The current study is about the feasibility of installing piezoelectricity at Kaohsiung Arena MRT Station. In order to determine how feasible it is to install this sort of technology, along with this study, some important information, such as the economic growth of Taiwan through the years, or the types of technology that Taiwan is using to produce its electrical energy, have been studied in detail.
Using tools, like for instance, SWOT and PEST will help to conclude whether piezoelectricity is an option or not to face global warming and the new policies related to green energies.
The research model is shown in Figure 21.
B. Qualitative Analysis
Due to the characteristics of the current study, it is based on qualitative analysis. In chapter two we get familiar with the different sources that Taiwan is using to supply electricity and from this understand the benefits and cons of each technology.
To Taiwan, with the purpose of meeting its future goals about denuclearization, and also to reduce its fossil fuel dependence, it is important to diversify its energetic matrix. The island has been investing a lot of money on solar and wind technologies, however, another technology will help Taiwan to accomplish its target.
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It is here where the piezoelectricity plays an interesting role that will be analyzed through SWOT and PEST analysis, to examine the piezoelectric as a new sort of technology to be considered in the country as an alternative method to produce electricity.
With SWOT we will be considered the strengths, weaknesses, opportunities, and threats, while PEST is about political, economic, social, and technical factors. Each of the factors mentioned above will be analyzed to determine the piezoelectric feasibility.
As was said in chapter 2, it turns out to be very important to give steps in the right direction, which means to mitigate the CO2 emissions in Taiwan. To move forward, Taiwan needs to get rid of its dependency on fossil fuels (coal, oil, and gas), given that, its total electricity production depends on these kinds of sources. Also, looking for alternative ways to produce electricity is important, due to the current political party ruling Taiwan, has its plan about the phase out the use of nuclear energy.
As a result, Taiwan has invested a lot of money on solar and wind energy, but Taiwan is an island with limited land, and that is why the importance of piezoelectric. This technology does not pretend to take over the total electricity production of the country, instead, it arises as a complement to other sorts of green technologies.
People worldwide have to walk from one place to another place, so it is important to detect where big crowds are concentrate and take advantage of it, to generate electricity.
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SWOT Analysis Piezoelectricity PEST Analysis
Replacement of Thermal-Generation
Reduction of CO
2Emissions
Policy
Recommendations
Figure 21.Research Framework.
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Chapter Four: Major Findings
A. Introduction of Kaohsiung Arena MRT Station
Kaohsiung is a city located in the south of Taiwan, it is one of the most important cities in the country and possesses some of the most prominent structures in the country. The city has grown through the years from a village until turn into the economic and political center of southern Taiwan. The city has some of the key industries that have helped Taiwan to get the title of one of the four Asian tigers, such as steel-making, oil refining, manufacturing, freight transport, and shipbuilding. (Wikipedia, 2020)
The Kaohsiung International Airport is the second airport regarding the number of passengers in Taiwan, and the Port of Kaohsiung is the largest and more important port in Taiwan.
Kaohsiung is well connected to other important cities in Taiwan such as Taichung or Taipei by high speed or conventional rail. (Wikipedia, 2020)
The city has a good transport system that allows its citizens to move into the city conveniently since it is well connected by a bus system and also a mass rapid transport (MRT), which is a robust metro system commonly known as Kaohsiung MRT.
Kaohsiung MRT has in total 45 stations and 3 lines, however, the study will be conducted taking into account which is the most convenient station considering some questions, such as, what are the stations with a high rate of passengers per day? What is the frequency of pedestrians? or What is the size of the station to be chosen in order to locate the tiles?
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Table 2. Daily Ridership in 2018 (unit: 1000 person). (Kaohsiung Rapid Transport Corp., 2018)
JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC
Average Daily Ridership Red Line 132.4 152.1 126.5 135.1 123.8 128.1 133.4 130.0 126.9 132.2 135.4 150.3 133.7 Orange Line 42.7 51.3 41.7 42.5 39.1 40.4 43.8 42.6 39.7 42.9 45.1 41.8 43.6 All Line 175.1 203.4 168.2 177.6 163.0 168.4 177.2 172.6 166.6 175.0 180.5 202.1 177.3
From the annual report of Metro Kaohsiung, it is possible to collect the data about which metro line is the one which carries the most passengers in the city, Table 2 shows the number of passengers per month on each line.
Figure 22.Average Daily Ridership in the months of 2018. (Kaohsiung Rapid Transport Corp., 2018)
As we can see in Figure 22, the red line is the one that carries the highest amount of passengers in every month of the years, however, this line has in total 23 stations. So, from the Kaohsiung City Government Transportation Bureau, it was also possible to know the figure of passengers that each MRT station holds.
