Techno-Economic Investigation of Solar Powered Electric Auto-Rickshaw for a Sustainable Transport System

energies

Article Techno-Economic Investigation of Solar Powered Electric Auto-Rickshaw for a Sustainable Transport System

K. S. Reddy 1,*, S. Aravindhan 1 and Tapas K. Mallick 2,*

1 Heat Transfer and Thermal Power Laboratory, Department of Mechanical Engineering, Indian Institute of Technology Madras, Chennai 600036, India; [email protected] 2 Environment and Sustainability Institute, University of Exeter, Penryn Campus, Penryn, Cornwall TR10 9FE, UK * Correspondence: [email protected] (K.S.R.); [email protected] (T.K.M.)

Academic Editor: Mario Collotta Received: 4 April 2017; Accepted: 24 May 2017; Published: 28 May 2017

Abstract: Technologies influencing alternative means of transportation have been expanding in recent years due to increasing urbanization and motorization. In this paper, a solar powered electric auto-rickshaw (SPEA) is designed and developed for Indian conditions. The vehicle developed is comprehensively analyzed techno-economically for its viability in the Indian market. The performance analysis of SPEA results in an optimal charging rate of 2 kWh per day with an average solar irradiance of 325 W/m2 on a typical sunny day. The discharging characteristics are studied based on different loading conditions. The vehicle achieved a maximum speed of 21.69 km/h with battery discharge rate of 296 W at 90 kg load and also reached a maximum discharge rate of 540 W at 390 kg loading with a maximum speed of 12.11 km/h. Environmental analysis of SPEA indicated that the yearly CO2 emissions of 1777 kg, 1987 kg and 1938 kg from using Compressed Natural Gas, Liquefied Petroleum Gas and gasoline engines respectively can be mitigated using SPEA. The financial analysis of SPEA concluded that the investor’s payback duration is 24.44% less compared to a gasoline-run vehicle. Socio-Economic analysis of SPEA discussed its significant advantages and showed 15.74% and 0.85% increase in yearly income over gasoline driven and battery driven vehicles.

Keywords: electric vehicle; solar power; techno-economic analysis; carbon emission mitigation; India

1. Introduction The global dependence on fossil fuels is increasing day by day, predominantly in the automobile sector, and they are expected to dominate till 2040 [1]. The prime causes of this dependence are people’s economic transition, rapid growth in vehicle ownership and changes in activity patterns of the people. This dependence has resulted in the pollution of the environment by increased carbon emissions.

1.1. Current Status of Carbon Emission in Transport Sector The statistics on country-wise petroleum consumption during the years 2000–2014 [2] shows India as the third largest consumer of petroleum, consuming about 3.9% of world’s petroleum reserves. Combustion of these fuels in automobiles generates gases like CO2 which enhance global warming. The CO2 measurement system developed by Earth System Research Laboratory, Colorado observed an increase of 11.5% in global atmospheric CO2 in the past decade [3]. A report on country-wise carbon emissions in the automobile sector by the World Bank [4] over the years 2000–2014, as depicted in Figure1, displays India as one of the major contributors of carbon emissions, accounting 5.9% of world’s CO2 emission.

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Energiesdepicted2017, 10, 754in Figure 1, displays India as one of the major contributors of carbon emissions, accounting2 of 15 5.9% of world’s CO2 emission.

FigureFigure 1. Country 1. Country wise wise carbon carbon emissions emissions (metric (metric kilotons) in in transportation transportation sector. sector.

The complication associated with conventional transport systems can be addressed by the Thedevelopment complication of alternative associated transport with conventionalsystems such as transport solar powered systems electric can vehicles, be addressed which are by the developmentgaining ofimportance alternative in transporttransforming systems automobile such as sector. solar powered India, a electriccountry vehicles,near to the which equator, are gaining is importancebestowed in transformingwith vast solar automobile energy potential sector. with India, annual a country solar nearradiation to the ranging equator, from is bestowed 1600–2200 with vast solarkWh/m energy2 [5]. potentialIndia is a withhome annual to more solar than radiation 2.5 million ranging auto-rickshaws from 1600–2200 (three-wheelers) kWh/m 2[6][5 and]. India the is a home toyearly more report than by 2.5 the million National auto-rickshaws Data Sharing and (three-wheelers) Accessibility Policy [6] and (NDSAP) the yearly [7] shows report an by increasing the National trend in the registration of new auto rickshaws every year over a decade. This rising trend confirms Data Sharing and Accessibility Policy (NDSAP) [7] shows an increasing trend in the registration of rickshaws are a suitable vehicle for electrification because of their low-speed application and use as new auto rickshaws every year over a decade. This rising trend confirms rickshaws are a suitable local transportation. vehicle for electrification because of their low-speed application and use as local transportation. 1.2. Literature Review 1.2. Literature Review Discussions on the present and future potential for electric vehicles (EV) give an explicit Discussionsawareness of on the the technological present and advancements future potential carried for electric out in vehiclesthis particular (EV) givefield. an EV, explicit in upcoming awareness of theyears, technological are predicted advancements to increase carriedglobal energy out in consumption this particular by 30% field. and EV, reduce in upcoming harmful carbon years, are predictedemissions to increase by 25–60% global [8]. Several energy energy consumption consumptio byn algorithms 30% and and reduce vehicle harmful operation carbon models emissions have by 25–60%been analyzed [8]. Several and validated energy consumptionby various authors algorithms which help and us vehicle in optimizing operation the vehicle models charging have been analyzedand anddischarging validated characteristics by various [9 authors,10]. Case which studies help of usEV inusage optimizing patterns theobserved vehicle incharging Northern and dischargingEurope characteristics [11] and Lisbon [9 [12],10]. help Case us studies to underst of EVand usagetheir energy patterns consumption observed incharacteristics, Northern Europe usage [11] patterns and environmental impacts. and Lisbon [12] help us to understand their energy consumption characteristics, usage patterns and The emphasis on charging EV using photovoltaic (PV) technology is up-and-coming due to a environmentalcontinuous impacts. decrease in the price of PV modules, concerns over the effects of greenhouse gases, global Theenergy emphasis policies onand charging an increase EV in usingprocurement photovoltaic of EV. Over (PV) the technology years, numerous is up-and-coming methods of charging due to a continuousEV using decrease PV technology in the price have of been PV modules, proposed concerns[13,14]. The over idea the of effects developing of greenhouse off-grid recharging gases, global energystations policies (using and solar an increase and wind in energy) procurement for charging of EV. EV Over during the years,day time numerous in vehicle methods parking locations of charging EV using[15] not PV only technology impacts the have energy been economy proposed but [also13,14 ev].idently The ideahelps ofto developingreduce the carbon off-grid footprint. recharging stations (usingThe idea solar of and incorporating wind energy) solar for PV charging modules EV in duringto passenger day time vehicles in vehicle has been parking prototyped locations by [15] not onlysome impacts of the top the automobile energy economy companies but as also it lessen evidentlys gasoline helps dependence to reduce and the significantly carbon footprint. cuts down fuel expenses, while also reducing carbon emission levels. The Japanese companies [16] Mazda and The idea of incorporating solar PV modules into passenger vehicles has been prototyped by some Toyota are the front runners in transforming this concept into reality. In the early 2000s Mazda’s 929 of the top automobile companies as it lessens gasoline dependence and significantly cuts down fuel luxury sedan came up with an optional solar roof to power their air-conditioning system. Toyota expenses,redesigned while alsoits model reducing Prius carbon Prime emissionto accommodate levels. a The 180 Japanese W solar panel companies to charge [16 ]the Mazda batteries and and Toyota are thepower front the runners car accessories. in transforming Ford Motor this Company concept into [17] reality.developed In thea product early 2000s “C-MAX Mazda’s Solar Energi” 929 luxury sedan came up with an optional solar roof to power their air-conditioning system. Toyota redesigned its model Prius Prime to accommodate a 180 W solar panel to charge the batteries and power the car accessories. Ford Motor Company [17] developed a product “C-MAX Solar Energi” with an off-vehicle solar concentrator made up of a special Fresnel lens to direct sunlight to the rooftop solar cells while enhancing the solar radiation to harness more power from highly efficient solar cells. Energies 2017, 10, 754 3 of 15

