The Use of Photovoltaic Panels-The New Economic Challenge for the Future: Albanian Case

The technology of photovoltaic (PV) systems is improving continuously in relation to their cost and performance, so their use is increased considerablyPV systems today are quite reliable in the different applications. The use of PV’s as the electrical power source for a residence has reducing the need for electricity. Refrigerators, air conditioners, electric water heaters, electric ranges, electric dryers, and washing machines are all large users of electricity [7]. Alternative sources of energy are available to greatly reduce the use of electrical energy. In this paper, we are focused on the concept of installation solar photovoltaic (PV) system that generally requires engineering services for each individual application. There is relevant information regarded to PV systems stand-alone (off grid) or grid connected (on grid) ones. On the other hand there are a lot of guidelines on the subject of the design process of a PV system such as: the calculation of the electrical load, the size of the PV System, PV subsystems – inverters, controllers, wiring, mounting PV panels, batteries, types of photovoltaic cells [1]. The purpose of this paper is to show how PV panels can be used on the environments of a public institution in Albania conditions, in particular in one of the Albanian University (UET). The results of the study will be based on accurate calculation of installed solar panels and initial cost of their installation. Furthermore, in this paper it will also discuss the main advantages and disadvantages of implementing of this contemporary technology in our country.


Introduction
The daily life issues like • High prices of electric power supply • Saving the Earth resources • Environmental protection Make the use of solar energy really imperative.Albania fortunately offers a great advantage in the applications of this technology, in view of the fact that the number of annual sunny days is very considerable.This research will bring a lot of profits to the institutions and interested businesses that will use of solar power systems in the future.Even the European University of Tirana will certainly profit from this research after the installation of a similar system.
The main objective of the study is to make the economic analysis and to note the benefits obtained from the use of the solar energy for the European University of Tirana and for all Educational Institutions in Albania.
The significance of the study is related to the improvement of these aspects: → The low cost for power supply in the Institution.→ Absence of technical failure as the ones randomly happening when power supplied by the national net.→ Social development.
At the end of the elaboration project, the Institution will have e new alternative source of electric energy.

What is a Solar Cell?
A solar cell, in other terms known as "a photovoltaic cell", is a unit that transforms solar energy into electricity by means of photovoltaic effect [8].
The modern solar cells are based on the principles of semiconductor physics.They are simply joint p-n photodiodes with a layer, which is very sensible to the light, placed in such a way to obtain a perpendicular position with the radiation from the sun (figure 1).

Solar cell types
There are three cell types that are classified by their manufacturing technology and the semiconductor type used (figure 2).silicon.The polycrystalline silicon PV module has lower conversion efficiency than single crystalline silicon PV module.Amorphous Silicon PV Module: Amorphous silicon (a-Si) PV module or thin-film silicon PV module absorbs light more effectively than crystalline silicon PV module, so it can be made thinner.It suits any applications, which do not require high efficiency and where keeping the low cost is important.The typical efficiency of amorphous silicon PV module is about 6%.Hybrid Silicon PV Module: A combination of single crystalline silicon surrounded by thin layers of amorphous silicon provides excellent sensitivity to lower light levels or indirect light.The Hybrid silicon PV module has the highest level of conversion efficiency about 17%.Photovoltaic systems for the production of electricity in Western countries, mainly in the eurozone, thanks to supportive policies have widely been applied recently.Their installation consists of two main categories [30]: On-grid Off-grid Technology of the installation of these two groups is the same; the only change is to the inverter, which gives the title to the system.For more detailed information we are explaining these two categories as follows [1].

On-Grid Systems
On-grid systems of the photovoltaic plants that produce electricity have the following components: Photovoltaic Modules The solar panels which can be polycrystalline or mono-crystalline, are able to capture solar energy and convert it into direct electrical energy.
Metallic structure (which may rotate or not in accordance with the rotation of the sun).Metallic structures are used for the installation and mechanical mounting of solar panels.This can be static or dynamic.Dynamic metallic structures have greater productivity from 35 to 45% more than the static ones.
Conductor of the direct current, because electricity produced by the panels is the direct electric current Meters of the electricity produced by the panels, distributed in the public network.Meters of the public electricity network When the electricity generated by the panels is not enough for the needs of the customer, then the latter gets the electric power from the public grid.Electric control panel.When overhaul and other interventions are required, the system must be turned off.The control panel facility, consisted of electrical relays and fuses, is necessary.
Inverter on-grid.To convert electricity into alternative electric current, the inverter is needed.And to make synchronization with the network, this inverter must be equipped with a synchronizing system, otherwise known as on -grid inverter.
Conductor of the alternative current.To distribute alternative energy, current wires are needed.They are connected to the load distribution panel of the premise or customer.Obviously, synchronization system is not needed for off-grid systems; therefore off-grid inverters have lower investment costs.But for these systems, the cost of the block of batteries is higher, which can raise the cost of the investment for the premise.The specific cost of the plant depends on the projects we will try to accomplish.Off-grid systems are applied mainly in rural areas, where there is no public electrification.

Technical Calculations for On-Grid Photovoltaic System
For technical calculations of the photovoltaic project the following should be known: 1.Power required for installation 2. Geographical position of the object 3. Physical surfaces that will be used for the installation of modules Examine the above points.

