Research ArticleTechnoeconomical Assessment of Optimum Design forPhotovoltaic Water Pumping System for Rural Area in Oman
Hussein A Kazem Ali H A Al-Waeli Atma H K Al-Kabi and Asma Al-Mamari
Faculty of Engineering Sohar University PO Box 44 311 Sohar Oman
Correspondence should be addressed to Hussein A Kazem hkazemsoharunieduom
Received 14 December 2014 Revised 16 March 2015 Accepted 17 March 2015
Academic Editor Elias Stathatos
Copyright copy 2015 Hussein A Kazem et al This is an open access article distributed under the Creative Commons AttributionLicense which permits unrestricted use distribution and reproduction in any medium provided the original work is properlycited
Photovoltaic (PV) systems have been used globally for a long time to supply electricity for water pumping system for irrigationSystem cost drops downwith time since PV technology efficiency and designmethodology have been improved and cost of wattagedrops dramatically in the last decade In the present paper optimumPV system design for water pumping system has been proposedfor Oman Intuitive and numerical methods were used to design the system HOMER software as a numerical method was usedto design the system to come up with optimum design for Oman Also REPSOM software has been used to find the optimumdesign based on hourly meteorological data The daily solar energy in Sohar was found to be 6182 kWhm2sdotday However it isfound that the system annual yield factor is 202466 kWhkWp Furthermore the capacity factor was found to be 2305 which ispromisingThe cost of energy and system capital cost has been compared with that of diesel generator and systems in literatureThecomparison shows that the cost of energy is 0180 0309 and 0790USDkWh for PV-REPSOM PV-HOMER and diesel systemsrespectively which sound that PV water pumping systems are promising in Oman
1 Introduction
The continuous increase in electrical global demand andconcern of environment due to pollution from human kindactivities leads to exploring new and clean energy technologyPhotovoltaics (PV) could be one of the important solutionssince it is clean and renewable and tested for a long periodof time It is currently widely used for different applicationsHowever in the past the drawback of PV was their highinitial cost in comparison with conventional energy systemsThe situation has been changed due to increase of fossil fuelprices and on the other hand PV technology prices get downefficiency has been increased andmanufacturing technologyhas been improved The increase in efficiency reflected inthe price of energy production This could be on the level ofmanufacturing or on the level of system design Optimizationis very important to find the optimum system componentsThe typical system components of PV systems are as followsPV module-array to generate DC power charger controllerand inverter to charge the storage battery and supply the ACload with power respectively
Different techniques are used for optimization of PVsystems [1] These techniques could be categorized intointuitive numerical and analytical techniques In numer-ical technique many software applications are available tooptimize energy systems HOMER is one of these softwareapplications HOMER is used to investigate the feasibility ofthe PV systemwhich is developed by theNational RenewableEnergy Laboratory (NREL) Renewable and nonrenewablesystem could be modeled by HOMER The algorithms of thesoftware are used to evaluate the system to find the feasiblesystem components in terms of technical and economicalside views [2] The author [1] designed MATLAB based userfriendly software tool called the REPSOM for optimal sizingof PV systems in Oman The developed REPSOM softwaretool aims to design PV system at minimum cost for OmanREPSOMcalculates the optimumPV array-module tilt anglewhich is used to perform the optimization of PV systemIn addition it calculates the optimum inverter size for thePV system Moreover REPSOM simulates the optimized PVsystem so as to investigate its performance for a period of oneyear
Hindawi Publishing CorporationInternational Journal of PhotoenergyVolume 2015 Article ID 514624 8 pageshttpdxdoiorg1011552015514624
2 International Journal of Photoenergy
The application of optimization techniques for designingPV systems for water pumping and other applications can befound in [3ndash7] In [3] the authors designed and investigatedhybrid PVdiesel generator system using HOMER to supplyvillagewith energy consumption of 279 kWhday in EthiopiaThe optimum design found 95 of energy to be provided byPV and 5 from a diesel generatorThe cost of the energy wasfound to be 0401 USDkWh In [4] the authors proposedwater pumping system supplied by PV array in AlgeriaThey developed optimum design using MATLAB The lossof power supply probability and life cycle cost are the twocriteria used to judge the system technically and economicallyto find the optimum design In [5 6] the authors designedPV system to power lighting load for lab and typical houseload inOman respectivelyThe authors usedHOMER to findthe optimum design and they claimed that the cost of energyis 0561 USDkWh and 0389 USDkWh respectively In [7]the authors proposed optimum design of hybrid PVbiomasssystem using HOMER to supply village in India The energywas used for cooking and to supply water pumping systemfor irrigation The cost of energy was found to be 0170USDkWh In [8] there is a comparison study of PV anddiesel generator supply water pumping system for irrigationin the Northern Badia of Jordan LPSP concept has beenused Comparison of PV and diesel engine pumping systemsshows that the cost is 020 USDm3 and 058 USDm3 forPV and diesel respectively It shows that the PV system iscost effective with respect to the diesel engine in rural areaBut cost is differing from site to site Also it is found thatdifferent options could be used to supply water pumpingsystems in rural area Standalone PV diesel generator orhybrid PV-diesel system is an option In this paper the PVwater pumping feasibility technical and economic analysisis presented for the system in Sohar Oman HOMER andREPSOM software applications have been used for designand assessment which contain a different system elementsselection cost of energy and pollution
2 Sohar Solar Energy
Sultanate of Oman lies between longitudes 51∘501015840E and59∘401015840E and latitudes 16∘401015840N and 26∘201015840N Oman climaticconditions in general are desert in most regions and humidnear the coast which is 1700 km long Also Oman has80ndash105 hours of daily sunshine duration peak hours of60ndash65 342 sunny days and average solar radiation of5197 kWhm2day [1]
Sohar is the second large city in Oman and representsthe heart of North Al-Batinah region It falls in North Omanon 24N and 56E latitude and longitude respectively Hourlysolar radiation data was measured for complete year forthis study The WS-STD1 weather station has been installedon Renewable Energy Lab in Sohar University The weatherstation comprises 11 sensors (solar global radiation directsolar radiation diffuse solar radiation rain wind speed anddirection solar energy air temperature ambient tempera-ture air pressure and relative humidity) with 2m mastcanopy and accessories Data logger was used to monitorand record the hourly data on computer for a complete year
The measured solar radiation data are shown in Figure 2The solar radiation in Sohar is various in the range of 32to 62 kWhm2day and in average of 555 kWhm2day withhigh clearing index as shown in Figure 3
3 Sizing of PV Water Pumping Systems
The PV systems are categorized based on the componentconfiguration into grid connected and standalone systemsThe grid connected system is used to generate and inject theenergy directly to the utility grid Examples of grid connectedPV array found in house roof and large scale PV plantsThe PV generates DC power which converted to AC withthe same grid specifications then it is integrated with thegrid The inverter was programmed and protected to take inconsideration the grid cutoff situation The grid connectedsystems not only are attractive for governments and industrialcompanies but also start to be attractive for individualsespecially in countries that have feed in tariff
The standalone PV system is mainly used in rural andisolated areas It works independently for the grid to supplyparticular AC or DC loads The stand-alone system could bean only PV array or it could connect with other renewablesources like wind solar thermal hydro- geothermal systemsand so forth or it could be connected with nonrenewablesources like diesel natural gas and so forth These hybridsystems are used widely as hybrid systems The simple stan-dalone PV system contains PV modules batteries (optional)for storage with charge controller and inverter in the case ofAC load Since the batteries are costly and need maintenancethe PV module could be used directly to supply commonloads on the day like water pumping systems [1]
PVwater pumping in general is cost effective in rural areaIt is an excellent choice for isolated and desert areas Besidesproviding energy from PV to the water pumping system ithas also reduced environmental pollutionOn the other handpure drinking water and water use for irrigation are a criticalneed in rural area in developing countries such as AfricaAsia and South America [9] There is old history for waterpumping systemManymethods have been used for pumpingwater utilizing different power sources These sources arenamely animal human hydro- solar and wind powersDefinitely the conventional engines use diesel or fossil fuelbeing also an option Recently due to the improvement inPV efficiency and reduction in PV prices solar PV becameattractive to supply water pumping systems Usually there arethree different applications for PV water pumping systemsirrigation livestock watering and village water supply Inthis section intuitive method was used to design PV waterpumping system as shown in Figure 1
31 Hydraulic Sizing The essential information for hydraulicsizing is the required daily water volume pumping head andhours per day pipe length and material and pump efficiencyand pressureThe pumping power is calculated as follows [8]
119875pump =120588119892 (ℎ + Δ119867)119876
120578
119887sdot 120578
119890
(1)
International Journal of Photoenergy 3
PV moduleCharge
controller and MPPT
Storage battery
Inverter
Load
Figure 1 Typical PV system components
1200
1000
800
600
400
200
0
Sola
r rad
iatio
n (W
m2)
1
353
705
1057
1409
1761
2113
2465
2817
3169
3521
3873
4225
4577
4929
5281
5633
5985
6337
6689
7041
7393
7745
8097
8449
Time (hours)
Figure 2 Mean hourly solar radiations for Sohar (April 2013ndashApril2014)
where 120588 is the water density kgm3 119892 is acceleration due togravity ms2 ℎ andΔ119867 are total pumping head and hydrauliclosses inm volume of flow119876 inm3s and 120578
119887and 120578119890are pump
and electric motor efficiencies respectivelyAlso the required hydraulic energy in kWhday is calcu-
where119881 is the volume required inm3day 120578119904is the subsystem
efficiency and 119864PV is the PV energy
32 PV System Sizing The PV array is used to convert solarenergy to DC electrical energy The quality of DC powerimproved through power conditioner and converted to ACpower using an inverterThe energy produced by PV array inkW is calculated and is given by [10]
119864PV = 119860PV times 119866119879 times 120578module times 120578inv times 120578wire (3)
where 119860PV is the area of the PV array in m2 and 119866119879is
daily solar radiation in kWhm2 120578module 120578inv and 120578wire areefficiencies of PV module inverter and wires respectivelyThe area 119860PV is calculated from (2) and (3) as follows
119860PV =120588119892ℎ119881
119866
119879120578PV120578119904 (4)
where 120578PV is the summation of module inverter and wireefficiencies Accordingly the required PV array power iscalculated in kW as follows
119875PV =119864
ℎ
119866
119879sdot 119865 sdot 119864
(5)
Global horizontal radiation7
6
5
4
3
2
1
0
Dai
ly ra
diat
ion
(kW
hm
2d
)
Jan
Feb
Mar
Apr
May
Jun Jul
Aug
Sep
Oct
Nov
Dec
10
08
06
04
02
00
Clea
rnes
s ind
ex
Clearness indexDaily radiation
Figure 3 Profile of solar radiation in Sohar Oman
where 119865 is the mismatch factor which is in the range of085ndash090 and 119864 is the daily subsystem efficiency 02ndash06typically [10 11] The PVpump system efficiency is given by
120578system =119875
ℎ
119875PV=
120588119892ℎ119881
119866
119879119860PV (6)
4 PV Water Pumping Systems ComponentsIn this study the proposed system consists of PV arraycontaining few modules charge controller and inverterbatteries for storage and the rest of system components likewires protections sensors andmodule structureThe systemconfiguration is shown in Figure 4 This figure shows thePV water pumping system proposed for irrigation in SoharOman It is worth mentioning that in this study the selectedwell depth is 16m static water level is 65m dynamic waterlevel is 72m well productivity is 81m3h design criteria are45m3day and pumphead is 18m In the coming subsectionsHOMER software will be used first to find the optimumsystem design
41 Water Pump The intuitive method discussed in Sections31 and 32 has been used to estimate the required PV systemcomponents Equations (2) and (5) are used to calculateenergy required for pumping water which is 2197 kWhdayand PV array is 088 kW Also themotor pumpwas estimatedto be 450W 230V and 50Hz It is worth mentioning that thepump works on peak hours
42 PVArray The solar cell is used to convert solar radiationinto electricity These cells are connected in series and areparallel to produce PV modules The PV modules alsoconnected series and are parallel to produce PV array Theproposed PV panels to be used in the system simulation are140 W (at static test condition STC insolation is 1000Wm2and temperature 25∘C) and 12V and have an estimatedcapital cost of USD 200W and replacement cost of USD107W This cost includes mounting hardware installationcommissioning wiring control system dealermark-ups andshippingThe estimated lifetime is 25 years A derating factorwas selected to be of 90 In this analysis we considered thepanels tilt angle to be 24∘ (Sohar latitude)
4 International Journal of Photoenergy
PV array
DCDC converter
ATS controller
DCAC converter
Charge controller
Battery
Normal timeDeficit time
Load
Storage tank
Pumping well
Irrigation system
Figure 4 PVwater pumping system configuration
43 Charger Controller and Inverter The charger controllerand inverter are electrical convert circuits which are used toconvert electric power from DC to DC and AC respectivelyThe lifetime of converters is up to 15 years with 94 efficiencyand estimated price of an inverter is USD 05W
44 Battery Batteries are used to store the energy producedby the PV array The battery efficiency depends on the stateof charge and discharge which affect the life of the batteryAlso it is worth mentioning that HOMER software doesnot take into consideration variation in temperature or anydegradation in battery performance In addition batteriesremain constant throughout their lifetime The proposedbattery has a 12V 200Ah capacity Its lifetime is consideredto be 12 years
5 Design and Assessment ofWater Pumping Systems
51 Technoeconomical Assessment Criteria To assess the sys-tem technically and economically four criteria have been usedin this study as follows
(i) Technical criteria capacity factor (CF) and yieldfactor (YF) are applied to evaluate the productivity ofthe proposed system
