*Article* **Analysis of Scenarios for the Insertion of Electric Vehicles in Conjunction with a Solar Carport in the City of Curitiba, Paraná—Brazil**

**Ana Carolina Kulik 1, Édwin Augusto Tonolo 1,\* , Alberto Kisner Scortegagna <sup>1</sup> , Jardel Eugênio da Silva <sup>2</sup> and Jair Urbanetz Junior <sup>1</sup>**


**Abstract:** The growing environmental impact and rising emission of greenhouse gases have accelerated the research toward renewable energy sources and electric vehicles since one of the main sources of pollution is the CO2 emissions produced by conventional combustion vehicles. This article presents the analysis of the energy balance between a photovoltaic carport with 4.89 kWp installed capacity and an EV, model Renault Fluence ZE DYN, driven in real conditions. The driving tests were performed during the winter season in the city of Curitiba, the capital of the state of Paraná, Brazil, with approximately 1.7 million inhabitants and 1.1 million vehicles. During the test period, we attempt to reproduce the citizen's daily routes through the city, presenting an average consumption of 15.75 kWh/100 km. The carport PV module's energy generation and in-plane incident irradiation were acquired to calculate the performance ratio, making a comparison after cleaning maintenance possible. The solar carport system has 4.89 kWp and has generated an average of 465.37 kWh during its 24 months of operation. The analysis scenarios consist of replacing part of the city's combustion vehicle fleet with the EVs (the same as used in the study) and thus determining how many replicas of the presented photovoltaic systems might be needed, as well as the area required for the installations. In a simulation with 15% of the fleet's replacement, it would be necessary to generate 17,151.8 MWh, which requires the construction of 36,856 carports, covering an area of approximately 1,105,685 m2. Finally, an economic comparison between an internal combustion vehicle and the EV determined that the expenditures involving electric energy to charge the batteries are 3.3 times lower than buying gasoline, assuming the same driving routines.

**Keywords:** vehicle charging stations; electric vehicles; energy consumption; energy generation; renewable energy sources

#### **1. Introduction**

The environmental degradation resulting from greenhouse gas emissions and the upcoming shortage of fossil fuels highlights the importance of generating energy with minimal environmental impacts, confirming the relevance of including different energy sources in the national energy matrix [1–3].

The transport sector is one of the biggest consumers of fossil fuels, contributing to the increase in greenhouse gas emissions and global warming [4]. In 2019, this sector produced 8.2 Gt of CO2 (gigatons of carbon dioxide), representing 24% of direct emissions from fuel combustion [5,6]. Public and private transportation both have a crucial role in the development of a region or entire country. However, there are also commonly associated problems such as pollution, fossil fuel consumption, noise, accidents, resources

**Citation:** Kulik, A.C.; Tonolo, É.A.; Scortegagna, A.K.; da Silva, J.E.; Urbanetz Junior, J. Analysis of Scenarios for the Insertion of Electric Vehicles in Conjunction with a Solar Carport in the City of Curitiba, Paraná—Brazil. *Energies* **2021**, *14*, 5027. https://doi.org/10.3390/ en14165027

Academic Editor: Wojciech Cieslik

Received: 28 July 2021 Accepted: 12 August 2021 Published: 16 August 2021

**Publisher's Note:** MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations.

**Copyright:** © 2021 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/).

use and waste, etc. [7]. Improvements aiming to decrease the dependence on these nonrenewable fuels and to reduce the environmental impacts are considered vital to ensure energy security and population welfare [7,8].

Knowing the need to decrease pollution (mainly air) around the globe, we must reduce the emissions caused by the transport sector by shifting away from the traditional fossil fuel-based concept to an alternative system [8–10]. With numerous objectives to be achieved (and quickly), electric vehicles (EVs) are set to be the key to shift into electric mobility, considering that they have already been playing a significant role in recent years [6,8].

The electric motor is characterized by high efficiency, lack of emissions, and lower noise, compared to traditional combustion engines [11–13]. In general, EVs have not been successful in the past because of the limitations in battery technology in terms of high weight and price, short life, and long charging time [14]. Supported by recent advances and developments in technology, they are now on the market as strong competitors to traditional internal combustion vehicles [12,14].

