Technical NoteOptimal conguration assessment of renewable energy in MalaysiaAhmed M.A. Haidar*, Priscilla N. John, Mohd ShawalFaculty of Electrical & Electronics Engineering, University Malaysia Pahang, Lebuhraya Tun Razak, 26300 Gambang, Pahang, Malaysiaarti cle i nfoArticle history:Received 7 May 2010Accepted 28 July 2010Available online 21 August 2010Keywords:Hybrid systemOptimal congurationTotal net present costPollutionabstractThispaper proposesthe useofaPVewindediesel generator hybridsystemin orderto determinetheoptimal conguration of renewable energy in Malaysia and to compare the production cost of solar andwindpowerwithitsannual yieldrelevant todifferent regionsinMalaysianamely, Johor, Sarawak,Penang and Selangor. The conguration of optimal hybrid systemis selected based on the bestcomponentsandsizingwithappropriateoperatingstrategytoprovideacheap, efcient, reliableandcost-effective system. The various renewable energy sources and their applicability in terms of cost andperformance are analyzed. Moreover, the annual yield and cost of energy production of solar and windenergyareevaluated. TheSimulations werecarriedout usingtheHOMERprogrambasedondataobtainedfromthe MalaysianMeteorological Centre. Results showthat, for Malaysia, a PVedieselgenerator hybrid system is the most suitable solution in terms of economic performance and pollution.However, thecostof productionof solarandwindenergyprovedtobecheaperandmoreenviron-mentally friendly than the energy produced from diesel generators. 2010 Elsevier Ltd. All rights reserved.1. IntroductionAn increasing interest in renewable energy resources has beenobserved for several years. The unconventional energy sources arenon-polluting, free intheir availability, andcontinuous. Thesefeaturesmakealternativeresourcesattractiveformanyapplica-tions [1]. However, Renewable Energy sources have unpredictablerandom behaviours, while, some of them, such as solar radiationand wind speed, have complementary proles. The exploitation ofenergy sources such as wind and photovoltaic energy is becomingnecessary and protable. In developing countries, this exploitationhas a vital range which goes beyond reducing the oil bill [2e4]. Theuse of renewable energy technology to meet energy demands hasbeen steadily increasing over the years. Because of the intermittentcharacteristics of solar irradiation and wind speed, which greatlyinuence the resulting energy production, the major aspects in thedesign of PV, wind generator and power generation systems are thereliable supply of power to consumers under varying atmosphericconditionsandthecorrespondingcost ofthetotalsystem [3]. Inparticular, an integrated approach makes a hybrid system the mostappropriateforisolatedcommunitiessuchasremoteislands[4].The combination of photovoltaic and wind energy sources inahybridelectricpowersystemcongurationisprovidinghighlyreliableandcost-effectivesolutionstomanyremote-sitepowerproblems especiallyinoff-gridareas. Ingeneral, HybridPowerSystems aredividedintotwodifferent categories: Stand-Alonesystems and Grid-Connected systems. PV and wind offer excellentinherentreliability, extendedmaintenanceintervals, andnofuelrequirement.PV systems are solar energy supply systems which have beenoperating since the 1990s. PV panels convert sunlight to electricalenergy which is used to supply power directly to electrical equip-ment and also feed energy into the public power grid. Generally, PVis considered an expensive method of producing electricity but itoffers acost-effectivealternativetoanexpensivegrid[5]. Thedevelopment of new PV technologies for application of PV in publicelectricity grids has grown rapidly. Recent PV technology uses PVcollectors that track the sun to allow collection of a greater amountof energy. The generation of electrical power from wind turbineshas beenproviding a signicant contributiontoworldenergyneeds. Duringthe1980s, windedieselsystemshavebeendevel-oped to a level where a number of such systems have been installedworldwide in pilot or demonstration projects. The development ofwindenergyis theonlynon-nuclear medium-termsolutiontoclimate change problems. Every kilowatt-hour produced fromwindreplaces one kilowatt-hour of green house gas produced byconventional generating plants [6].For the last six years, the electricity sector in Malaysia has grownrapidly