(ii) Economic criteria payback period (PBP) and the costof energy (CoE) are used to assess the feasibility of theproposed system
The ratio of actual annual energy output to the amount ofenergy the PV array would generate if it operates at full rated
power (119875119903) for 24 h per day for a year represents the annual
capacity factor which is calculated as follows
CF = YF8760
=
119864PVannual(119875
119877times 8760)
(7)
Meanwhile the daily monthly or annual net AC energyoutput of the system divided by the peak power of theinstalled PV array at STC represents the yield factor whichis calculated as follows [12]
YF =119864PV (kWhyear)PVWP (kWp)
(8)
On the other hand the cost of energy and payback periodcriteria are used to assess the system economically The lifecycle cost (LCC) of a PV system may also include costs forsystem design installation labor site preparation operationand maintenance costs The life cycle cost is calculated asfollows
LCC = 119862capital +119899
sum
1
119862OampM sdot 119877PW
+
119899
sum
1
119862replacement sdot 119877PW minus 119862salvage sdot 119877PW
(9)
The different components taken into account in calculat-ing LCC are as follows capital cost 119862capital replacementcost 119862replacement maintenance cost 119862OampM and salvage value119862salvage119877PW represents the present value of each factor whichis calculated using the future sum of money (119865
119898) in a given
year (119873) at a given discount rate (119868)
119877PW =119865
119898
(1 + 119868)
119873 (10)
International Journal of Photoenergy 5
Table 1 Modelled PV system specification
PV arrayPV module rated power 140WpMaximum voltage 177Maximum current 791Open circuit voltage 221Short circuit current 868Efficiency 139Temperature coefficient of Voc minus036kTemperature coefficient of Isc 006k
InverterRated power 08 kWAC voltage 220ndash240Efficiency 940
Table 2 Economic assumption of PV system
Component Capital Lifetime Replacement OampM Fuel($kW) (years) ($) ($) ($)
After calculating LCC the cost of energy is calculated using
CoE = LCCsum
119899
1119864PVannual
(11)
where 119864PVannual is the annual energy production of the PVsystem while 119899 is the system lifetime in years Finally thepayback period is calculated as follows
PBP =119862capital (USD)
[119864PVannual (kWhyear) times CoE (USDkWh) times 119877PW]
(12)
52 Optimum System Design In this research solar waterpumping system has been designed for irrigation in SoharOman This system contains 045 kWp water pump Thesystem has been installed at Sohar zone for research workpurposes The feasibility of the proposed solar water pump-ing system was designed and analyzed using HOMER andREPSOM to find the optimum system component HOMERand REPSOM were used to model different system elementsand check the component physical behaviour and its life cyclecost The optimum system components have been selectedbased on their technical and economic merits Table 1 showsthe specification of the optimummodule and inverter
The schematic diagram in HOMER model for the builtPV system is presented in Figure 5 Since the solar radiationis high enough between 1100AM and 400 PM it is worthgenerating electricity in this period to supply the pump tofill the tank The economic assumptions of the system andthe load analysis calculation are given in Tables 2 and 3respectively
Table 3 Scaled data for simulation
Data source SyntheticDaily noise 15Hourly noise 20Scaled annual average 222 kWhdayScaled peak load 0809 kWLoad factor 0114
Water pump
810W peak
Converter
Ac DC
PV
6FM200D
22 kWhd
Figure 5 HOMER schematic diagram for the solar PV waterpumping system
The suggested PVmodule for simulation of the optimumsystemused in this study is 12 V 140WpDifferent PVmodulecapacities are introduced and considered in the analysiswhich is in the range of 1ndash10 modules The suggested batterywas 12V 200Ah capacities with estimated cost of 140USDAlso for sensitivity analysis the range of batteries is assumedto be 1ndash5 battery banks Furthermore the inverter efficiencywas assumed to be 94 for all considered sizes with estimatedcost of 05 USDW and lifetime of 15 yearsThe inverter rangewas selected to be 01ndash10 kW for analysis consideration
6 Discussion and Analysis
After running the system model in HOMER 704 feasiblesolutions are found and out of these 10 best solutions rankedaccording to the system minimum net present cost (NPC)and cost of energy (CoE) are shown in Table 4 The tableshows that the greatest optimal result is achieved when thesystem is composed of 084 kW PV array (6 modules) 4batteries and 08 kW inverter The optimum solution to thetotal NPC is 3200 USD with operating cost of 63 USDyearand the cost of energy equals 0309 USDkWh On theother hand REPSOM found that the optimum result isachieved when the system is composed of 056 kW PV array(4 modules) 2 batteries and 045 kW inverter FurthermoreREPSOM optimum solution found that the total NPC is1880 USD with operating cost of 33 USDyear and the cost
6 International Journal of Photoenergy
Table 4 Optimum solution for the proposed PV system using HOMER
PV(kW) 6FM200D Conv
(kW)Initialcapital
Operatingcost ($yr)
TotalNPC
COE($kWh)
Renfrac
Capacityshortage
084 4 08 $ 2400 63 $ 3200 0309 100 000
084 4 09 $ 2450 64 $ 3265 0315 100 000
070 5 08 $ 2300 76 $ 3269 0316 100 000
084 4 10 $ 2500 65 $ 3331 0322 100 000
070 5 09 $ 2350 77 $ 3335 0322 100 000
070 5 10 $ 2400 78 $ 3400 0328 100 000
098 4 08 $ 2640 63 $ 3440 0332 100 000
098 4 09 $ 2690 64 $ 3505 0338 100 000
084 5 08 $ 2540 76 $ 3509 0339 100 000
098 4 10 $ 2740 65 $ 3571 0345 100 000
of energy equals 018 USDkWh It is worth mentioning thatoptimum tilt angle was found to be 27∘ for Sohar
The fossil fuel generator has been simulated for compar-ison to supply the same water pump as shown in Figure 6There are different types of generators commercially available(propane diesel biofuel and gasoline) In this study thediesel fuel generator has been used since it is more efficientand has a longer lifetime in comparison with others andbecause it is the used fuel in Oman as it is considered asone of the suppliers of fuel Rural Areas Electricity Company(RAECO) generation system fuel is diesel Its diesel price issubsidies from the Omani Government and accounted for 46BaizaLitre which is equivalent to 038 USDLitre [12] Onthe other hand it is found that global diesel price on January2014 is 138 USDLitre [13] In this part the water pumpsystem supplied from diesel generator has been investigatedfor comparison with designed PV systems
The fuel price tested 038 and 138 USDLitre with andwithout the government subsidy respectivelyThe price of thegenerator is 500 USD and we considered the generator size of500W in the analysis To compare the PV system results withthe diesel generator to choose the best and costless systemthe analysis shows that a size of 1000W generator has beenestimated with capital operating and total net cost being1000 USD 562 (USDyr) and 8185 USD respectively asshown in Table 5 The CoE is found to be 079 (USDkWh)which is considered to be high as compared with CoE of theproposed PV system (018 and 0309 (USDkWh))
The energy generated shares from REPSOM proposedsystem are shown in Figure 7 PV system availability is calcu-lated as the percentage of time that a power system is capableof meeting load requirements where it is found that thesystem availability is 98 It is found that REPSOMoptimumsystem availability is higher than HOMER and intuitivemethod systems However Figure 7 shows the complete yearperformance of the proposed system From the figure it isclearly seen that the solar energy covers most of the systemload and the battery is intensively used through the year timewhich makes it able to supply the load in some extremely
Water pump
810W peak22 kWhd
Generator 1
AC
Figure 6 HOMER schematic diagrams for the diesel generatorwater pumping system
cloudy days However it is found that the system annual yieldfactor is 202466 kWhkWp Furthermore the capacity factorwas found to be 2305 which is promising since the typicalone is 21
Emission of green-house gases from the fuel of theequivalent conventional system is important Adopting solarPV systems will protect the environment from the harmfulgreen-house gases Table 6 shows the polluted emissionsproduced by the diesel generator used to supply the waterpump Furthermore in comparison between subsidized andnonsubsidized fuel cost it is found that the CoE is 079 and1228 USDkWh respectively This means that besides theprotection of the environment the cost of diesel is relativelyhigh and part of the cost covered by the government couldbe used for other economic projects if the PV technology hasbeen adopted
The comparisons of the cost of energy in the modelledsystem are shown in Table 7 The proposed system cost isacceptable in comparison with the cost of PV systems in
International Journal of Photoenergy 7
Table 5 Diesel system results for 038USDLitre
Label(kW)
Initialcapital
Operatingcost ($yr)
TotalNPC
COE($kWh)
Renfrac
Capacityshortage
Diesel(L)
Label(hrs)
10 $ 1000 562 $ 8185 0790 000 000 351 1825
50 100 150 200 250 300 3500
500
Day
Generated energy by PVLoad demand
50 100 150 200 250 300 350minus500
0500
Day
Energy balance
50 100 150 200 250 300 3500
051
Day
Battery SOC
50 100 150 200 250 300 3500
100200
Day
Deficit energy
Ener
gy (k
Wh)
Ener
gy (k
Wh)
Ener
gy (k
Wh)
SOC
()
Figure 7 Proposed system hourly performance sample
[4] [5] [6] [14] and [15] 0401 0561 0389 021ndash0304and 0361ndash0327 USDkWh respectively Also it is foundthat the cost of PV systems is promising in comparison withthe proposed diesel system (0790 and 1228 USDkWh) andthe energy cost of diesel engine system in [15 16] 05581USDkWh Furthermore regardless of the fact that hybridsystems technically and economically are effective it is foundthat the proposed PV system is economical in comparisonwith [8] where the cost of energy is 0200ndash0580 USDkWhwhich make PV water pumping system be a good option forirrigation in rural areas of Oman
7 Conclusions
In this study PV water pumping system for Sohar Oman hasbeen designed and assessed Optimum selection of systemcomponents PV modules inverter charger controller andbatteries Oman has been determined The system has adaily load of 222 kWhday 084 kW PV modules 4 batteries(12 V and 200Ah) and 08 kW inverter The results haveshown that the optimum cost of PV system energy 0309USDkWh is attractive option in comparison with the costof diesel engine energy 079 USDkWh Also it is found that
Proposed PV research (REPSOM) 0180 PVProposed PV research (HOMER) 0309 PVSubsidized diesel system 0790 DieselNonsubsidized diesel system 1228 Diesel([4] Bakelli et al 2011) 0401 PV([5] Salam et al 2013) 0561 PV([6] Kazem et al 2013) 0389 PV([8] Al-Smairan 2012) 0200ndash0580 PV-diesel([17] Al-Badi et al 2011) 021ndash0304 PV([14] Al-Badi et al 2012) 0327ndash0361 PV([15] annual report 2010) 0558 Diesel([16] annual report 2011) 0558 Diesel
most PV system options are feasible more than the dieselgenerator option Also investigations show that the proposedsystem is cost effective with designed systems in literatureIn addition it is found that PV solar water pumping systemscould be an excellent option for irrigation in rural areas ofOman Moreover the analysis shows that replacing dieselgenerator by PV system will protect the environment fromgreen-house gas emission 924 kgyear of CO
2 228 kgyear of
CO 0253 kgyear of NOx 0172 kgyear of HC 186 kgyearof SO
2 and 204 kgyear of suspended particles
Conflict of Interests
The authors declare that there is no conflict of interestsregarding the publication of this paper
Acknowledgments
The research leading to these results has received ResearchProject Grant Funding from the Research Council of theSultanate of Oman Research Grant Agreement ORG SU EI
8 International Journal of Photoenergy
11 010 and FURAPC2HKENGEE The authors would liketo acknowledge support from theResearchCouncil ofOman
References
[1] H A Kazem and T Khatib Photovoltaic Power System Prospec-tive in Oman Technical and Economical Study LAP LAMBERTAcademic Publishing Saarbrucken Germany 1st edition 2013
[2] A Al-Karaghouli and L L Kazmerski ldquoOptimization and life-cycle cost of health clinic PV system for a rural area in southernIraq using HOMER softwarerdquo Solar Energy vol 84 no 4 pp710ndash714 2010
[3] Z Girma ldquoHybrid renewable energy design for rural electrifi-cation in Ethiopiardquo Journal of Energy Technologies and Policyvol 3 no 13 pp 38ndash52 2013
[4] Y Bakelli A H Arab and B Azoui ldquoOptimal sizing ofphotovoltaic pumping system with water tank storage usingLPSP conceptrdquo Solar Energy vol 85 no 2 pp 288ndash294 2011
[5] M A Salam A Aziz A H A Alwaeli andH A Kazem ldquoOpti-mal sizing of photovoltaic systems using HOMER for SoharOmanrdquo International Journal of Renewable Energy Research vol3 no 2 pp 301ndash307 2013
[6] H A Kazem A A Alkurwi M M Alabdul Salam and A HA Alwaeli ldquoLevelized electricity cost for photovoltaic systemin Sohar-Omanrdquo in Proceedings of the IEEE 8th InternationalConference and Exhibition on Ecological Vehicles and RenewableEnergies (EVER rsquo13) Monte-Carlo Monaco March 2013
[7] R Mishra and S Singh ldquoSustainable energy plan for a villagein punjab for self energy generationrdquo International Journal ofRenewable Energy Research vol 3 no 3 pp 640ndash646 2013
[8] M Al-Smairan ldquoApplication of photovoltaic array for pumpingwater as an alternative to diesel engines in Jordan Badia TallHassan station case studyrdquo Renewable and Sustainable EnergyReviews vol 16 no 7 pp 4500ndash4507 2012
[9] K Meah S Ula and S Barrett ldquoSolar photovoltaic waterpumpingmdashopportunities and challengesrdquo Renewable and Sus-tainable Energy Reviews vol 12 no 4 pp 1162ndash1175 2008
[10] H A Kazem T Khatib and K Sopian ldquoSizing of a standalonephotovoltaicbattery system at minimum cost for remote hous-ing electrification in Sohar Omanrdquo Energy and Buildings vol61 pp 108ndash115 2013
[11] H A Kazem T Khatib K Sopian and W Elmenreich ldquoPer-formance and feasibility assessment of a 14kW roof top grid-connected photovoltaic power system under desertic weatherconditionsrdquo Energy and Buildings vol 82 pp 123ndash129 2014
[12] Authority for Electricity Regulation in Oman ldquoStudy onrenewable resourcesrdquo Final Report Authority for ElectricityRegulation in Oman Muscat Oman 2008
[13] Fuel Price Report 2014 httpwwwcatalistcom[14] A H Al-Badi M AL-Toobi S AL-Harthy Z Al-Hosni and
A AL-Harthy ldquoHybrid systems for decentralized power gener-ation in Omanrdquo International Journal of Sustainable Energy vol31 no 6 pp 411ndash421 2012
[15] Annual Report 2010 Rural Areas Electricity Company MuscatOman 2010
[16] 2011 Annual report from Rural Areas Electricity CompanyOman
[17] A H Al-Badi M H Albadi A M Al-Lawati and A S MalikldquoEconomic perspective of PV electricity in Omanrdquo Energy vol36 no 1 pp 226ndash232 2011
