Delft University of Technology
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Specialization: Transport Engineering and Logistics
Report number: 2016.TEL.8070
Title:
An energy and operational costs
comparison of the future
transport system on the TU Delft
campus
Author:
G.D. Vossers
Title (in Dutch) Een energie en operationele kosten vergelijking van het OV van de toekomst op de TU Delft campus
Assignment: research assignment
Confidential: no
Initiator (university): Dr. W.W.A. Beelaerts van Blokland Supervisor: Dr. W.W.A. Beelaerts van Blokland
1 2016.TEL.8070
An energy and operational costs comparison of the
future transport system on the TU Delft campus
A comparison between Campus Advanced Transport System and the current busses and trams
Research assignment. September 2016. Report number: 2016.TEL.8070
Daan Vossers (1515845)
Transport Engineering Delft University of TechnologyDelft, the Netherlands G.D.Vossers@student.tudelft.nl
Dr. W.W.A. Beelaerts van Blokland
Department Maritime & Transport TechnologyDelft University of Technology Delft, the Netherlands
W.W.A.BeelaertsvanBlokland@tudelft.nl
Abstract — In this report an answer is given to the question:
Can energy be saved with the use of pods on the campus and is this less expensive than the current public transport? A Campus Automated Transport System (CATS) can save energy consumption compared with busses and/or tram if multiple people share a ride in one pod, mostly because of the low occupancy rate of the current busses. Not only energy is saved, also CO2 emissions can be reduced. Two different demand scenarios are discussed, one with a constant daily demand and another with the current timetable. The operational costs of the new system are presumable higher, although this depends on the number of vehicles used for this service.
I. INTRODUCTION
Figure 1 The three modalities: the pod (CATS), the MAN’s LION CITY bus and the Avenio tram (clockwise)
Nowadays the public transport on local level exists mainly out of busses and/or trams. Schematic views of these vehicles are in Figure 1. The vehicles have a large capacity between 30-230 per vehicle to fulfil the daily demand. For the ease of use these vehicles drive on a fixed time schedule during daytime, with some extra services in rush hour. The vehicles always drive their full cycle, even there is no demand. Most of the time these vehicles only use a small percentage of their available capacity. A possible solution to this problem is a smaller and smarter vehicle, like Campus Automated Transport System (CATS). CATS is a system designed by the TU Delft, and consists of multiple free ranging vehicles. These small vehicles are the so called pods. A possible appearance of this this pod is shown in the top left of Figure 1. A pod is a 4-wheel vehicle for multiple passengers. The pods drive on demand; a
passenger calls one pod with an app or another device. There are comparable free ranging transport solutions for instance the Heathrow Ultra Pod and the Rivium Shuttle in Rotterdam, although they differ in capacity per pod, cruising speed, infrastructure and/or service. Not all technical specifications of the proposed CATS are mentioned in this report, like the control system and hazard detection, however the important features for calculating the energy consumption are mentioned.
Figure 2 Route of public transport from Delft Station to TU Delft Campus The track of the public transport from Delft Station to the campus follows a fixed route (Figure 2). It starts at the Westvest, subsequently the Zuidwal, St Sebastiaansbrug, Michiel de Ruyterweg, Mekelpark and ends at Technopolis, where there is a reserve opportunity. The track is four kilometres long and has multiple stops on its way. For this research all modalities use this route, stops and infrastructure. Connection with the touristic highlights is also an option, for instance the Porcelyene Fles and the historic city centre. Coaches with tourists can drop off their passengers at the edge of the city and from there the tourists can take a pod to their destination.
II. ENERGY CONSUMPTION BY MODALITY
Three different modalities are compared for this research, CATS, busses and trams. A schematic view of these vehicles is shown in Figure 1. First, the energy consumption of each vehicle is described. The relevant literature and calculations are mentioned for all the three modalities. The unit kilowatt-hour per kilometre is introduced for comparing the different vehicles.
MODALITY CATS. The vehicles of CATS are called pods. A pod is a small electric 4-wheel rubber-tired vehicle, with a capacity of 6 persons, which can all sit. It is also possible for a disabled person to use a pod, there is place for one wheelchair. The pod is a free ranging vehicle, there is no human driver. The design specifications are listed in Table 1 below.