alongside the nations economy, especially within theindustrial and manufacturing sector [7]. Renewable energy is*Corresponding author.E-mail address: ahaidar67@yahoo.com (A.M.A. Haidar).Contents lists available at ScienceDirectRenewable Energyj ournal homepage: www. el sevi er. com/ l ocat e/ renene0960-1481/$e see front matter 2010 Elsevier Ltd. All rights reserved.doi:10.1016/j.renene.2010.07.024Renewable Energy 36 (2011) 881e888expected to become increasingly important in Malaysias electricitygeneration. It is mainly driven by the increased awareness of envi-ronmentalconcernsovertheadverseconsequencesoffossil-fuelandnuclear power. Oil andgas havebeenthe mainenergysources inMalaysia. However, withits gas reserves estimatedtolast foranother 33 years and oil reserves another 19 years, the Malaysiangovernment is strengthening the role of renewable energy as thefth cornerstone of energy generation. Many manufacturingcompanies in Malaysia are already trying to save energy costs, butthecommercial demandforenergyisprojectedtocontinueitsupwardtrend, from1244 Pet Joules in2000 toanestimated2218 PetJoules in 2010 [8]. Renewable energy is now recognized as a majorsource of energy for the 21st century and beyond. The importance ofrenewableenergyasanenablerofstrongeconomicgrowthwasfurther reinforced in the 9th Malaysian Plan (2006e2010), coupledwithanemphasisonenergyefciencybothinproductionandutilization, whilemeetingenvironmental objectives. Renewableenergy is expected to contribute 350 MWto the total energy supplyby 2010 in Malaysia, which is projected to reach 3128 Pet Joules [8].The climatic conditions in Malaysia are favourable for the develop-ment of solar energy due to its abundant sunshine.Many studies have been conducted to evaluate the effectivenessof renewable energy in replacing fossil-fuel to produce electricity.The design and control of hybrid systems have beenstudiedextensively by proposing a probabilistic model based on thesimulation of a windediesel system using statistical data of loadsand wind speed [9]. Other researchers have used data fromvariouslocations in the world to describe the latest advances inPVewindedieselebatteries hybrid systems [10]. Several simulationalgorithms for PVewindebattery systems have been presented, inwhichtheeconomicvalueof hybridsystemswasconsideredinorder to obtain a limit in terms of battery capacity that depends onthedesiredchargingordischargingcycletime[11]. Theperfor-mance of possible variants and the effect of energy demandmanagementonPVewindedieselebatterysystemswereinvesti-gatedinRefs. [12e14]. Thesimulationof areal hybridPVedie-selebatterysystemlocatedinAlaskawasappliedinRef. [15]. APVewindedieselebattery systemfor remote areas in the farnorthern province of Cameroon was designed in Ref. [16].Inthis work, anoptimizationtechnique is implementedtoevaluate the economic performance of the proposed hybrid systemand to determine the optimal location of the hybrid system basedon weather data and load prole. The paper is organized as follows:anoverviewof datacollectionis giveninSection2, Section3illustratesthehybridsystem. Theformulationof theproblemispresented in Section 4. The results and discussion are outlined inSection 5. Finally, a conclusion is given in Section 6.2. Data collectionThe four Malaysian States that have been chosen for this studyare located in different areas; Johor is located in the South, Sarawakin the East, Pulau Pinang in the North and Selangor in the West. Allthe data required to analyse the hybrid system are described in thissection and a map of Malaysia is shown in Fig. 1.2.1. Solar radiationSolar radiationis a reliable source of energy that is receivedintheform of relatively diffuse energy. Its daily cycle varies and may beinuenced greatly by meteorological conditions such as cloud, hazeand fog. Being radiant energy, solar energy cannot be stored directly.The total amount of solar radiationfor Global Radiationis comprisedof direct and diffuse solar radiation. Direct Radiation receives solarradiation directly from the orb of the sun and Diffuse Radiation issolar radiation re-reected from the Earth.Global solarradiationdata are readily available and reliable for all locations. This type ofradiation is of interest forat panel and tracking PV power gener-ationsystems. As hourly data for solar radiationarenot available, themonthly averaged global radiation data were taken fromNASA. Thesynthesized 8760 hourly values for a single year were created usingthe Graham algorithm. The solar radiation data for all four Statescould be obtained by determining the latitude and longitude of alllocations. The latitude and longitude for Johor is 2