The application of optimization techniques for designingPV systems for water pumping and other applications can befound in [3ndash7] In [3] the authors designed and investigatedhybrid PVdiesel generator system using HOMER to supplyvillagewith energy consumption of 279 kWhday in EthiopiaThe optimum design found 95 of energy to be provided byPV and 5 from a diesel generatorThe cost of the energy wasfound to be 0401 USDkWh In [4] the authors proposedwater pumping system supplied by PV array in AlgeriaThey developed optimum design using MATLAB The lossof power supply probability and life cycle cost are the twocriteria used to judge the system technically and economicallyto find the optimum design In [5 6] the authors designedPV system to power lighting load for lab and typical houseload inOman respectivelyThe authors usedHOMER to findthe optimum design and they claimed that the cost of energyis 0561 USDkWh and 0389 USDkWh respectively In [7]the authors proposed optimum design of hybrid PVbiomasssystem using HOMER to supply village in India The energywas used for cooking and to supply water pumping systemfor irrigation The cost of energy was found to be 0170USDkWh In [8] there is a comparison study of PV anddiesel generator supply water pumping system for irrigationin the Northern Badia of Jordan LPSP concept has beenused Comparison of PV and diesel engine pumping systemsshows that the cost is 020 USDm3 and 058 USDm3 forPV and diesel respectively It shows that the PV system iscost effective with respect to the diesel engine in rural areaBut cost is differing from site to site Also it is found thatdifferent options could be used to supply water pumpingsystems in rural area Standalone PV diesel generator orhybrid PV-diesel system is an option In this paper the PVwater pumping feasibility technical and economic analysisis presented for the system in Sohar Oman HOMER andREPSOM software applications have been used for designand assessment which contain a different system elementsselection cost of energy and pollution
2 Sohar Solar Energy
Sultanate of Oman lies between longitudes 51∘501015840E and59∘401015840E and latitudes 16∘401015840N and 26∘201015840N Oman climaticconditions in general are desert in most regions and humidnear the coast which is 1700 km long Also Oman has80ndash105 hours of daily sunshine duration peak hours of60ndash65 342 sunny days and average solar radiation of5197 kWhm2day [1]
Sohar is the second large city in Oman and representsthe heart of North Al-Batinah region It falls in North Omanon 24N and 56E latitude and longitude respectively Hourlysolar radiation data was measured for complete year forthis study The WS-STD1 weather station has been installedon Renewable Energy Lab in Sohar University The weatherstation comprises 11 sensors (solar global radiation directsolar radiation diffuse solar radiation rain wind speed anddirection solar energy air temperature ambient tempera-ture air pressure and relative humidity) with 2m mastcanopy and accessories Data logger was used to monitorand record the hourly data on computer for a complete year
The measured solar radiation data are shown in Figure 2The solar radiation in Sohar is various in the range of 32to 62 kWhm2day and in average of 555 kWhm2day withhigh clearing index as shown in Figure 3
3 Sizing of PV Water Pumping Systems
The PV systems are categorized based on the componentconfiguration into grid connected and standalone systemsThe grid connected system is used to generate and inject theenergy directly to the utility grid Examples of grid connectedPV array found in house roof and large scale PV plantsThe PV generates DC power which converted to AC withthe same grid specifications then it is integrated with thegrid The inverter was programmed and protected to take inconsideration the grid cutoff situation The grid connectedsystems not only are attractive for governments and industrialcompanies but also start to be attractive for individualsespecially in countries that have feed in tariff
The standalone PV system is mainly used in rural andisolated areas It works independently for the grid to supplyparticular AC or DC loads The stand-alone system could bean only PV array or it could connect with other renewablesources like wind solar thermal hydro- geothermal systemsand so forth or it could be connected with nonrenewablesources like diesel natural gas and so forth These hybridsystems are used widely as hybrid systems The simple stan-dalone PV system contains PV modules batteries (optional)for storage with charge controller and inverter in the case ofAC load Since the batteries are costly and need maintenancethe PV module could be used directly to supply commonloads on the day like water pumping systems [1]
PVwater pumping in general is cost effective in rural areaIt is an excellent choice for isolated and desert areas Besidesproviding energy from PV to the water pumping system ithas also reduced environmental pollutionOn the other handpure drinking water and water use for irrigation are a criticalneed in rural area in developing countries such as AfricaAsia and South America [9] There is old history for waterpumping systemManymethods have been used for pumpingwater utilizing different power sources These sources arenamely animal human hydro- solar and wind powersDefinitely the conventional engines use diesel or fossil fuelbeing also an option Recently due to the improvement inPV efficiency and reduction in PV prices solar PV becameattractive to supply water pumping systems Usually there arethree different applications for PV water pumping systemsirrigation livestock watering and village water supply Inthis section intuitive method was used to design PV waterpumping system as shown in Figure 1
31 Hydraulic Sizing The essential information for hydraulicsizing is the required daily water volume pumping head andhours per day pipe length and material and pump efficiencyand pressureThe pumping power is calculated as follows [8]
119875pump =120588119892 (ℎ + Δ119867)119876
120578
119887sdot 120578
119890
(1)
International Journal of Photoenergy 3
PV moduleCharge
controller and MPPT
Storage battery
Inverter
Load
Figure 1 Typical PV system components
1200
1000
800
600
400
200
0
Sola
r rad
iatio
n (W
m2)
1
353
705
1057
1409
1761
2113
2465
2817
3169
3521
3873
4225
4577
4929
5281
5633
5985
6337
6689
7041
7393
7745
8097
8449
Time (hours)
Figure 2 Mean hourly solar radiations for Sohar (April 2013ndashApril2014)
where 120588 is the water density kgm3 119892 is acceleration due togravity ms2 ℎ andΔ119867 are total pumping head and hydrauliclosses inm volume of flow119876 inm3s and 120578
119887and 120578119890are pump
and electric motor efficiencies respectivelyAlso the required hydraulic energy in kWhday is calcu-
where119881 is the volume required inm3day 120578119904is the subsystem
efficiency and 119864PV is the PV energy
32 PV System Sizing The PV array is used to convert solarenergy to DC electrical energy The quality of DC powerimproved through power conditioner and converted to ACpower using an inverterThe energy produced by PV array inkW is calculated and is given by [10]
119864PV = 119860PV times 119866119879 times 120578module times 120578inv times 120578wire (3)
where 119860PV is the area of the PV array in m2 and 119866119879is
daily solar radiation in kWhm2 120578module 120578inv and 120578wire areefficiencies of PV module inverter and wires respectivelyThe area 119860PV is calculated from (2) and (3) as follows
119860PV =120588119892ℎ119881
119866
119879120578PV120578119904 (4)
where 120578PV is the summation of module inverter and wireefficiencies Accordingly the required PV array power iscalculated in kW as follows
119875PV =119864
ℎ
119866
119879sdot 119865 sdot 119864
(5)
Global horizontal radiation7
6
5
4
3
2
1
0
Dai
ly ra
diat
ion
(kW
hm
2d
)
Jan
Feb
Mar
Apr
May
Jun Jul
Aug
Sep
Oct
Nov
Dec
10
08
06
04
02
00
Clea
rnes
s ind
ex
Clearness indexDaily radiation
Figure 3 Profile of solar radiation in Sohar Oman
where 119865 is the mismatch factor which is in the range of085ndash090 and 119864 is the daily subsystem efficiency 02ndash06typically [10 11] The PVpump system efficiency is given by
120578system =119875
ℎ
119875PV=
120588119892ℎ119881
119866
119879119860PV (6)
4 PV Water Pumping Systems ComponentsIn this study the proposed system consists of PV arraycontaining few modules charge controller and inverterbatteries for storage and the rest of system components likewires protections sensors andmodule structureThe systemconfiguration is shown in Figure 4 This figure shows thePV water pumping system proposed for irrigation in SoharOman It is worth mentioning that in this study the selectedwell depth is 16m static water level is 65m dynamic waterlevel is 72m well productivity is 81m3h design criteria are45m3day and pumphead is 18m In the coming subsectionsHOMER software will be used first to find the optimumsystem design
41 Water Pump The intuitive method discussed in Sections31 and 32 has been used to estimate the required PV systemcomponents Equations (2) and (5) are used to calculateenergy required for pumping water which is 2197 kWhdayand PV array is 088 kW Also themotor pumpwas estimatedto be 450W 230V and 50Hz It is worth mentioning that thepump works on peak hours
42 PVArray The solar cell is used to convert solar radiationinto electricity These cells are connected in series and areparallel to produce PV modules The PV modules alsoconnected series and are parallel to produce PV array Theproposed PV panels to be used in the system simulation are140 W (at static test condition STC insolation is 1000Wm2and temperature 25∘C) and 12V and have an estimatedcapital cost of USD 200W and replacement cost of USD107W This cost includes mounting hardware installationcommissioning wiring control system dealermark-ups andshippingThe estimated lifetime is 25 years A derating factorwas selected to be of 90 In this analysis we considered thepanels tilt angle to be 24∘ (Sohar latitude)
4 International Journal of Photoenergy
PV array
DCDC converter
ATS controller
DCAC converter
Charge controller
Battery
Normal timeDeficit time
Load
Storage tank
Pumping well
Irrigation system
Figure 4 PVwater pumping system configuration
43 Charger Controller and Inverter The charger controllerand inverter are electrical convert circuits which are used toconvert electric power from DC to DC and AC respectivelyThe lifetime of converters is up to 15 years with 94 efficiencyand estimated price of an inverter is USD 05W
44 Battery Batteries are used to store the energy producedby the PV array The battery efficiency depends on the stateof charge and discharge which affect the life of the batteryAlso it is worth mentioning that HOMER software doesnot take into consideration variation in temperature or anydegradation in battery performance In addition batteriesremain constant throughout their lifetime The proposedbattery has a 12V 200Ah capacity Its lifetime is consideredto be 12 years
5 Design and Assessment ofWater Pumping Systems
51 Technoeconomical Assessment Criteria To assess the sys-tem technically and economically four criteria have been usedin this study as follows
(i) Technical criteria capacity factor (CF) and yieldfactor (YF) are applied to evaluate the productivity ofthe proposed system
(ii) Economic criteria payback period (PBP) and the costof energy (CoE) are used to assess the feasibility of theproposed system
The ratio of actual annual energy output to the amount ofenergy the PV array would generate if it operates at full rated
power (119875119903) for 24 h per day for a year represents the annual
capacity factor which is calculated as follows
CF = YF8760
=
119864PVannual(119875
119877times 8760)
(7)
Meanwhile the daily monthly or annual net AC energyoutput of the system divided by the peak power of theinstalled PV array at STC represents the yield factor whichis calculated as follows [12]
YF =119864PV (kWhyear)PVWP (kWp)
(8)
On the other hand the cost of energy and payback periodcriteria are used to assess the system economically The lifecycle cost (LCC) of a PV system may also include costs forsystem design installation labor site preparation operationand maintenance costs The life cycle cost is calculated asfollows
LCC = 119862capital +119899
sum
1
119862OampM sdot 119877PW
+
119899
sum
1
119862replacement sdot 119877PW minus 119862salvage sdot 119877PW
(9)
The different components taken into account in calculat-ing LCC are as follows capital cost 119862capital replacementcost 119862replacement maintenance cost 119862OampM and salvage value119862salvage119877PW represents the present value of each factor whichis calculated using the future sum of money (119865
119898) in a given
year (119873) at a given discount rate (119868)
119877PW =119865
119898
(1 + 119868)
119873 (10)
International Journal of Photoenergy 5
Table 1 Modelled PV system specification
PV arrayPV module rated power 140WpMaximum voltage 177Maximum current 791Open circuit voltage 221Short circuit current 868Efficiency 139Temperature coefficient of Voc minus036kTemperature coefficient of Isc 006k
InverterRated power 08 kWAC voltage 220ndash240Efficiency 940
Table 2 Economic assumption of PV system
Component Capital Lifetime Replacement OampM Fuel($kW) (years) ($) ($) ($)
After calculating LCC the cost of energy is calculated using
CoE = LCCsum
119899
1119864PVannual
(11)
where 119864PVannual is the annual energy production of the PVsystem while 119899 is the system lifetime in years Finally thepayback period is calculated as follows
PBP =119862capital (USD)
[119864PVannual (kWhyear) times CoE (USDkWh) times 119877PW]
(12)
52 Optimum System Design In this research solar waterpumping system has been designed for irrigation in SoharOman This system contains 045 kWp water pump Thesystem has been installed at Sohar zone for research workpurposes The feasibility of the proposed solar water pump-ing system was designed and analyzed using HOMER andREPSOM to find the optimum system component HOMERand REPSOM were used to model different system elementsand check the component physical behaviour and its life cyclecost The optimum system components have been selectedbased on their technical and economic merits Table 1 showsthe specification of the optimummodule and inverter
The schematic diagram in HOMER model for the builtPV system is presented in Figure 5 Since the solar radiationis high enough between 1100AM and 400 PM it is worthgenerating electricity in this period to supply the pump tofill the tank The economic assumptions of the system andthe load analysis calculation are given in Tables 2 and 3respectively
Table 3 Scaled data for simulation
Data source SyntheticDaily noise 15Hourly noise 20Scaled annual average 222 kWhdayScaled peak load 0809 kWLoad factor 0114
Water pump
810W peak
Converter
Ac DC
PV
6FM200D
22 kWhd
Figure 5 HOMER schematic diagram for the solar PV waterpumping system
The suggested PVmodule for simulation of the optimumsystemused in this study is 12 V 140WpDifferent PVmodulecapacities are introduced and considered in the analysiswhich is in the range of 1ndash10 modules The suggested batterywas 12V 200Ah capacities with estimated cost of 140USDAlso for sensitivity analysis the range of batteries is assumedto be 1ndash5 battery banks Furthermore the inverter efficiencywas assumed to be 94 for all considered sizes with estimatedcost of 05 USDW and lifetime of 15 yearsThe inverter rangewas selected to be 01ndash10 kW for analysis consideration
6 Discussion and Analysis
After running the system model in HOMER 704 feasiblesolutions are found and out of these 10 best solutions rankedaccording to the system minimum net present cost (NPC)and cost of energy (CoE) are shown in Table 4 The tableshows that the greatest optimal result is achieved when thesystem is composed of 084 kW PV array (6 modules) 4batteries and 08 kW inverter The optimum solution to thetotal NPC is 3200 USD with operating cost of 63 USDyearand the cost of energy equals 0309 USDkWh On theother hand REPSOM found that the optimum result isachieved when the system is composed of 056 kW PV array(4 modules) 2 batteries and 045 kW inverter FurthermoreREPSOM optimum solution found that the total NPC is1880 USD with operating cost of 33 USDyear and the cost