with an off-vehicle solar concentrator made up of a special Fresnel lens to direct sunlight to the Energiesrooftop2017 solar, 10, 754 cells while enhancing the solar radiation to harness more power from highly efficient3 of 15 solar cells. This paper deals with the development of solar powered electric auto-rickshaws (SPEA) as an This paper deals with the development of solar powered electric auto-rickshaws (SPEA) as an alternate to conventional auto rickshaws. Thus the study on the usage pattern of a conventional auto alternate to conventional auto rickshaws. Thus the study on the usage pattern of a conventional rickshaw in Indian cities paves a way to understand the economics of its usage and helps in sizing auto rickshaw in Indian cities paves a way to understand the economics of its usage and helps in the PV/battery for the proposed system [18]. The performance of a solar vehicle is governed mainly sizing the PV/battery for the proposed system [18]. The performance of a solar vehicle is governed by the solar PV efficiency [19], selection of motor [20] and battery system [21]. Alongside the mainly by the solar PV efficiency [19], selection of motor [20] and battery system [21]. Alongside the development of solar electric vehicles, hybridizing conventional vehicles with solar energy [22,23] development of solar electric vehicles, hybridizing conventional vehicles with solar energy [22,23] proves to be energy efficient and also partly lessens the carbon emissions. The studies by Mani and proves to be energy efficient and also partly lessens the carbon emissions. The studies by Mani and Kreutzmann [24] and Hannan et al. [25] lay the foundation for this present work by highlighting the Kreutzmann [24] and Hannan et al. [25] lay the foundation for this present work by highlighting importance of sustainable transportation and discussing the important design and performance the importance of sustainable transportation and discussing the important design and performance parameters associated with solar powered electric auto-rickshaws. parameters associated with solar powered electric auto-rickshaws. Thus, from the literature review, it is implicit that an outright solar powered vehicle has not yet Thus, from the literature review, it is implicit that an outright solar powered vehicle has not yet been developed for public commuting, though some plug-in hybrid car models that incorporate solar been developed for public commuting, though some plug-in hybrid car models that incorporate solar PV panels for charging the battery and powering accessories are available. The literature discussed PV panels for charging the battery and powering accessories are available. The literature discussed above has helped to define and discuss the problem effectively and also guided us to address the above has helped to define and discuss the problem effectively and also guided us to address the knowledge gap between the work carried out in recent past and present work. The optimization of knowledge gap between the work carried out in recent past and present work. The optimization of SPEA and its techno-economic analysis has been carried out to study the feasibility of the system for SPEA and its techno-economic analysis has been carried out to study the feasibility of the system for Indian conditions and compared with existing conventional vehicles. This paper focuses on charging Indian conditions and compared with existing conventional vehicles. This paper focuses on charging existing electric vehicles using solar PV technology. In detail, the charging and discharging patterns existing electric vehicles using solar PV technology. In detail, the charging and discharging patterns of of batteries, economic analysis of vehicles and mitigation of CO2 on implementing SPEA has also batteries, economic analysis of vehicles and mitigation of CO on implementing SPEA has also been been discussed. This paper is further organized as follows.2 Section 2 explains the design and discussed. This paper is further organized as follows. Section2 explains the design and development development of SPEA, Section 3 communicates the performance analysis of SPEA, furthermore of SPEA, Section3 communicates the performance analysis of SPEA, furthermore Sections4 and5 sections 4 and 5 enlighten the environmental and economic analysis of SPEA respectively. enlighten the environmental and economic analysis of SPEA respectively.

2.2. Design Design and and Development Development of of the the Solar Solar Powered Powered Electric Electric Auto-Rickshaw Auto-Rickshaw (SPEA) (SPEA)

2.1.2.1. Principle Principle and and Operation Operation TheThe operating operating principle principle of of the the proposed proposed solar solar vehicle vehicle is is briefly briefly explained explained in in Figure Figure2a. 2a. Solar Solar PV PV panelspanels are are fixed fixed on on the the vehicle vehicle roof, roof, which which convert convert the the sun’s sun’s energy energy directly directlyinto intoelectrical electrical energy.energy. TheThe maximum maximum power power point point tracking tracking (MPPT) (MPPT) controller controller is incorporated is incorporated to extract to extract the maximum the maximum power outpower of solar out panelsof solar for panels charging for thecharging lead-acid the lead automotive-acid automotive batteries. batteries The Brushless. The Brushless Direct Current Direct (BLDC)Current electric (BLDC) motor electric is employed motor is employed to convert to the conver batteryt the power battery into power mechanical into mechanical drive energy. drive BLDCenergy. motorsBLDC aremotors reliable, are reliable, safe to handlesafe to handle and operate and operate with minimum with minimum noise withnoise less with frictional less frictional losses. losses. The motorThe motor controller controller provided provided along along with thewith motor the motor senses se thenses position the position of the of stator the stator and energizesand energizes the rotorthe rotor accordingly accordingly using using the Hallthe Hall Effect Effect sensor. sensor. Power Power from from the the motor motor is transmittedis transmitted to to the the wheels wheels throughthrough differential differential gears. gears. The The modified modified vehicle vehicle with with solar solar PV PV panels panels is is depicted depicted in in Figure Figure2b,c. 2b,c.