270N/103

500E,Sarawak 1

290N/110

200E, Pulau Pinang 5

280N/100

300E andSelangor 2

540N/101

470E [17]. Fig. 2 shows the percentage differ-ence of solar radiation for all four States.2.2. Wind speedWind is a form of solar energy caused by the uneven heating ofthe atmosphere by the sun, irregularities in the earths surface, andby the rotation of the earth. Changing wind patterns are caused bythe earths terrain, bodies of water, and vegetative cover. Wind owor motion energy can generate electricity through wind turbines.The kinetic energy in the wind is converted into mechanical powerby turning the blade, thus producing electricity through the shaftthat is connected to the generator. Over the years, wind speeds havebeen increasing, making wind energy even stronger. The wind datafor Johor and Pulau Pinang were obtained fromthe weather stationFig. 1. Map of Malaysian States.24%24%25%27%Johor Sarawak Pulau Pinang SelangorFig. 2. Percentage of annual averaged solar radiation for all four States.A.M.A. Haidar et al. / Renewable Energy 36 (2011) 881e888 882installedatUniversiti SainsMalaysia. Selangorswinddatawereobtained from the weather station installed at Universiti Kebang-saanMalaysia. As for SarawakandJohor, thewinddatawereobtainedfromtheMeteorological centresinthoseStates. Fig. 3shows the percentage difference of wind speed for all States.2.3. Load demandNowadays, electricity is supplied to different types of domesticandindustrial customers. Thedrivetoincreasethedemandonpower is due to the increasing population and depletion of fossil-fuels. Power consumption patternsareinuencedby thevarioustypes of consumer, type of electricity usage and the time of usagewhich depends on human and economic activity. The load demandconsidered in this study is divided into two parts which are similarloaddemandandspecic loaddemand. Johors loaddemandsrepresentatypicaldaily loadcurve ofa wire productionfactory.Sarawaks daily load demand was taken from a sample size of 34detached house consumers. As for Pulau Pinang and Selangor, thedaily load demand came from the hourly average electrical load ofa single house. The load data fromall four States used to analyse thehybrid system are depicted in Fig. 4.3. PVewindediesel generator hybrid systemThe PVewindediesel generator hybrid system is a combinationof PV panels, wind turbines, generators and other components suchasbatteriesandconvertersasshowninFig. 5. Foreachofthesecomponents, informationregardingtypical market pricesinUSDollarsandpowergenerationstatisticswereobtained. Ahybriddistributedpowergenerationsystemwasdesigned. Thesystemconsists of one or more renewable sources such as wind and solarandthediesel generatorsystemactsasback-upinthecaseofinadequacy of renewablesources.The hybrid system enables therenewablesourcestocomplementeachotherandthusensuresbetter utilization. To accommodate the loaddemand, a singlerenewable source usually tends to be oversized [17,18]. In a hybridsystem, thevariouscomponentscancomplementeachotherbyutilizing their individual capacities and improving the load factorsof the generators. Maintenance andreplacement costs canbereduced when renewable resources are used properly. The initialcapital cost of a hybrid system is high and thus long-lasting reliableandcost-effectivesystemsareneeded. Adetailedexplanationofthe components used in the hybrid system is given in this section.3.1. Solar PV panelsThe initial cost of a 75 WSolar PV panel is $548 witha replacement cost of $92. Each PV panel produces direct currentand its tracking systemis set along the horizontal axis and adjusteddaily. Thede-ratingfactor, whichisafactorwhichaccountsforlosses duetotemperatureeffects anddirt, is 80%. Thegroundreectance of solar radiation is 20% and the lifetime expectancy ofthe solar PV panels is 25 years.3.2. Wind turbineThe wind turbine model used in this system is the Windside 2Awhich has a capacity of 0.6 kW of direct current. The initial cost ofthe wind turbine is $6048 and the replacement cost is $5901, withannual