6 International Journal of Photoenergy
Table 4 Optimum solution for the proposed PV system using HOMER
PV(kW) 6FM200D Conv
(kW)Initialcapital
Operatingcost ($yr)
TotalNPC
COE($kWh)
Renfrac
Capacityshortage
084 4 08 $ 2400 63 $ 3200 0309 100 000
084 4 09 $ 2450 64 $ 3265 0315 100 000
070 5 08 $ 2300 76 $ 3269 0316 100 000
084 4 10 $ 2500 65 $ 3331 0322 100 000
070 5 09 $ 2350 77 $ 3335 0322 100 000
070 5 10 $ 2400 78 $ 3400 0328 100 000
098 4 08 $ 2640 63 $ 3440 0332 100 000
098 4 09 $ 2690 64 $ 3505 0338 100 000
084 5 08 $ 2540 76 $ 3509 0339 100 000
098 4 10 $ 2740 65 $ 3571 0345 100 000
of energy equals 018 USDkWh It is worth mentioning thatoptimum tilt angle was found to be 27∘ for Sohar
The fossil fuel generator has been simulated for compar-ison to supply the same water pump as shown in Figure 6There are different types of generators commercially available(propane diesel biofuel and gasoline) In this study thediesel fuel generator has been used since it is more efficientand has a longer lifetime in comparison with others andbecause it is the used fuel in Oman as it is considered asone of the suppliers of fuel Rural Areas Electricity Company(RAECO) generation system fuel is diesel Its diesel price issubsidies from the Omani Government and accounted for 46BaizaLitre which is equivalent to 038 USDLitre [12] Onthe other hand it is found that global diesel price on January2014 is 138 USDLitre [13] In this part the water pumpsystem supplied from diesel generator has been investigatedfor comparison with designed PV systems
The fuel price tested 038 and 138 USDLitre with andwithout the government subsidy respectivelyThe price of thegenerator is 500 USD and we considered the generator size of500W in the analysis To compare the PV system results withthe diesel generator to choose the best and costless systemthe analysis shows that a size of 1000W generator has beenestimated with capital operating and total net cost being1000 USD 562 (USDyr) and 8185 USD respectively asshown in Table 5 The CoE is found to be 079 (USDkWh)which is considered to be high as compared with CoE of theproposed PV system (018 and 0309 (USDkWh))
The energy generated shares from REPSOM proposedsystem are shown in Figure 7 PV system availability is calcu-lated as the percentage of time that a power system is capableof meeting load requirements where it is found that thesystem availability is 98 It is found that REPSOMoptimumsystem availability is higher than HOMER and intuitivemethod systems However Figure 7 shows the complete yearperformance of the proposed system From the figure it isclearly seen that the solar energy covers most of the systemload and the battery is intensively used through the year timewhich makes it able to supply the load in some extremely
Water pump
810W peak22 kWhd
Generator 1
AC
Figure 6 HOMER schematic diagrams for the diesel generatorwater pumping system
cloudy days However it is found that the system annual yieldfactor is 202466 kWhkWp Furthermore the capacity factorwas found to be 2305 which is promising since the typicalone is 21
Emission of green-house gases from the fuel of theequivalent conventional system is important Adopting solarPV systems will protect the environment from the harmfulgreen-house gases Table 6 shows the polluted emissionsproduced by the diesel generator used to supply the waterpump Furthermore in comparison between subsidized andnonsubsidized fuel cost it is found that the CoE is 079 and1228 USDkWh respectively This means that besides theprotection of the environment the cost of diesel is relativelyhigh and part of the cost covered by the government couldbe used for other economic projects if the PV technology hasbeen adopted
The comparisons of the cost of energy in the modelledsystem are shown in Table 7 The proposed system cost isacceptable in comparison with the cost of PV systems in
International Journal of Photoenergy 7
Table 5 Diesel system results for 038USDLitre
Label(kW)
Initialcapital
Operatingcost ($yr)
TotalNPC
COE($kWh)
Renfrac
Capacityshortage
Diesel(L)
Label(hrs)
10 $ 1000 562 $ 8185 0790 000 000 351 1825
50 100 150 200 250 300 3500
500
Day
Generated energy by PVLoad demand
50 100 150 200 250 300 350minus500
0500
Day
Energy balance
50 100 150 200 250 300 3500
051
Day
Battery SOC
50 100 150 200 250 300 3500
100200
Day
Deficit energy
Ener
gy (k
Wh)
Ener
gy (k
Wh)
Ener
gy (k
Wh)
SOC
()
Figure 7 Proposed system hourly performance sample
[4] [5] [6] [14] and [15] 0401 0561 0389 021ndash0304and 0361ndash0327 USDkWh respectively Also it is foundthat the cost of PV systems is promising in comparison withthe proposed diesel system (0790 and 1228 USDkWh) andthe energy cost of diesel engine system in [15 16] 05581USDkWh Furthermore regardless of the fact that hybridsystems technically and economically are effective it is foundthat the proposed PV system is economical in comparisonwith [8] where the cost of energy is 0200ndash0580 USDkWhwhich make PV water pumping system be a good option forirrigation in rural areas of Oman
7 Conclusions
In this study PV water pumping system for Sohar Oman hasbeen designed and assessed Optimum selection of systemcomponents PV modules inverter charger controller andbatteries Oman has been determined The system has adaily load of 222 kWhday 084 kW PV modules 4 batteries(12 V and 200Ah) and 08 kW inverter The results haveshown that the optimum cost of PV system energy 0309USDkWh is attractive option in comparison with the costof diesel engine energy 079 USDkWh Also it is found that
Proposed PV research (REPSOM) 0180 PVProposed PV research (HOMER) 0309 PVSubsidized diesel system 0790 DieselNonsubsidized diesel system 1228 Diesel([4] Bakelli et al 2011) 0401 PV([5] Salam et al 2013) 0561 PV([6] Kazem et al 2013) 0389 PV([8] Al-Smairan 2012) 0200ndash0580 PV-diesel([17] Al-Badi et al 2011) 021ndash0304 PV([14] Al-Badi et al 2012) 0327ndash0361 PV([15] annual report 2010) 0558 Diesel([16] annual report 2011) 0558 Diesel
most PV system options are feasible more than the dieselgenerator option Also investigations show that the proposedsystem is cost effective with designed systems in literatureIn addition it is found that PV solar water pumping systemscould be an excellent option for irrigation in rural areas ofOman Moreover the analysis shows that replacing dieselgenerator by PV system will protect the environment fromgreen-house gas emission 924 kgyear of CO
2 228 kgyear of
CO 0253 kgyear of NOx 0172 kgyear of HC 186 kgyearof SO
2 and 204 kgyear of suspended particles
Conflict of Interests
The authors declare that there is no conflict of interestsregarding the publication of this paper
Acknowledgments
The research leading to these results has received ResearchProject Grant Funding from the Research Council of theSultanate of Oman Research Grant Agreement ORG SU EI
8 International Journal of Photoenergy
11 010 and FURAPC2HKENGEE The authors would liketo acknowledge support from theResearchCouncil ofOman
References
[1] H A Kazem and T Khatib Photovoltaic Power System Prospec-tive in Oman Technical and Economical Study LAP LAMBERTAcademic Publishing Saarbrucken Germany 1st edition 2013
[2] A Al-Karaghouli and L L Kazmerski ldquoOptimization and life-cycle cost of health clinic PV system for a rural area in southernIraq using HOMER softwarerdquo Solar Energy vol 84 no 4 pp710ndash714 2010
[3] Z Girma ldquoHybrid renewable energy design for rural electrifi-cation in Ethiopiardquo Journal of Energy Technologies and Policyvol 3 no 13 pp 38ndash52 2013
[4] Y Bakelli A H Arab and B Azoui ldquoOptimal sizing ofphotovoltaic pumping system with water tank storage usingLPSP conceptrdquo Solar Energy vol 85 no 2 pp 288ndash294 2011
[5] M A Salam A Aziz A H A Alwaeli andH A Kazem ldquoOpti-mal sizing of photovoltaic systems using HOMER for SoharOmanrdquo International Journal of Renewable Energy Research vol3 no 2 pp 301ndash307 2013
[6] H A Kazem A A Alkurwi M M Alabdul Salam and A HA Alwaeli ldquoLevelized electricity cost for photovoltaic systemin Sohar-Omanrdquo in Proceedings of the IEEE 8th InternationalConference and Exhibition on Ecological Vehicles and RenewableEnergies (EVER rsquo13) Monte-Carlo Monaco March 2013
[7] R Mishra and S Singh ldquoSustainable energy plan for a villagein punjab for self energy generationrdquo International Journal ofRenewable Energy Research vol 3 no 3 pp 640ndash646 2013
[8] M Al-Smairan ldquoApplication of photovoltaic array for pumpingwater as an alternative to diesel engines in Jordan Badia TallHassan station case studyrdquo Renewable and Sustainable EnergyReviews vol 16 no 7 pp 4500ndash4507 2012
[9] K Meah S Ula and S Barrett ldquoSolar photovoltaic waterpumpingmdashopportunities and challengesrdquo Renewable and Sus-tainable Energy Reviews vol 12 no 4 pp 1162ndash1175 2008
[10] H A Kazem T Khatib and K Sopian ldquoSizing of a standalonephotovoltaicbattery system at minimum cost for remote hous-ing electrification in Sohar Omanrdquo Energy and Buildings vol61 pp 108ndash115 2013
[11] H A Kazem T Khatib K Sopian and W Elmenreich ldquoPer-formance and feasibility assessment of a 14kW roof top grid-connected photovoltaic power system under desertic weatherconditionsrdquo Energy and Buildings vol 82 pp 123ndash129 2014
[12] Authority for Electricity Regulation in Oman ldquoStudy onrenewable resourcesrdquo Final Report Authority for ElectricityRegulation in Oman Muscat Oman 2008
[13] Fuel Price Report 2014 httpwwwcatalistcom[14] A H Al-Badi M AL-Toobi S AL-Harthy Z Al-Hosni and
A AL-Harthy ldquoHybrid systems for decentralized power gener-ation in Omanrdquo International Journal of Sustainable Energy vol31 no 6 pp 411ndash421 2012
[15] Annual Report 2010 Rural Areas Electricity Company MuscatOman 2010
[16] 2011 Annual report from Rural Areas Electricity CompanyOman
[17] A H Al-Badi M H Albadi A M Al-Lawati and A S MalikldquoEconomic perspective of PV electricity in Omanrdquo Energy vol36 no 1 pp 226ndash232 2011
Figure 2 Mean hourly solar radiations for Sohar (April 2013ndashApril2014)
where 120588 is the water density kgm3 119892 is acceleration due togravity ms2 ℎ andΔ119867 are total pumping head and hydrauliclosses inm volume of flow119876 inm3s and 120578
119887and 120578119890are pump
and electric motor efficiencies respectivelyAlso the required hydraulic energy in kWhday is calcu-
where119881 is the volume required inm3day 120578119904is the subsystem
efficiency and 119864PV is the PV energy
32 PV System Sizing The PV array is used to convert solarenergy to DC electrical energy The quality of DC powerimproved through power conditioner and converted to ACpower using an inverterThe energy produced by PV array inkW is calculated and is given by [10]
119864PV = 119860PV times 119866119879 times 120578module times 120578inv times 120578wire (3)
where 119860PV is the area of the PV array in m2 and 119866119879is
daily solar radiation in kWhm2 120578module 120578inv and 120578wire areefficiencies of PV module inverter and wires respectivelyThe area 119860PV is calculated from (2) and (3) as follows
119860PV =120588119892ℎ119881
119866
119879120578PV120578119904 (4)
where 120578PV is the summation of module inverter and wireefficiencies Accordingly the required PV array power iscalculated in kW as follows
119875PV =119864
ℎ
119866
119879sdot 119865 sdot 119864
(5)
Global horizontal radiation7
6
5
4
3
2
1
0
Dai
ly ra
diat
ion
(kW
hm
2d
)
Jan
Feb
Mar
Apr
May
Jun Jul
Aug
Sep
Oct
Nov
Dec
10
08
06
04
02
00
Clea
rnes
s ind
ex
Clearness indexDaily radiation
Figure 3 Profile of solar radiation in Sohar Oman
where 119865 is the mismatch factor which is in the range of085ndash090 and 119864 is the daily subsystem efficiency 02ndash06typically [10 11] The PVpump system efficiency is given by
120578system =119875
ℎ
119875PV=
120588119892ℎ119881
119866
119879119860PV (6)
4 PV Water Pumping Systems ComponentsIn this study the proposed system consists of PV arraycontaining few modules charge controller and inverterbatteries for storage and the rest of system components likewires protections sensors andmodule structureThe systemconfiguration is shown in Figure 4 This figure shows thePV water pumping system proposed for irrigation in SoharOman It is worth mentioning that in this study the selectedwell depth is 16m static water level is 65m dynamic waterlevel is 72m well productivity is 81m3h design criteria are45m3day and pumphead is 18m In the coming subsectionsHOMER software will be used first to find the optimumsystem design
41 Water Pump The intuitive method discussed in Sections31 and 32 has been used to estimate the required PV systemcomponents Equations (2) and (5) are used to calculateenergy required for pumping water which is 2197 kWhdayand PV array is 088 kW Also themotor pumpwas estimatedto be 450W 230V and 50Hz It is worth mentioning that thepump works on peak hours
42 PVArray The solar cell is used to convert solar radiationinto electricity These cells are connected in series and areparallel to produce PV modules The PV modules alsoconnected series and are parallel to produce PV array Theproposed PV panels to be used in the system simulation are140 W (at static test condition STC insolation is 1000Wm2and temperature 25∘C) and 12V and have an estimatedcapital cost of USD 200W and replacement cost of USD107W This cost includes mounting hardware installationcommissioning wiring control system dealermark-ups andshippingThe estimated lifetime is 25 years A derating factorwas selected to be of 90 In this analysis we considered thepanels tilt angle to be 24∘ (Sohar latitude)
4 International Journal of Photoenergy
PV array
DCDC converter
ATS controller
DCAC converter
Charge controller
Battery
Normal timeDeficit time
Load
Storage tank
Pumping well
Irrigation system
Figure 4 PVwater pumping system configuration
43 Charger Controller and Inverter The charger controllerand inverter are electrical convert circuits which are used toconvert electric power from DC to DC and AC respectivelyThe lifetime of converters is up to 15 years with 94 efficiencyand estimated price of an inverter is USD 05W
44 Battery Batteries are used to store the energy producedby the PV array The battery efficiency depends on the stateof charge and discharge which affect the life of the batteryAlso it is worth mentioning that HOMER software doesnot take into consideration variation in temperature or anydegradation in battery performance In addition batteriesremain constant throughout their lifetime The proposedbattery has a 12V 200Ah capacity Its lifetime is consideredto be 12 years
5 Design and Assessment ofWater Pumping Systems
51 Technoeconomical Assessment Criteria To assess the sys-tem technically and economically four criteria have been usedin this study as follows
(i) Technical criteria capacity factor (CF) and yieldfactor (YF) are applied to evaluate the productivity ofthe proposed system
(ii) Economic criteria payback period (PBP) and the costof energy (CoE) are used to assess the feasibility of theproposed system
The ratio of actual annual energy output to the amount ofenergy the PV array would generate if it operates at full rated
power (119875119903) for 24 h per day for a year represents the annual
capacity factor which is calculated as follows
CF = YF8760
=
119864PVannual(119875
119877times 8760)
(7)
Meanwhile the daily monthly or annual net AC energyoutput of the system divided by the peak power of theinstalled PV array at STC represents the yield factor whichis calculated as follows [12]