EVs can be divided into battery electric vehicles (BEVs), plug-in hybrid electric vehicles (PHEVs), and fuel cell electric vehicles (FCEVs) [15]. BEVs are only powered by an electric motor and traction batteries [16]. FCEVs use fuel cells to deliver energy and power the electric motor [16]. Hybrid vehicles have two sources and are powered by an internal combustion engine and batteries [16,17]. They are not completely free of nonrenewable fuels but cost less and can be used to travel long distances without stopping to recharge [16,17].

EVs are known for their low maintenance, high performance and efficiency, and zero air pollutant emissions, explaining their infiltration into the automobile market [15]. Along with increasing environmental concerns and energy-related issues, EVs have become one of the main subjects of research [16].

In the year 2020, there were 10 million electric vehicles moving around the globe, an increase of 43% compared to 2019, with BEVs accounting for nearly 66% of the sales. The sales forecast, in a stated policies scenario, declares that the EV stock in the year 2030 will be approximately 150 million [18].

The largest fleet can be found in China, representing 45% of the global electric car stock [18]. The Brazilian market is developing at a slow pace, and according to [19], approximately 44 thousand EVs have been sold, representing less than 0.1% of the total national fleet.

Public accessibility to chargers increased by 45%, considering both slow and fast chargers, reaching 1.3 million stations [18]. In [20], an explanation about the different kinds of plugs and charging levels is presented, pointing out the major characteristics and differences. However, [18] found that when the power is lower than 22 kW, it is considered a slow charge. Interurban transportation is one of the cases in which EVs may not be able to provide a solution yet, due to the large distances between locations. To guarantee safe interurban transportation, [21] proposed the deployment of fast-charging infrastructure on the highways.

Continuous population growth and urban expansion have led to an increase in demand for electricity [22]. Reduced carbon emissions are one of the main goals in urban planning and energy policies [7,23]. With the cost of electricity generated by solar power decreasing significantly and becoming competitive, the rapid development of photovoltaic (PV) infrastructure was achieved, along with a strong market. The design flexibility of PV systems allows the energy to be generated with a wide range of options, meeting the needs of distinct levels of consumers, from homes to large industries [23,24].

The global installed capacity of renewable energies grew by more than 250 GW (gigawatts) in 2020, led by photovoltaic solar energy, and it is estimated that approximately 29% of the electricity generated in 2020 came from renewable resources. For the sixth consecutive year, renewable energy system installations have surpassed those of fossil fuel and nuclear power capacity combined. More specifically, the photovoltaic solar energy segment showed an increase of approximately 22% in installed capacity, with 139 GW being added. The greatest demand for photovoltaic solar has occurred in China, the United States of America, Europe, and emerging markets around the world. The global installed capacity is approximately 760 GW, which includes both on-grid and off-grid solar generation capacity, compared to a total of less than 40 GW just ten years earlier [25].

Renewable energy sources for electricity generation, and the electrification of the transport sector, offer great potential for reducing the use of fossil fuels–one of the major causes of air pollution and health problems globally [12,26]. Thus, the benefits between photovoltaic energy production and EV charging are greater when the integration between charging stations and photovoltaic systems are considered, on what is a promising solution to the abovementioned environmental problems [3,14,24,27]. To make the best use of both technologies, the EVs must be charged during the day, using the energy generated by the PV system or other renewable energy sources [28].

The combination of EV charging stations and PV generation can be achieved through the construction of solar car parking, also named solar canopies or solar carports. These structures are built to park a car under, and PV modules are installed on their roofs to generate electricity. These systems are versatile and can be used in the most diverse places, such as markets, hotels, shopping malls, restaurants, public institutions, country houses, camping areas, shopping centers, business parks, sports centers, train stations, airports, etc., benefiting areas that in most cases are available to be reshaped [6,14,29]. Any of these places can provide convenient charging while the EVs are parked, supporting the development and use of renewable energy systems [22,23].

During the life cycle of a PV module, situations like natural degradation, possible components failure, various weather conditions, electrical stress, and others are faced that momentarily and/or permanently alter some characteristics [30]. Out of the main encountered situations, dust accumulation is one the most common, defined by the particles that cover the module surface, blocking the cells from receiving the energy from the sun, negatively impacting the PV energy generation [30,31]. During wet seasons, when it rains more frequently, there is less dirt accumulation compared to dry seasons, which can be accredited to the rain's natural cleaning [32,33]. Although it is not as effective as a deep cleaning made by a human or machine, it still exhibits positive effects.