(a)

Figure 2. Cont.

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(b) (c)

FigureFigure 2. 2. (a(a) )Line Line diagram diagram of of solar solar po poweredwered electric electric auto-ricks auto-rickshawhaw (SPEA) (SPEA) operation; operation; ( (bb)) SPEA SPEA model model developeddeveloped in in Solid Solid Works; Works; and ( c ()c) Fabricated Fabricated SPEA SPEA at at IIT IIT Madras. Madras.

2.2.2.2. Design Design and and Development Development of of SPEA SPEA TheThe three-wheeler SPEASPEA developed developed for for this this research research was assembledwas assembled and tested and attested Indian at InstituteIndian Instituteof Technology-Madras, of Technology-Madras, India (12.9908 India◦ N, (12.9908° 80.2357◦ E).N, As80.2357° the electric E). As auto the rickshaw electricis auto already rickshaw available, is alreadythe speciﬁcations available, arethe tospecifications accommodate are solar to acco panelsmmodate and supporting solar panels equipment and supporting on the existing equipment vehicle. on theThe existing parameters vehicle. related The toparameters this research related have to been this derivedresearch from have various been derived studies from and arevarious discussed studies in anddetail are below. discussed in detail below.

(1)(1)Maximum Maximum solar solar radiation radiation available available on on the the vehicle vehicle sloped sloped surface surface TheThe maximum maximum incident incident radiation radiation on on the the solar solar panel panel for for the the given given location location is is found found out out using using the the followingfollowing expression: expression: = − ϕ + δ + β SSmodule =S incident sin(sin([9090 φ + δ] +β)) (1)(1) wherewhere Smodule is solar radiation radiation incident incident on on the the solar solar module module in in watt watt per per square square meter, meter, SSincident isis solarsolar radiation radiation measured measured perpendicular perpendicular to to the the sun sun in in watt watt per per square square meter, meter, φϕ isis the the latitude latitude of of the the consideredconsidered location location in in degrees, degrees, δδ isis declination declination angle angle in in degrees degrees and and ββ isis tilt tilt angle angle of of the the module module measuredmeasured from from the the horizontal horizontal in in degrees degrees. TheThe expression expression for for declination declination angle angle δδ isis given given by: by: δ δ = 23.45 = 23.45× ×sin sin[360/365[360/365 ×× (284(284 + d)]+ d)] (2)(2) where d is the day of the year. where d is the day of the year. (2) Height of center of gravity calculation (2) Height of center of gravity calculation The height of center of gravity determines the stability of the vehicle considering its total weight and wheelbaseThe height distance. of center It of is gravity significant determines to determine the stability the load of the transfer vehicle between considering the itsfront total and weight rear and wheelbase distance. It is signiﬁcant to determine the load transfer between the front and rear wheels. Height of center of gravity (h) is found out by [26]: wheels. Height of center of gravity (h ) is found out by [26]: wheelbaseCG distance × difference in vehicle weight h = wheelbase distanceTotal weight× difference of vehicle in x vehicle tan of slopeweight of trackWb (WFR − WF) (3) hCG = W (W W ) = (3) Total weight of vehicle= x tan of slope of track mv tan θ m tanθ

TheThe approximate approximate height height of of center center of of gravity gravity (h(hCG)) computedcomputed using using this this formula formula is is 834 834 mm mm consideringconsidering the the vehicle vehicle mass mass ( (mmv) )as as 330 330 kg, kg, wheelbase wheelbase distance distance (W (W)b )as as 1022 1022 mm, mm, θθ asas 2 2 degrees degrees whereaswhereas WFR & W& W Fareare the the weight weight of of front front tires tires while while rear rear wheel wheel of of the the vehicle vehicle is is raised raised and and kept kept horizontallyhorizontally level level respectively. respectively. The difference in weight WWFR W− WF is found found to to be be 9.4 9.4 kg. kg. The The position position ofof the the centre centre of of gravity gravity is is also also influenced inﬂuenced by by the the number number of passengers riding in the vehicle.

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(3) Wind load calculation Wind load primarily affects the support structure design as it exerts stress on the structure externally. It is a function of the velocity of the vehicle, as the wind load varies with velocity of the vehicle exponentially. Wind load is expressed as [24]:

2 Fw = 0.613 ACDV (4)

The wind load Fw depends on the drag co-efficient (CD), vehicle frontal area (A) and velocity of the vehicle (V). Fw is calculated to be 6 kg by assuming CD as 1.05 (drag co-efficient of a cube), V as 30 km/h and A as 1.30 sq. m. (4) Power requirement and selection of motor The power requirement to propel SPEA should be enough overcome wind drag, gravitational force and rolling resistance. Aerodynamics involved in the design of a vehicle will have a significant impact on its performance. Generally, the aerodynamic drag increases gradually with an increase in vehicle speed, but at higher speeds the drag becomes proportional to the square of speed, thus increasing the drag. The Rolling resistance of a body is proportional to the weight of the body normal to the surface of travel (W). Power requirement is computed by [24]. Required power (Pr) ≥ wind drag + rolling resistance + gravitational force:

2 Pr ≥ 0.5ρCDAV + W(Cr cos θ + sin θ)V (5)

3 where Pr is Power required in Watts, ρ is air density in kg/m , CD is drag coefficient, A is vehicle frontal area in sq. m, V is vehicle speed in m/s, W is vehicle mass in kg, Cr is Co-efficient of rolling resistance and θ is slope of track in degrees. (5) Battery bank capacity Battery bank capacity is selected based on the total power needed for the required duration in a day and the battery efficiency. Battery bank will act as a secondary or backup power source for the vehicle during cloudy or rainy days. The weight of battery also concerns the traveling performance of the vehicle. Thus choosing the capacity of the battery bank is a critical part of designing a solar powered system. Battery bank capacity is selected using the following relation:

power required × operating duration Pr t Pb = = (6) battery efﬁciency × battery voltage × maximum DOD × days of autonomy ηbVb(DOD)n

The capacity of battery (Pb) is found out to be 425 Ah considering required power (Pr) as 3 kW, operating duration (t) as 8 h per day and 1 day of autonomy (n). The parameters associated with the battery such as battery efficiency (ηb), depth of discharge (DOD) and battery voltage (Vb) are considered as per available battery specifications [27]. The complete hardware related to the solar electric vehicle is presented in Table1. Of the batteries used for solar applications, the lead acid batteries are largely used in India because of their moderate price tag and robust usage. Thus from a commercialization and economic point of view, the authors wish to consider lead acid batteries for this analysis. (6) Travelling distance The maximum distance that a SPEA of specific weight could travel is calculated by [21]:

energy conversion efﬁciency × Energy from solar panels ηEs Dvehicle = = (7) Vehicle tractive force Tf Energies 2017, 10, 754 6 of 15

The distance travelled by SPEA is deﬁned as the ratio of product of electric vehicle energy conversion efﬁciency (η), energy from solar panels (Es) and the vehicle tractive force (Tf). As discussed above, the calculation of solar radiation available on the vehicle surface forms the foundation of the design process. Based on the available solar radiation, the power required for the vehicle, capacity of batteries and travelling distance are found out. In order to accompany solar PV panels, the steel structures are designed and assembled with the help of height of the center of gravity and wind load calculations.