YF =119864PV (kWhyear)PVWP (kWp)
(8)
On the other hand the cost of energy and payback periodcriteria are used to assess the system economically The lifecycle cost (LCC) of a PV system may also include costs forsystem design installation labor site preparation operationand maintenance costs The life cycle cost is calculated asfollows
LCC = 119862capital +119899
sum
1
119862OampM sdot 119877PW
+
119899
sum
1
119862replacement sdot 119877PW minus 119862salvage sdot 119877PW
(9)
The different components taken into account in calculat-ing LCC are as follows capital cost 119862capital replacementcost 119862replacement maintenance cost 119862OampM and salvage value119862salvage119877PW represents the present value of each factor whichis calculated using the future sum of money (119865
119898) in a given
year (119873) at a given discount rate (119868)
119877PW =119865
119898
(1 + 119868)
119873 (10)
International Journal of Photoenergy 5
Table 1 Modelled PV system specification
PV arrayPV module rated power 140WpMaximum voltage 177Maximum current 791Open circuit voltage 221Short circuit current 868Efficiency 139Temperature coefficient of Voc minus036kTemperature coefficient of Isc 006k
InverterRated power 08 kWAC voltage 220ndash240Efficiency 940
Table 2 Economic assumption of PV system
Component Capital Lifetime Replacement OampM Fuel($kW) (years) ($) ($) ($)
After calculating LCC the cost of energy is calculated using
CoE = LCCsum
119899
1119864PVannual
(11)
where 119864PVannual is the annual energy production of the PVsystem while 119899 is the system lifetime in years Finally thepayback period is calculated as follows
PBP =119862capital (USD)
[119864PVannual (kWhyear) times CoE (USDkWh) times 119877PW]
(12)
52 Optimum System Design In this research solar waterpumping system has been designed for irrigation in SoharOman This system contains 045 kWp water pump Thesystem has been installed at Sohar zone for research workpurposes The feasibility of the proposed solar water pump-ing system was designed and analyzed using HOMER andREPSOM to find the optimum system component HOMERand REPSOM were used to model different system elementsand check the component physical behaviour and its life cyclecost The optimum system components have been selectedbased on their technical and economic merits Table 1 showsthe specification of the optimummodule and inverter
The schematic diagram in HOMER model for the builtPV system is presented in Figure 5 Since the solar radiationis high enough between 1100AM and 400 PM it is worthgenerating electricity in this period to supply the pump tofill the tank The economic assumptions of the system andthe load analysis calculation are given in Tables 2 and 3respectively
Table 3 Scaled data for simulation
Data source SyntheticDaily noise 15Hourly noise 20Scaled annual average 222 kWhdayScaled peak load 0809 kWLoad factor 0114
Water pump
810W peak
Converter
Ac DC
PV
6FM200D
22 kWhd
Figure 5 HOMER schematic diagram for the solar PV waterpumping system
The suggested PVmodule for simulation of the optimumsystemused in this study is 12 V 140WpDifferent PVmodulecapacities are introduced and considered in the analysiswhich is in the range of 1ndash10 modules The suggested batterywas 12V 200Ah capacities with estimated cost of 140USDAlso for sensitivity analysis the range of batteries is assumedto be 1ndash5 battery banks Furthermore the inverter efficiencywas assumed to be 94 for all considered sizes with estimatedcost of 05 USDW and lifetime of 15 yearsThe inverter rangewas selected to be 01ndash10 kW for analysis consideration
6 Discussion and Analysis
After running the system model in HOMER 704 feasiblesolutions are found and out of these 10 best solutions rankedaccording to the system minimum net present cost (NPC)and cost of energy (CoE) are shown in Table 4 The tableshows that the greatest optimal result is achieved when thesystem is composed of 084 kW PV array (6 modules) 4batteries and 08 kW inverter The optimum solution to thetotal NPC is 3200 USD with operating cost of 63 USDyearand the cost of energy equals 0309 USDkWh On theother hand REPSOM found that the optimum result isachieved when the system is composed of 056 kW PV array(4 modules) 2 batteries and 045 kW inverter FurthermoreREPSOM optimum solution found that the total NPC is1880 USD with operating cost of 33 USDyear and the cost
6 International Journal of Photoenergy
Table 4 Optimum solution for the proposed PV system using HOMER
PV(kW) 6FM200D Conv
(kW)Initialcapital
Operatingcost ($yr)
TotalNPC
COE($kWh)
Renfrac
Capacityshortage
084 4 08 $ 2400 63 $ 3200 0309 100 000
084 4 09 $ 2450 64 $ 3265 0315 100 000
070 5 08 $ 2300 76 $ 3269 0316 100 000
084 4 10 $ 2500 65 $ 3331 0322 100 000
070 5 09 $ 2350 77 $ 3335 0322 100 000
070 5 10 $ 2400 78 $ 3400 0328 100 000
098 4 08 $ 2640 63 $ 3440 0332 100 000
098 4 09 $ 2690 64 $ 3505 0338 100 000
084 5 08 $ 2540 76 $ 3509 0339 100 000
098 4 10 $ 2740 65 $ 3571 0345 100 000
of energy equals 018 USDkWh It is worth mentioning thatoptimum tilt angle was found to be 27∘ for Sohar
The fossil fuel generator has been simulated for compar-ison to supply the same water pump as shown in Figure 6There are different types of generators commercially available(propane diesel biofuel and gasoline) In this study thediesel fuel generator has been used since it is more efficientand has a longer lifetime in comparison with others andbecause it is the used fuel in Oman as it is considered asone of the suppliers of fuel Rural Areas Electricity Company(RAECO) generation system fuel is diesel Its diesel price issubsidies from the Omani Government and accounted for 46BaizaLitre which is equivalent to 038 USDLitre [12] Onthe other hand it is found that global diesel price on January2014 is 138 USDLitre [13] In this part the water pumpsystem supplied from diesel generator has been investigatedfor comparison with designed PV systems
The fuel price tested 038 and 138 USDLitre with andwithout the government subsidy respectivelyThe price of thegenerator is 500 USD and we considered the generator size of500W in the analysis To compare the PV system results withthe diesel generator to choose the best and costless systemthe analysis shows that a size of 1000W generator has beenestimated with capital operating and total net cost being1000 USD 562 (USDyr) and 8185 USD respectively asshown in Table 5 The CoE is found to be 079 (USDkWh)which is considered to be high as compared with CoE of theproposed PV system (018 and 0309 (USDkWh))
The energy generated shares from REPSOM proposedsystem are shown in Figure 7 PV system availability is calcu-lated as the percentage of time that a power system is capableof meeting load requirements where it is found that thesystem availability is 98 It is found that REPSOMoptimumsystem availability is higher than HOMER and intuitivemethod systems However Figure 7 shows the complete yearperformance of the proposed system From the figure it isclearly seen that the solar energy covers most of the systemload and the battery is intensively used through the year timewhich makes it able to supply the load in some extremely
Water pump
810W peak22 kWhd
Generator 1
AC
Figure 6 HOMER schematic diagrams for the diesel generatorwater pumping system
cloudy days However it is found that the system annual yieldfactor is 202466 kWhkWp Furthermore the capacity factorwas found to be 2305 which is promising since the typicalone is 21
Emission of green-house gases from the fuel of theequivalent conventional system is important Adopting solarPV systems will protect the environment from the harmfulgreen-house gases Table 6 shows the polluted emissionsproduced by the diesel generator used to supply the waterpump Furthermore in comparison between subsidized andnonsubsidized fuel cost it is found that the CoE is 079 and1228 USDkWh respectively This means that besides theprotection of the environment the cost of diesel is relativelyhigh and part of the cost covered by the government couldbe used for other economic projects if the PV technology hasbeen adopted
The comparisons of the cost of energy in the modelledsystem are shown in Table 7 The proposed system cost isacceptable in comparison with the cost of PV systems in
International Journal of Photoenergy 7
Table 5 Diesel system results for 038USDLitre
Label(kW)
Initialcapital
Operatingcost ($yr)
TotalNPC
COE($kWh)
Renfrac
Capacityshortage
Diesel(L)
Label(hrs)
10 $ 1000 562 $ 8185 0790 000 000 351 1825
50 100 150 200 250 300 3500
500
Day
Generated energy by PVLoad demand
50 100 150 200 250 300 350minus500
0500
Day
Energy balance
50 100 150 200 250 300 3500
051
Day
Battery SOC
50 100 150 200 250 300 3500
100200
Day
Deficit energy
Ener
gy (k
Wh)
Ener
gy (k
Wh)
Ener
gy (k
Wh)
SOC
()
Figure 7 Proposed system hourly performance sample
[4] [5] [6] [14] and [15] 0401 0561 0389 021ndash0304and 0361ndash0327 USDkWh respectively Also it is foundthat the cost of PV systems is promising in comparison withthe proposed diesel system (0790 and 1228 USDkWh) andthe energy cost of diesel engine system in [15 16] 05581USDkWh Furthermore regardless of the fact that hybridsystems technically and economically are effective it is foundthat the proposed PV system is economical in comparisonwith [8] where the cost of energy is 0200ndash0580 USDkWhwhich make PV water pumping system be a good option forirrigation in rural areas of Oman
7 Conclusions
In this study PV water pumping system for Sohar Oman hasbeen designed and assessed Optimum selection of systemcomponents PV modules inverter charger controller andbatteries Oman has been determined The system has adaily load of 222 kWhday 084 kW PV modules 4 batteries(12 V and 200Ah) and 08 kW inverter The results haveshown that the optimum cost of PV system energy 0309USDkWh is attractive option in comparison with the costof diesel engine energy 079 USDkWh Also it is found that
Proposed PV research (REPSOM) 0180 PVProposed PV research (HOMER) 0309 PVSubsidized diesel system 0790 DieselNonsubsidized diesel system 1228 Diesel([4] Bakelli et al 2011) 0401 PV([5] Salam et al 2013) 0561 PV([6] Kazem et al 2013) 0389 PV([8] Al-Smairan 2012) 0200ndash0580 PV-diesel([17] Al-Badi et al 2011) 021ndash0304 PV([14] Al-Badi et al 2012) 0327ndash0361 PV([15] annual report 2010) 0558 Diesel([16] annual report 2011) 0558 Diesel
most PV system options are feasible more than the dieselgenerator option Also investigations show that the proposedsystem is cost effective with designed systems in literatureIn addition it is found that PV solar water pumping systemscould be an excellent option for irrigation in rural areas ofOman Moreover the analysis shows that replacing dieselgenerator by PV system will protect the environment fromgreen-house gas emission 924 kgyear of CO
2 228 kgyear of
CO 0253 kgyear of NOx 0172 kgyear of HC 186 kgyearof SO
2 and 204 kgyear of suspended particles
Conflict of Interests
The authors declare that there is no conflict of interestsregarding the publication of this paper
Acknowledgments
The research leading to these results has received ResearchProject Grant Funding from the Research Council of theSultanate of Oman Research Grant Agreement ORG SU EI
8 International Journal of Photoenergy
11 010 and FURAPC2HKENGEE The authors would liketo acknowledge support from theResearchCouncil ofOman
References
[1] H A Kazem and T Khatib Photovoltaic Power System Prospec-tive in Oman Technical and Economical Study LAP LAMBERTAcademic Publishing Saarbrucken Germany 1st edition 2013
[2] A Al-Karaghouli and L L Kazmerski ldquoOptimization and life-cycle cost of health clinic PV system for a rural area in southernIraq using HOMER softwarerdquo Solar Energy vol 84 no 4 pp710ndash714 2010
[3] Z Girma ldquoHybrid renewable energy design for rural electrifi-cation in Ethiopiardquo Journal of Energy Technologies and Policyvol 3 no 13 pp 38ndash52 2013
[4] Y Bakelli A H Arab and B Azoui ldquoOptimal sizing ofphotovoltaic pumping system with water tank storage usingLPSP conceptrdquo Solar Energy vol 85 no 2 pp 288ndash294 2011
[5] M A Salam A Aziz A H A Alwaeli andH A Kazem ldquoOpti-mal sizing of photovoltaic systems using HOMER for SoharOmanrdquo International Journal of Renewable Energy Research vol3 no 2 pp 301ndash307 2013
[6] H A Kazem A A Alkurwi M M Alabdul Salam and A HA Alwaeli ldquoLevelized electricity cost for photovoltaic systemin Sohar-Omanrdquo in Proceedings of the IEEE 8th InternationalConference and Exhibition on Ecological Vehicles and RenewableEnergies (EVER rsquo13) Monte-Carlo Monaco March 2013
[7] R Mishra and S Singh ldquoSustainable energy plan for a villagein punjab for self energy generationrdquo International Journal ofRenewable Energy Research vol 3 no 3 pp 640ndash646 2013
[8] M Al-Smairan ldquoApplication of photovoltaic array for pumpingwater as an alternative to diesel engines in Jordan Badia TallHassan station case studyrdquo Renewable and Sustainable EnergyReviews vol 16 no 7 pp 4500ndash4507 2012
[9] K Meah S Ula and S Barrett ldquoSolar photovoltaic waterpumpingmdashopportunities and challengesrdquo Renewable and Sus-tainable Energy Reviews vol 12 no 4 pp 1162ndash1175 2008
[10] H A Kazem T Khatib and K Sopian ldquoSizing of a standalonephotovoltaicbattery system at minimum cost for remote hous-ing electrification in Sohar Omanrdquo Energy and Buildings vol61 pp 108ndash115 2013
[11] H A Kazem T Khatib K Sopian and W Elmenreich ldquoPer-formance and feasibility assessment of a 14kW roof top grid-connected photovoltaic power system under desertic weatherconditionsrdquo Energy and Buildings vol 82 pp 123ndash129 2014
[12] Authority for Electricity Regulation in Oman ldquoStudy onrenewable resourcesrdquo Final Report Authority for ElectricityRegulation in Oman Muscat Oman 2008
[13] Fuel Price Report 2014 httpwwwcatalistcom[14] A H Al-Badi M AL-Toobi S AL-Harthy Z Al-Hosni and
A AL-Harthy ldquoHybrid systems for decentralized power gener-ation in Omanrdquo International Journal of Sustainable Energy vol31 no 6 pp 411ndash421 2012
[15] Annual Report 2010 Rural Areas Electricity Company MuscatOman 2010
[16] 2011 Annual report from Rural Areas Electricity CompanyOman
[17] A H Al-Badi M H Albadi A M Al-Lawati and A S MalikldquoEconomic perspective of PV electricity in Omanrdquo Energy vol36 no 1 pp 226ndash232 2011
43 Charger Controller and Inverter The charger controllerand inverter are electrical convert circuits which are used toconvert electric power from DC to DC and AC respectivelyThe lifetime of converters is up to 15 years with 94 efficiencyand estimated price of an inverter is USD 05W
44 Battery Batteries are used to store the energy producedby the PV array The battery efficiency depends on the stateof charge and discharge which affect the life of the batteryAlso it is worth mentioning that HOMER software doesnot take into consideration variation in temperature or anydegradation in battery performance In addition batteriesremain constant throughout their lifetime The proposedbattery has a 12V 200Ah capacity Its lifetime is consideredto be 12 years
5 Design and Assessment ofWater Pumping Systems
51 Technoeconomical Assessment Criteria To assess the sys-tem technically and economically four criteria have been usedin this study as follows
(i) Technical criteria capacity factor (CF) and yieldfactor (YF) are applied to evaluate the productivity ofthe proposed system
(ii) Economic criteria payback period (PBP) and the costof energy (CoE) are used to assess the feasibility of theproposed system
