Smart Mobility for Green University Campus

Michela Longo, Chowdhury Akram Hossain, Dept. of Energy

Politecnico di Milano Milano (Italy)

michela.longo@polimi.it, chowdhuryakram.hossain@polimi.it

Mariacristina Roscia Dept. of Enegineering University of Bergamo

Dalmine (Italy) cristina.roscia@unibg.it

Abstract— The solution to integrate renewable energy sources and electric mobility can bring many economic benefits to the environment, both at the urban level and not alone, also it is one of the many roads for the future of mobility. The aim of this research describe a possible draft of green mobility sharing, based on power from renewable sources in order to feed a system of shared transport, in order to optimize traffic flows of vehicles, as well as the achievement of a zero impact of emissions to local towns, where the pollution is already high.

Index Terms-- electric vehicles, green energy, distributed energy resources, smart mobility.

I. INTRODUCTION The automotive sector is one of the industry’s most

important parts in the world and is the subject of special attention from governments around the world, especially for the prestige that this entails and the amount of labor that involves this sector. It should however be emphasized that the automotive industry, and in general the field of transport, is characterized by the fact of being an industrial sector which over the years has failed to bring great innovations, presenting basically the same technology for several decades. Only in recent years, driven by regulations in terms of environmental protection and emission reduction, the car is evolving towards a reduction in fuel consumption and power than fossil fuels to reduce emission [1-2].

The term Smart mobility is a new way of thinking about mobility [3-6]. That involves managing flows in relation to the demand of people and goods, optimizing the use and development of resources and integrated infrastructures. In addition, models of smart mobility can be worth up to 5 percent of GDP in one year, which can make it self-sustainable transport system within the innovative smart city. Another key element is the environmental cost of the mobility system, which often is not taken into account. In Italy, it is estimated at 8-10 billion euro per year, due to the impact on the health of PM10 and of the ozone.

A smart mobility is an enabler to achieve the new urban models of smart city, today's primary goal and not only for European countries [7, 8]. In the world, the testing of new mobility is producing real results and it is vital that projects

are implemented in the smart key and are replicable in order to achieve best practices. In fact, some smart mobility technology solutions can be developed and successfully implemented on a local scale, but the real benefits for the creation of smart cities, can be enabled if it can be ensured that the design and technology are implied on a large scale [9-11].

The aim of this work is to highlight the potentials those we offer with the integration of the technologies, photovoltaic systems and electric vehicles applied on Bergamo’s campus. The article suggests possible solutions for sustainable mobility and can take advantage of all the properties and the potentials offered by vehicles with electrical and photovoltaic technology, including energy efficiency and emissions reduction.

II. THE STUDY OF BERGAMO’S CAMPUS

A. General Descriction The U.S.C. (University Sports Centre) is located in

Dalmine. It is a part of the Engineering Faculty, easily accessible from the Economic and Law Faculty of Bergamo Campus (Caniana street), and from Language Faculty of the Upper Town. This has an area of total 14,000 m2, about which 4,000 m2 are covered with buildings (Fig. 1). The centre has been equipped with a photovoltaic system with a capacity of 100 kWp, active from May 2011.

Figure 1. Overhead Maps of the U.S.C. (University Sports Centre)

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The Fig. 1 shows the presence of a parking space with a capacity of maximum 50 vehicles. It can be proposed to implement some charging points for electric vehicles, capable of exploiting the energy produced by the photovoltaic system located on the roof of the building. This solution is one of many possible with a view to sustainable mobility and is directed both to vehicles owned by the University of Bergamo and also can be used for multiple services in case of a future supply or replacement of the vehicle fleet, both vehicles ownership of the numerous visitors to the sports centre.

B. Characteristics and description of photovoltaic system The photovoltaic system has a peak power of 100 kWp. To

estimate the solar electricity generation, we have utilized the PVGIS software. The main characteristics on the PV power plant installed in Bergamo’s Campus (Fig. 2) and used as inputs for PVGIS program are crystalline silicon cells, tilt angle is equal to 15° and Azimuth value is 30°. The estimated system losses are a default value of 14%.

Figure 2. Building U.S.C. integrated with photovoltaic system

The informations obtained for the program are:

• Ed: Average daily electricity production from the given system (kWh)

• Em: Average monthly electricity production from the given system (kWh)

• Hd: Average daily sum of global irradiation per square meter received by the modules of the given system (kWh/m2)

• Hm: Average sum of global irradiation per square meter received by the modules of the given system (kWh/m2)

The mountly trend Em [kWh] is reported in Figure 3.

Figure 3. Average monthly electricity production from the given system (kWh) in Dalmine (Italy)

Applying the PVGIS software the average monthly global radiation has been derived. The trend of this radiation can been extracted by the following equation obtained by applying the method of Least Squares:

Hd = 0.168·m4 - 4.23·m3 + 29.8·m2 - 40.1·m + 77.4 (1)

where m =1-12 that represents the current month.

Considering the global radiations estimated with (1) and the yearly electricity produced is estimated in 119000 kWh. In this work it is supposed that this energy could be completely available for the charging of the electric vehicles that rich the Bergamo’s Campus.