Table 1. Hardware speciﬁcation of the SPEA designed.

S. No. Particulars Specifications 1 Solar Panels [28] Bosch Solar Module c-Si M 60 Rated Output 245 W each Dimensions 1660 × 990 × 50 mm No. of cells per panel 60× mono-crystalline solar cells Efficiency 17.6–18% 2 MPPT Controller [29] Phocos CX48 System voltage 24/48 V auto recognition Max charge/load current 40 A Efficiency 96–98% 3 Battery bank [27] Exide Invaplus Tubular battery Rated Output 100 Ah, 12 V (4 no. in series) Depth of discharge 80% (First 1500 cycles) Overall efficiency 60% 4 Motor [30] Brushless DC motor Rated Output 1000 W Motor controller output 1000 W 5 Dimensions of SPEA (L × B × H) 2600 × 950 × 1200 mm 6 Wheelbase and wheel size 800 mm & 3–12 7 Load capacity & no. of passengers 330 kg & 6 + 1 passengers 8 Clearance and frontal area 180 mm & 1.3 m2

3. Performance Analysis of SPEA The performance analysis is basically executed to test the charging and discharging characteristics of the solar vehicle. The battery placed in the solar vehicle was charged using PV panels placed on top of the vehicle. The charging and discharging characteristics were separately tested and explained in this section. The experiments were carried out to analyze the performance of the vehicle on a typical sunny day. The DC voltage and current were measured using MASTECH (Taipei, Taiwan) [31] make digital multi-meter and instantaneous solar irradiance was measured using PMA 2144 class II pyranometer (Solar Light Company, Inc., Glenside, PA, USA) [32]. The accuracies of measuring instruments associated with the measurement of parameters such as vehicle speed, DC voltage, DC current and irradiance were found out to be ±4.0%, ±1.0%, ±1.5% and ±2.5% respectively. The irradiance incident on the panels and the electrical output from PV panels over a day is shown in Figure3. As discussed, the charging characteristics of the vehicle purely depend on the irradiance and the photovoltaic panel speciﬁcations. The PV panel output followed the same pattern as radiation intensity over the day. It reached the peak value during the noon period (11 a.m. to 2 p.m.). The overall rated power output of the panels as mentioned in Table1 is 490 W (2 panels of 245 W) but for the measured average irradiance per day of 325 W/m2 on the tilted PV panel surface, the power output was around 250 W. Thus, a day-long charge should yield about 2 units i.e., 2 kWh of power. Energies 2017, 10, 754 7 of 15 Energies 2017, 10, 754 7 of 15

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FigureFigure 3. 3.Variation Variation of of measured measured solarsolar irradianceirradiance and photovoltaic photovoltaic (PV) (PV) panel panel output output over over a day. a day.

The FigurerelationFigure 3. 3. Variation betweenVariation of ofvehicle measured measured speed solar solar andirradiance irradiance discharge and and photovoltaic photovoltaic rate is illustrated (PV) (PV) panel panel in output output Figure over over 4. a a Thisday. day. test was conductedThe relation with betweena variable vehicle load ranging speed from and no discharge load (only rate the is vehicle’s illustrated weight) in Figure to 4004. kg This which test was was conductedthe maximumTheThe with relation relation a weight variable between between the load vehicle vehicle vehicle ranging can speed speed from hold. and and no The discharge loaddischarge weight (only ra ra theoftete theis vehicle’sis illustrated illustrated vehicle weight) in in in thisFigure Figure to context 400 4. 4. This kgThis refers which test test was towas was the the maximumsummationconductedconducted weight of with with the the a avehicle’s variable vehiclevariable canload weight,load hold.ranging ranging the The weightfrom from weight no no oflo lo ofadsolarad the(only (only vehiclepanels, the the vehicle’s vehicle’s insupport this contextweight) weight) structure to refersto 400 400 and kg tokg batterieswhich the which summation was was and ofalso thethethe vehicle’sthe maximummaximum driver’s weight, weight. weightweight the theThethe weight vehiclemaximumvehicle of cansolarcan speeds hold.hold. panels, TheThe achiev support weightweighted at ofof structure the thethe loads vehiclevehicle and0 kg inin batteries(no thisthis load), contextcontext and 90 kg,refers alsorefers 160the toto kg, thedriver’sthe 230 weight.kg summationandsummation The 390 maximum kg ofwereof the the 29.6vehicle’s speedsvehicle’s km/h,achieved weight, weight, 21.69 km/h,the the at theweight weight 18.69 loads of ofkm/h, 0solar solar kg (no 15.92panels, panels, load), km/h support support 90 and kg, structure12.11 160structure kg, km/h 230 and and respectively. kg batteries batteries and 390 and and kg The were 29.6maximum km/h,alsoalso the the 21.69 driver’s speeddriver’s km/h, at weight. weight. each 18.69 loading The The km/h, maximum maximum condition 15.92 speeds speeds km/h directly achiev achiev and de 12.11ededpends at at the km/hthe onloads loads the respectively. 0 0 pullingkg kg (no (no load), load),capability The 90 90 maximum kg, kg, of160 160 the kg, kg, motor. speed230 230 at kg and 390 kg were 29.6 km/h, 21.69 km/h, 18.69 km/h, 15.92 km/h and 12.11 km/h respectively. The eachThe loadingkg discharge and 390 condition kg voltage were directly 29.6 and km/h, current depends 21.69 trends km/h, on theare 18.69 pullingdepic km/h,ted capability in 15.92 Figure km/h of 5 theforand the motor. 12.11 390 km/h Thekg load. dischargerespectively. The maximum voltage The and maximum speed at each loading condition directly depends on the pulling capability of the motor. currentdischargedmaximum trends rate arespeed depictedachieved at each in wasloading Figure 540 condition5W for with the a 390directly load kg of load. de 390pends Thekg movingon maximum the pulling at a discharged speed capability of 12.11 rate of the achievedkm/h. motor. This was TheThe discharge discharge voltage voltage and and current current trends trends are are depic depictedted in in Figure Figure 5 5 for for the the 390 390 kg kg load. load. The The maximum maximum 540performance W with a load test of is 390carried kg movingout on a atstraight a speed flat of track 12.11 of km/h. 1.56 km This distance performance for each test loading is carried case. outFrom on a dischargeddischarged rate rate achieved achieved was was 540 540 W W with with a a load load of of 390 390 kg kg moving moving at at a a speed speed of of 12.11 12.11 km/h. km/h. This This straightthe graph, flat track it could of 1.56 be kmunderstood distance that for eachthe battery loading discharge case. From rate the increases graph, it in coulditially be with understood respect to that performanceperformance test test is is carried carried out out on on a a straight straight flat flat track track of of 1.56 1.56 km km distance distance for for each each loading loading case. case. From From vehicle speed and tends to be unchanged up to a certain range of vehicle speed (15 km/h). Once the the batterythethe graph, graph, discharge it it could could rate be be increasesunderstood understood initially that that the the with battery battery respect discharge discharge to vehicle rate rate speedincreases increases and in in tendsitiallyitially towith with be unchangedrespect respect to to up vehicle speeds up further, there was a sudden increase in discharge rate noted in all loading scenarios. to a certainvehiclevehicle rangespeed speed ofand and vehicle tends tends to speedto be be unchanged unchanged (15 km/h). up up Onceto to a a certain certain the vehicle range range of speedsof vehicle vehicle up speed speed further, (15 (15 km/h). therekm/h). wasOnce Once a the suddenthe increasevehiclevehicle in discharge speeds speeds up up rate further, further, noted there there in allwas was loading a a sudden sudden scenarios. increase increase in in discharge discharge rate rate noted noted in in all all loading loading scenarios. scenarios.