Table 1 Design specifications of CATS (adapted from earlier research [18])
Capacity 6 persons / 1 wheelchair
Maximum speed 40 km/h (11.11 m/s) Cruising speed 25 km/h (6.94 m/s) Weight 500 kg (empty) Dimensions (l/w/h) 3.93/1.99/2.75 m Acceleration 0.75 m/s2 Deceleration 1.50 m/s2
Rolling resistance coefficient 0.01 Air friction coefficient 0.60
Regeneration level 50%
With the information of the above table the average energy consumption is determined. First the energy consumption during driving at cruising speed is calculated. The distance needed for accelerating is 32.2 meter and for decelerating 16.1 meter, and with this, the energy for acceleration and deceleration is determined. The pod saves its energy which is produced during braking, it is assumed that the 50% of the energy is regenerated, this is lower than for instance a high-end vehicle as the Tesla Roadster with a regeneration level of 64% [17]. The distance between two successive stops is taken from the route displayed in Figure 2. In the calculations it is assumed that the pod does not skip a stop, so each ride between two successive stops is 625 meter. The pod can drive continuously between the stops and does not have to stop for example traffic lights or crossing cyclists.
The unit of the energy consumption is in kWh/km, this unit is normally used in literature for energy comparisons of public transport vehicles. Since the number of people inside the pod does matter for the energy consumption, all different loading possibilities are taken into account. The weight of an average person is 80 kg and the empty weight of a pod is 500 kg. The results of this are listed in Table 2.
As mentioned earlier, there is room for one wheelchair in the pod, but in that case there is no space left over for 6 other passengers, thus the maximum occupancy is 6 passengers.
Table 2 Energy consumption of the pod
Number of passengers
Weight Energy consumption
6 980 kg 0.113 kWh/km 5 900 kg 0.111 kWh/km 4 820 kg 0.109 kWh/km 3 740 kg 0.107 kWh/km 2 660 kg 0.104 kWh/km 1 580 kg 0.103 kWh/km 0 500 kg 0.101 kWh/km
MODALITY BUS. The RET and Veolia, the bus operators of the Haaglanden region and on the campus of the university, use MAN’s LION CITY busses [16]. These are 12-meter-long CNG-fuelled busses, with a capacity of 70 people [11]. The empty weight is 12.200 kg and the maximum speed is 100 km/h. Research organization CE Delft has measured the energy consumption of these busses [3][16], the relevant information is listed in Table 3. Sometimes the RET uses busses on diesel, these busses have a slightly higher consumption, but this is negligible; for instance, an empty CNG bus uses 1.76 kWh/km compared with 1.61 kWh/km for a diesel fuelled bus.
Table 3 Energy consumption of the bus
Load scenario Passengers Weight Energy consumption
Empty 0 12.200 kg 1.76 kWh/km
Average 13 13.320 kg 1.89 kWh/km
Half-full 35 15.000 kg 2.07 kWh/km
Full 70 17.800 kg 2.25 kWh/km
MODALITY TRAM. The HTM, the operator of the future trams, will use new trams for line 19, which is the line from the station to the campus [7]. These trams are the Avenio build by Siemens Rail Systems. The tram is 35-meter-long and has a capacity of 238 people (70 sit, 168 stand) [14]. The energy consumption of this type of tram is not measured yet, although there are results known of similar trams, like the Flexity Outlook/Swift, the Variobahn and the Stagecoach-Supertram [2][5][8][10][13]. These are respectively 3.7/4.1/3.9/4.5 kWh/km. The adapted results of these researches are listed in Table 4. The assumed value for the energy consumption of the Avenio filled at average capacity is 3.88 kWh/km. The number of passengers does not affect the energy consumption very much, the difference between an empty and full tram is only 5%.
The energy consumption of the old tram, GTL8, is 4.7 kWh/km, but this tram will only be used in emergencies [9].
Table 4 Energy consumption of the tram
Load scenario Passengers Weight Energy consumption
Empty 0 50.700 kg 3.80 kWh/km
Average 50 54.700 kg 3.88 kWh/km
Half-full 119 60.220 kg 3.94 kWh/km
3 2016.TEL.8070 III. ENERGY COMPARISON WITH A CONSTANT DEMAND
To compare the different modalities a fixed number of daily passengers is taken, in this case 5000 passengers a day. The daily service of each modality is from 6.00h in the morning till 21.59h in the evening. During normal service the demand is 250 passengers per hour. However, there are two major rush-hours, these are early observed and mentioned in a report about the feasibility of the CATS [18]. In the morning from 8.00h till 8.59 there is an enormous rise of demand because all students and staff start studying/working at these times. The demand rises with 300%, so the hourly demand is 750 passengers. In the afternoon there is also a larger demand, although this rush-hour is more evenly spread between 16.00h and 17.59h. The hourly demand is here 500 passengers.
