Technical Report, Final Draft
See Neng Wei
Neng Wei
graduated from Singapore Polytechnic with a diploma in civil engineering with
business in 2014. He has interests in architecture and structural design, which
led him to pursue civil engineering. He was involved in the tender construction
of National University Singapore’s science canteen during his polytechnic
internship. At present, he is an undergraduate student in civil engineering at
Singapore Institute of Technology.
Umar Abdul
Aziz Bin Ahmad Shamsuddin
Umar Abdul
Aziz graduated from Singapore Polytechnic with a diploma in architecture in
2015. His passion lies in the design of buildings and structures as well as
mathematics. During his architectural internship stint, he has been involved in
several projects including the construction of the Singapore Land Transport
Authority Downtown Line 2 tunnel. At present, he is an undergraduate student in
civil engineering at Singapore Institute of Technology.
Teo Shu
Min
Shu Min
graduated from Singapore Polytechnic with a diploma in civil engineering with
business in 2017. Her passion lies in the structural design of buildings and
their structural plans. She has been involved in drafting construction drawings
for a project located in Qurayyat, Oman, for an independent water project
during her internship. At present, she is an undergraduate student in civil
engineering at Singapore Institute of Technology.
Executive
Summary................................................................................................................ iv
1 Introduction....................................................................................................................... 1
2 Problem statement............................................................................................................ 2
3 Purpose Statement............................................................................................................ 2
4 Proposed Solution............................................................................................................. 2
4.1 Case Study - OLEV........................................................................................................ 3
4.2 Application of OLEV in Singapore............................................................................... 5
4.3 Benefits of Proposed Solution....................................................................................... 6
4.4 Evaluation of Proposed Solution................................................................................... 7
5 Methodology..................................................................................................................... 8
5.1 Primary Research........................................................................................................... 8
5.2 Secondary Research....................................................................................................... 8
6 Conclusion......................................................................................................................... 8
References................................................................................................................................ 9
Appendix A
Appendix B
Executive
Summary
This proposal describes a research project carried out by
our team in response to a call for engineering problem-solution proposals. In
this proposal, the team addresses the problems of the BYD K9 electric buses,
such as its battery technology and plug-in charging system, which the Land
Transport Authority (LTA) are using in a pilot study. The buses' batteries are
unsuitable for Singapore's warm and humid climate, which reduces electric bus
battery efficiency and shorten bus travel range. The plug-in charging cables and
limited charging locations in the current system also prove inconvenient for
bus drivers. Having these problems would
render the overall electric bus system inefficient.
The proposal details our team’s suggested modification to
the current system and discusses its benefits and limitations. The team
proposes a solution that uses the Shaped Magnetic Field In-Resonance (SMFIR)
technology to enable electric buses to be charged wirelessly when stationary or
while in motion. This technology allows smaller batteries to be utilised in
electric bus, thus reducing the bus self-weight, and improves overall system
efficiency and travel range.
The proposal also discusses the team's objective, which
is to recommend to LTA to conduct a pilot study in the Punggol Digital District
on the usage of SMFIR in electric buses in order to assess its feasibility in
Singapore.
1 Introduction
Singapore is ranked first in Asia,
and second globally as the most sustainable city. However, based on International
Energy Agency (IEA) 2016 data, Singapore ranks 26th out of 142 countries in
terms of emissions per capita due to its small size and dense population
(National Climate Change Secretariat, 2018). Nonetheless, Singapore has always
been committed to achieve its aims to achieve a 36% reduction goal in carbon
emissions intensity by 2030 based on its 2005 emissions (Feng, 2015).
Singapore’s
transportation sector contributes 15.32% to the total greenhouse gas emissions
in 2016 (Feng, 2015). While the usage of electric vehicle (EV) is one way to
reduce greenhouse emissions, the country is facing challenges to fully embrace
the usage of EVs as the main means of commute. Challenges such as the high cost
of EVs, Singapore’s limited EV infrastructure and the considerable safety
aspects of plug-in EVs generally deter local consumers and Singapore’s public
transport operators to jump on the EV bandwagon. According to Kuttan (2017), EV drivers are afraid of travelling
long distances with the risk of their vehicle batteries running flat. He added
that the accessibility of fast chargers is the only factor that will encourage
people to be more open to conventional EV.