Figure 4. Impact of discharge rate on vehicle speed. FigureFigureFigure 4. 4. Impact4. Impact Impact of of of dischargedischarge discharge rate raterate on on vehicle vehicle vehicle speed. speed. speed.

Figure 5. Discharge voltage and current trends at 390 kg load. FigureFigureFigure 5. 5. 5.Discharge Discharge Discharge voltagevoltage voltage and current current trendstrends trends at at at390 390 390 kg kg kgload. load. load.

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3.1.3.1. Hourly Hourly Solar Solar Availability Availability and and Mobility Mobility Patterns Patterns TheThe mobility mobility pattern pattern of ofthe the vehicle vehicle is influenced is inﬂuenced by the by insolation the insolation rate during rate duringsunshine sunshine hours. Thehours. yearly The solar yearly resource solar for resource this particular for this location particular was locationcollected wasfrom collectedthe Indian from Meteorological the Indian DepartmentMeteorological (IMD) Department solar radiation (IMD) database solar radiation and NREL’s database National and Solar NREL’s Radiation National Database Solar Radiation(NSRDB) [33].Database The month-wise (NSRDB) [33 solar]. The radiation month-wise profile solar on the radiation tilted surface proﬁle onis calculated the tilted surfaceand presented is calculated in Figure and 6.presented in Figure6.

FigureFigure 6. 6. IncidentIncident radiation radiation profile proﬁle for for lo locationcation considered considered (IIT (IIT Madras). Madras).

The typical mobility pattern was designed based on the standardized driving cycle. The driving The typical mobility pattern was designed based on the standardized driving cycle. The driving cycle for low load vehicles followed in India is based on the European Urban Driving Cycle (EUDC). cycle for low load vehicles followed in India is based on the European Urban Driving Cycle (EUDC). From Table 2, it is evident that the acceleration and deceleration limits and top speed are mismatched From Table2, it is evident that the acceleration and deceleration limits and top speed are mismatched in the vehicle under study. Thus, a new driving cycle developed by Lukic et al. [14] for auto rickshaws in the vehicle under study. Thus, a new driving cycle developed by Lukic et al. [14] for auto rickshaws was used for this study. The driving cycle was designed using the tool Advanced Vehicle Simulator was used for this study. The driving cycle was designed using the tool Advanced Vehicle Simulator (ADVISOR) [34]. The data such as maximum speed, acceleration and deceleration were the input (ADVISOR) [34]. The data such as maximum speed, acceleration and deceleration were the input parameters of this study. The driving cycle thus developed is shown in Figure 7. parameters of this study. The driving cycle thus developed is shown in Figure7.

Table 2. Comparison of standard driving cycle and driving cycle considered for this study. Table 2. Comparison of standard driving cycle and driving cycle considered for this study. Parameter Standard Indian Driving Cycle Cycle Considered for This Study ParameterTime (s) Standard 1244 Indian Driving Cycle Cycle Considered 3300 for This Study DistanceTime (s) (km) 10.6 1244 12.8 3300 MaxDistance Speed (km) (km/h) 90 10.6 29.6 12.8 MaxAve Speed Speed (km/h) (km/h) 31.1 90 11.12 29.6 AveMax Speed Accel (km/h) (m/s2) 0.6 31.1 1.31 11.12 2 MaxMax Accel Decel (m/s (m/s2)) −1.4 0.6−0.4 1.31 2 MaxAve Decel Accel (m/s (m/s2)) 0.6 −1.4 0.33 −0.4 2 AveAve Accel Decel (m/s (m/s)2) −0.8 0.6−0.4 0.33 2 − − AveIdle Decel Time (m/s (s) ) 388 0.8 83 0.4 Idle Time (s) 388 83 No of Stops 13 79 No of Stops 13 79

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FigureFigure 7. 7. VehicleVehicle speed speed variation variation with respect to time.

3.2.3.2. Impact Impact of of the the Monsoon Monsoon Season Season on on the the Performance Performance of of the the Vehicle InIn a a South South Asian Asian country country like like India, India, the the influenc influencee of ofmonsoon monsoon season season on the on theperformance performance of the of vehiclethe vehicle is significant is significant due due to profuse to profuse cloud cloud cover cover and and ineffective ineffective solar solar radiation. radiation. The The location location (IIT (IIT Madras,Madras, Chennai, Chennai, India) India) considered considered for for the the study, study, is particularly affected by the northeast monsoon duringduring November andand December.December. This This issue issue was was managed managed in in the the developed developed vehicle vehicle by by providing providing a DC a DCelectric electric port port along along with AC-DCwith AC-DC adapter adapter for charging for charging the batteries the batteries using grid using supply. grid Itsupply. was estimated It was estimatedthat the average that the speed average of the speed vehicle of the reduces vehicle by redu 3–13%ces during by 3–13% this during time of this the yeartime [of35 ]the due year to poor[35] duevisibility to poor issues. visibility It was issues. also It concluded was also concluded that the power that the required power torequired cruise theto cruise vehicle the would vehicle be would 6% to be16% 6% more to 16% during more rains during because rains of because broken of down broken roads down and roads traffic and amid traffic rains. amid During rains. this During monsoon, this monsoon,3 kWh/day 3 ofkWh/day electricity of from electricity the grid from was usedthe grid for charging was used the vehicle.for charging The environmentalthe vehicle. The and environmentaleconomic impact and of economic the monsoon impact on theof the vehicle monsoon is discussed on the invehicle the forthcoming is discussed sections in the forthcoming in detail. sections in detail. 4. Environmental and Economic Analysis of SPEA 4. EnvironmentalThough the structural and Economic and performance Analysis of analysis SPEA of SPEA gives an overall picture of the feasibility of SPEAThough for Indianthe structural conditions, and itperformance is essential toanalysis evaluate of SPEASPEA from gives a social,an overall environmental picture of andthe feasibilityeconomic pointof SPEA of view.for Indian This sectionconditions, presents it is esse a detailedntial to analysis evaluate of SPEA the vehicle from a from social, carbon environmental mitigation, andfinancial economic and socio-economic point of view. perspectives.This section presents a detailed analysis of the vehicle from carbon mitigation, financial and socio-economic perspectives. 4.1. Mitigation of CO2 Emission