operatingandmaintenancecostsof $148. Thehubandanemometer of this wind turbine is located at a height of 15 m andit is estimated to serve for 25 years.3.3. Diesel generatorTheinitial costof a1 kWACdiesel generatoris$2508witha replacement cost of $2360 and hourly maintenance of $0.03. Thisdiesel generator is estimated to operate during 15,000 h with a loadratio of 30%. The diesel used for this generator is priced at $2.17 perlitre.3.4. ConverterA converter is required for a system in which DC componentsserve as an AC load or vice versa. It can function as a rectier whichconverts AC to DC, an inverter which converts DC to AC, or both. In34%19%26%21%Johor Sarawak Pulau Pinang SelangorFig. 3. Percentage of wind speed for all four States.48%24%6%22%Johor Sarawak Pulau Pinang SelangorFig. 4. Percentage of load demand for all four States.Fig. 5. Design of wind/PV/generator hybrid power system.A.M.A. Haidar et al. / Renewable Energy 36 (2011) 881e888 883this system, the initial capital cost of a 45 kW converter is $14,264with a replacement cost of $14,264. The expectedlifetime oftheconverter is 25 years in which the efciency of the inverter is 90%and the rectier 85%.3.5. BatteryThe battery used in this hybrid systemis a Hoppecke6OPzS600, ratedatanominalvoltageof2 V, withacapacityof600 Ah and a lifetime throughput (amount of energy that can becycled through the battery before it has to be replaced) of2083 kWh.The cost of asingle batteryis $504andthereplace-ment cost is $492 with operating and maintenance costs of $0.59.One battery is added per string and each battery has only 4 yearsof life expectancy.4. System modellingThe aim of this optimization is to evaluate the feasibility of thehybridsystemandtoestimatethelife-cyclecostof thesystem.The efciency of the hybrid system is evaluated by allocating therenewableenergytothemicro-grid. Furthermore, theeffect ofrenewable energy on the total net present cost of the systemwill beassessed when achieving the optimal conguration of the hybridsystem. The optimal conguration is determined by optimizing theobjectivefunctionof thetotal net present cost fortheselectedhybrid system as shown in Fig. 6. The software program is used asatool toperformiterations byrunningmultipleoptimizationsunder a range of input assumptions to gauge the effects of uncer-taintyorchangesinmodelinputsandtosearchfortheoptimalsystemconguration[19,20]. Thecalculationusedtoobtainthesize of the search space is,21 11 11 15 21 800; 415 (1)This search space includes 800,415 distinct system congurationsandthe possible values of the decisionvariables comprise of800,415 different combinations; 21 sizes of PV array, multiplied by11 wind turbine quantities, multiplied by 11 sizes of diesel gener-ator, multiplied by 15 battery quantities, multiplied by 21 sizes ofconverter. In the optimization process, every system congurationin the search space is simulated and the feasible ones are displayedin a table, sorted by net present cost.The balance of energy from the hybrid system is determined byoptimizing the following equation:PIN Pout Ploss(2)wherePINeenergysourceofthesystemconsistingofPVarray,wind turbine and diesel generator; Poute load demand; Plosse lossof energy.The PVarrayis modelledas recommendedinRef. [21], asadevicethatproducesDCelectricityindirectproportiontotheglobal solar radiation. Therefore, the power output of the PV arraycan be found fromPpv Ypvfpv

GTGT;STC

1 apTC TC;STC(3)If there is no effect of temperature on the PV array, the temperaturecoefcient of the power is zero, thus the above equation simpliesto:Ppv Vpvfpv

GTGT;STC

(4)whereYpveratedcapacityof PVarray, meaningpoweroutputunder standard test conditions [kW]; fpve PV de-rating factor [%];GTe solar radiation incident on PV array in current time step [kW/m2]; GT;STCeincident radiationunder standardtest conditions[1 kW/m2]; ape temperature coefcient of power [%/

C]; Tce PVcell temperature in current time step [

