Economic Viability of Photovoltaic Systems in a Rural Community in Brazil

Solar energy can be converted directly into electricity using photovoltaic cell technology. It is considered as the technology of the future because it uses the Sun, a clean and inexhaustible source. Thus, this study aimed to evaluate the economic viability in energy generation of a photovoltaic system in a rural community in the district of Rio do Salto. The rural community is in the municipality of Cascavel, western region of the state of Paraná, geographical coordinates latitude 25°8′31′′S, longitude 53°19′40′′W and altitude 781 m. Rio do Salto has regulations of 19 blocks with 241 properties. The evaluated properties belonged to block 11. The project was feasible when the payback period of the investment occurred within the expected photovoltaic system life cycle and if the internal rate of return (IRR) was higher than the minimum attractiveness expected for the project. To ensure the viability of this power generation system, the average consumption over the 12-month period should be higher than the rate of availability of the concessionaire that the owner should pay. This value varied according to the connection type (single-phase: 30 kWh, two-phase: 50 kWh and three-phase: 100 kWh). Property 9 was the only one that did not show conditions for photovoltaic system for not reaching the minimum connection tariff of the concessionaire.

necessities to meet their demands (Corbusier, 2000;Rogner, 2000;Guimarães, 2004;Ultramari, 2005;Ortega, 2008;Almeida & Soares, 2009). To install photovoltaic system in rural areas, the measurement data must be performed in places close to where the system is to be deployed, since the radiation incident at each terrestrial site is extremely variable. The connection and customer service, regardless of the size of the rural area, is carried out by ANEEL (2008) and BEN (2014). Pinho (2008) points out that in addition to the regular daily and annual variations due to the apparent movement of the Sun, climatic conditions (clouds) as well as the general atmosphere composition cause irregular variations.
Thus, this work aimed to evaluate the economic viability of photovoltaic power generation systems so that the rural community of Rio do Salto became self-sufficient in the production of energy for local consumption.

Location Characterization
The study site was Rio do Salto (geographical coordinates latitude 25°8′31″S, longitude 53°19′40″W and altitude 781 m), in the rural area, 32 km from Cascavel, Western region of the state of Paraná.
The area perimeter is 402,367.84 m 2 . The area has 19 blocks divided into 241 properties (Perfil Municipal, 2015).
The study area was block 11 dues to the typology of the buildings, rural and social functions, services and housing, pavement of the differentiated streets, location in the middle of the urban area/heat island, presenting differentiated facades and each property having a differentiated ground use.
All constructions in block 11 were evaluated and compared with the information in the municipality database.

Monthly Energy Demand in Rio do Salto
It was made performed the energy demand of Rio do Salto to identify the number of consuming units and their respective consumer classes, and thus to size the photovoltaic generation system to make the site self-sufficient in energy generation.
It was made considered the year 2014 as the basis for energy demand calculations. Data referring to the consumption in kWh and the number of consuming units (divided by classes), from January to December 2014 were provided by the local electric energy concessionaire (Companhia Paranaense de Energia-COPEL).
It was made evaluated only classes 1 and 3, which are directly linked to residential and commercial use, respectively. Therefore, it was made carried out the survey of consumption information only in the buildings of block 11, and based on their annual consumption, it was made performed the analysis between the energy production of the photovoltaic panels with the energy consumption, to the sampling place, and later, it was made defined the average for the implantation in the consumer constructions of class 1 and 3 in the entire district.
To achieve the proposed goal of surveying the energy consumption of the various housing units/energy consuming units, it was made performed several field visits to talk to all the owners, residents or tenants of the research residences, as well as in loco verification of their entrance standards (Figure 1). Thus, the proposal to carry out this work, based on the condominium law and ANEEL regulations, proposed to develop microgeneration for each property, and to link them in a single CPF, of the owner of the properties.

Energy Demand for Each Property
The hypothesis was microgeneration unified for each individual property, except for properties 1 and 2, where there was only one residence.
Based on the results, it was made confirmed that the implantation feasibility of photovoltaic systems proved to be advantageous from the moment it is implanted for a set of residences, a factor explicitly demonstrated and identified in the sum of the values, and the average of monthly consumption, since most of them are still low to justify the implementation of photovoltaic assemblies for isolated residences.
To be feasible to install a photovoltaic system, the residence must have at least a two-phase electrical installation; however, to solve this problem, it would be necessary to adapt only one building to install the system, and later through the ANEEL criterion of compensation, to compensate the expenses of other residences, using the condominium system and placing all invoices in a single CPF or CNPJ.