4.1. MitigationVehicles fueledof CO2 byEmission petroleum-based fuels such as gasoline, Liqueﬁed Petroleum Gas (LPG) and CompressedVehicles fueled Natural by Gas petr (CNG)oleum-based contribute fuels tosuch CO as2 emissions.gasoline, Liquefied The carbon Petroleum emission Gas that (LPG) can and be mitigated by using a solar powered electric vehicle instead of a petroleum-fueled vehicle over a Compressed Natural Gas (CNG) contribute to CO2 emissions. The carbon emission that can be mitigatedperiod of 25by yearsusing (considereda solar powere as thed electric vehicle vehicle lifetime) instead is studied of a inpetroleum-fueled this section. Any vehicle hydrocarbon over a periodon stoichiometric of 25 years (considered combustion as will the produce vehicle lifetime) CO2 and is H studied2O. The in amount this section. of CO Any2 discharged hydrocarbon during on stoichiometric combustion of gasoline (Equation (8)), LPG (Equation (9)) and CNG (Equation (10)) by stoichiometric combustion will produce CO2 and H2O. The amount of CO2 discharged during stoichiometricbalancing the chemicalcombustion equations of gasoline was (Equation found out (8)), to be LPG 3.09 (Equation kg, 3 kg and(9)) and 2.75 CNG kg respectively (Equation (10)) for unit by balancingweight (kg) the of chemical fuel and equations in terms of was per found liter of out fuel, to 2.296be 3.09 kg, kg, 2.983 3 kg kg and and 2.75 2.35 kg kg respectively of CO2 was for emitted unit respectively. Then, CO emission in kg/km of fuel was calculated by assuming the vehicle runs about weight (kg) of fuel and2 in terms of per liter of fuel, 2.296 kg, 2.983 kg and 2.35 kg of CO2 was emitted 25 km per liter of fuel. If the vehicle’s mileage was about 15,000 km per year i.e., 50 km per day for 300 respectively. Then, CO2 emission in kg/km of fuel was calculated by assuming the vehicle runs about 25sunny km per days liter [5], of then, fuel. 1776.6 If the kg vehicle’s of CO2 mileagewas emitted was usingabout CNG15,000 engine, km per 1986.6 year ofi.e., kg 50 CO km2 wasper emittedday for using gasoline engine, 1938.3 kg of CO was emitted using LPG engine for a duration of a year. Thus, 300 sunny days [5], then, 1776.6 kg of2 CO2 was emitted using CNG engine, 1986.6 of kg CO2 was the amount of CO mitigated for 25 years was calculated and the results are depicted in Figure8. emitted using gasoline2 engine, 1938.3 kg of CO2 was emitted using LPG engine for a duration of a year. Thus, the amount of CO2 mitigated for 25 years was calculated and the results are depicted in 2C H + 25O → 16CO + 18H O + energy (8) Figure 8. 8 18 2 2 2

Energies 2017, 10, 754 10 of 15

Energies 2017, 10, 754 10 of 15 2C8H18 + 25O2 → 16CO2 + 18H2O + energy (8)

C3H8 + 5O2 → 3CO2 + 4H2O + energy (9) C3H8 + 5O2 → 3CO2 + 4H2O + energy (9) CH4 + 2O2 → CO2 + 2H2O + energy (10) CH4 + 2O2 → CO2 + 2H2O + energy (10)

FigureFigure 8. 8.Mitigation Mitigation of of carbon-dioxide carbon-dioxide emissionemission over SPEA lifetime. lifetime.

The amount of CO2 mitigated mentioned above assumes the vehicle is completely served by The amount of CO mitigated mentioned above assumes the vehicle is completely served by solar power throughout2 its lifetime, but in reality the vehicle is also charged using the grid during solarthe power rainy season. throughout its lifetime, but in reality the vehicle is also charged using the grid during the rainy season. The amount of CO2 produced using the grid is expressed as: The amount of CO2 produced using the grid is expressed as: Net CO2 from grid = 0.85(Grid power (in kWh/day) × No. of days per year) (11)

TheNet amount CO2 from of CO grid2 mitigated= 0.85 (perGrid year power was (foundin kWh/day to be 153) × kgNo. by ofconsidering days per year3 kWh/day) (11)of electricity from the grid consumed for 60 rainy days in a year (Average rainy days in Chennai [36]). The amount of CO2 mitigated per year was found to be 153 kg by considering 3 kWh/day of electricity4.2. Financial from Analysis the grid of consumed SPEA Using for RETScreen 60 rainy days in a year (Average rainy days in Chennai [36]).

4.2. FinancialFinancial Analysis analysis of SPEA of SPEA Using was RETScreen carried using RETScreen v4 [37], a software package developed by the Canadian government to analyze the financial viability of renewable energy systems and compareFinancial with analysis available of SPEA conventional was carried systems. using RETScreenCash flow analysis v4 [37], ais software used to packagepredict the developed payback by theperiod Canadian of the government system. The to rate analyze of interest the financial for payback viability (I) was of renewable calculated energyusing: systems and compare with available conventional systems. Cash flow1+discountrate analysis is used to predict the payback period of the I = 1 (12) system. The rate of interest for payback (Ir) was1 + calculated inflation rate using: The payback interest rate was found1 out+ discount to be 4%. rate The important parameters associated with I = − 1 (12) this analysis are presented in Table r3. The1 vehicle+ inflation life represents rate the duration of vehicle usage when it can be utilized in an efficient and economical way. The life of vehicle considered for analysis was 25The years. payback interest rate was found out to be 4%. The important parameters associated with this analysis are presented in Table3. The vehicle life represents the duration of vehicle usage when it can be utilized in an efficientTable 3. and Assumptions economical in cash way. flow The analys life ofis vehicleof SPEA consideredand gasoline forvehicle. analysis was 25 years.