III. CONNECTIONS AND SERVICES FOR CAMPUS The University of Bergamo offers numerous study courses

and services, distributed in many departments located in different locations in the territory of Bergamo city and its province, as in the case of the campus of Faculty of Engineering and the U.S.C. in Dalmine. Depending on the type of transport, the distances are calculated with a traditional vehicle according to the actual road routes, assuming U.S.C. as a starting point.

Figure 4. Typical map is used for the calukate the distance between different zones where A is Caniana street and B is Engineering Faculty

The locations are distributed in the different academic activities as follows:

• Law, Science business, Economic Faculty in Bergamo (Caniana Street);

• Humanities and Social Sciences Faculty in Upper Town of Bergamo (Sant’Agostino square);

• Languages, Literatures and Communication Faculty, in Rosate square (Bergamo);

• Humanities University located in Bergamo (Pignolo Street);

• Engineering University in Dalmine.

In addition to the locations of different departments, it is also important to include the various university residences

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during the academic year that are residence for approximately 150 students.

• Residence of University in Bergamo (Garibaldi Street);

• Residence of University in Dalmine, which is part of the Campus of Engineering and is located about 200 m by U.S.C. (Verdi Street);

• Residence of University in Bergamo (Caboto Street).

The paths are relative only for measured connections between the seats they are distributed in the educational areas and those of services, to provide a calculation that relates the autonomy of electric vehicles in terms of consumption and distance covered. Fig. 5 shows the distance between U.S.C. and the different locations mentioned above.

Figure 5. Distances between U.S.C. and different locations university

The idea to sustainable and intelligent mobility integrated at the University of Bergamo is not only a mechanism that connect the structures each other, but it is also the ability to offer a variety of other services. This opportunity can be created and delivered through the use of electric vehicles.

IV. CHARACTERISTICS OF ELECTRIC VEHICLES, EFFICIENCY AND CONSUMPTION

The use of innovation in vehicles plays a central role in sustainable mobility, in order to provide the services described in the previous section, it is necessary to obtain an overview of the categories offered in the market nowadays. Electric vehicles have more efficiency in terms of energy with respect to almost all internal combustion engines. A gasoline engine has an efficiency of 25 - 28%, a diesel approaching to 40%, while an induction electric motor in alternating current has an efficiency of 90%, along with other facts that it does not produce exhaust fumes, or gas emissions and generate a virtually zero pollution if supplied with energy from renewable sources.

a) Busses: This vehicles have driving range that can be

up to 200 km. Battery capacity can range 180 kWh and the typical traction power is in the range of 65-150 kW. Typical

maximum speed is 120 km/h and the number of seats is between 14 and 40.

b) Van: This vehicle has driving range that can be up to 80-150 km; battery capacity can range 22.5 kWh and the typical traction power is in the range of 30/60 kW or 70/140 kW. Typical maximum speed is 110 km/h and the number of seats is between 2 and 8.

c) Electric car: This vehicle has driving range that can be up to 140-185 km; battery capacity can range 20 kWh and the typical traction power is in the range of 60 kW. Typical maximum speed is 150 km/h and the number of seats is between 2 and 5.

d) Scooter: This vehicles has driving range that can be up to 40-150 km; Battery capacity can range 3.75 kWh and the typical traction power is in the range of 0.5-130 kW. Typical maximum speed is 45-220 km/h and the number of seats is equal to 2.

e) E-Bike: This type of vehicle is used both for private or sharing use. It has driving range that can be up to 40 km; Battery capacity can rang 0.36 kWh and the typical traction power is in the range of 250/350/500 W. Typical maximum speed is equal to 25-40 km/h.

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Table I shows the standard features of the vehicles mentioned, such as the battery capacity and energy consumption.

TABLE I. CHARACTERSITCS OF VEHICLES

Battery Capacity [kWh]

Driving range [km]

Consumption [kWh/km]

Busses 180 150 1.2

Van 22.5 130 0.17

Electric Car 20 175 0.13

Scooter 3.75 60 0.06

E-Bike 0.36 40 0.009

Assuming a path that connects all the main venues of the University of Bergamo, with its starting point at the U.S.C., the total kilometers that a generic electric vehicle should cover would be equal to 33 km.

This distance is quite affordable considering the characteristics of the vehicles listed above. In addition, it is important to remember that 60% of European drivers travel about 30 km per day. Assuming that the energy produced by the photovoltaic system, (in this case will be considered to be less than value estimated), is totally bound to each category of vehicle, we can make an estimate of the number of those who can enjoy the benefits of this service.

Let’s assume that 73% of the production of the photovoltaic system is used to supply electric vehicles (busses, van, E-car, E-bike and Scooter), and the remaining 27% will be used for different purposes (such as, e.g. lightening).

Table II reports the standard features of the previously listed vehicles with 86,406 kWh available per year. Specifically, each raw of this table displays estimates of potential electric vehicles charging and trips by vehicle type.