Installed Quipment
For the design of a project and budget proposal with the local company Master Solar, it was made used the Technical Norms of 905,200 (COPEL, 2016), in which standards, equipment, connection types, technical specifications and design are established to develop the micro power generation project for residences.
After preparing the project proposal, it was made looked on the ANEEL (2010) for the list of materials approved by the concessionaire to implement photovoltaic systems for the micro/mini-generation of energy, interconnected to the concessionaire grid in the energy compensation system (grid tie) for buildings.
Thus, the budget based on the calculations and obeying the materials approved by the concessionaire. Table 1 shows the quantitative summary of the equipment used to install the residential photovoltaic system, stipulated for the properties.
As shown in the Table, the kits offered by the local company are sold in even numbers and are not suitable for all situations.
Thus, the variation of equipment occurs only in the number of photovoltaic panels for energy generation, in relation to the other equipment of the whole photovoltaic assembly. The only difference is that the capacity/load with which they work is larger depending on the number of panels and/or power generation.
Another detail observed when developing the project and budget with the local company is that it works with what it was made can call photovoltaic generation kits; by observing the worksheet, it turns out that in many cases the numbers of photovoltaic panels are repeated, and by analyzing the technical specifications in the budgets presented by it, the technical specifications of the used equipment are standard according to the demand to be generated for each unit, and/or set of consumer units.

Econom
For payba available ( The analy system eq manufactu                  In all the analyzed properties, except property 9, energy consumption is equal to or less than the minimum consumption that the owner will have to pay monthly to the distributor; all other properties show an attractive profitability for the photovoltaic system implantation.
The average cost for implantation in all housing units and/or isolated consumer unit is R$ 29,864.24, with average NPV of R$ 16,436.20, and average return time of 6 years and 4 months, for properties in which system deployment is feasible. Property 9 was disregarded from the analysis for not presenting average consumption values higher than the basic energy connection rates with the concessionaire. Installing the photovoltaic system for a set of residences and/or buildings in rural areas is feasible due to the consumption of each property, that is, it is feasible only for places where energy consumption is high, as in the case of properties 3, 5, 8, 11, 12, 15, 16, 17 and 18. The implementation is interesting in the unified properties 1 and 2 and property 7, where at the end of the 25-year period they are not profitable in the system installation; however, at the end of this period, the outstanding amount to pay off the investment is less than the annual average payback.
The return on investment is much faster due to higher energy consumption of each property, that is, the higher the installed capacity and the shorter the return on investment.
The photovoltaic assemblies (kits) are an economically viable alternative within the proposal of this research of photovoltaic power generation system in a rural community and of the current legislations.
Subsequently, it is suggested suggesting carrying out the feasibility analysis for the photovoltaic system implantation in the whole community, since the implementation of lot 11 was viable.
Installing photovoltaic systems for electric energy generation in the rural community can provide the improvement and maintenance of the activities and services provided in these places.
To ensure the viability of this power generation system, the average consumption over the 12-month period should be higher than the rate of availability of the concessionaire that the owner should pay. This value varies according to the connection type (single-phase: 30 kWh, two-phase: 50 kWh and three-phase: 100 kWh). Property 9 was the only one that did not show conditions for photovoltaic system for not reaching the minimum connection tariff of the concessionaire.

Conclusion
Properties 3,5,8,11,12,15,16,17 and 18 showed a return within the stipulated period. The average return of R$ 35,324.79, oscillating between the maximum return of R$ 46,784.76 on property 17 and a minimum return of R$ 7,842.06 on property 15, with an average variation of 579% in value among them.
The average payback time is 6 years and 4 months.
The average investment cost for installation of the system is R$ 29,864.24, ranging from a maximum of R$ 42,800.00 (system installed in property 11) and a minimum of R$ 26,258.00 (systems installed in unified properties, 1 and 2).