The ratio of actual annual energy output to the amount ofenergy the PV array would generate if it operates at full rated
power (119875119903) for 24 h per day for a year represents the annual
capacity factor which is calculated as follows
CF = YF8760
=
119864PVannual(119875
119877times 8760)
(7)
Meanwhile the daily monthly or annual net AC energyoutput of the system divided by the peak power of theinstalled PV array at STC represents the yield factor whichis calculated as follows [12]
YF =119864PV (kWhyear)PVWP (kWp)
(8)
On the other hand the cost of energy and payback periodcriteria are used to assess the system economically The lifecycle cost (LCC) of a PV system may also include costs forsystem design installation labor site preparation operationand maintenance costs The life cycle cost is calculated asfollows
LCC = 119862capital +119899
sum
1
119862OampM sdot 119877PW
+
119899
sum
1
119862replacement sdot 119877PW minus 119862salvage sdot 119877PW
(9)
The different components taken into account in calculat-ing LCC are as follows capital cost 119862capital replacementcost 119862replacement maintenance cost 119862OampM and salvage value119862salvage119877PW represents the present value of each factor whichis calculated using the future sum of money (119865
119898) in a given
year (119873) at a given discount rate (119868)
119877PW =119865
119898
(1 + 119868)
119873 (10)
International Journal of Photoenergy 5
Table 1 Modelled PV system specification
PV arrayPV module rated power 140WpMaximum voltage 177Maximum current 791Open circuit voltage 221Short circuit current 868Efficiency 139Temperature coefficient of Voc minus036kTemperature coefficient of Isc 006k
InverterRated power 08 kWAC voltage 220ndash240Efficiency 940
Table 2 Economic assumption of PV system
Component Capital Lifetime Replacement OampM Fuel($kW) (years) ($) ($) ($)
After calculating LCC the cost of energy is calculated using
CoE = LCCsum
119899
1119864PVannual
(11)
where 119864PVannual is the annual energy production of the PVsystem while 119899 is the system lifetime in years Finally thepayback period is calculated as follows
PBP =119862capital (USD)
[119864PVannual (kWhyear) times CoE (USDkWh) times 119877PW]
(12)
52 Optimum System Design In this research solar waterpumping system has been designed for irrigation in SoharOman This system contains 045 kWp water pump Thesystem has been installed at Sohar zone for research workpurposes The feasibility of the proposed solar water pump-ing system was designed and analyzed using HOMER andREPSOM to find the optimum system component HOMERand REPSOM were used to model different system elementsand check the component physical behaviour and its life cyclecost The optimum system components have been selectedbased on their technical and economic merits Table 1 showsthe specification of the optimummodule and inverter
The schematic diagram in HOMER model for the builtPV system is presented in Figure 5 Since the solar radiationis high enough between 1100AM and 400 PM it is worthgenerating electricity in this period to supply the pump tofill the tank The economic assumptions of the system andthe load analysis calculation are given in Tables 2 and 3respectively
Table 3 Scaled data for simulation
Data source SyntheticDaily noise 15Hourly noise 20Scaled annual average 222 kWhdayScaled peak load 0809 kWLoad factor 0114
Water pump
810W peak
Converter
Ac DC
PV
6FM200D
22 kWhd
Figure 5 HOMER schematic diagram for the solar PV waterpumping system
The suggested PVmodule for simulation of the optimumsystemused in this study is 12 V 140WpDifferent PVmodulecapacities are introduced and considered in the analysiswhich is in the range of 1ndash10 modules The suggested batterywas 12V 200Ah capacities with estimated cost of 140USDAlso for sensitivity analysis the range of batteries is assumedto be 1ndash5 battery banks Furthermore the inverter efficiencywas assumed to be 94 for all considered sizes with estimatedcost of 05 USDW and lifetime of 15 yearsThe inverter rangewas selected to be 01ndash10 kW for analysis consideration
6 Discussion and Analysis
After running the system model in HOMER 704 feasiblesolutions are found and out of these 10 best solutions rankedaccording to the system minimum net present cost (NPC)and cost of energy (CoE) are shown in Table 4 The tableshows that the greatest optimal result is achieved when thesystem is composed of 084 kW PV array (6 modules) 4batteries and 08 kW inverter The optimum solution to thetotal NPC is 3200 USD with operating cost of 63 USDyearand the cost of energy equals 0309 USDkWh On theother hand REPSOM found that the optimum result isachieved when the system is composed of 056 kW PV array(4 modules) 2 batteries and 045 kW inverter FurthermoreREPSOM optimum solution found that the total NPC is1880 USD with operating cost of 33 USDyear and the cost
6 International Journal of Photoenergy
Table 4 Optimum solution for the proposed PV system using HOMER
PV(kW) 6FM200D Conv
(kW)Initialcapital
Operatingcost ($yr)
TotalNPC
COE($kWh)
Renfrac
Capacityshortage
084 4 08 $ 2400 63 $ 3200 0309 100 000
084 4 09 $ 2450 64 $ 3265 0315 100 000
070 5 08 $ 2300 76 $ 3269 0316 100 000
084 4 10 $ 2500 65 $ 3331 0322 100 000
070 5 09 $ 2350 77 $ 3335 0322 100 000
070 5 10 $ 2400 78 $ 3400 0328 100 000
098 4 08 $ 2640 63 $ 3440 0332 100 000
098 4 09 $ 2690 64 $ 3505 0338 100 000
084 5 08 $ 2540 76 $ 3509 0339 100 000
098 4 10 $ 2740 65 $ 3571 0345 100 000
of energy equals 018 USDkWh It is worth mentioning thatoptimum tilt angle was found to be 27∘ for Sohar
The fossil fuel generator has been simulated for compar-ison to supply the same water pump as shown in Figure 6There are different types of generators commercially available(propane diesel biofuel and gasoline) In this study thediesel fuel generator has been used since it is more efficientand has a longer lifetime in comparison with others andbecause it is the used fuel in Oman as it is considered asone of the suppliers of fuel Rural Areas Electricity Company(RAECO) generation system fuel is diesel Its diesel price issubsidies from the Omani Government and accounted for 46BaizaLitre which is equivalent to 038 USDLitre [12] Onthe other hand it is found that global diesel price on January2014 is 138 USDLitre [13] In this part the water pumpsystem supplied from diesel generator has been investigatedfor comparison with designed PV systems
The fuel price tested 038 and 138 USDLitre with andwithout the government subsidy respectivelyThe price of thegenerator is 500 USD and we considered the generator size of500W in the analysis To compare the PV system results withthe diesel generator to choose the best and costless systemthe analysis shows that a size of 1000W generator has beenestimated with capital operating and total net cost being1000 USD 562 (USDyr) and 8185 USD respectively asshown in Table 5 The CoE is found to be 079 (USDkWh)which is considered to be high as compared with CoE of theproposed PV system (018 and 0309 (USDkWh))
The energy generated shares from REPSOM proposedsystem are shown in Figure 7 PV system availability is calcu-lated as the percentage of time that a power system is capableof meeting load requirements where it is found that thesystem availability is 98 It is found that REPSOMoptimumsystem availability is higher than HOMER and intuitivemethod systems However Figure 7 shows the complete yearperformance of the proposed system From the figure it isclearly seen that the solar energy covers most of the systemload and the battery is intensively used through the year timewhich makes it able to supply the load in some extremely
Water pump
810W peak22 kWhd
Generator 1
AC
Figure 6 HOMER schematic diagrams for the diesel generatorwater pumping system
cloudy days However it is found that the system annual yieldfactor is 202466 kWhkWp Furthermore the capacity factorwas found to be 2305 which is promising since the typicalone is 21
Emission of green-house gases from the fuel of theequivalent conventional system is important Adopting solarPV systems will protect the environment from the harmfulgreen-house gases Table 6 shows the polluted emissionsproduced by the diesel generator used to supply the waterpump Furthermore in comparison between subsidized andnonsubsidized fuel cost it is found that the CoE is 079 and1228 USDkWh respectively This means that besides theprotection of the environment the cost of diesel is relativelyhigh and part of the cost covered by the government couldbe used for other economic projects if the PV technology hasbeen adopted
The comparisons of the cost of energy in the modelledsystem are shown in Table 7 The proposed system cost isacceptable in comparison with the cost of PV systems in
International Journal of Photoenergy 7
Table 5 Diesel system results for 038USDLitre
Label(kW)
Initialcapital
Operatingcost ($yr)
TotalNPC
COE($kWh)
Renfrac
Capacityshortage
Diesel(L)
Label(hrs)
10 $ 1000 562 $ 8185 0790 000 000 351 1825
50 100 150 200 250 300 3500
500
Day
Generated energy by PVLoad demand
50 100 150 200 250 300 350minus500
0500
Day
Energy balance
50 100 150 200 250 300 3500
051
Day
Battery SOC
50 100 150 200 250 300 3500
100200
Day
Deficit energy
Ener
gy (k
Wh)
Ener
gy (k
Wh)
Ener
gy (k
Wh)
SOC
()
Figure 7 Proposed system hourly performance sample
[4] [5] [6] [14] and [15] 0401 0561 0389 021ndash0304and 0361ndash0327 USDkWh respectively Also it is foundthat the cost of PV systems is promising in comparison withthe proposed diesel system (0790 and 1228 USDkWh) andthe energy cost of diesel engine system in [15 16] 05581USDkWh Furthermore regardless of the fact that hybridsystems technically and economically are effective it is foundthat the proposed PV system is economical in comparisonwith [8] where the cost of energy is 0200ndash0580 USDkWhwhich make PV water pumping system be a good option forirrigation in rural areas of Oman
7 Conclusions
In this study PV water pumping system for Sohar Oman hasbeen designed and assessed Optimum selection of systemcomponents PV modules inverter charger controller andbatteries Oman has been determined The system has adaily load of 222 kWhday 084 kW PV modules 4 batteries(12 V and 200Ah) and 08 kW inverter The results haveshown that the optimum cost of PV system energy 0309USDkWh is attractive option in comparison with the costof diesel engine energy 079 USDkWh Also it is found that
Proposed PV research (REPSOM) 0180 PVProposed PV research (HOMER) 0309 PVSubsidized diesel system 0790 DieselNonsubsidized diesel system 1228 Diesel([4] Bakelli et al 2011) 0401 PV([5] Salam et al 2013) 0561 PV([6] Kazem et al 2013) 0389 PV([8] Al-Smairan 2012) 0200ndash0580 PV-diesel([17] Al-Badi et al 2011) 021ndash0304 PV([14] Al-Badi et al 2012) 0327ndash0361 PV([15] annual report 2010) 0558 Diesel([16] annual report 2011) 0558 Diesel
most PV system options are feasible more than the dieselgenerator option Also investigations show that the proposedsystem is cost effective with designed systems in literatureIn addition it is found that PV solar water pumping systemscould be an excellent option for irrigation in rural areas ofOman Moreover the analysis shows that replacing dieselgenerator by PV system will protect the environment fromgreen-house gas emission 924 kgyear of CO
2 228 kgyear of
CO 0253 kgyear of NOx 0172 kgyear of HC 186 kgyearof SO
2 and 204 kgyear of suspended particles
Conflict of Interests
The authors declare that there is no conflict of interestsregarding the publication of this paper
Acknowledgments
The research leading to these results has received ResearchProject Grant Funding from the Research Council of theSultanate of Oman Research Grant Agreement ORG SU EI
8 International Journal of Photoenergy
11 010 and FURAPC2HKENGEE The authors would liketo acknowledge support from theResearchCouncil ofOman
References
[1] H A Kazem and T Khatib Photovoltaic Power System Prospec-tive in Oman Technical and Economical Study LAP LAMBERTAcademic Publishing Saarbrucken Germany 1st edition 2013
[2] A Al-Karaghouli and L L Kazmerski ldquoOptimization and life-cycle cost of health clinic PV system for a rural area in southernIraq using HOMER softwarerdquo Solar Energy vol 84 no 4 pp710ndash714 2010
[3] Z Girma ldquoHybrid renewable energy design for rural electrifi-cation in Ethiopiardquo Journal of Energy Technologies and Policyvol 3 no 13 pp 38ndash52 2013
[4] Y Bakelli A H Arab and B Azoui ldquoOptimal sizing ofphotovoltaic pumping system with water tank storage usingLPSP conceptrdquo Solar Energy vol 85 no 2 pp 288ndash294 2011
[5] M A Salam A Aziz A H A Alwaeli andH A Kazem ldquoOpti-mal sizing of photovoltaic systems using HOMER for SoharOmanrdquo International Journal of Renewable Energy Research vol3 no 2 pp 301ndash307 2013
[6] H A Kazem A A Alkurwi M M Alabdul Salam and A HA Alwaeli ldquoLevelized electricity cost for photovoltaic systemin Sohar-Omanrdquo in Proceedings of the IEEE 8th InternationalConference and Exhibition on Ecological Vehicles and RenewableEnergies (EVER rsquo13) Monte-Carlo Monaco March 2013
[7] R Mishra and S Singh ldquoSustainable energy plan for a villagein punjab for self energy generationrdquo International Journal ofRenewable Energy Research vol 3 no 3 pp 640ndash646 2013
[8] M Al-Smairan ldquoApplication of photovoltaic array for pumpingwater as an alternative to diesel engines in Jordan Badia TallHassan station case studyrdquo Renewable and Sustainable EnergyReviews vol 16 no 7 pp 4500ndash4507 2012
[9] K Meah S Ula and S Barrett ldquoSolar photovoltaic waterpumpingmdashopportunities and challengesrdquo Renewable and Sus-tainable Energy Reviews vol 12 no 4 pp 1162ndash1175 2008
[10] H A Kazem T Khatib and K Sopian ldquoSizing of a standalonephotovoltaicbattery system at minimum cost for remote hous-ing electrification in Sohar Omanrdquo Energy and Buildings vol61 pp 108ndash115 2013
[11] H A Kazem T Khatib K Sopian and W Elmenreich ldquoPer-formance and feasibility assessment of a 14kW roof top grid-connected photovoltaic power system under desertic weatherconditionsrdquo Energy and Buildings vol 82 pp 123ndash129 2014
[12] Authority for Electricity Regulation in Oman ldquoStudy onrenewable resourcesrdquo Final Report Authority for ElectricityRegulation in Oman Muscat Oman 2008
[13] Fuel Price Report 2014 httpwwwcatalistcom[14] A H Al-Badi M AL-Toobi S AL-Harthy Z Al-Hosni and
A AL-Harthy ldquoHybrid systems for decentralized power gener-ation in Omanrdquo International Journal of Sustainable Energy vol31 no 6 pp 411ndash421 2012
[15] Annual Report 2010 Rural Areas Electricity Company MuscatOman 2010
[16] 2011 Annual report from Rural Areas Electricity CompanyOman
[17] A H Al-Badi M H Albadi A M Al-Lawati and A S MalikldquoEconomic perspective of PV electricity in Omanrdquo Energy vol36 no 1 pp 226ndash232 2011
PV arrayPV module rated power 140WpMaximum voltage 177Maximum current 791Open circuit voltage 221Short circuit current 868Efficiency 139Temperature coefficient of Voc minus036kTemperature coefficient of Isc 006k
InverterRated power 08 kWAC voltage 220ndash240Efficiency 940
Table 2 Economic assumption of PV system
Component Capital Lifetime Replacement OampM Fuel($kW) (years) ($) ($) ($)
After calculating LCC the cost of energy is calculated using
CoE = LCCsum
119899
1119864PVannual
(11)
where 119864PVannual is the annual energy production of the PVsystem while 119899 is the system lifetime in years Finally thepayback period is calculated as follows
PBP =119862capital (USD)
[119864PVannual (kWhyear) times CoE (USDkWh) times 119877PW]
(12)