The power required for installation
Albanian legislation does not include a special treatment for the exploitation of energy resources from solar panels.Therefore, power installation for solar photovoltaic panels, in order of not to create a disagreement with the distribution operator, or furthermore with the ERE (Energy Regulatory Agency), have the installed capacity calculated based on the consumption of the electricity for one calendar year, in a way that the balance of exchanged energy for a full year to be bigger or equal to zero.So, at the end of a calendar year the difference between the electricity meters of the public network with the electricity meter of PV plant, that distributes the electricity to the national system must be greater or The graph of figure 6 gives a better view of the monthly energy consumption for the University.As seen from the graph of figure 6 energy consumption for August is two low, due to the fact that during this period the university buildings are closed for the summer vacations.Another fact that is also worth mentioning is that the electricity consumption in January is lower than other months; this is related to the fact of the End of Year holidays.If we compare the energy consumption from February to March it seems that we have a declining tendency, with the arrival of spring and not using heating equipment.During April, we will assume that the consumption should be lower, but it is in contrary higher since the weather conditions could be changing, this can impose the use of heating or cooling equipment.From May to July there is a slight increase in electricity consumption, related to the fact that the use of equipment for cooling the building, which is a normal for such of the premise.Eel .-Installed power 12 -months of a full calendar year Applying formula 6.1 we get the average monthly consumption of electricity UET s.
Based on average monthly and the annual energy consumption we calculate the peak power of the photovoltaic solar panels installation.
We know that the geographical position of Albanian is quite favorable for the application of technologies that utilize the solar energy.From the records of NANR there are over 280 sunny days in a year, with an average of over six hours daily of very hot sun.The experience shows that a photovoltaic plant installed in the Tirana works on average 8 to 10 hours a daily.
A very important element is the typology of the installation, static or dynamic; the lasted increases the production activity by 35-45 % compared to static installation.The use of the dynamic technology should require more the space, which for the project in question is limited.For this reason our calculations will be based on the static installation.Experience shows that a photovoltaic plant with static installation, the rate of electricity efficiency is 51 % in a full calendar year.
( 2 ) where : 365 -days of a calendar year PI -installed power 8 -Average working hours for a day 0,51 -Average efficiency factor of the photovoltaic plant for one calendar year.Based on the formula 2, we determine the peak power of the installation of photovoltaic modules.So, the power installation must be 192 kWp; we round up to the value 200 kWp To reach this value we have selected poly-crystalline module with 250Wp power.The number of panels is: (3 ) where n -the number of panels, PI --installed power Pp -power of panel.Based on the formula 3, we calculate the number of panels that will be installed.
Electricity produced from the solar panels depends on the angle of which panel face the sun, therefore their production varies in time during the day, from morning to evening.Based on international experience, photovoltaic solar panels installed on the static way in our country, produce energy by 60 % to 75 % of maximum installed capacity.Exploitation factor based on practical experience for a calendar year is 0,51 ( 4 ) Where -exploitation factor in percentage, 51 % .P -effective power Based on the formula 4, we determine the effective power productivity:

The geographical location of the object
The geographical position of the object consists in identifying geographical facility.We have taken into account the way that the object is exposed to sunlight, would be chosen the objects preferably oriented toward the south that have enough space (surfaces) available for installation of modules.To find out about our project we used the satellite surveillance facility.As you can see in Figure 9, the full object is positioned to South and the terrace is going to be used for the installation of the plant.

Physical surfaces that will be used for the installation of modules
Choosing the physical position that will be used for the installation of photovoltaic modules is a very important step, because this will directly affect the efficiency of the plant.If for producing 1 kWp installed power will require 7m 2 up to 15 m 2 surface area, then for the production of the 200 kWp plant the surface area needed is going to be from 1400 m 2 to 2400 m 2 .The terrace 'surfaces of the object for a single building is approximately 1200 m 2 , both buildings about 2400 m 2 , which is enough for the installation of 200KWp power plant.

Methods
To achieve the objectives set out are using these methods: a. Analytical is used to analyse the economic situation through the study of literature, scientific analysis, the relationship of variables and factors.b.Comparative is used to compare the electricity consumption of a year from the network with those obtained from solar energy c.Statistical is used to summarize the data and results in tables and graphical representation of the theoretical structure As we mentioned above, the best part of the investment cost of the plant is required for the block batteries, especially when it is essential their self-sufficiency (autonomy).In addition, we refer the table 2 for the cost of entire plant.From our experience and the international ones, we conclude that costs of the electrical transmitters and the metal structure do not exceed 15% of the investment cost for the inverters and the modules.

Economic Analysis of On-Grid Photovoltaic System
For understanding economic benefits in time, we follow calculating method, on the basis of available data.The produced energy by the PV plant for one day will be estimated: ( 5 ) Where: Eel.d -generated electrical energy for a day hd -average hours of sunshine per day Assuming that in Albania average hours of sunshine per day are 8-10, then the productivity of the plant will be : As for the full calendar year the electrical energy generated by the plant will be : ( 6 ) Where: Eel.y -generated electrical energy for a year 365 -days a year, in which the plant works an average of 51 % of nominal power Then for a year electrical energy generated will be:

Figure 2 :
Figure 2: Types of PV Module Crystalline Silicon PV Module: Two types of crystalline silicon (c-Si) are used to produce PV module; single crystalline silicon or known as mono-crystalline silicon and multi-crystalline silicon, also called polycrystalline

Figure 3 :Figure 5 :
Figure 3: On-grid photovoltaic system [28] These kinds of plants are widely used in urban and electrified rural zones.

Figure 6 .
Figure 6.Monthly energy consumption for EUTFrom Table1the total consumption for a calendar year is Eel .= 286,440.00(kWh / year).Based on this we calculate the average monthly energy consumption:

Figure 9 .
Figure 9.The geographical location of the object [36]

Table 1 :
For the premises in question (EUT -European University of Tirana) we have access to the records of the electrical energy consumed annually.Data records that have been made available by the UET's administration, are presented in Table1and in graphical form in figure8.Electricity consumption by UET for a calendar year Table 1 the total consumption for a calendar year is Eel .= 286,440.00(kWh / year).Based on this we calculate the average monthly energy consumption:

Table 2 .
Estimate the supply and installation of a hybrid system.