According to the document (Appendix 1), Zuoying MRT station is the one that holds the highest number of passengers per day, however, given that Kaohsiung Arena MRT station is
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surrounded for many popular places, the frequency of passengers seems to be higher, and the difference of passenger between the stations is not that big, it is the chosen one to develop the study. Also, the idea of choosing an MRT Station with average traffic of passengers is to check the amount of energy that can be generated from it and then determine how convenient to implement this solution in other places.
Kaohsiung Arena MRT station is located along the red line in Zuoying District and it is named after Kaohsiung Arena. The station has two levels and the plans of the first level (concourse level plan) are shown in Figure 23 and second level (platform level plan) in Figure 24.
Figure 23.Kaohsiung Arena MRT Station Concourse Level Plan. (Kaohsiung Metro, 2020)
In Figure 23, we can observe the distribution and the sections of the concourse level of the Kaohsiung Arena MRT Station.
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Figure 24.Kaohsiung Arena MRT Station Platform Level Plan. (Kaohsiung Metro, 2020)
In Figure 24, is appreciated the platform plan level, in both pictures above are some references by numbers, these references are named below.
1. Escalator 2. Elevator 3. Stairs
4. Public Phone 5. Toilets
6. Ticketing Gate
7. Automatic Ticket Issuing Machine 8. Information
9. AED
B. Installation of Piezoelectricity
The electricity consumption of Kaohsiung Rapid Transit Corporation (KRTC) in 2018 was around 137 million kilowatts per hour (kWh), which represents an increase of 0.03% of the previous year considering that it was 134 million kWh. TaiPower, the company that provides the electrical energy to the Mass Rapid Transport, increase the electricity rate at 3% average per year.
Considering this, energy-saving with continuous improvement of energy use efficiency is necessary to reduce costs in the electricity bill, likewise, reducing the emissions of CO2. (Kaohsiung Metro, 2020)
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Considering that there are 45 stations in total operating by KRTC, and the total electrical consumption of the company was 137 million kWh during 2018, we will assume the electrical consumption was the same in each station.
137,000,000 kWh / 45 = 3,044,444.44 kWh per year
It means 3.04 million kWh was the electrical consumed per station in 2018, now we are going to figure out the consumption of energy per day.
3.044.444,44 kWh / 365 days = 8,341 kWh per day
The average electric consumption per station on a single day during 2018 was roughly 8,341 kWh, now considering that Kaohsiung MRT Station is one of the stations with high electric consume, and in order to have a small margin of error, we will suppose the consume per day of this station is the obtained value, 8,341 kWh per day. However, given that piezoelectric, as well as the other existing renewable energies, this technology lacks reliability, since it does not produce energy in a static condition, which means, if there are not people in the station or just a few people, the amount of energy will not be enough to supply its requirements.
Therefore, the installation of piezoelectric is with the purpose of acting as support of the main source of energy, and in this way help to reduce the electric cost of the station, which in turn will be reflected in a reduction of amounts of CO2.
The first step is to identify the piezoelectric existing in the market. Although there is a considerable amount of piezoelectric in the market, only those which their application is aimed at pedestrians will be considered. Below, Table 3 helps to select the type of piezoelectric tiles according to the electricity production, cost of the tiles, and its size.
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Table 3.Piezoelectric technology types (specifications, price, lifespan) (Solban, 2019)
With table 4 is possible to check the best function for using the tiles, shapes, materials, and configuration of each type.
Table 4. Piezoelectric technology types according to uses and features. (Elhalwagy, 2017)
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Due to its high cost, we will discard the tiles of the company Sustainable Energy Floor (SEF), then the tiles that will be considered are produced by Waynergy Floor, and Pavegen. Both companies offer slabs with technology that can be used indoor or outdoor. Pavegen tiles will be selected to conduct the study because the slabs after being tested, they generated more power than Waynergy slabs, and also are more affordable (Bekzhanova, 2019).
Moreover, we have to consider the price of one square meter of Pavegen tiles might be lower at the moment of installing piezoelectric tiles, in 2018 the CEO of the company stated that in the upcoming years the price of the slabs would decrease around $125 USD per square meter.
(Knowles, 2018)
Figure 25. Pavegen Tiles in London. (Mashaleh, 2018)
As we can see in Figures 23 and 24, Kaohsiung Arena MRT station is big enough to hold a big number of pedestrian, so identifying the right location to place the tiles is important in order
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to get the maximum power of them, it because is relevant to consider some limitations, and the price of the slabs plays an important role in the current study.