TABLE II. ESTIMATION OF POTENTIAL ELECTRIC VEHICHLE CHARGING AND TRIPS

Richarge/year km/year Trips/mouth Trips/days

Busses 480 72005 198 6

Van 3,840 576040 1586 51

E-Car 3600 630043 1735 55

Scooter 23041 1382496 30808 122

E-Bike 240016 9600666 26448 853

It can be noted, that a bus could travel a total of 72005 km in one year, which is equivalent to a transport service that

serves all locations of the University with a frequency of six times per day. This is based on assuming that, all the energy is used for this category and is always available in order to ensure their daily journey.

This estimation, however, allows us to point out that the plant and the production that we are considering, when it is entirely supplied to each category of vehicle. It can allow us to recharge 480 times/year a buses, 3840 times/year a van, 3600 times/year an electric car, a scooter for a total of 23041 times/year, 240016 times/year e-bike.

The evaluation of the emissions of CO2 for each mobility transport per km traveled can be observed from the figure 4. In addition to emissions avoided for the production of the same amount of energy through the photovoltaic (62.7 t per year), electric mobility will remove large amounts of harmful emissions such as CO2 emissions (Fig. 6).

The assessments made so far have shown the potential of integration between the production of renewable energy and electric vehicles.

Figure 6. CO2 emissions avoided.

Afterwards, will be made an estimation of the number of vehicles and therefore of the possible services that the university will be able to offer. It uses the average daily production (Ed) system designed to U.S.C. In specific the 72% (Ed = 238 kWh) of the average production of the system during a year obtained by the technology that has the lower yield, assuming it is kept constantly available.

TABLE III. FIRST ESTIMATION OF THE DAYLY NUMBER OF CHARGING AND TRIPS

Total Ed [kWh]

% Ed [kWh]

Total km viable

Trips/days

Busses 158.4 67 132 4

Van 11.22 5 66 2

E-Car 25.74 10 198 6

Scooter 35.64 15 594 18

E-Bike 6.1 4 101 3

Total 238 100 1091 33

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From Table III, it can be seen if the bus absorbs 67% of the energy available; it may perform 4 trips referring to the line previously hypothesized. The remaining percentage of energy can be distributed to a van for various uses and services of the University, where, with only 4% of energy available we can use 2 times the reference.

In addition to meet some services, further remaining energy can be used for charging cars, scooters, e-bikes in different percentages, owned by the U.S.C., staffs, students or visitors to the sports center. For the last three categories mentioned, the number of trips is the number of vehicles to which a sufficient amount of charging for an autonomy that allows it to cover equivalent to that of reference, that is 33 km away.

TABLE IV. SECOND ESTIMATION OF THE DAILY NUMBER OF CHARGING AND TRIPS

Total Ed [kWh]

% Ed [kWh]

Total km viable

Trips/days

Busses 79.2 33 66 2

Van 22.44 9 132 4

E-Vehicles 107.25 45 825 25

Scooter 24.11 11 401 12

E-Bike 5 2 555 16

Total 238 100% 1979 59

The variability of services can be developed and distributed in different ways, because the same services could be offered with different frequencies during the days of the week or month. In Table IV we have considered only two trips per day for the scheduled service of the bus, hence the percentage of remaining energy could be used in different quantities to other categories of vehicles. In this case, the residual percentage of energy is used for charging favoring more cars (45%), allowing charging to a 25 trips or 25 vehicles which need autonomy for distances less than or equal to 33 km.

Considering the latter choice, which allows the different categories of vehicles to cover a certain distance based on their efficiency in terms of CO2 emissions avoided; we can appreciate how important electric mobility can be considered at the urban level in the period of one year.

Figure 7. CO2 emissions avoided.

V. CONCLUSION

In this work, it has been proposed an idea for sustainable mobility for university campus that exploit the synergy between different technologies both for electric vehicle and photovoltaic system.

Under various hypotheses, it was decided initially to allocate all of the energy produced by the photovoltaic system installed in the University Sports Centre (U.S.C.) of Bergamo University (Italy) to each category of electric vehicle such as buses, vans, cars, scooters and e-bikes already available on the European market.

What emerges from the analysis is that the reduction of CO2 emissions avoided by using electric vehicles and by exploiting energy produced by a 100 kWp system, which is in the order of 62.7 tons per year.

Subsequently it was assumed to use the average daily production. However, there are so many considerations to make concerning these assumptions, one of which obviously affects the system, which has been equipped to the U.S.C. As mentioned earlier, the installation has been done to ensure better energy efficiency of the entire sports center, which has a total consumption that is around 300,000 kWh for year. In conclusion from what has come out with a view to sustainable mobility and intelligent for the University of Bergamo, it can be said that allocating a variable percentage of the energy produced by the photovoltaic system of U.S.C. can create and offer services through its electric vehicles and charging points, to all categories of users. These possibilities can be exploited with the affordable costs also getting an economic return, becoming Bergamo and green University

The further work for this research can be very interesting, which will be to eliminate the inverter present in the photovoltaic system. This option will permit to reduce the costs and the maintenance of system.

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