52 Optimum System Design In this research solar waterpumping system has been designed for irrigation in SoharOman This system contains 045 kWp water pump Thesystem has been installed at Sohar zone for research workpurposes The feasibility of the proposed solar water pump-ing system was designed and analyzed using HOMER andREPSOM to find the optimum system component HOMERand REPSOM were used to model different system elementsand check the component physical behaviour and its life cyclecost The optimum system components have been selectedbased on their technical and economic merits Table 1 showsthe specification of the optimummodule and inverter
The schematic diagram in HOMER model for the builtPV system is presented in Figure 5 Since the solar radiationis high enough between 1100AM and 400 PM it is worthgenerating electricity in this period to supply the pump tofill the tank The economic assumptions of the system andthe load analysis calculation are given in Tables 2 and 3respectively
Table 3 Scaled data for simulation
Data source SyntheticDaily noise 15Hourly noise 20Scaled annual average 222 kWhdayScaled peak load 0809 kWLoad factor 0114
Water pump
810W peak
Converter
Ac DC
PV
6FM200D
22 kWhd
Figure 5 HOMER schematic diagram for the solar PV waterpumping system
The suggested PVmodule for simulation of the optimumsystemused in this study is 12 V 140WpDifferent PVmodulecapacities are introduced and considered in the analysiswhich is in the range of 1ndash10 modules The suggested batterywas 12V 200Ah capacities with estimated cost of 140USDAlso for sensitivity analysis the range of batteries is assumedto be 1ndash5 battery banks Furthermore the inverter efficiencywas assumed to be 94 for all considered sizes with estimatedcost of 05 USDW and lifetime of 15 yearsThe inverter rangewas selected to be 01ndash10 kW for analysis consideration
6 Discussion and Analysis
After running the system model in HOMER 704 feasiblesolutions are found and out of these 10 best solutions rankedaccording to the system minimum net present cost (NPC)and cost of energy (CoE) are shown in Table 4 The tableshows that the greatest optimal result is achieved when thesystem is composed of 084 kW PV array (6 modules) 4batteries and 08 kW inverter The optimum solution to thetotal NPC is 3200 USD with operating cost of 63 USDyearand the cost of energy equals 0309 USDkWh On theother hand REPSOM found that the optimum result isachieved when the system is composed of 056 kW PV array(4 modules) 2 batteries and 045 kW inverter FurthermoreREPSOM optimum solution found that the total NPC is1880 USD with operating cost of 33 USDyear and the cost
6 International Journal of Photoenergy
Table 4 Optimum solution for the proposed PV system using HOMER
PV(kW) 6FM200D Conv
(kW)Initialcapital
Operatingcost ($yr)
TotalNPC
COE($kWh)
Renfrac
Capacityshortage
084 4 08 $ 2400 63 $ 3200 0309 100 000
084 4 09 $ 2450 64 $ 3265 0315 100 000
070 5 08 $ 2300 76 $ 3269 0316 100 000
084 4 10 $ 2500 65 $ 3331 0322 100 000
070 5 09 $ 2350 77 $ 3335 0322 100 000
070 5 10 $ 2400 78 $ 3400 0328 100 000
098 4 08 $ 2640 63 $ 3440 0332 100 000
098 4 09 $ 2690 64 $ 3505 0338 100 000
084 5 08 $ 2540 76 $ 3509 0339 100 000
098 4 10 $ 2740 65 $ 3571 0345 100 000
of energy equals 018 USDkWh It is worth mentioning thatoptimum tilt angle was found to be 27∘ for Sohar
The fossil fuel generator has been simulated for compar-ison to supply the same water pump as shown in Figure 6There are different types of generators commercially available(propane diesel biofuel and gasoline) In this study thediesel fuel generator has been used since it is more efficientand has a longer lifetime in comparison with others andbecause it is the used fuel in Oman as it is considered asone of the suppliers of fuel Rural Areas Electricity Company(RAECO) generation system fuel is diesel Its diesel price issubsidies from the Omani Government and accounted for 46BaizaLitre which is equivalent to 038 USDLitre [12] Onthe other hand it is found that global diesel price on January2014 is 138 USDLitre [13] In this part the water pumpsystem supplied from diesel generator has been investigatedfor comparison with designed PV systems
The fuel price tested 038 and 138 USDLitre with andwithout the government subsidy respectivelyThe price of thegenerator is 500 USD and we considered the generator size of500W in the analysis To compare the PV system results withthe diesel generator to choose the best and costless systemthe analysis shows that a size of 1000W generator has beenestimated with capital operating and total net cost being1000 USD 562 (USDyr) and 8185 USD respectively asshown in Table 5 The CoE is found to be 079 (USDkWh)which is considered to be high as compared with CoE of theproposed PV system (018 and 0309 (USDkWh))
The energy generated shares from REPSOM proposedsystem are shown in Figure 7 PV system availability is calcu-lated as the percentage of time that a power system is capableof meeting load requirements where it is found that thesystem availability is 98 It is found that REPSOMoptimumsystem availability is higher than HOMER and intuitivemethod systems However Figure 7 shows the complete yearperformance of the proposed system From the figure it isclearly seen that the solar energy covers most of the systemload and the battery is intensively used through the year timewhich makes it able to supply the load in some extremely
Water pump
810W peak22 kWhd
Generator 1
AC
Figure 6 HOMER schematic diagrams for the diesel generatorwater pumping system
cloudy days However it is found that the system annual yieldfactor is 202466 kWhkWp Furthermore the capacity factorwas found to be 2305 which is promising since the typicalone is 21
Emission of green-house gases from the fuel of theequivalent conventional system is important Adopting solarPV systems will protect the environment from the harmfulgreen-house gases Table 6 shows the polluted emissionsproduced by the diesel generator used to supply the waterpump Furthermore in comparison between subsidized andnonsubsidized fuel cost it is found that the CoE is 079 and1228 USDkWh respectively This means that besides theprotection of the environment the cost of diesel is relativelyhigh and part of the cost covered by the government couldbe used for other economic projects if the PV technology hasbeen adopted
The comparisons of the cost of energy in the modelledsystem are shown in Table 7 The proposed system cost isacceptable in comparison with the cost of PV systems in
International Journal of Photoenergy 7
Table 5 Diesel system results for 038USDLitre
Label(kW)
Initialcapital
Operatingcost ($yr)
TotalNPC
COE($kWh)
Renfrac
Capacityshortage
Diesel(L)
Label(hrs)
10 $ 1000 562 $ 8185 0790 000 000 351 1825
50 100 150 200 250 300 3500
500
Day
Generated energy by PVLoad demand
50 100 150 200 250 300 350minus500
0500
Day
Energy balance
50 100 150 200 250 300 3500
051
Day
Battery SOC
50 100 150 200 250 300 3500
100200
Day
Deficit energy
Ener
gy (k
Wh)
Ener
gy (k
Wh)
Ener
gy (k
Wh)
SOC
()
Figure 7 Proposed system hourly performance sample
[4] [5] [6] [14] and [15] 0401 0561 0389 021ndash0304and 0361ndash0327 USDkWh respectively Also it is foundthat the cost of PV systems is promising in comparison withthe proposed diesel system (0790 and 1228 USDkWh) andthe energy cost of diesel engine system in [15 16] 05581USDkWh Furthermore regardless of the fact that hybridsystems technically and economically are effective it is foundthat the proposed PV system is economical in comparisonwith [8] where the cost of energy is 0200ndash0580 USDkWhwhich make PV water pumping system be a good option forirrigation in rural areas of Oman
7 Conclusions
In this study PV water pumping system for Sohar Oman hasbeen designed and assessed Optimum selection of systemcomponents PV modules inverter charger controller andbatteries Oman has been determined The system has adaily load of 222 kWhday 084 kW PV modules 4 batteries(12 V and 200Ah) and 08 kW inverter The results haveshown that the optimum cost of PV system energy 0309USDkWh is attractive option in comparison with the costof diesel engine energy 079 USDkWh Also it is found that
Proposed PV research (REPSOM) 0180 PVProposed PV research (HOMER) 0309 PVSubsidized diesel system 0790 DieselNonsubsidized diesel system 1228 Diesel([4] Bakelli et al 2011) 0401 PV([5] Salam et al 2013) 0561 PV([6] Kazem et al 2013) 0389 PV([8] Al-Smairan 2012) 0200ndash0580 PV-diesel([17] Al-Badi et al 2011) 021ndash0304 PV([14] Al-Badi et al 2012) 0327ndash0361 PV([15] annual report 2010) 0558 Diesel([16] annual report 2011) 0558 Diesel
most PV system options are feasible more than the dieselgenerator option Also investigations show that the proposedsystem is cost effective with designed systems in literatureIn addition it is found that PV solar water pumping systemscould be an excellent option for irrigation in rural areas ofOman Moreover the analysis shows that replacing dieselgenerator by PV system will protect the environment fromgreen-house gas emission 924 kgyear of CO
2 228 kgyear of
CO 0253 kgyear of NOx 0172 kgyear of HC 186 kgyearof SO
2 and 204 kgyear of suspended particles
Conflict of Interests
The authors declare that there is no conflict of interestsregarding the publication of this paper
Acknowledgments
The research leading to these results has received ResearchProject Grant Funding from the Research Council of theSultanate of Oman Research Grant Agreement ORG SU EI
8 International Journal of Photoenergy
11 010 and FURAPC2HKENGEE The authors would liketo acknowledge support from theResearchCouncil ofOman
References
[1] H A Kazem and T Khatib Photovoltaic Power System Prospec-tive in Oman Technical and Economical Study LAP LAMBERTAcademic Publishing Saarbrucken Germany 1st edition 2013
[2] A Al-Karaghouli and L L Kazmerski ldquoOptimization and life-cycle cost of health clinic PV system for a rural area in southernIraq using HOMER softwarerdquo Solar Energy vol 84 no 4 pp710ndash714 2010
[3] Z Girma ldquoHybrid renewable energy design for rural electrifi-cation in Ethiopiardquo Journal of Energy Technologies and Policyvol 3 no 13 pp 38ndash52 2013
[4] Y Bakelli A H Arab and B Azoui ldquoOptimal sizing ofphotovoltaic pumping system with water tank storage usingLPSP conceptrdquo Solar Energy vol 85 no 2 pp 288ndash294 2011
[5] M A Salam A Aziz A H A Alwaeli andH A Kazem ldquoOpti-mal sizing of photovoltaic systems using HOMER for SoharOmanrdquo International Journal of Renewable Energy Research vol3 no 2 pp 301ndash307 2013
[6] H A Kazem A A Alkurwi M M Alabdul Salam and A HA Alwaeli ldquoLevelized electricity cost for photovoltaic systemin Sohar-Omanrdquo in Proceedings of the IEEE 8th InternationalConference and Exhibition on Ecological Vehicles and RenewableEnergies (EVER rsquo13) Monte-Carlo Monaco March 2013
[7] R Mishra and S Singh ldquoSustainable energy plan for a villagein punjab for self energy generationrdquo International Journal ofRenewable Energy Research vol 3 no 3 pp 640ndash646 2013
[8] M Al-Smairan ldquoApplication of photovoltaic array for pumpingwater as an alternative to diesel engines in Jordan Badia TallHassan station case studyrdquo Renewable and Sustainable EnergyReviews vol 16 no 7 pp 4500ndash4507 2012
[9] K Meah S Ula and S Barrett ldquoSolar photovoltaic waterpumpingmdashopportunities and challengesrdquo Renewable and Sus-tainable Energy Reviews vol 12 no 4 pp 1162ndash1175 2008
[10] H A Kazem T Khatib and K Sopian ldquoSizing of a standalonephotovoltaicbattery system at minimum cost for remote hous-ing electrification in Sohar Omanrdquo Energy and Buildings vol61 pp 108ndash115 2013
[11] H A Kazem T Khatib K Sopian and W Elmenreich ldquoPer-formance and feasibility assessment of a 14kW roof top grid-connected photovoltaic power system under desertic weatherconditionsrdquo Energy and Buildings vol 82 pp 123ndash129 2014
[12] Authority for Electricity Regulation in Oman ldquoStudy onrenewable resourcesrdquo Final Report Authority for ElectricityRegulation in Oman Muscat Oman 2008
[13] Fuel Price Report 2014 httpwwwcatalistcom[14] A H Al-Badi M AL-Toobi S AL-Harthy Z Al-Hosni and
A AL-Harthy ldquoHybrid systems for decentralized power gener-ation in Omanrdquo International Journal of Sustainable Energy vol31 no 6 pp 411ndash421 2012
[15] Annual Report 2010 Rural Areas Electricity Company MuscatOman 2010
[16] 2011 Annual report from Rural Areas Electricity CompanyOman
[17] A H Al-Badi M H Albadi A M Al-Lawati and A S MalikldquoEconomic perspective of PV electricity in Omanrdquo Energy vol36 no 1 pp 226ndash232 2011
Table 4 Optimum solution for the proposed PV system using HOMER
PV(kW) 6FM200D Conv
(kW)Initialcapital
Operatingcost ($yr)
TotalNPC
COE($kWh)
Renfrac
Capacityshortage
084 4 08 $ 2400 63 $ 3200 0309 100 000
084 4 09 $ 2450 64 $ 3265 0315 100 000
070 5 08 $ 2300 76 $ 3269 0316 100 000
084 4 10 $ 2500 65 $ 3331 0322 100 000
070 5 09 $ 2350 77 $ 3335 0322 100 000
070 5 10 $ 2400 78 $ 3400 0328 100 000
098 4 08 $ 2640 63 $ 3440 0332 100 000
098 4 09 $ 2690 64 $ 3505 0338 100 000
084 5 08 $ 2540 76 $ 3509 0339 100 000
098 4 10 $ 2740 65 $ 3571 0345 100 000
of energy equals 018 USDkWh It is worth mentioning thatoptimum tilt angle was found to be 27∘ for Sohar
The fossil fuel generator has been simulated for compar-ison to supply the same water pump as shown in Figure 6There are different types of generators commercially available(propane diesel biofuel and gasoline) In this study thediesel fuel generator has been used since it is more efficientand has a longer lifetime in comparison with others andbecause it is the used fuel in Oman as it is considered asone of the suppliers of fuel Rural Areas Electricity Company(RAECO) generation system fuel is diesel Its diesel price issubsidies from the Omani Government and accounted for 46BaizaLitre which is equivalent to 038 USDLitre [12] Onthe other hand it is found that global diesel price on January2014 is 138 USDLitre [13] In this part the water pumpsystem supplied from diesel generator has been investigatedfor comparison with designed PV systems
The fuel price tested 038 and 138 USDLitre with andwithout the government subsidy respectivelyThe price of thegenerator is 500 USD and we considered the generator size of500W in the analysis To compare the PV system results withthe diesel generator to choose the best and costless systemthe analysis shows that a size of 1000W generator has beenestimated with capital operating and total net cost being1000 USD 562 (USDyr) and 8185 USD respectively asshown in Table 5 The CoE is found to be 079 (USDkWh)which is considered to be high as compared with CoE of theproposed PV system (018 and 0309 (USDkWh))
The energy generated shares from REPSOM proposedsystem are shown in Figure 7 PV system availability is calcu-lated as the percentage of time that a power system is capableof meeting load requirements where it is found that thesystem availability is 98 It is found that REPSOMoptimumsystem availability is higher than HOMER and intuitivemethod systems However Figure 7 shows the complete yearperformance of the proposed system From the figure it isclearly seen that the solar energy covers most of the systemload and the battery is intensively used through the year timewhich makes it able to supply the load in some extremely
Water pump
810W peak22 kWhd
Generator 1
AC
Figure 6 HOMER schematic diagrams for the diesel generatorwater pumping system
cloudy days However it is found that the system annual yieldfactor is 202466 kWhkWp Furthermore the capacity factorwas found to be 2305 which is promising since the typicalone is 21