According to a case study conducted in Japan in 2009, the company JR East installed a power-generating floor not all over the station, but at the ticketing gates in one station with high traffic, the intention was to generate enough electricity to power the monitors and the ticket machines in the station. (Laumann, 2017)
Figure 26. Proposed Tiles Location. (Elhalwagy, 2017)
Choosing a different place to locate the tiles than the ticketing gates, could be not suitable given that pedestrians tend to scatter in the station, and it will not be possible to take the maximum power from the tiles, so locating them on the ticketing gates, just as the case study in Japan, is the right option, since all the passengers have to cross the ticketing gates either to go in or out of the station. The proposed location for the tiles can be observed in Figure 26.
C. Replacement of Thermal Generation
The Kaohsiung Arena MRT Station is fed with electricity generated from fossil fuels, the purpose is to know how many piezoelectric tiles would be necessary to replace the thermal generation.
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To make the analysis is required to know the amount of power that Pavegen tiles can generate per day. In total, and according to the Republic of China calendar, in the year 107, Kaohsiung Arena Station had 5,205,631 passengers going into the station, and 5,366,932 passengers going out from the station, through the whole year (Appendix 1), considering that a year has 365 days, in average the passengers going into the station was 14,262 passengers per day, and passengers going out from the station 14,703.92, it means around 29,000 people transit the station per day.
Figure 27.Pavegen working model. (Boby, 2014)
Figure 27 shows the representation of the working model of Pavegen tiles, to generate energy the person must give a step on the tile, then the energy can be stored or consume immediately depending on the requirements of the company.
According to Pavegen, a single tile can generate 5 joules or what is the same 5 watts per step, to generate this energy a person should have an average weight of 60 to 70 kg, and we assumed the electrical consume of the station is 9,000 kWh per day, and this information along with the number of pedestrians, allow us to calculate the number of required tiles to supply the electric consume of the station.
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First of all, we will convert kWh into Joules using the next formula.
1 𝑘𝑊ℎ = 3,412 𝐵𝑇𝑈, 𝑤ℎ𝑒𝑟𝑒, 1 𝐵𝑇𝑈 = 1,055 𝐽𝑜𝑢𝑙𝑒𝑠.
1 𝑘𝑊ℎ = 3,412 ∗ 1,055 = 3,600,000 𝐽𝑜𝑢𝑙𝑒𝑠 𝐸𝐽 =9,000 kWh day * 3,600,000 = 32,400,000.000 Joules
The electric consumption of the station per day reaches 32,400,000,000 Joules. And also, as we said above, one tile can generate 5 Joules.
32,400,000,000 Joules / 5 Joules= 6,480,000,000 Joules per tile
We know that Kaohsiung Arena MRT Station holds an average of 29,000 pedestrians per day, with this information we can calculate the footsteps required to power the station.
6,480,000,000 Joules per tile / 29,000 Pedestrian = 223,448.28 footsteps
To generate 6,480,000,000 joules, are required about 223,449 footsteps of each pedestrian per day in order to supply the electric consumption with piezoelectricity.
Assuming every pedestrian hits 30 times the piezoelectric tiles, and that there are 7,000 tiles arranged in the station where each tile costs about $78 USD, under these conditions the energy produced would cover the electric consumption of the station per year. However, the cost per square meter is $620 USD, which indicates that the final value of the tiles will reach roughly
$546,000 USD, and the fact that it is impossible to get the maximum power of each tile, it is non-viable condition.
Considering the place where the tiles will be located, the ticketing gates, and the chances to hit them 30 times, it makes of it, an impossible situation to set a big amount of tiles. It means
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that using piezoelectricity to replace thermal energy by itself is not an option, on one hand, because of the high cost of the tiles and on the other hand because to produce electricity through piezoelectric requires and external factor, it is kinetic energy.
Despite this technology is not suitable to supply the total consumption of the station, it might be a good complement source to produce electrical energy to reduce the electric consumption of the station. Given the location of the ticket gates, the objective is to place 1.5 square meters of the tiles on each gate, just as it is shown in Figure 28.
Figure 28. Location of the Tiles on each ticketing gate.
In the station there are ten gates, so, in total there will be fifteen square meters of Pavegen tiles, it means one-half square meter per ticketing gate. The proposal mat of Pavegen tiles for each ticketing gate is 300 cm x 50 cm in order to make it fit on the floor.
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There are two scenarios, the first one is with the price of $620 US dollars per square meter of Pavegen tiles and the second one, with a price of $125 US dollars per square meter.
Below it is shown the key data considering the first scenario, in table 5 we can observe the cost of the piezoelectric tiles along with the amount of energy that will produce in the proposed scenario.