Summing up the hourly demand gives a total 5000 passengers per day. The distribution of the hourly demand is visible in Figure 3.
The hourly demand is 250 passengers from 6.00h to The route of each vehicle is the earlier mentioned two-way ride of 8 kilometres. Table 5 and Figure 4 show the results of each modality. In Table 5 the number between brackets is the number of passengers in each vehicle.
MODALITY CATS. The maximum capacity of the pod is 6 persons; it is only assumed that the average occupancy is 4 persons [18]. However, for all 6 loading scenarios the energy consumption is calculated. If the occupancy rate of the pods is higher, less trips have to be made and also less vehicles are needed to satisfy the given demand. In Table 5 the number of pods needed is listed. With the calculated energy consumption of Table 2 the total daily consumption is calculated.
MODALITY BUS. For the bus there are 3 different loading scenarios. In the first case the busses are all fully loaded, each with 70 passengers. To transport 5000 passengers at least 72 trips have to be made. The second scenario is the current timetable (2016). In this timetable 137 trips are made on daily base [21].The average occupancy of the busses is 35 people, however in the earlier mentioned rush-hours the busses are fully loaded. In the third scenario there are 13 passengers in each bus, which is the current average occupancy rate for busses in the Haaglanden region [16]. With the energy consumption listed in Table 3 the daily energy consumption of each scenario is calculated.
MODALITY TRAM. Like the bus there are 3 different loading scenarios for the tram. In all scenarios only the tram is available to transport the 5000 people, there is no bus service available. The first scenario is at maximum capacity per tram (238 passengers), with 22 daily trips. The other scenario is the intended timetable of tram 19 [7]. 66 trips a day are scheduled, the average occupancy of the tram is in this case 76 passengers,
here as well are the trams fully loaded in the rush-hour, with the corresponding energy consumptions. In the last scenario is the average occupancy of passengers in the Haaglanden region, with an occupancy of 50 passengers [16].
MODALITY TRAM AND BUS. In the future timetable, there will be both trams and busses. The number of trips planned are respectively 66 and 100. Since the travel time, comfort, charge and availability of these 2 modalities are almost equal, it is assumed that passengers do not have a preferred choice for bus or tram. The occupancy rate of each vehicle is around 20%, i.e. 56 per tram and 13 per bus.
Table 5 Total daily energy consumption per modality
Passengers per vehicle
Vehicles Energy [kWh]
remark
CATS 6 14 0.75E+03 full
5 16 0.88E+03
4 20 1.09E+03 expected
3 27 1.43E+03
2 40 2.08E+03
1 79 4.12E+03
Bus 70 2 1.30E+03 full
35 4 2.33E+03 timetable
13 7 5.82E+03 average
Tram 238 1 0.71E+03 full
76 2 2.06E+03 timetable
50 2 3.10E+03 average
Tram + Bus 56 + 13 2 + 2 2.24E+03 timetable
In Table 5 the results of all loading scenarios are listed. The hourly energy consumption is first calculated, only the total daily consumption is shown in this figure. The rows presented in bolt are the most imported scenarios, since these are the scenarios according to the timetable. These results are discussed hereafter. The data of the above table is made visible in Figure 4.
Figure 4 Daily energy consumption
If the energy consumption of the pods is compared to the consumption of a bus driving according timetable, the pod Figure 3 Constant hourly demand for public transport
uses less energy if the loading rate is between 2 to 6 passengers. Since it is assumed that the average loading rate of the pod is 4, the CATS is a better, in terms of energy consumption, option than the bus. With an expected loading rate of 4 passengers the CATS save 53% of energy relative to the bus. Relative to the tram, the energy savings are 47%. Compared with a combined use of tram and bus, the energy savings for the CATS are 51%.
If all vehicles drive with maximum capacity the tram is the least energy consuming, after that the CATS (5.6% more) and finally the bus (83% more). However, the number of daily trips of all modalities is in this case respectively 22, 834 and 72 trips a day. Thus, the CATS has the highest frequency, the bus a slightly higher frequency then the tram, so the average waiting time will be lowest for the CATS (1 minute) compared with the tram (22 minutes).
Another appreciable fact is that the combined use of bus and tram saves a little energy (8%) compared with the use of only busses.
