theDepartment.

FormstoregisterareobtainablefromanyofficeoftheDepartment.Registrationcannotbeturneddownordenied,if

thewateruseisofalegitimatemeans.

Thefollowingisabasicoutlineoftheprocessestoobtainawateruselicense11

:

ApplicationsareobtainedandsubmittedtoDWAFregionaloffices. The regional office will assess the applications and advise on the requirements. The Regional office will

furthermakearecommendationtothedelegatedofficial.

Theregional office will thensubmittheapplication to theHead Office:Chief Directorate: Water Useforfurtherhandling.

TheChiefDirectorate:WaterUsewillreviewthelicenseapplicationforcompliancewiththePolicy TheChiefDirector:WaterUsewillthenmakerecommendationsfortheMinistertomakeadecision. ApplicantsmayappealthedecisionstotheWaterTribunal.

FormoredetailedinformationrefertoAGuidetotheRegistrationofWaterUseUndertheNationalWaterAct(Act

36of1998)andseetheinstructionsatwww.dwaf.gov.za/Projects/WARMS

5.BarrierstoImplementationThemanychallengesfacingsmallhydropowerexploitationaregenerallysharedbarriersofrenewableenergyindustry

andindependentpowerproducers.Thesebarriersarethelackofclearandconsistentpoliciesonrenewableenergy

and associated requisite budgetary allocations to create an enabling environment for mobilising resources and

encouraginginvestment.Furthermore,theabsenceoflowcost,longtermfinancingmodelstoproviderenewablesto

customersataffordablepriceswhileensuringthattheindustryremainssustainableexasperatesdevelopment.

Microhydrofacesthefollowingspecificissues12

:

Limitedaccesstoappropriatetechnologies,withspecialtechnicalchallengesduetothelocalcontextofsmallheadsandhighvolumesorveryhighheadsandlowvolumes.

Limitedinfrastructureinthefieldsofmanufacturing,installationandoperation.Eventhemostrudimentaryturbinesorpartsthatarecriticaltomaintenancehavelimitedmanufacturingsupportonthecontinent.An

example is the unavailable capacity to manufacture highdensity polyvinyl pipes that can serve as good

penstocks few countries have these products and as a result implementation at simple sites has been

hampered.(However,duetothepresenceoftheminingindustryinSouthAfrica,thereisalargeindustrial

support base in existence, capable of providing the needed expertise for manufacture, servicing and

refurbishmentofessentialhydropowerproducts,whichisprimarilyminingtypeequipment.)13

Limitedcapacitytodesignanddevelopmicrohydroforareassometimesconsideredtooremote.Generally,SouthAfricahaslimitedcapacityofexpertstoundertakemicrohydrofeasibilitystudies.

TheregulatoryadministrationissuesrequiredfortheWaterUseLicense.(TheDepartmentofWaterAffairsissaidtohaveastrategytoguidetheprojectdevelopmentofhydropower).

ThemicrohydroexperienceinthePhilippinesisthatoffgridelectrificationishinderedbyhighupfrontcostsandthe

needforgovernmentinterventionandsubsidy14

.

11GuidelinefortheDevelopmentofRenewableEnergyProjects,2008EthekwiniMunicipalityKnowledgeRepository

12SmallhydropowerforruralelectrificationinSouthAfricausingexperiencesfromotherAfricancountries,KlunneCSIR2009

13

BaselineStudy:HydropowerinSouthAfrica,DepartmentofMineralsandEnergy,CapacityBuildinginEnergyEfficiencyandRenewableEnergy(CaBEERE)2002

14DepartmentofEnergy,Philippineswww.doe.gov.ph/ER/Hydropower.htm


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GovernmenthaveestablishedtheWorkingforEnergyprogrammewhichwelcomesprojectdevelopersinterestedin

providingsustainableenergysolutionstoruralcommunities,usingspecificallymicrohydro15

.

15Moreinformationatwww.reee.sacities.net/resources/wfe.htm

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