Today, Singapore’s buses dominantly run on natural gas
and diesel. With greater awareness on environmental sustainability, the Land
Trasport Authority will be buying 50 new hybrid buses and 60 new pure-electric
buses (Lim, 2017). The Chinese-manufactured BYD K9 pure-electric buses which
will be tested by Go-Ahead Singapore needs five to 10 hours charging time to
travel 250 km. These buses emit no greenhouse gas emission or noise, thus
reducing air and noise pollution. Their traveling distance, however, will be
reduced due to the warm and humid climate in Singapore with additional battery
power used for cooling (Lim, 2016).
E-buses have zero emissions, run quieter than
conventional buses, contribute less to the carbon footprint, require less
maintenance, and are much cheaper in the long run, as compared to diesel buses.
However, high turnover rate of buses in Singapore, limited charging periods,
and heavy battery requirements make electric buses unsustainable in Singapore.
To eliminate these problems, the usage of wireless charging technology in
e-buses can be implemented.
2 Problem statement
An ideal
pure-electric bus system in Singapore should be both energy efficient and
self-sustaining, and has good accessibility to charging points. However, the
BYD K9 e-buses tested are not equipped with the optimum battery and charging
technology to meet this ideal whilst facing Singapore's challenging climate. By
implementing wireless charging technology, Singapore's e-bus system will be
able to attain both optimal efficiency and self-sustainability, and an
improvement in charging accessibility.
3 Purpose Statement
The purpose of this report is to outline to
LTA the advantages of wireless charging technology for electric buses, which
tackles the challenges in the current system and propose to it to conduct a
pilot study to test the feasibility of the wireless charging system.
4 Proposed Solution
The
solution to the problems of battery and charging technology is to use wireless
charging. ‘Wireless charging technology’ or power transfer through magnetic
induction has been tested since the early 2000s on electric buses in several
countries like Italy, China, USA, Japan and Korea. Inductive charging requires a charging station which has an induction
coil in it. These coils are embedded in roads, thus replacing conventional
charging kiosks. When electric current is applied through the coil, an
electromagnetic field is produced, which transfers energy across the gap to a
corresponding induction coil in a pickup device. The device then converts
the energy from a magnetic field back into usable electric current, which is
used to charge batteries (Thomson, 2014). These e-buses receive power
without physical contact unlike the conventional usage of electric cables for
plug-in EVs. The charging process is thus simplified as buses need not be
charged only in the bus depot or interchange but instead charged on the roads.
4.1 Case
Study - OLEV
An example
for this technology was tested by Korea Advanced Institute of Science and
Technology (KAIST). KAIST is the first in the world to introduce Shaped
Magnetic Field in Resonance (SMFIR) technology that safely delivers energy to
an electric vehicle wirelessly while the vehicle is in motion. It was developed
as part of KAIST’s Online Electric Vehicle (OLEV) project. The SMFIR technology
granted OLEV buses the ability to be charged stationary or while in motion. It
eliminated the need for remote static charging stations while introducing
charging infrastructure in roads. Through the development of SMFIR, the
company’s e-buses utilised smaller, less expensive batteries, which in turn
reduced the vehicle weight. With a lighter load, the buses expanded less energy,
thus pitting it at a higher operational efficiency against other wireless
charging technologies. Moreover, wireless charging coils installed beneath the
road surface caused minimal impact on the cityscape and freed land, which would
have been used for building charging kiosks, for other usage.
A pickup
device installed under the vehicle works to gather the magnetic field
efficiently from power grids embedded in the road and convert it into electric
energy for vehicle operation. The pickup coils are tuned to a 20kHz resonant
frequency and are modelled to have maximised exposure to the generated magnetic
field. As a result, the efficiency of the magnetic power transmission can be
maximized while decreasing magnetic field leakage (Suh, 2011).
Figure 1: Simplified concept of power transfer
using SMFIR (KAIST, n.d.)