IV. ENERGY COMPARISON WITH CURRENT TIMETABLE The daily energy consumption of each modality can also be compared with the current demand of passengers and the current and future timetable. The energy consumption of the CATS, the bus and the combined use of tram and bus are calculated. Unlike last section there is no scenario with only the tram, because in the future timetable there is always a combined service with trams and busses together. Students of the Transport Engineering and Logistics department have count the number of passengers each hour [18]. There are three peaks in the demand, these can be explained by the morning and afternoon rush-hour, and one peak during lunch time. Again the morning rush-hour has a larger peak demand than the one in the afternoon. The total daily energy consumptions are listed in Table 6 and Figure 6.
MODALITY CATS. According to the report of the feasibility of the CATS [18], the following number of pods is needed each hour, Figure 5.
Figure 5 Number of pods needed for a daily service
The energy consumption of the pods per hour is the number of pods needed times the energy consumption listed in Table 2. The average occupancy of the pods is in this scenario 5 passengers per trip, with a corresponding energy consumption of 0.111 kWh/km. There is one exception, in the morning rush-hour, between 8.00h and 8.59h the pods are fully loaded, the energy consumption is then 0.113 kWh/km.
MODALITY BUS. In the current timetable there is a total of 137 bus services, divided over the day, with more services in the rush-hours. This is the same timetable as in section III. When the tramline is finished, the tram takes over some of the
services. If you compare the demand and the number of bus services, there are on average 13 passengers in each bus during normal service and the busses are fully loaded (70 passengers) in the morning rush-hour and half loaded (35 passengers) in the afternoon rush-hour. The corresponding energy consumption of the busses is respectively 1.89, 2.07 and 2.25 kWh/km (Table 3).
MODALITY TRAM AND BUS. As mentioned above, the tram takes over some service of the bus. In total 66 of the bus services will be replaced by the tram [7]. Both vehicles are average loaded, this is around 20% of its capacity [5].
The total daily energy consumption is listed in Table 6 below.
Table 6 Total daily energy consumption per modality
Trips Passengers Energy [kWh]
CO2 [ton/day] CATS 314 1606 0.63E+03 0.5
Bus 137 3208 2.19E+03 1.7
Tram + Bus 100 + 66 6038 4.25E+03 2.5 At first sight the energy consumption of the CATS is much lower than the bus (71%) and the bus and tram combined (85%). This also applies for the CO2 emissions, although the proportions differ. CATS saves 29% of CO2 pollutions relative to the bus and 80% relative to the tram and bus combined. More information about the calculation of the CO2 emission is given in section V CO2 emissions. However, the number of passengers transported by each modality differs also signified. The hourly energy consumption is plotted in Figure 6 below.
Figure 6 Energy consumption on an average day
In literature also another KPI for energy consumption, instead of [kWh/km], is used, namely kilowatt-hour per passenger kilometre [kWh/pkm][3][5]. This is the consumption divided by the number of transported passengers.
5 2016.TEL.8070 The results of this other KPI are shown in Figure 7. The
energy consumption per passenger kilometre is most of the time the lowest for the CATS. CATS uses in the off hours only 34% of the energy busses use and 53% compared with the tram and bus. Only in the rush-hours the other modalities are slightly more energy efficient, although this difference is less than 5%. The drop in energy consumption per passenger for busses and tram can be explained, since the number of passengers per vehicle doesn’t influent the energy consumption per vehicle that much (16% more energy consumption, with 4 times more passengers, Table 3).
When comparing Figure 6 and Figure 7 another conclusion can be drawn; the combined use of busses and trams costs more energy than only the use of the bus. Although, more passengers are transported with the bus and trams, thus when using another KPI, kWh/pkm, the combined use is more energy efficient.
V. CO2 EMISSIONS
The energy consumption is not the only important feature of each modality, also the CO2 emissions are important. The amount of CO2 pollution differs a lot per modality, since the pod and tram are electric and the bus is fuelled with CNG.
In literature there are three different stages for expressing the CO2 emissions of a vehicle; Well-to-tank (WTT), Tank-to-wheel (TTW) and Well-to-Tank-to-wheel (WTW). The well-to-tank emissions incorporates the fuel production, processing and transport. The second stage, tank-to-wheel, is the emission generated by the vehicle itself. Well-to-wheel emissions are these two stages combined. Electric vehicles do not generate emissions in the second stage. For a complete overview of the CO2 emissions, therefore, the complete cycle (WTW) is taken.