C]; Tc,STCe PV celltemperature under standard test conditions [25 C].A wind turbine functions by converting the kinetic energy of thewind into rotationalkinetic energy in the turbine and lastly intoelectrical energy. Theconvertedenergydependsonwindspeedandtheswept areaof theturbine. Equation(5) calculates therotationalkineticpowerproducedinawindturbineatitsratedwind speed [22].P 12rAv3(5)This is theminimumwindspeedat whichawindturbineproducesitsratedpower. Thetheoretical maximumpoweref-ciency of any design of wind turbine is 0.59. This is called the powercoefcient andit isdenedasCp max 0.59. Hence, thepowercoefcient needs to be factored into equation (5) and the extract-able power from the wind is given by:Pavail 12rAv3CPmax(6)where, P epower (W); r edensity (kg/m3); A eswept area (m2); v ewind speed (m/s).The renewable fractionis the portionof the systems totalenergy production originating from renewable power sources. Therenewable power fraction is calculated by dividing the total annualrenewable power production (the energy produced by the PV array,windturbines, hydro-turbine, andbio-gasfuelledgenerators)bythe total energy production. The equation for the renewable frac-tion is;Fren Eren HrenEtot Htot(7)where Erenerenewable electrical production (kWh); Hrenerenewablethermalproduction;Etotetotalelectricalproduction;Htot e total thermal production.The total annual electrical production of the generator is basedon the specic fuel consumption and given by Fig. 6. Hybrid system conguration.A.M.A. Haidar et al. / Renewable Energy 36 (2011) 881e888 884Egen FtotFspec(8)where Ftote total annual generator fuel consumption (L/year); Fspece average amount of fuel consumed by generator (L/kWh).Thebatterybankis a collectionof oneor more individualbatteries. Inthiswork, thesimulatedsystemisasinglebatterymodelledasadevicecapableofstoringacertainamountofDCelectricityat xedround-tripenergy efciency, withlimitsastohow quickly it can be charged or discharged, how deeply it can bedischargedwithoutcausingdamage, andhowmuchenergycancycle through it before it needs to be replaced. The charging anddischarging capacities are calculated as follows:Battery charging:Pt Pbt 1 1 s Pbht Pblt=hbi hbb(9)Battery discharging:Pbt Pbt 1 1 s Pbht=hbi Pblt (10)wherePbebatteryenergyintimeinterval; Pbhetotal energygenerated by PV array; Pble load demand in time interval;hbieinverter efciency;hbbe battery charging efciency;se self dis-charging factor.The evaluation of the system in terms of economics is achievedby optimizing the total net present cost to get the optimal cong-urationofthehybridsystem. Thetotalnetpresentcost(NPC)isused here to represent the life-cycle cost of a system. The life-cyclecost of analysis compares all costs that occur within the life span ofthe system. The NPCincludes the cost of initial construction,component replacement, maintenance, fuel, plus the cost of buyingpowerfromthegridandmiscellaneouscostssuchaspenaltiesresulting from pollutant emissions. Revenue includes income fromselling power to the grid, plus any salvage value that occurs at theend of the project lifetime:CNPC Cann;totCRFi; Rproj (11)where Cann,tote total annualized cost ($/year); ie annual interestrate(%);Rprojeprojectlifetime(year);whereCRFisthecapitalrecovery factor and can be found from:CRFi; N i1 iN1 iN1(12)where N is the number of years.The initial capital cost of a component is used to calculate thetotal installed cost of that component at the beginning of the hybridsystem. The equation used to obtain this result is:Cacap Ccap CRFproj(13)where Cacape Annualized capital cost; CRFproje CRF project.The salvage value is the value remaining in a component of thepower system at the end of the hybrid system lifetime. The systemis assumed to follow a linear depreciation in the value of compo-nents and the salvage value is based on the replacement cost ratherthantheinitial capital cost, meaningthat thesalvagevalueofa component is directly proportional to its remaining life and thiscan be expressed mathematically as:S CrepRremRcomp(14)whereRremeremaininglifeofcomponent;Rcompecomponentlifetime (year); Crepe replacement cost ($).The following levelized cost of energy (COE) is the average costperkWhofuseful electrical energyproducedbythesystem. TocalculatetheCOE, theannualizedcostofproducingelectricityisdivided by the total useful electric energy production. The equationfor the COE is as follows:COE Cann;tot CboilerEthermalEprim;AC Eprim;DC Edef Egrid;sales(15)where Cann,tote total annualized cost of system ($/year); Cboilereboiler marginal cost ($/kWh); Ethermale total thermal load servedFig. 