S. No. Parameters SPEA Gasoline Vehicle Table 3. Assumptions in cash ﬂow analysis of SPEA and gasoline vehicle. 1 Vehicle life 25 years 25 years 2 Inflation rate 3.65% 3.65% S. No.3 ParametersDiscount rate 7.75% SPEA 7.75% Gasoline Vehicle 1 Vehicle lifeINR 25 130,000 yearsINR 175,000 25 years 4 Capital costs 2 Inﬂation rate(USD3.65% * 1950) (USD 2625) 3.65% 3 Discount rateINR 7.75% 5000 INR 10,000 7.75% 5 Annual O&M costs INR 130,000 INR 175,000 4 Capital costs (USD 75) (USD 150) * 1 INR = 0.015 USD(USD as on *March 1950) 2017. (USD 2625) INR 5000 INR 10,000 5 Annual O&M costs The inflation rate is defined as the rate at which the(USD price 75) of the vehicle is (USDexpected 150) to reach based on the country’s economy. It was* as 1 INRsumed = 0.015 as USD3.65%. as onCapital March cost 2017. refers to the cost of the vehicle and

The inflation rate is defined as the rate at which the price of the vehicle is expected to reach based on the country’s economy. It was assumed as 3.65%. Capital cost refers to the cost of the Energies 2017, 10, 754 11 of 15 Energies 2017, 10, 754 11 of 15 vehicleother costs and which other costsare accountable which are accountable during delivery during of deliverythe vehicle. of theThese vehicle. also include These also registration include registrationcharges and charges other andtaxes other which taxes were which incurred were incurred for a passenger for a passenger vehicle. vehicle. Annual Annual operation operation and andmaintenance maintenance cost costwere were the costs the costs that thatare incurred are incurred for the for operation, the operation, maintenance, maintenance, preservation, preservation, and andprotection protection of the of thevehicle vehicle on onan anannual annual basis. basis. Lastly, Lastly, the the payback payback period period was was the the time time required required for for a aperson person or or a acompany company to to recover recover its its complete complete investment investment in in buying buying the the vehicle. vehicle. BasedBased onon thethe inputinput parameters,parameters, thethe paybackpayback periodperiod waswas foundfound outout toto bebe 4.54.5 yearsyears forfor gasolinegasoline runrun vehiclesvehicles andand 3.43.4 yearsyears forfor SPEASPEA andand thethe resultingresulting trendstrends areare plottedplotted inin FigureFigure9 .9. The The graph graph starts starts fromfrom the the negative negative side side of of cash cash flow flow stating stating that that an an investment investment of particularof particular capital capital is spent is spent towards towards the vehiclethe vehicle purchase. purchase. As the Asyears the years progress, progress, the payback the payback adds adds up and up progressesand progresses towards towards the positive the positive side ofside cumulative of cumulative cash flow.cash flow. Thus Thus SPEA SPEA is benefiting is benefiting the investor the investor as its as payback its payback duration duration is 24.44% is 24.44% less thanless than the gasoline the gasoline run vehicle. run vehicle.

FigureFigure 9.9. CumulativeCumulative cashcash ﬂowflow analysisanalysis overover SPEASPEA lifetime.lifetime.

4.3.4.3. Socio-EconomicSocio-Economic AnalysisAnalysis ofof SPEASPEA Socio-economicSocio-economic analysisanalysis ofof gasolinegasoline driven,driven, batterybattery drivendriven andand solarsolar poweredpowered electricelectric vehiclesvehicles waswas performedperformed inin orderorder toto differentiate differentiate and and showcase showcase their their respective respective impacts impacts on on society. society. (1)(1) Comparative feature study TheThe vehiclesvehicles taken taken for for study study differ differ by theirby their basic ba operationalsic operational features. features. Table4 explainsTable 4 explains the features the offeatures vehicles of invehicles detail. in The detail. important The important parameters para suchmeters as such energy as energy source, source, prime moverprime mover and the and other the accessoriesother accessories involved involved in the vehiclesin the ve werehicles studied were studied and compared. and compared.

TableTable 4.4. ComparisonComparison ofof VehicleVehicle features. features.

Gasoline Driven Vehicle Electric Vehicle Gasoline Driven Vehicle Electric Vehicle S. No.S. No. Parameters Parameters SPEASPEA (GDV)(GDV) [38] [38 ] (EV)(EV) [ 30[30]] 1 Energy source Gasoline/LPG Grid/Batteries Solar panels 1 Energy source Gasoline/LPG Grid/Batteries Solar panels 2 Energy storage Fuel tank Batteries Batteries 2 Energy storage Fuel tank Batteries Batteries Wide variety of sources Extraction of energy Wide variety of sources 3 Extraction of energyCrude oil (Non-renewable) (Both renewable and Solar energy 3 Crude oil (Non-renewable) (Both renewable and Solar energy (energy(energy source) source) non-renewable) Internal Combustion Engine Brushless DC motor Internal Combustion 4 4Prime Primemover mover AC/DCAC/DC motormotor Brushless DC motor (BLDC) Engine(ICE) (ICE) (BLDC) VariableVariable speed speed gearbox gearbox 5 5Speed Speedcontrol control Motor controllercontroller Motor Motor controller controller (Manual/Automatic)(Manual/Automatic) 6 6 Prime mover Prime mover power power 6.6 kW 6.6 kWat 5000 at 5000 rpm rpm 1 1 kW kW 1 kW 1 kW Single control,Single control,foot operated foot 7 7Braking Braking system system MechanicalMechanical DrumDrum brakes brakes Mechanical Mechanical Drum Drum brakes brakes operatedhydraulic hydraulic brakes brakes Front:Front: HelicalHelical coil coil spring spring Front:Front: Helical Helical coil coil spring spring Front and Rear HelicalHelical coil coil spring spring and and andand hydraulic hydraulic shock andand hydraulic hydraulic shock 8 Front and Rear 8 Suspension hydraulichydraulic double double acting acting shockabsorber absorber shock absorber Suspension shock absorber shock absorber Rear: LeafLeaf Spring Spring Rear:Rear: Leaf Leaf Spring Spring (double-eye(double-eye with with U-Bolts) U-Bolts) (double-eye(double-eye with with U-Bolts) U-Bolts)

(2) Comparative study on social aspects

Energies 2017, 10, 754 12 of 15

(2) Comparative study on social aspects The social considerations involved in the vehicles are very important as they reﬂect the impact of the vehicle on the environment. Some of the social considerations of prime importance are safety aspects involved in the vehicle, fuel usage, vehicle mileage and harmful discharge of emissions to the environment. These considerations are compared in Table5 for the vehicles taken for study.