According to the article “KAIST OLEV Transport System,” on the website
KAIST OLEV (n.d.), the usage of the SMFIR technology has a power transmission
efficiency of 85% at a ground height of 20 cm and 75kW of power capacity. This
is by far the most efficient wireless power transfer system available for
commercial deployment to e-buses. The SMFIR technology also enables OLEV buses
to have battery size and weight of 20% of the batteries used in conventional
e-bus. Additionally, the provision of power supply infrastructure embedded on
five to 15 percent of the whole bus route is sufficient to wirelessly power an
OLEV bus for its operation. OLEV complies with the international
electromagnetic fields (EMF) standard of 62.5mG, which is within the safety
standard for EMF exposure. The usage of smart power segments allows activation
of power supply in roads only when the OLEV buses are in range. As a result, it
readies power transmission to other road consumers.
Figure 2: Overview of power supply
infrastructure (KAIST, n.d.)
4.2
Application of OLEV in Singapore
While the
idea of revamping the public bus system in Singapore into wireless may seem
far-fetched, a pilot study can be first conducted to assess the feasibility of
the OLEV system on Singapore’s public buses and roads. As part of the
engineering design and development process, a bus route can be selected within
the Punggol Digital District to apply the power supply infrastructure. The
route will operate a couple of OLEV buses over a 6km one-way trip, which will
take approximately 20 minutes for each trip. The objective of this test is to
design the most efficient and optimized power supply infrastructure. This
includes identifying how long the powered track should be, where it should be
installed, and what combination of the segments should be laid. As a rule of
thumb, the powered track should be installed where the driving power exceeds
the battery discharge capacity, so that the buses can have enough power to be
driven. The segments can be installed at bus idling locations such as bus
stations, bus stops and traffic junctions, which would maximize charging time
of the buses.
4.3
Benefits of Proposed Solution
Amongst all EV bus technology developed around the globe,
KAIST's OLEV system is most potent in resolving the issues with conventional
e-buses. In today's competitive market, it is crucial that strategic decisions
on investments are made. In this section, our team outlines some of the key
benefits of OLEV that LTA may consider.
1.
The OLEV system provides
Singapore with a more efficient e-bus alternative to the conventional plug-in
BYD K9 e-bus as an OLEV bus is lighter due to its reduced battery weight and
size, and more convenient as it charges wirelessly. This will improve battery
efficiency, allow e-buses to use less power to travel and reduce charging time
and frequency.
2.
The OLEV system eliminates the need to build
expensive charging facilities. Not only will this reduce costs, it will also
increase land space efficiency as freed land can be reserved for other usage.
Additionally, the system will improve the accessibility of charging locations
for e-buses and other EVs as power segments can be installed into the road
network all-over Singapore.
3.
The OLEV system is self-sustaining, which
will transform Singapore's urban transportation. OLEV e-buses can be charged
automatically with the removal of manual charging and heavy charging cables. The system can
also be incorporated into other EVs, such as e-cars, trains and autonomous
vehicles, thus revamping Singapore's EV population.
4. The success of developing OLEV will entail a promising return for
Singapore's global standing as a pioneer in the advancement of EV systems in
the tropical region.
4.4
Evaluation of Proposed Solution
In order to
address doubts on the feasibility of implementing OLEV in Singapore, the
challenges of implementing OLEV will be evaluated and discussed. The two main
challenges are high infrastructure cost and performance uncertainty.
1.
The installation of induction coils into
existing road infrastructure may incur significant costs and traffic disruption
to existing system. The proposed locations of charging segments on Singapore’s
roads such as bus depots, bus stops and traffic junctions, must also be studied.
These locations are ideal for charging e-buses, but traffic junctions
necessitate the usage of the GLIDE system which
detects the presence of vehicles and pedestrians at the junctions of major
roads. Little is known on the effect of magnetic coupling on the GLIDE system’s
wire sensors. Through the pilot study, more in-depth understanding of the cost
breakdown and effects of OLEV on existing infrastructure can be studied.
2.
Given that Singapore would be the first
tropical country to test wirelessly charged buses using the OLEV system, its
performance here may not yield the same result as that in Korea where this
system was developed and tested. As there is a lack of data, there is an
uncertainty in OLEV battery efficiency and SMFIR charging efficiency in Singapore's
climate. Through the pilot study, the performance of OLEV can be further
assessed and developed for further improvements.