Each modality has its own CO2 emissions indicator, which are listed in Table 7 [12][16][22]. The values selected for CATS, are values of comparable electric cars, i.e. same battery size and same weight. The WTW for a CNG fuelled bus is 141 g/pkm, this does not differ much for a diesel fuelled bus with 142 g/pkm. Of course for both electric vehicles, CATS and tram, it depends of the energy that is used is green (renewable) or grew (fossil fuels); hereby the WTT indicators differ slightly [22].
Table 7 Average CO2 emissions indicator
WTT [g/pkm] TTW [g/pkm] WTW [g/pkm] CATS 77 0 77 Bus 26 115 141 Tram 91 0 91
These indicators are average emissions per passenger kilometre. For calculating the total emission per vehicle a correction factor is introduced [12]. This is correction factor is depending on the number of passengers per vehicle and the vehicle itself. In Table 8 these factors are listed. Multiplying this factor with the emission indicator of Table 7 gives the CO2 emission in gram per kilometre. With the given scenario in section III, the total CO2 emission per modality is calculated, each modality transports 5000 passengers. The data of Table 5 and Table 8 are thus the same scenarios.
Table 8 CO2 emissions for all modalities Passengers per vehicle Corr. factor CO2 emissions g/km g/day Ton/year CATS 6 1,18 91,01 6,07E+05 157,8 5 1,14 88,02 7,04E+05 183,1 4 1,11 85,12 8,51E+05 221,3 3 1,07 82,33 1,10E+06 285,5 2 1,03 79,62 1,59E+06 414,0 1 1,00 77,00 3,08E+06 800,8 Bus 70 14,00 1974,00 1,14E+06 295,6 35 10,50 1480,50 1,62E+06 421,9 13 9,75 1374,75 4,23E+06 1100,9 Tram 238 33,32 3032,12 0,53E+06 138,7 76 35,72 3250,52 2,60E+06 676,1 50 35,00 3185,00 1,68E+06 437,2 Tram + Bus 56 + 13 44,80 + 9,75 4076,80 + 1374,75 3,25E+06 845,6
The results of the last column, the tonnage CO2 produced per year, is plotted in Figure 8 below. Here, a year exists of 52 weeks, with 5 working days a week.
Figure 8 Daily tonnage of CO2 emissions by modality Figure 7 Energy consumption per passenger kilometre
Overall the CO2 emissions of the CATS are lower than the emission of the busses that drive according to current timetable, i.e. with 35 passengers per vehicle. It the best case, when each pod has 6 passengers, 63% of CO2 emission can be saved. With an expected occupancy of 4 persons per pod, 49% less emission is emitted. Only if the pods are filled with just one passenger, the emissions are higher, 90%.
Comparing the CATS with the tram, CATS is also less polluting. Only if the tram is fully loaded, it emits less CO2 then a full pod, namely 13%. If both modalities have the expected occupancy, the pod emits 68% less CO2 on a daily base.
With the future timetable where busses and trams are combined, CATS saves a lot of CO2 emission, namely 74%.
VI. DAILY COSTS COMPARISON
Not only the energy consumption of the public transport is important, also the costs of each system. The capital expenditures (CAPEX) are not part of this research. The operational costs (OPEX) of each modality mostly depends on the number of vehicles needed to meet the daily demand. In Table 9 below the number of vehicles is listed. The results in Table 9 are applicable to the constant demand scenario described in section III.
MODALITY CATS. The operational costs for the pods are estimated since the pods are not manufactured yet. The estimation is based on a research by the TU Delft, on information of the London Heathrow Pods and on the RIVIUM shuttle in Rotterdam [1][18][20]. For instance, the operational costs of the London Heathrow Pods are €3,4m a year, with a total of 21 pods.
It is assumed that there is an exponential relationship between the number of pods and the costs per pods. I.e. with more pods the costs per pod are lower, however the total costs are higher.
MODALITY TRAM AND/OR BUS. The operational costs for both bus and tram are investigated by CE Delft, CROW-KpVV and others [3][4][6]. The operational costs for a CNG bus are 108 €/h and for a tram 207 €/h. This costs included: personnel costs, vehicle costs (including equipment), mileage costs (maintenance, fuel), the overhead costs, such as housing, ICT, marketing and management. A full cycle time from the Station to the Campus for these vehicle takes 28 minutes; thus each vehicle can make 2 full cycles in 1 hour.
Daily costs are based on 16-hour service time. Multiply this costs with 52 weeks and 5 working days a week, gives the annual costs of each system.