Table 5. Comparison of social consideration involved in vehicles.

S. No. Parameters GDV EV SPEA No tail pipe No tail pipe 1 Emissions NOx, CO, HC and CO 2 emissions emissions 2 Maximum speed range 50 to 60 km/h [28] 25–30 km/h [22] 25–30 km/h 18 to 20 km/L (City) Battery capacity: 80 km per 3 Mileage 25 km/L (Highway) 70–80 km complete charging

(3) Economic study The economic study of vehicles considered for the study is tabulated in Table6. The preliminary economic study on these vehicles was carried out with some assumptions which are pointed out below.

• The distance covered by the vehicle per day was assumed to be 50 km (10 trips of 5 km). • The auto fare has been calculated as per Tamilnadu passenger auto rickshaw fare norms [39] i.e., INR 25 for first 2 km and INR 15 for the rest of distance covered per trip. • The charges such as lifetime tax, vehicle registration charges, driver fitness certificate charges etc. were included in the overall vehicle cost. • Petroleum fuel cost was assumed based on the price details mentioned by Indian oil corporation limited [40] and battery charging cost was assumed to be INR 10 per kWh. • This study was assumed for the Chennai urban conditions. So the gasoline run vehicle’s mileage was assumed to be 20 km/L.

Table 6. Economic analysis the vehicles involved in the study.

S. No. Parameters GDV EV SPEA INR 165,000 INR 150,000 INR 110,000 (USD 1950) (USD * 2315) (USD 1650) (approx.) 1 Vehicle overall cost (approx.) (approx.) (vehicle cost = INR 110,000; battery (incl. of vehicle cost, (incl. of vehicle cost, bank cost = INR 20,000; solar panel cost of registration etc.) battery bank cost, etc.,) cost = INR 26,000; Panel mounting frame = INR 9000) Yearly revenue INR 390,000 INR 390,000 INR 390,000 2 (based on assumptions) (USD 5850) (USD 5850) (USD 5850) Inspection and INR 20,000 INR 15,000 INR 26,000 3 maintenance (I &M) (USD 300) (USD 225) (USD 390) INR 60,000 INR 20,000 INR 6,000 4 Fuel cost/charging cost (USD 900) (USD 300) (USD 90) Taxes and other INR 5000 INR 5000 INR 5000 5 documentation charges (Depreciation, Insurance) (USD 75) (USD 75) (USD 75) INR 85,000 INR 40,000 INR 37,000 6 Yearly expenditure (USD 1275) (USD 600) (USD 555) INR 305,000 INR 350,000 INR 353,000 7 Yearly income (USD 4575) (USD 5250) (USD 5610) * 1 INR = 0.015 USD as on March 2017. Energies 2017, 10, 754 13 of 15

The operational and maintenance (I&M) cost is a variable parameter which increases with vehicle mileage and depends on driving patterns. The I&M cost for EV and SPEA was assumed as INR 15,000 and INR 26,000. The I&M cost, which accounts up to 4.5% of its annual income, includes the cost of routine maintenance on the vehicle, wear and tear of machinery, and component replacement costs. Both in EV and SPEA, the component which has to be replaced periodically is the battery. The battery’s life is determined by its number of charge cycles. Since both these vehicles use batteries as the power source, it was assumed to be replaced every 4 years. The maintenance cost of SPEA was higher as the solar PV panels incorporated were subjected to timely maintenance. The fuel cost for EV and SPEA was assumed as INR 20,000 and INR 6000. The fuel cost for EV was more than SPEA as it utilizes grid power for charging batteries whereas SPEA was charged mostly using solar energy. The SPEA was found to be an economically viable solution with 15.74% and 0.85% proﬁtable than gasoline operated and electric vehicle respectively. As far as the economics of this vehicle are concerned, the calculations based on Chennai are presented. This calculation can be generalized and applied all over India as the auto rickshaw tariff and the prices of gasoline don’t change drastically from place to place, as shown in Table7.

Table 7. Auto fare and gasoline rate at key urban regions of India.

Auto tariff * [39] Gasoline Rate * City Minimum Fare Fare above min. Fare (Rs./km) (Rs./L) Chennai Rs. 25-first 2 km 15.00 71.16 Mumbai Rs. 15-first 1 km 10.00 74.42 New Delhi Rs. 25-first 2 km 8.00 68.07 Kolkata Rs. 25-first 2 km 12.00 70.66 Pune Rs. 18-first 1.5 km 12.31 71.30 Ahmedabad Rs. 11-first 1.5 km 7.50 70.05 Bengaluru Rs. 25-first 2 km 13.00 73.00 * As on April 2017.

5. Conclusions The solar powered electric vehicle (SPEA) was designed, optimized and tested effectively for Indian conditions in this research article. The performance analysis of the vehicle demonstrated the charging and discharging characteristics of the battery at varied load conditions. The solar PV output followed the same trend as radiation intensity over a day and experienced a maximum charging rate of 250 W. A day-long charging of batteries on a typical sunny day yielded 2 units (2 kWh) of power. The battery discharging characteristics were studied at variable loading (number of passengers) conditions. The maximum discharge of 540 W was recorded at 390 kg load when the vehicle was moving at a speed of 12.11 km/h. The maximum vehicle speed of 21.7 km/h was achieved at a discharge of 296 W when it was loaded with 90 kg. The environmental analysis of SPEA assessed the yearly CO2 emissions that could be mitigated using SPEA. The results displayed CO2 emissions of 1777 kg, 1987 kg and 1938 kg from using CNG, LPG and gasoline engines respectively, which can certainly be mitigated by using SPEA instead of conventional vehicles for the period of 25 years. The financial analysis of SPEA identified a payback duration 24.44% less compared to a gasoline-run vehicle. Socio-economic analysis of SPEA discussed its significant benefits and showed 15.74% and 0.85% rise in yearly income over gasoline driven and battery-driven electric vehicles. With these outcomes of the analyses discussed, the developed SPEA could be a suitable alternative for local and low-speed transit. SPEA not only mitigates carbon emissions but also progresses the livelihood of mankind in terms of economy and sustainability.

Acknowledgments: The ﬁnancial support provided by the Department of Science and Technology (DST), Government of India through the research project No. DST/SEED/INDO-UK/002/2011 is duly acknowledged. Energies 2017, 10, 754 14 of 15

Author Contributions: K.S. Reddy and S. Aravindhan designed the experiments; S. Aravindhan performed the experiments whereas K.S. Reddy analyzed the data and designed the outline of this paper; with the guidance of K.S. Reddy and Tapas K. Mallick, the paper has been incepted by S. Aravindhan. Conﬂicts of Interest: The authors declare no conﬂict of interest.

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