7. Daily load prole.Fig. 8. Monthly load prole.Table 1Summarized total net present cost of optimal hybrid conguration.Location Total net present cost($)Cost of energy($/kWh)Load demand(kWh/d)Johor 34,867 0.722 8.5Sarawak 39,210 0.812 8.5Pulau Pinang 38,618 0.800 8.5Selangor 37,731 0.781 8.5A.M.A. Haidar et al. / Renewable Energy 36 (2011) 881e888 885(kWh/year); Eprim,ACeACprimaryloadserved(kWh/year); Eprim,DCeDC primary load served (kWh/year); Edefe deferrable load served(kWh/year); Egrid,salese total grid sales (kWh/year).Theamount of power obtainedfromsolar radiationcanbecalculated from [23]:Ppv hpv Npvp Npvs Vpv Ipv(16)wherehpveconversionefciencyof PV; Npvpenumberof PVpanelsinparallel; Npvsenumberof PVpanelsinseries; VpveOperatingvoltageof PVpanels; IpveOperatingcurrent of PVpanels.Thefuel consumptionof thediesel generatorismodelledasbeing dependent on the output power and can be found from:ConsG BG PNG AG PG(17)where PN_Ge Nominal power (kW); PGe Output power of dieselgenerator (kW); AG&BGeCoefcients of consumptioncurve,dened by user (l/kWh).Theamountof powerobtainedfromthewindspeedcanbecalculated as:Pw hw hg 0:5 ra Cp A V3r(18)where Pwe Wind turbine power output;hwe Efciency of windturbine; hgeEfciency of generator; raeDensity of air; CpePowercoefcientof windturbine;AeWindturbinesweptarea;VreWind velocity.The cost of energy from the diesel generator can be divided intotwo parts. The rst part is the xed cost of energy which representsthe cost per hour of simply running the generator withoutproducing any electricity. Therst part is calculated from:Cgen;fixed Com;fixed Crep;genRgen F0YgenCfuel;eff(19)whereCon,geneO&Mcost($/h);Crep,geneReplacementcost($);Rgene Generator lifetime (h); FOe Fuel curve intercept coefcient(L/kWh); YgeneCapacity of generator (kW); Cfuel,effeEffective priceof fuel ($/L).Thesecondpartofthecostofenergyisthemarginalcostofenergy which represents the additional cost per kilowatt-hour ofproducing electricity from the generator. This cost is given by:Cgen;mar F1Cfuel;eff(20)whereF1e Fuel curve slope (L/kWh); Cfuel,effe Effective price offuel ($/L).5. Results and discussionThe optimal conguration is evaluatedbased on the collecteddata and loads from all four States. For the purpose of comparison,similarloadswereappliedtoaPVarrayewindedieselgeneratorhybridsystemobtainedfromNibongTebal inPulauPinang. Thefeasibility of using renewable power based on the production costof solar power and wind power utilization is analyzed andcomparedwithits annual yield. Theresults obtainedarethencompared with the total energy produced and the cost of energyfrom the diesel generator.Figs. 7 and 8 showthe daily and monthly load proles applied tothesystem, thesameloadswereassumedforallStateswithoutchanging the original solar radiation and wind speed data collectedfrom each four State. Table 1 summarizes the total net present costoftheoptimalhybridsystemfor25yearsintheStatesofJohor,Sarawak, Pulau Pinang and Selangor. The optimal hybrid system forthese four States is a PVediesel generator hybrid system. Referringto Table 1, it can be noted that Johor has the lowest total net presentcost of $34,867 and the lowest cost of energy of 0.722$/kWh fol-lowed by Selangor, Pulau Pinang and lastly Sarawak. Thus, the ideallocation for installing a PVediesel generator hybrid system wouldbe the State of Johor and this is proven by the results given in Table1, where the total net present cost ofthe system for Johor is thelowest amongst locations.Table 2Amount of pollutants produced from a PVediesel generator hybrid system.Pollutant emissions(kg/year)StatesJohor Sarawak Pulau Pinang SelangorCO2296 125 53.9 478CO 0.731 0.308 0.133 1.18UHC 0.0809 0.0341 0.0147 0.131PM 0.0551 0.0232 0.01 0.089SO20.594 0.251 0.108 0.961NOx6.52 2.75 1.19 10.5Fig. 9. Frequency changes in PV power over 24 h in Johor.Fig. 10. Frequency changes in PV power over 24 h in Pulau Pinang.Table 3PV output for Johor, Sarawak, Pulau Pinang and Selangor.Location Maximum poweroutput (kW)Total power production(kWh/year)Levelized cost ofenergy ($/kWh)Johor 21.4 35,731 0.734Sarawak 13.3 20,135 0.880Pulau Pinang 3.15 4926 0.859Selangor 9.38 15,048 1.117A.M.A. Haidar et al. / Renewable Energy 36 (2011) 881e888 886The hybrid system includes a traditional fossil-fuel-redgenerator and thus pollutants originate from the consumption offuel and biomass in the generator. Table 2 shows the total amountof each pollutant produced annually by the diesel generators for allfour States. The