Technical Economic Analysis of the Installation of A Photovoltaic System in the Municipality of Moa

Summary In this work, an economic technical analysis of the implementation of a photovoltaic system to supply a group of 6 offices in the town of Moa is carried out. The study is carried out with the support of the calculation tool PVSyst and using the criteria Net Present Value, Internal Rate of Return and Recovery Period for the economic evaluation. The results indicated that the installation can generate 391,419MWh/a. The Net Present Value resulted from321423.54 USD, while the Internal Rate of Return was 14.64%, higher than the imposed rate of 12%. On the other hand, the Recovery Period of the investment was 6.09 years. The economic evaluation criteria indicate that the variant can be accepted, since it offers income during its useful life..


Introduction
Photovoltaic systems installed on roofs are increasingly common, since they not only stop occupying extensions that could be part of some productive, cultural process, etc. But also guarantee the supply of energy in the same place where it is consumed, which contributes to the minimization of distribution losses. On the other hand, several works demonstrate that in the region of the Americas there is good potential for the exploitation of renewable energy resources, specifically the exploitation of energy from the Sun using photovoltaic systems [1][2][3]. In the country, the energy context is directed to the development of renewable energy sources, including photovoltaic solar energy. Within the guidelines of the economic and social policy approved in the VI congress, the Communist Party of Cuba refers to the use of alternative energy sources in guideline 247, in which it is proposed to promote the use of different renewable sources energy, prioritizing those that have the greatest economic effect. This contributes to the fact that several researchers are based on the potential of the country in terms of the use of photovoltaic solar energy [4,5].
In order to comply with the country's energy policy, the need arises to carry out studies related to the issue of photovoltaic solar energy in available spaces, in this case, taking advantage of the roof of buildings.
The literature consulted on the subject is very varied. Some authors consider the technical aspect in the dimensioning of the installation, and that most of them rely on computational calculation tools such as HOMER, RETScreen, PVSyst, among others, the latter being one of the most widely used [5,6]. On the other hand, the economic profit is based fundamentally on the criteria of the Net Present Value (NPV) and the Recovery Period (PR) [6][7][8]. However, the Internal Rate of Return (IRR) criterion allows us to know the slack that exists with respect to the real value of the interest rate.
In this work, an economic technical analysis is carried out for the installation of a photovoltaic system connected to the network, on rooftops, in the town of Moa. The PVSyst calculation tool is used to estimate the energy generated and the arrangement of panels.

Case study
The municipality of Moa is located in the northwest portion of the Holguín province with coordinates 20,390 North latitude and 74,560 West longitude. The location is proposed to be located on the roofs of 6 offices, for a total area of 1709m 2 , as shown in Figure   1.
For the year 2019, the total consumption of the offices was 196.66MWh, distributed by months as shown in Figure 2.

Photovoltaic modules
The study is carried out considering DSM-270 series modules manufactured in the Pinar del Río Province, which is made up of 60 solar cells of 156.75mm x 156.75mm format, connected in series.
Its characteristics are shown in Table 1.

PVSyst software
The PVSyst software is a tool used to model the behavior

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192 facilities can be dimensioned, taking into account the solar radiation that it would receive depending on its location thanks to its meteorological database, and which takes into account the casting of shadows thanks to the simulation of the movement of the Sun during the day. This is one of the most widely used tools for energy evaluation studies of photovoltaic systems due to the relative simplicity with which it can be manipulated [5,6].

Economic evaluation
To

Arrangement of the whole and generated energy
For the simulation, an inclination angle of 180 is taken into account, the results of which determined that a total of 868 photovoltaic modules can be located in the 6 offices for an installed power of approximately 234.36 kW. In addition, a monthly load survey is carried out for each office and their total consumption is estimated. Figure 3 represents the total consumption of the premises, symbolized by the blue line and the energy produced by the plant, represented by the orange line, according to the results offered by the software.

Economic evaluation
The economic evaluation is carried out based on the initial investment of the study, which considers the essential elements for the implementation of the photovoltaic system. Table 2 shows the elements considered in this investigation for the commissioning of the site. From Table 2 it follows that the initial investment is 807,743 USD. Taking into account that the energy generated by the installation is 391,419MWh/a, it generates cash flows equivalent to 58712.85USD/a, assuming an energy cost of 150USD/MWh generated. Table 3 shows the results obtained from the economic evaluation study. To calculate the NPV, an interest rate of 12% is considered, used to study projects in the country. The VAN of 321423.54 indicates the income that could be obtained with the commissioning of the installation for the 25 years of its useful life that the manufacturer guarantees. On the other hand, the IRR of 14.64% is higher than the interest rate (12%) used in the study, so the work can be accepted. The time in which the investment is recovered is 6.09 years, a relatively short value compared to the 25-year life of the installation.

Conclusion
a) The installation guarantees an energy of 391,419MWh/a per year with 868 connected modules.
b) The commissioning of the installation requires an initial investment of 291,743 USD, which, taking into account the economic results, recovers in approximately 6 years. c) The economic evaluation criteria indicate that the variant can be accepted, since it offers income during its useful life.