Table 5. Cost and generation of electricity using Piezoelectric-Scenario 1.
Number of tiles arrangement (1.5sqr meter) 10 Price of one-half sqr meter of tiles [USD] $930
Steps on the tiles 15
Average Users per Day 29,000
Total Steps Users 435,000
Energy per Step [Joules] 6
Total Energy per Day [Joules] 2,610,000
Total Energy per Day [kWh] 0.73
Total Energy per Year [kWh] 264.63 Total Energy 20 Years [kWh] 5,292.50 Price of kWh in a lifetime [USD] $1.17
As we can see in table 5, the total energy produced during the lifetime of the tiles (20 years) is 5,292.5 kWh, which means, the price of a kilowatt-hour using piezoelectric will be $1.17 USD.
Now, the Taiwan electricity price of thermal energy, in 2019 for business or industries was $0.129 USD per kWh (Global Petrol Prices, 2019), which implies a big difference on the electricity price using piezoelectric tiles.
Table 6. Electricity price thermal energy in Kaohsiung Arena MRT Station-Scenario 1.
Electrical Consume of the Station per day 8,340.94 kWh Price of kWh Thermal Energy, 2019 [USD] $ 0.129
Price per kWh on a day [USD] $ 1,075.98
Price of electricity in one year (2019) [USD] $392,733.3 Electricity Bill in 20 years kWh [increasing 3% per year] $ 11,992,811.5
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In Table 6, we have the electric consumption of Kaohsiung Arena MRT Station per day, the price of a kilowatt-hour from Thermal Energy in 2019, the price of electricity that Metro Company pays per day and per year, and finally considering that Metro Company claims the electricity bill increases in average 3%, the projection of the electricity bill in 20 years, all the price units in US dollars.
Table 7. Electricity Saves using piezoelectric in Kaohsiung Arena MRT Station- Scenario 1.
Electricity generated in the Station per day [kWh] 0.73 kWh
Saves in [USD] per day $0.093525
Saves in a year [USD] $34.14
Saves in 20 years [USD] $1,042.42
Cost per kWh of the tiles [USD per kWh] $1.75
In Table 7, it shows the electricity generated per day from the tile and the saves generated with the piezoelectric tiles in Kaohsiung Arena MRT Station, where the saves in 20 years will be
$1,042.42 US dollars. In the first scenario, we can observe that the price of kilowatt-hour from thermal energy is $0.129 US dollar and from piezoelectric tiles is $1.75 US dollars, where the last one is 13.62 times more expensive. We can see that there is a big difference when comparing the prices of one and another technology.
Now we will consider the second scenario, with a price of $125 US dollars per square meter of Pavegen tiles.
Table 8.Cost and generation of electricity using Piezoelectric-Scenario 2.
Number of tiles arrangement (1.5 sqr mt) 10 Price of an sqr meter of tiles [USD] $187
Steps on the tiles 15
Average Users per Day 29,000
Total Steps Users 435,000
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Energy per Step [Joules] 6
Total Energy per Day [Joules] 2,610,000 Total Energy per Day [kWh] 0.73 Total Energy per Year [kWh] 264.63 Total Energy 20 Years [kWh] 5,292.50 Price of kWh in a lifetime [USD] $0.35
Table 8 is shown the same information as Table 7, but here the difference is about costs, the price of the tiles is different, and also the cost of a kilowatt-hour in the lifetime of the tiles.
Due to, we already know the key data about the price of thermal energy that was generated in Table 6, we will continue with the saves using piezoelectric in the second scenario.
Table 9.Electricity Saves using piezoelectric in Kaohsiung Arena MRT Station- Scenario 2.
Electricity generated in the Station per day [kWh] 0.73 kWh
Saves in [USD] per day $0.093525
Saves in a year [USD] $34.14
Saves in 20 years [USD] 1,042.42
Cost per kWh of the tiles [USD per kWh] $0.3533
With the second scenario, we can notice the difference between the price of thermal energy and piezoelectricity, given that here, the cost per kWh of tiles comes to $0.3533 US dollars, however, it is still more expensive than thermal energy about 2.73 times.
Table 10.The unit cost of electric generation.
Source of Energy Scenario 1 Scenario 2 Thermal $0.129 $0.129 Piezoelectric $1.75 $0.3533
Relation 13.57 2.74
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In Table 10, we can see in summary what was found concerning the cost per unit of electrical generation, where clearly shows that piezoelectric is more expensive than thermal energy.
In Table 10, we can see in summary what was found concerning the cost per unit of electrical generation, where clearly shows that piezoelectric is more expensive than thermal energy.