types of pollutant released from diesel generatorsare carbon dioxide (CO2), carbon monoxide (CO), unburnedhydrocarbons (UHC), particulate matter (PM), sulfur dioxide (SO2)and nitrogen oxides (NOx). These results are based on the amountof diesel fuel burned and the hours of generators run-time. Of allthe States, a diesel generator in Selangor has the highest amount ofpollutant emissions in a year, whereas the lowest level of pollutionreleasedfromdiesel generatorswouldbeintheStateof PulauPinang. Referring to Table 1 and taking into account the effect ofpollutionontheenvironment, itcanbeconcludedthatthebestlocation for a PVediesel generator hybrid system would be in theState of Pulau Pinang. This is due to the lowest amount of pollutionand the total net present cost of the systemwhich is only $3751. Onthe other hand, the total net present cost in Johor is less than PulauPinang but the amount of pollution is higher.The capacities of the solar panels used in this study differ fromeach other based on the amount of solar radiation received at theirlocations andtheappliedloads. Toobtainthemaximumsolarradiationpower, thePVpanel is xedonahorizontal axisandadjusted daily. The output of the PV panel is in Watts and the dataarecollectedforeachhourinaday. Anexampleof thepowermeasurements producedfromthePVpanel for Johor &PulauPinang is depictedinFigs. 9 and10, andTable 3 shows themaximumpoweroutput, total powerproductioninayearandlevelized cost of energy for every kWh of energy obtained from thePV panel for all four States.The capacities of wind turbines differ from each other based onthe amount of wind speed received at their locations. The output ofthe wind turbine is in Watts and the data are collected for each hourinaday. Table4summarizesthemaximumpoweroutput, totalpower production in a year and levelized cost of energy for everykWh of energy obtained from the wind turbine.The data for the daily yield of solar energy and wind speed areanalyzed to determine the potential of utilizing solar energy andwind energy in Malaysia, by comparing the cost of solar and windpower production with the cost of energy produced from a dieselgenerator. A generator consumes fuel to produce electricity and thegeneratedpowerdependsontheoutput capacityandthus, thecapacity, operating hours of generation and type of consumed fuelwill determinethelifetimeof thegenerator. Table5showsthemaximumpoweroutput, total powerproductioninayearandlevelized cost of energy for every kWh of energy obtained from thediesel generator.Tables 6e8 show the difference between the energy producedevery ve years from a PV panel, wind turbine and diesel generatorfor the States of Johor, Sarawak, Pulau Pinang and Johor. Accordingto the yearly energy yield data collected for all four States, it can beconcluded that in 25 years, the cost of energy produced fromthe PVpanel will increase inproportionwith the annual solar energy yield.Table 6 shows the result calculated for the total solar energy yieldand the cost of energy production for the States of Johor, Sarawak,Pulau Pinang and Selangor.From the yearly energy yield data collected for all four States, itcanbenotedthatin25years, thecost ofenergy producedfroma wind turbine willincrease in proportion with the annual windenergy yield. Table 7 shows the results for the total wind energyyield and cost of energy production for the States of Johor, Sarawak,Pulau Pinang and Selangor. From Table 8, it is seen that the totalenergycostincreasesinproportionwiththeenergycostof thediesel generator over 25 years.The difference between the energy produced everyve yearsfromthewindturbine andthe diesel generator canbe seenclearly in Tables 6e8. The total energy produced from a PV panelishigherthantheenergygeneratedfromadiesel generatorintheStates of PulauPinangandSelangor. Incontrastto thetotalenergyproducedfromaPVpanel, thetotal energyproducedfrom wind turbines is almost negligible compared to the energygeneratedfromdiesel generatorsforall fourStates. Moreover,the cost of energy produced from solar radiation for some Statesis practically half the cost of energy generated fromdieselgenerators. The cost of energy production from a diesel generatoris much higher than the cost of energy produced from a PV panel.Thus, this showsthatsolarpoweriseconomically cheaperthanthepowergeneratedfromadiesel