Abstract
Urban Mobility is one of the most critical issues at the present. Public
transport in connection with feeder bus system is proposed to be one
of the main solution. Chulalongkorn University has a feet of electric
feeder bus in operation for a few years now. The feet service is,
however, to be improved because of current limitations in battery
energy capacity and long battery charging time. This paper aims to
examine the total cost of ownership (TCO) of the electric feeder
buses using various types of energy storage. The results on the
sensitivity analysis highlight the major parameters that exert strong
infuence in the TCOs. The fast charging system using supercapacitor
battery bus shows the lowest TCO for the present bus feet. The travel
distance (km/year) and operational years were illustrated to be the top
two parameters that exert major infuence towards the TCO.
Introduction
Nowadays, air pollution is one of the most critical environment
problems in urban area especially Bangkok. Therefore, various
technology has been develop to decrease air pollution. An electric
vehicle, consequently, is selected to be one of the main solution for
the future.
Chulalongkorn University has a feet of electric feeder bus in
operation for a few years now. The shuttle buses were designed for
the real use including a bus specifcation, a charging process and an
operating method. To improve service quality, however, there is an
analysis needed in several aspects such as consistency feet
management [1], a decrease in battery capacity which can be used the
total cost of ownership (TCO) for calculating expenses throughout
the useful life of the shuttle buses.
TCO is widely used for an investment analysis which does not only
describe expenses in more detail apart from an overall expense, but
also helps reducing unnecessary payments. Furthermore, the
calculating process of TCO could be adapted for many different
systems; for instance, applying TCO for electric vehicle which
consist of various factors namely battery, maintenance process,
vehicle insurance, etc. [2, 3, 4, 5, 6].
Input parameters for the TCO analysis are applied sensitivity
analysis to identify the most infuencing parameter of TCO and to
decrease forecasting error of the parameters [5,6]. In general, the
sensitivity analysis can be illustrated in spider plot graph format with
percentage deviation representing an impact of TCO towards the
changes of each parameter.
There are many case studies applying the sensitivity analysis to TCO
study. Firstly, the analysis was used to identify palm biodiesel
production life cycle costs testing uncertainty in international prices of
the end result [7]. Secondly, the sensitivity analysis of marine
renewable energy research clearly showed that only a little change in
input could cause massive impact on marine renewable energy
investment [8]. Apart from the effect of marine energy investment, the
analysis also showed the method to reduce an investment cost.
Thirdly, the study of electric public bus transport system in Swedish
illustrated factors infuencing TCO to compare degree of impacts
towards TCO by using Tornado graph [4]. The previous studies show
TCO and sensitivity analysis for passenger cars and big size buses in
which lack of analysis for medium size buses or feeder buses. In
addition, the vehicle energy consumptions were taken from
manufacturers or users which the operating conditions are not realistic.
This paper aims to analyze TCO of feeder electric bus which are
smaller and lighter in comparison with mass transit, as a consequence,
it is believed that an energy consumption would be different.
Moreover, the collected data for this research is gathered from the
shuttle bus currently on service which aids input parameters to be
more realistic. In addition, various sources of energy use for electric
feed buses are taking into account. For this study, three types of
battery are analyzed namely lead acid, lithium-ion and supercapacitor.
Sensitivity Analysis of the Total Cost of Ownership for
Electric Feeder Bus Using Various Types of Energy Storage
2016-01-1721
TSAE-16IC-1721
Published 03/27/2016
Wachira Nilprapunt and Angkee Sripakagorn
Chulalongkorn University
CITATION: Nilprapunt, W. and Sripakagorn, A., "Sensitivity Analysis of the Total Cost of Ownership for Electric Feeder Bus Using
Various Types of Energy Storage," SAE Technical Paper 2016-01-1721, 2016, doi:10.4271/2016-01-1721.
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