Table 9 Costs of all modalities Passengers
per vehicle
Vehicles needed
Daily OPEX Yearly (millions) CATS 6 14 € 9.800 € 2,5 5 16 € 10.800 € 2,8 4 20 € 12.600 € 3,3 3 27 € 15.100 € 3,9 2 40 € 17.900 € 4,6 1 79 € 18.200 € 4,7 Bus 70 2 € 3.500 € 0,9 35 4 € 6.900 € 1,3 13 7 € 12.100 € 3,1 Tram 238 1 € 3.400 € 0,9 76 2 € 6.700 € 1,7 50 2 € 6.700 € 1,7 Tram + Bus 56 + 13 2 + 2 € 10.100 € 2,6 To make the results from the above table visible are they plotted in the figure underneath. Again, the values from the above table are from the scenarios described in section III. The bolt lines are the expected number of passengers and vehicles.
Figure 9 Daily costs per modality
Comparing all the costs mentioned in Table 9 the CATS is an expensive system. Assuming that the loading rate of the pods is 4 passengers, as in section III, the daily costs €12.600,-. The daily costs for an average filled bus in the Haaglanden (13 passengers) are almost equal €12.100,- [16]. However, this is not the case at the campus. When the busses drive according to the timetable, the busses at the campus are better filled (35 passengers), see also Table 5. The daily costs for the bus are in this case €5.200,-, which are less than a half of the costs comparing with the CATS (41%).
However, in the future there will be a combined service with busses and trams, and the daily costs of this service are €10.100,-. This is 80% of the costs for the CATS.
The only way CATS is less expensive than the busses and/or trams, is when the pods are always fully loaded.
0 2 4 6 8 10 12 14 16 18 20 €/ da y (x 10 00 ) Modality [passengers] €/day
7 2016.TEL.8070 VII. CONCLUSION AND RECOMMENDATIONS
The two different energy consumption scenarios, constant demand and the current timetable, leads to several conclusions. The first conclusion is that a new transport system on the campus, CATS, can be more energy efficient than the current busses. However, some conditions have to be fulfilled. Multiple passengers have to share one pod, with a minimum of 2 passengers to use less energy than an average filled bus. With an expected loading rate of 4 passengers, the energy consumption of CATS is 53% lower than the energy consumption of the bus. This also complies for an average filled tram, here the energy savings are 47%. The CO2 emissions are in both cases also lower for the CATS. 49% lower relative to the bus and 68% lower than the tram. In the future there will be a combined service of trams and busses, relative to this CATS saves 51% of energy and 74% of CO2 emissions on an average day.
A fully loaded pod with 6 passengers uses also less energy than a fully loaded bus, the CATS use 41% less energy. If the CATS is compared to a fully loaded tram, the tram is more energy efficient than the pod. This is because the loading rate of a tram is not that significant for the energy consumption. CATS use 6% more energy is this cause.
Comparing the energy consumption of CATS with busses and/or trams driving according a fixed time schedule, the pods use less energy. CATS uses 71% less energy than the bus and 85% less energy than the bus and tram combined. The reduction is CO2 emissions are 29% and 80%. This is explainable since the CATS only drive when there is demand, and the busses and tram drive according a fixed timetable, even if there are no passengers.
Therefore, another KPI is introduced, an energy consumption per transported passenger, kWh/pkm. Comparing the energy consumptions with this KPI, the CATS uses in the off peak hours less energy than the other modalities. It uses 34% of the energy the bus uses and the CATS uses 53% of the energy of the combined use of bus and trams. Only in the rush-hour, when the busses and trams are fully loaded, these modalities use almost the same amount of energy per passenger (± 5%).
Not only the energy consumptions are compared, also the operational costs of all modalities is investigated. The daily operating costs of CATS are higher than the current busses and can be slightly lower than the costs for the combined use of bus and tram, although some conditions must be met. The estimated daily costs for the bus and for the busses combined with the tram are respectively €6.900,- and €10.100,-. The daily costs of the CATS, without investment costs, are between €9.800,- and €18.200,- depending of the number of vehicles needed. If there are between 14 and 16 pods needed for the service, the loading rate of each pod is 5 or 6, then the operational costs are almost equal as the costs for tram and bus. However, these costs are the first estimates for the costs of the CATS, further research is recommended.
Out of scope for this research was the combined use of CATS with busses and/or trams. In this research the modalities
are not working together, it would be interesting to research if CATS can be a complement to the current public transport. This can cause a total lower daily energy consumption and lower operational costs.
Another recommendation is to make a simulation of the exact route of the pods, for a better and more realistic energy consumption overview. Also start location and the direction of each passenger have to be modelled for a detailed overview of all passenger flows.
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