Emission of green-house gases from the fuel of theequivalent conventional system is important Adopting solarPV systems will protect the environment from the harmfulgreen-house gases Table 6 shows the polluted emissionsproduced by the diesel generator used to supply the waterpump Furthermore in comparison between subsidized andnonsubsidized fuel cost it is found that the CoE is 079 and1228 USDkWh respectively This means that besides theprotection of the environment the cost of diesel is relativelyhigh and part of the cost covered by the government couldbe used for other economic projects if the PV technology hasbeen adopted
The comparisons of the cost of energy in the modelledsystem are shown in Table 7 The proposed system cost isacceptable in comparison with the cost of PV systems in
International Journal of Photoenergy 7
Table 5 Diesel system results for 038USDLitre
Label(kW)
Initialcapital
Operatingcost ($yr)
TotalNPC
COE($kWh)
Renfrac
Capacityshortage
Diesel(L)
Label(hrs)
10 $ 1000 562 $ 8185 0790 000 000 351 1825
50 100 150 200 250 300 3500
500
Day
Generated energy by PVLoad demand
50 100 150 200 250 300 350minus500
0500
Day
Energy balance
50 100 150 200 250 300 3500
051
Day
Battery SOC
50 100 150 200 250 300 3500
100200
Day
Deficit energy
Ener
gy (k
Wh)
Ener
gy (k
Wh)
Ener
gy (k
Wh)
SOC
()
Figure 7 Proposed system hourly performance sample
[4] [5] [6] [14] and [15] 0401 0561 0389 021ndash0304and 0361ndash0327 USDkWh respectively Also it is foundthat the cost of PV systems is promising in comparison withthe proposed diesel system (0790 and 1228 USDkWh) andthe energy cost of diesel engine system in [15 16] 05581USDkWh Furthermore regardless of the fact that hybridsystems technically and economically are effective it is foundthat the proposed PV system is economical in comparisonwith [8] where the cost of energy is 0200ndash0580 USDkWhwhich make PV water pumping system be a good option forirrigation in rural areas of Oman
7 Conclusions
In this study PV water pumping system for Sohar Oman hasbeen designed and assessed Optimum selection of systemcomponents PV modules inverter charger controller andbatteries Oman has been determined The system has adaily load of 222 kWhday 084 kW PV modules 4 batteries(12 V and 200Ah) and 08 kW inverter The results haveshown that the optimum cost of PV system energy 0309USDkWh is attractive option in comparison with the costof diesel engine energy 079 USDkWh Also it is found that
Proposed PV research (REPSOM) 0180 PVProposed PV research (HOMER) 0309 PVSubsidized diesel system 0790 DieselNonsubsidized diesel system 1228 Diesel([4] Bakelli et al 2011) 0401 PV([5] Salam et al 2013) 0561 PV([6] Kazem et al 2013) 0389 PV([8] Al-Smairan 2012) 0200ndash0580 PV-diesel([17] Al-Badi et al 2011) 021ndash0304 PV([14] Al-Badi et al 2012) 0327ndash0361 PV([15] annual report 2010) 0558 Diesel([16] annual report 2011) 0558 Diesel
most PV system options are feasible more than the dieselgenerator option Also investigations show that the proposedsystem is cost effective with designed systems in literatureIn addition it is found that PV solar water pumping systemscould be an excellent option for irrigation in rural areas ofOman Moreover the analysis shows that replacing dieselgenerator by PV system will protect the environment fromgreen-house gas emission 924 kgyear of CO
2 228 kgyear of
CO 0253 kgyear of NOx 0172 kgyear of HC 186 kgyearof SO
2 and 204 kgyear of suspended particles
Conflict of Interests
The authors declare that there is no conflict of interestsregarding the publication of this paper
Acknowledgments
The research leading to these results has received ResearchProject Grant Funding from the Research Council of theSultanate of Oman Research Grant Agreement ORG SU EI
8 International Journal of Photoenergy
11 010 and FURAPC2HKENGEE The authors would liketo acknowledge support from theResearchCouncil ofOman
References
[1] H A Kazem and T Khatib Photovoltaic Power System Prospec-tive in Oman Technical and Economical Study LAP LAMBERTAcademic Publishing Saarbrucken Germany 1st edition 2013
[2] A Al-Karaghouli and L L Kazmerski ldquoOptimization and life-cycle cost of health clinic PV system for a rural area in southernIraq using HOMER softwarerdquo Solar Energy vol 84 no 4 pp710ndash714 2010
[3] Z Girma ldquoHybrid renewable energy design for rural electrifi-cation in Ethiopiardquo Journal of Energy Technologies and Policyvol 3 no 13 pp 38ndash52 2013
[4] Y Bakelli A H Arab and B Azoui ldquoOptimal sizing ofphotovoltaic pumping system with water tank storage usingLPSP conceptrdquo Solar Energy vol 85 no 2 pp 288ndash294 2011
[5] M A Salam A Aziz A H A Alwaeli andH A Kazem ldquoOpti-mal sizing of photovoltaic systems using HOMER for SoharOmanrdquo International Journal of Renewable Energy Research vol3 no 2 pp 301ndash307 2013
[6] H A Kazem A A Alkurwi M M Alabdul Salam and A HA Alwaeli ldquoLevelized electricity cost for photovoltaic systemin Sohar-Omanrdquo in Proceedings of the IEEE 8th InternationalConference and Exhibition on Ecological Vehicles and RenewableEnergies (EVER rsquo13) Monte-Carlo Monaco March 2013
[7] R Mishra and S Singh ldquoSustainable energy plan for a villagein punjab for self energy generationrdquo International Journal ofRenewable Energy Research vol 3 no 3 pp 640ndash646 2013
[8] M Al-Smairan ldquoApplication of photovoltaic array for pumpingwater as an alternative to diesel engines in Jordan Badia TallHassan station case studyrdquo Renewable and Sustainable EnergyReviews vol 16 no 7 pp 4500ndash4507 2012
[9] K Meah S Ula and S Barrett ldquoSolar photovoltaic waterpumpingmdashopportunities and challengesrdquo Renewable and Sus-tainable Energy Reviews vol 12 no 4 pp 1162ndash1175 2008
[10] H A Kazem T Khatib and K Sopian ldquoSizing of a standalonephotovoltaicbattery system at minimum cost for remote hous-ing electrification in Sohar Omanrdquo Energy and Buildings vol61 pp 108ndash115 2013
[11] H A Kazem T Khatib K Sopian and W Elmenreich ldquoPer-formance and feasibility assessment of a 14kW roof top grid-connected photovoltaic power system under desertic weatherconditionsrdquo Energy and Buildings vol 82 pp 123ndash129 2014
[12] Authority for Electricity Regulation in Oman ldquoStudy onrenewable resourcesrdquo Final Report Authority for ElectricityRegulation in Oman Muscat Oman 2008
[13] Fuel Price Report 2014 httpwwwcatalistcom[14] A H Al-Badi M AL-Toobi S AL-Harthy Z Al-Hosni and
A AL-Harthy ldquoHybrid systems for decentralized power gener-ation in Omanrdquo International Journal of Sustainable Energy vol31 no 6 pp 411ndash421 2012
[15] Annual Report 2010 Rural Areas Electricity Company MuscatOman 2010
[16] 2011 Annual report from Rural Areas Electricity CompanyOman
[17] A H Al-Badi M H Albadi A M Al-Lawati and A S MalikldquoEconomic perspective of PV electricity in Omanrdquo Energy vol36 no 1 pp 226ndash232 2011
Figure 7 Proposed system hourly performance sample
[4] [5] [6] [14] and [15] 0401 0561 0389 021ndash0304and 0361ndash0327 USDkWh respectively Also it is foundthat the cost of PV systems is promising in comparison withthe proposed diesel system (0790 and 1228 USDkWh) andthe energy cost of diesel engine system in [15 16] 05581USDkWh Furthermore regardless of the fact that hybridsystems technically and economically are effective it is foundthat the proposed PV system is economical in comparisonwith [8] where the cost of energy is 0200ndash0580 USDkWhwhich make PV water pumping system be a good option forirrigation in rural areas of Oman
7 Conclusions
In this study PV water pumping system for Sohar Oman hasbeen designed and assessed Optimum selection of systemcomponents PV modules inverter charger controller andbatteries Oman has been determined The system has adaily load of 222 kWhday 084 kW PV modules 4 batteries(12 V and 200Ah) and 08 kW inverter The results haveshown that the optimum cost of PV system energy 0309USDkWh is attractive option in comparison with the costof diesel engine energy 079 USDkWh Also it is found that
Proposed PV research (REPSOM) 0180 PVProposed PV research (HOMER) 0309 PVSubsidized diesel system 0790 DieselNonsubsidized diesel system 1228 Diesel([4] Bakelli et al 2011) 0401 PV([5] Salam et al 2013) 0561 PV([6] Kazem et al 2013) 0389 PV([8] Al-Smairan 2012) 0200ndash0580 PV-diesel([17] Al-Badi et al 2011) 021ndash0304 PV([14] Al-Badi et al 2012) 0327ndash0361 PV([15] annual report 2010) 0558 Diesel([16] annual report 2011) 0558 Diesel
most PV system options are feasible more than the dieselgenerator option Also investigations show that the proposedsystem is cost effective with designed systems in literatureIn addition it is found that PV solar water pumping systemscould be an excellent option for irrigation in rural areas ofOman Moreover the analysis shows that replacing dieselgenerator by PV system will protect the environment fromgreen-house gas emission 924 kgyear of CO
2 228 kgyear of
CO 0253 kgyear of NOx 0172 kgyear of HC 186 kgyearof SO
2 and 204 kgyear of suspended particles
Conflict of Interests
The authors declare that there is no conflict of interestsregarding the publication of this paper
Acknowledgments
The research leading to these results has received ResearchProject Grant Funding from the Research Council of theSultanate of Oman Research Grant Agreement ORG SU EI
8 International Journal of Photoenergy
11 010 and FURAPC2HKENGEE The authors would liketo acknowledge support from theResearchCouncil ofOman
References
[1] H A Kazem and T Khatib Photovoltaic Power System Prospec-tive in Oman Technical and Economical Study LAP LAMBERTAcademic Publishing Saarbrucken Germany 1st edition 2013
[2] A Al-Karaghouli and L L Kazmerski ldquoOptimization and life-cycle cost of health clinic PV system for a rural area in southernIraq using HOMER softwarerdquo Solar Energy vol 84 no 4 pp710ndash714 2010
[3] Z Girma ldquoHybrid renewable energy design for rural electrifi-cation in Ethiopiardquo Journal of Energy Technologies and Policyvol 3 no 13 pp 38ndash52 2013
[4] Y Bakelli A H Arab and B Azoui ldquoOptimal sizing ofphotovoltaic pumping system with water tank storage usingLPSP conceptrdquo Solar Energy vol 85 no 2 pp 288ndash294 2011
[5] M A Salam A Aziz A H A Alwaeli andH A Kazem ldquoOpti-mal sizing of photovoltaic systems using HOMER for SoharOmanrdquo International Journal of Renewable Energy Research vol3 no 2 pp 301ndash307 2013
[6] H A Kazem A A Alkurwi M M Alabdul Salam and A HA Alwaeli ldquoLevelized electricity cost for photovoltaic systemin Sohar-Omanrdquo in Proceedings of the IEEE 8th InternationalConference and Exhibition on Ecological Vehicles and RenewableEnergies (EVER rsquo13) Monte-Carlo Monaco March 2013
[7] R Mishra and S Singh ldquoSustainable energy plan for a villagein punjab for self energy generationrdquo International Journal ofRenewable Energy Research vol 3 no 3 pp 640ndash646 2013
[8] M Al-Smairan ldquoApplication of photovoltaic array for pumpingwater as an alternative to diesel engines in Jordan Badia TallHassan station case studyrdquo Renewable and Sustainable EnergyReviews vol 16 no 7 pp 4500ndash4507 2012
[9] K Meah S Ula and S Barrett ldquoSolar photovoltaic waterpumpingmdashopportunities and challengesrdquo Renewable and Sus-tainable Energy Reviews vol 12 no 4 pp 1162ndash1175 2008
[10] H A Kazem T Khatib and K Sopian ldquoSizing of a standalonephotovoltaicbattery system at minimum cost for remote hous-ing electrification in Sohar Omanrdquo Energy and Buildings vol61 pp 108ndash115 2013
[11] H A Kazem T Khatib K Sopian and W Elmenreich ldquoPer-formance and feasibility assessment of a 14kW roof top grid-connected photovoltaic power system under desertic weatherconditionsrdquo Energy and Buildings vol 82 pp 123ndash129 2014
[12] Authority for Electricity Regulation in Oman ldquoStudy onrenewable resourcesrdquo Final Report Authority for ElectricityRegulation in Oman Muscat Oman 2008
[13] Fuel Price Report 2014 httpwwwcatalistcom[14] A H Al-Badi M AL-Toobi S AL-Harthy Z Al-Hosni and
A AL-Harthy ldquoHybrid systems for decentralized power gener-ation in Omanrdquo International Journal of Sustainable Energy vol31 no 6 pp 411ndash421 2012
[15] Annual Report 2010 Rural Areas Electricity Company MuscatOman 2010
[16] 2011 Annual report from Rural Areas Electricity CompanyOman
[17] A H Al-Badi M H Albadi A M Al-Lawati and A S MalikldquoEconomic perspective of PV electricity in Omanrdquo Energy vol36 no 1 pp 226ndash232 2011
11 010 and FURAPC2HKENGEE The authors would liketo acknowledge support from theResearchCouncil ofOman
References
[1] H A Kazem and T Khatib Photovoltaic Power System Prospec-tive in Oman Technical and Economical Study LAP LAMBERTAcademic Publishing Saarbrucken Germany 1st edition 2013
[2] A Al-Karaghouli and L L Kazmerski ldquoOptimization and life-cycle cost of health clinic PV system for a rural area in southernIraq using HOMER softwarerdquo Solar Energy vol 84 no 4 pp710ndash714 2010
[3] Z Girma ldquoHybrid renewable energy design for rural electrifi-cation in Ethiopiardquo Journal of Energy Technologies and Policyvol 3 no 13 pp 38ndash52 2013
[4] Y Bakelli A H Arab and B Azoui ldquoOptimal sizing ofphotovoltaic pumping system with water tank storage usingLPSP conceptrdquo Solar Energy vol 85 no 2 pp 288ndash294 2011
[5] M A Salam A Aziz A H A Alwaeli andH A Kazem ldquoOpti-mal sizing of photovoltaic systems using HOMER for SoharOmanrdquo International Journal of Renewable Energy Research vol3 no 2 pp 301ndash307 2013
[6] H A Kazem A A Alkurwi M M Alabdul Salam and A HA Alwaeli ldquoLevelized electricity cost for photovoltaic systemin Sohar-Omanrdquo in Proceedings of the IEEE 8th InternationalConference and Exhibition on Ecological Vehicles and RenewableEnergies (EVER rsquo13) Monte-Carlo Monaco March 2013
[7] R Mishra and S Singh ldquoSustainable energy plan for a villagein punjab for self energy generationrdquo International Journal ofRenewable Energy Research vol 3 no 3 pp 640ndash646 2013
[8] M Al-Smairan ldquoApplication of photovoltaic array for pumpingwater as an alternative to diesel engines in Jordan Badia TallHassan station case studyrdquo Renewable and Sustainable EnergyReviews vol 16 no 7 pp 4500ndash4507 2012
[9] K Meah S Ula and S Barrett ldquoSolar photovoltaic waterpumpingmdashopportunities and challengesrdquo Renewable and Sus-tainable Energy Reviews vol 12 no 4 pp 1162ndash1175 2008
[10] H A Kazem T Khatib and K Sopian ldquoSizing of a standalonephotovoltaicbattery system at minimum cost for remote hous-ing electrification in Sohar Omanrdquo Energy and Buildings vol61 pp 108ndash115 2013
[11] H A Kazem T Khatib K Sopian and W Elmenreich ldquoPer-formance and feasibility assessment of a 14kW roof top grid-connected photovoltaic power system under desertic weatherconditionsrdquo Energy and Buildings vol 82 pp 123ndash129 2014
[12] Authority for Electricity Regulation in Oman ldquoStudy onrenewable resourcesrdquo Final Report Authority for ElectricityRegulation in Oman Muscat Oman 2008
[13] Fuel Price Report 2014 httpwwwcatalistcom[14] A H Al-Badi M AL-Toobi S AL-Harthy Z Al-Hosni and
A AL-Harthy ldquoHybrid systems for decentralized power gener-ation in Omanrdquo International Journal of Sustainable Energy vol31 no 6 pp 411ndash421 2012
[15] Annual Report 2010 Rural Areas Electricity Company MuscatOman 2010
[16] 2011 Annual report from Rural Areas Electricity CompanyOman
[17] A H Al-Badi M H Albadi A M Al-Lawati and A S MalikldquoEconomic perspective of PV electricity in Omanrdquo Energy vol36 no 1 pp 226ndash232 2011
