Performance of Low Speed Electric Two-wheelers in the Urban Traffic Conditions: A Case Study in Kolkata Academic research paper on "Agriculture, forestry, and fisheries"

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Energy Procedia 90 (2016) 238 - 244

5th International Conference on Advances in Energy Research, ICAER 2015, 15-17 December

2015, Mumbai, India

Performance of Low Speed Electric Two-wheelers in the Urban Traffic Conditions: a Case Study in Kolkata

Deepanjan Majumdar*, Archisman Majumder, Tushar Jash

School of Energy Studies, Jadavpur University, Kolkata 700032, India

Abstract

The present study discusses the performance of the electric two-wheeled vehicles on the basis of their running conditions in present day traffic in the urban regions. In this study, survey based results and experimental outcomes were compared with that of the conventional IC engine counterpart for the road conditions in the city of Kolkata. The specific energy consumption of the electric variants were found to be 155.64 kJ/km and 114.5 kJ/km from the experimental and survey results, respectively, compared to 810 kJ/km of the conventional two-wheelers. The specific energy cost and the specific CO2 emission were also obtained from the study.

©2016 The Authors.Published by ElsevierLtd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.Org/licenses/by-nc-nd/4.0/).

Peer-review under responsibility of the organizing committee of ICAER 2015

Keywords: Electric two-wheelers; specific energy consumption; specific CO2 emission; specific cost; road transport

1. Introduction

The rapid economic development of India has been accompanied with increase in the road transportation activities in urban and rural areas of the country. About 80% of the total passenger transportation has been reported to be shared by road transport sector [1]. The major transportation activities have been reported in the urban and adjoining areas. Along with the economic progress, privatized mode of transport has experienced much preference

* Corresponding author. Tel.: +91 99 03 448 450; E-mail address: deepanjanmajumdar@yahoo.in

1876-6102 © 2016 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

Peer-review under responsibility of the organizing committee of ICAER 2015 doi: 10.1016/j.egypro.2016.11.190

Nomenclature

pkm passenger-kilometer

among the commuters. The maximum share among the privatized mode of transport has been marked by the two wheeled vehicles, which consist of mopeds, motorcycles, and scooters, playing the most important role in this sector. The low energy consumption compared to other forms of heavier vehicles, smaller size, and easy maneuverability in the heavy traffic conditions have been the major advantages of two-wheelers for the transportation of one or two passengers at a time [2].The energy intensity for conventional two-wheelers in India varies from 0.55 to 0.45 MJ/ pkm for 2 stroke and 4 stroke models, respectively [3]. By the end of March, 2010, the total number of registered two-wheelers was 71.8 million, which constituted 50.63% of total vehicle fleet in India [4]. Again, 50% of the total gasoline consumption of the country has been reported to be consumed by the two wheel vehicle fleet and the average daily travel for a two-wheeler in India has been reported to be 24 km [2].

Presently, electric two-wheelers have penetrated the two-wheeler vehicle market, which are undoubtedly an energy efficient mode of transport. Electric two-wheelers have two major variants; the low speed and the high speed models. According to the daily average distance as recorded for the two-wheelers in India, the electric scooters may be quite suitable for parallel running along with that of the conventional two-wheelers. But the lower load carrying capacity and shorter distance travel per charge are the two major drawbacks for the electric two-wheelers.

Earlier study on small scale electric scooter trial showed that the energy consumption for electric scooters has been 0.45 MJ/ km and that zero emission can be achieved if the electricity for charging can be derived from renewable sources [5]. But the trial electric scooters had motor ratings of 3 kW, which are mainly the high speed variants. Greaves et.al [6] studied the suitability of Battery Electric Vehicles (BEVs) with prevailing traffics, based on GPS data records of daily driving patterns in the city of Sydney. The results encourage the adoption of BEVs among the vehicle owners. Again the impact of real-world driving pattern has been studied by Amjad et.al on the energy consumption pattern of a hybrid electric two-wheeler, in the city of Coimbatore [2]. The study estimated the fuel efficiency and all electric range for a prototype and its simulated performance for both Indian Driving Cycle and real-world driving cycle. Regarding the use of two-wheelers in India a recent study suggested that, two-wheelers would be the preferred mode of transport in 2035 and that electric two-wheelers of low cost and limited range were mostly suitable for intra city driving [7]. In the present study the suitability of low speed electric two-wheelers with the present urban conditions have been analyzed for the traffic conditions at Kolkata city in West Bengal.

Government of India has launched the National Electric Mobility Mission Plan (NEMMP) for the development of electric and hybrid vehicle technology in the country and its acceptance in the transport sector, and from the recent financial year the subsidy under this scheme has been implemented to reduce the capital cost of the electric vehicles. Thus the cost involved in the electric vehicle may reduce leading to the market penetration of electric vehicles.

2. Methodology

The present study comprised of two separate procedures; firstly, the data for the operating conditions of the electric two-wheelers were collected by conducting primary surveys among the vehicle owners with formatted questionnaires. The daily travel data have been recorded from the available odometers, over a month. The energy consumption data were also provided by the owners and were also estimated from the battery capacity. A daily pattern of utilization of electric two-wheelers was thus obtained. Secondly, the real time performance of an electric two-wheeler was studied as a part of the experiment, for obtaining the energy consumption data and the performance characteristics with the present traffic conditions. The experiment has been conducted based on a low speed electric two-wheeler available in the market. The data from the electric two-wheeler study has been analyzed to obtain its pattern of energy consumption at different loading conditions, its performance in present day traffic and to check the suitability with different traffic conditions. The specification of the vehicle under study as shown in Fig.1 has been provided in Table 1.