generatorandenvironmen-tally friendly.Table 4Wind turbine output for Johor, Sarawak, Pulau Pinang and Selangor.Location Maximum poweroutput (kW)Total power production(kWh/year)Levelized cost ofenergy ($/kWh)Johor 0.42 159 1.054Sarawak 0.05 27.6 1.150Pulau Pinang 0.07 90.8 1.457Selangor 0.17 44.8 1.197Table 5Diesel generator output for Johor, Sarawak, Pulau Pinang and Selangor.Location Maximum poweroutput (kW)Total power production(kWh/year)Levelized cost ofenergy ($/kWh)Johor 1.405 23,267 5.75Sarawak 1.409 11,617 3.00Pulau Pinang 3.089 5633 1.81Selangor 2.329 16,148 2.329Table 6Total energy yield of PV panel for Johor, Sarawak, Pulau Pinang and Selangor.Location Year 1 5 10 15 20 25Johor Power(kWh/yr)35,731 178,655 357,310 535,965 714,620 893,275Cost ($) 26,226 131,130 262,260 393,390 524,520 655,650Sarawak Power(kWh/yr)20,135 100,675 201,350 302,025 402,700 503,375Cost ($) 17,718 88,590 177,180 265,770 354,360 442,950Pulau Pinang Power(kWh/yr)4926 24,630 49,260 73,890 98,520 123,150Cost ($) 4231 21,155 42,310 63,465 84,620 105,775Selangor Power(kWh/yr)15,048 75,240 150,480 225,720 300,960 376,200Cost ($) 16,808 84,040 168,080 252,120 336,160 420,200Table 7Total energy yield of wind turbine for Johor, Sarawak, Pulau Pinang and Selangor.Location Year 1 5 10 15 20 25Johor Power (kWh/yr) 159 795 1590 2385 3180 3975Cost ($) 168 840 1680 2520 3360 4200Sarawak Power (kWh/yr) 27.6 138 276 414 552 690Cost ($) 32 160 320 480 640 800Pulau Pinang Power (kWh/yr) 90.8 454 908 1362 1816 2270Cost ($) 132 660 1320 1980 2640 3300Selangor Power (kWh/yr) 44.8 224 448 672 896 1120Cost ($) 54 270 540 810 1080 1350A.M.A. Haidar et al. / Renewable Energy 36 (2011) 881e888 8876. ConclusionIn this work, a PV arrayewindediesel generator hybrid systemmodel is proposed to appraise the optimal conguration ofRenewable Energy in Malaysia and to compare the production costsof solar and wind power utilization with their annual yields rele-vant to different regions namely Johor, Sarawak, Penang andSelangor. The conguration of the optimal hybrid systemis selectedbased on the best components and sizing with appropriate oper-atingstrategytoprovideanefcient, reliableandcost-effectivesystem. The optimal hybrid system selectedin terms oftotalnetpresent cost is a PV arrayegenerator hybrid system as proven fromtheresultspresentedinSection4. Thissystemconsistsof aPVarray,diesel generator,battery and converter. The PV arrayegen-erator hybrid systemis a more appropriate systemcompared to thewind turbine hybrid system due to the favourable meteorologicalconditionsof solarenergyinall fourStates. Asforcost, thePVhybridsystemis better thanawindhybridsystem. It canbeconcluded that the suggested location of a PV arrayediesel gener-ator hybrid systemwould be in the State of Johor. However, in termsof pollution, the best place to install a PVediesel generator systemthat emits minimal pollution would be in the State of Pulau Pinangand this can be conrmed from the summary of the results of thefeasibilitystudywhicharepresentedinSection4. Finally, theoptimal congurationofhybridsystemfordifferentlocationsinMalaysiahasbeendetermined. This ndingwill helptoinstallsources of renewable energy in places that will ensure lowcost andperformance of hybrid systems. The comparison of the annual yieldfor solar energy with the cost of production considering pollution isan important factor that can be used to develop an environmentallysafer and cleaner renewable energy source.References[1] Borowy BS, Salameh ZM. Optimum photovoltaic array size for a hybrid wind/PV system. IEEE Trans Energy Convers 1994;9(3):482e8.[2] Belfkira R, NichitaC, Barakat G. 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RenewEnergy 2007;32(7):33e46.Table 8Total generation fromdiesel generator for Johor, Sarawak, Pulau Pinang andSelangor.Location Year 1 5 10 15 20 25Johor Power(kWh)23,267 116,335 232,670 349,005 465,340 58,168Cost ($) 13,379 668,925 12,279 200,678 26,757 33,447Sarawak Power(kWh)11,617 58,085 116,170 174,255 232,340 29,043Cost ($) 34,851 174,255 348,510 522,765 697,020 87,128Pulau Pinang Power(kWh)5633 28,165 56,330 84,495 112,660 14,086Cost ($) 10,195 50,975 101,950 152,925 203,900 25,488Selangor Power(kWh)16,148 80,740 161,480 242,220 322,960 40,370Cost ($) 37,608 188,040 376,080 564,120 752,160 94,020A.M.A. Haidar et al. / Renewable Energy 36 (2011) 881e888 888