5 Methodology
5.1 Primary
Research
Primary research in the form of interviews
were conducted with SIT-UoG’s Deputy Programme Director for Civil Engineering,
Dr. Kum Yung Juan, and SIT’s Programme Director for Telematics (Intelligent
Transportation Systems Engineering), Dr. Zheng Jianxin. The interviews enabled
the team to gain insights and opinions from experts on electric vehicles and
the feasibility of the wireless charging system for electric buses. The
interview transcript with Dr. Kum and the summarised interview with Dr. Zheng
can be found in Appendix A.1 and A.2 respectively.
5.2 Secondary
Research
Online
sources are used for the information of the different wireless charging
technologies tested in other countries. After evaluating the different
technologies, the OLEV system by KAIST has been widely quoted in this report
due to its extensive design information and its feasibility as a solution to
the problems mentioned.
6 Conclusion
To conclude, the implementation of wirelessly charged
e-buses for Singapore's public bus system could be one way to solve the
problems associated with e-buses, and potentially be a game changer in EV
uptake. It provides a more efficient and self-sustaining system compared to
conventional e-buses, eliminates the need for building expensive charging
facilities which in turn, frees up land for other uses, and improves Singapore's
image when proven successful. Hence, our
team proposes to LTA to conduct a pilot study to assess the costs &
benefits of the OLEV system before implementing fully into Singapore’s roads.
Fischer, M. (2016, December 7). Scandinavia’s first electric bus with
wireless fast charging. News
from Vattenhall. Retrieved March 13, 2018 from https://news.vattenfall.com/en/article/scandinavia-s-first-electric-bus-wireless-fast-charging
KAIST. (n.d.). KAIST OLEV Transport System [Brochure]. Retrieved March
4, 2018 from http://www.smfir.co.kr/20120323/sub02/KAIST_OLEV_en.pdf
Kim, D. J. (2015, May 15). Wireless
Charging Electric Bus. Retrieved March 4, 2018 from https://kmatrix.kaist.ac.kr/wireless-charging-electric-bus/
Lim, A. (2017, March 9). LTA to expand trials of hybrid,
electric buses. The Straits Times.
Retrieved March 27, 2018 from http://www.straitstimes.com/singapore/transport/lta-to-expand-trials-of-hybrid-electric-buses
Lim, A. (2016, August 6). E-bus to ply public
route in trail lasting six months. The Straits Times. Retrieved March 3,
2018 from http://www.straitstimes.com/singapore/e-bus-to-ply-public-route-in-trial-lasting-six-months
Matt, B. (2013). Electric avenue: Korean
buses now wirelessly charge as they drive. Retrieved March 12, 2018 from https://www.theverge.com/2013/8/7/4596898/korea-wireless-charging-buses-kaist-olev
National Climate Change Secretariat. (2018). Singapore's Emission Profile. Retrieved March 30, 2018 from https://www.nccs.gov.sg/climate-change-and-singapore/national-circumstances/singapore's-emissions-profile
National Environment Agency. (2016, December
16). Singapore second biennial
update report 2016. Retrieved March 10, 2018 from http://www.nea.gov.sg/docs/default-source/energy-waste/climate-change/second-biennial-update-report-(16-dec-2016).pdf
One Motoring. (n.d.). Green Link Determining
(GLIDE) System. Retrieved March 7, 2018 from: https://www.onemotoring.com.sg/content/onemotoring/en/on_the_roads/traffic_management/intelligent_transport_systems/glide.print.html
Suh, I. S. (2011). Application of
Shaped Magnetic Field in Resonance (SMFIR) technology to future urban
transportation (Research Report). Retrieved March 27, 2018 from: http://www.buspress.eu/wp-content/uploads/2013/08/CIRP-Design-2011-Paper34-Suh.pdf
Suh, N.
P., Cho, D. H., & Rim, C.T. (2011). Design of On-Line Electric Vehicle
(OLEV). Retrieved March 1, 2018 from http://www.springer.com/cda/content/document/cda_downloaddocument/9783642159725-c1.pdf?SGWID=0-0-45-1121840-p174067862
Thomson, K. (2014). Problems with Wireless
Charging. Retrieved March 3, 2018 from: https://cambrionix.com/blog/problems-with-wireless-charging/
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