Fig. 1 Test electric two-wheeler

Table 1 Test electric two-wheeler specifications

Vehicle weight 94 kg

Battery type VRLA Deep Discharge

Battery capacity 24 Ah

Electricity consumption /charge 1.25 units

Charging time 6 - 8 hrs

Motor type and Power BLDC (Hub motor) and 250 W

Max speed and range 25 km/hr and 70-75 km/ charge

Pay Load capacity 75 kg

Courtesy: Electrotherm (I) India

The charging facility for the test vehicle was established at the University premises, where the energy consumption data has been recorded by the energy meters. The routes for on-road testing of vehicle performance have been identified considering the limited range of the electric two-wheeler and non-availability of charging points elsewhere. These routes included heavy traffic zones during the morning peak hours, medium traffic at afternoon hours, and heavy traffic at evening hours. The performance of the vehicle has also been studied in the low traffic zones at extreme southern fringes of the city. The routes identified have been shown in Fig. 2.

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The data for speed variations, distance traversed, and route of travel have been obtained by GPS tracking method. The corresponding distances traversed along with the energy consumed have been tabulated to find the energy consumption pattern. The energy cost has been obtained from the tariff rate of the electricity utility of the region. In this study the electricity utility tariff from CESC Ltd. has been considered at INR 6.41/ kWh. Again, the charging procedure includes emission of CO2 at the thermal power stations. Thus the CO2 emissions related to the charging of electric two-wheelers has also been calculated. CO2 emissions at thermal power stations have been considered at 1.281 kg/kWh [8].

3. Results and Discussion

The result of the survey conducted among the electric two-wheeler owners had revealed that the purpose of the vehicle utilization has been versatile in nature, from local commuting to delivery of goods. The study showed that the numbers of electric two-wheelers were very less compared to the IC engine counterparts. The major purpose of use of the electric two-wheelers has been limited to local services. A daily usage pattern available from the survey has been shown in Fig. 3. The average daily usage of the electric two-wheeler has been 26.2 km.

The on road tests reveals that electric two-wheelers have been energy efficient than the similar vehicles propelled by IC engines. The major counterpart of the electric two-wheelers has been considered to be the present day scooters having continuous variable transmission technologies; this is because of the comparable sizes, carrying capacities, kerb weights and wheel sizes. But the maximum speed and load carrying capacity have been far different. The maximum speed and accelerating capability of the low speed electric two-wheeler does not match with that of the IC engine vehicles. The high speed variants of the electric two-wheelers have the capability to develop greater speed and acceleration to match with the conventional counterparts [5]. But the high speed variants are less popular as these require similar legal procedures like that of the IC engine vehicles. Thus the experiment was performed with low speed variant of electric two-wheelers, having a maximum speed limit of 25 km/ h. Fig. 4 A-D shows the speed time variation for the electric two-wheeler, obtained from GPS tracking, for different times of the day and routes.

Fig. 3 Daily travel pattern for electric two-wheeler

Fig. 4 Speed time variation of Electric Two-wheeler

The average moving speeds for the test two-wheeler varied from 16.68 km/h to 12 km/ h depending on the traffic conditions, whereas the maximum speed attained during the tests, varied between 36.11 km/ h to 22.03 km/ h. The maximum speeds of about 30 km/ h were achieved during the down slope movement on flyovers. In the Fig 5, the charging regime of the test vehicle for each trip has been shown.

The specific energy consumption rate for the test electric two-wheeler has been found to be 155.64 kJ/km compared to 810.67 kJ/km for the conventional scooters. Tables 2-4 show the comparison between electric two-wheelers and the conventional scooters from the energy consumption and environmental perspective.

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Fig. 5 Charging regime of test vehicle

Table 2 Comparison between conventional scooters and low speed electric two-wheelers

Vehicle Propulsion Technology Maximum Speed (km/ h) Maximum^ Distance)Per

Conventional Scooters SI engine >80 225

Electric two-wheelers BLDC* motor 25 75 - 95

*BLDC - Brushless DC

Table 3 Energy consumption and cost

Vehicle Specific Energy Consumption (kJ/km) Energy Cost (INR/km)

Conventional Scooters 810.67 1.65

Electric two-wheeler (Survey) 114.50 0.20

Electric two-wheeler (On-road Test) 155.64 0.28

Table 4 Environmental impact

Vehicle Specific CO2 emission (g CO2/ km) Specific CO2 emission Considering Technical Losses in Transmission at 11.8% (g CO2/ km) [9]

Conventional Scooters 54.10 -

Electric two-wheeler (Survey) 40.74 45.55

Electric two-wheeler (On-road Test) 55.38 61.91

The test results obtained from surveys reveals that average energy consumption per kilometer of the electric two-wheelers was about 19 % of that of the conventional scooters and also corresponds to the estimated electric two-wheeler consumption in India by Saxena et.al [10]. The specific CO2 emission results showed that the electric two-wheeler test vehicle emitted about 14% more CO2 than the conventional scooters, considering the transmission losses. But the emissions, in case of electric two-wheelers occur at the generating stations, which thus remains centralized and can be controlled unlike that of the conventional ones that directly affects the urban air quality.

4. Conclusions

The low speed electric two-wheeler has been found to be energy efficient than that of the conventional counterparts. Among the two major variants of electric two-wheelers; the low speed ones have been mostly preferred by the electric vehicle adopters, as these require no legal procedures like the high speed variants. As obtained from the survey, the utilization of these vehicles has been purely local, within an average to and fro distance of 30 km. This is also due to the absence of charging facilities other than household or office premises. Though being energy efficient than the IC engine counterparts, the environmental factor remains challenging, being at the similar level compared to that of the conventional scooters. The maximum speed, load carrying and accelerating capacities, have been the major disadvantages of these vehicles.

References

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