The use of photovoltaic energy generation together with EV charging infrastructure still poses challenges, mainly because of the uncertain energy demand pattern of EVs, which is based on the drivers' behavior and preferences and the intermittence of the PV generation [9,34]. Ref. [24] presented a complete study of the vehicles' charging requirements based on the period of the year, distance traveled, and location of the route. Meanwhile, ref. [35] modeled the driving patterns and energy demand of the EV for the country of Austria. Studies in the field are essential for accurate planning of the investments aiming to promote electric mobility [36].

EVs represent a storage capacity, in a great new approach known as Vehicle-to-Grid (V2G), which gives the option of a bidirectional energy flow, positively affecting the vehicle and the grid; this can be interpreted as another functionality for intelligent energy networks (smart-grids) [29,34]. It can supply back-up electricity, shift the electricity load, and respond quickly to balance the grid, representing a new important power source [15]. The work presented by [15] centers the attention on a technical and economic analysis for the application of V2G techniques in the power grid.

In 2012, the National Electric Energy Agency—ANEEL, released Resolution 482 for the regulation of the distributed energy generation in Brazil, which was amended in 2015 [37]. It is classified as micro-generation when the PV installation is up to 75 kW (kilowatt) and mini generation for 75 kW to 5 MW (megawatt). It also gives the consumer the possibility to exchange the surplus energy through a free loan with the grid, reducing the energy bill and generating energy credits that can be consumed within 60 months [38]. The energy does not need to be generated at the time or in the month it is consumed [39].

The constant increase in energy demand, at least in Brazil, has been leading to an increase in the contribution of non-renewable energy sources in the production of Primary

Energy, as can be seen in [40]. Observing the graphics, it can be seen that from 1970 to 1999, the production of renewable sources was greater than the non-renewable ones, a scenario that was reversed after the year 2000. Although both cases are presenting a growing pattern, non-renewable energy production is growing at a higher rate. There is another challenge regarding the grid voltage stability [41]. Ref. [42] proposes a combination of different local resources to alleviate the potential grid problems. Charging EVs through renewable power generation systems must be optimized in order to reduce the cost of operation and the grid problems. Based on the Brazilian regulation, ref. [43] proposed a tariff model for public access points, reducing the costs for the consumer.

In our work, considering an EV, we intend to define how much electrical energy is consumed during daily and monthly driving routines, considering only working days during the winter season in the city of Curitiba, Brazil. Regarding the PV systems, the energy generation data and local irradiation information are acquired, making it possible to calculate the performance ratio. At first, it is discussed if there are improvements in the energy generation efficiency by performing a cleaning service in the modules. Examining the integration of both technologies, it is discussed if the installed PV system is capable of generating the electric vehicle required energy that was measured during the tests. Based on fleet substitution scenarios, the manuscript discusses how many carports may be necessary to recharge the EVs batteries in each condition. An economic analysis to compare the monthly fuel costs of an EV and an internal combustion vehicle is presented.

The scope of this study includes the energy generated by the carport during its 24 months of operation, covering two parking spaces. In addition, the electric vehicle's actual consumption will be displayed. Finally, the performance ratio of the PV system will be presented, and the maintenance of the modules will be discussed.

#### **2. Materials and Methods**

The aim of this study is the evaluation and analyses of the energy generated by a PV system installed on the parking lot of the university and the required energy for charging an EV, emulating the average driven distance by the citizen from the city of Curitiba, state of Paraná, Brazil. The analysis of energy generation from the PV system is verified from July 2019 (date when it was inaugurated) until June 2021, totalizing 24 months.

The average EV energy consumption is also presented. The following questions were evaluated: How much energy does an electric vehicle in the city consume for its daily activities? Does the 4.89 kWp (kilowatt-peak) carport photovoltaic system guarantee the energy demand necessary to power two electric vehicles?

The system performance ratio is also calculated, and after the cleaning results are presented, the system maintenance and meteorological factors that influence its operation are discussed.

This article presents an analysis of two stages of energy conversion. The first one studies the energy consumption of the electric vehicle Renault Fluence ZE DYN in real daily conditions of the urban environment, while the second one deals with the maintenance of energy generation of the solar carport. Figure 1 illustrates the proposed division.

#### *2.1. Electric Vehicle*

The electric vehicle used in the driving tests is a Renault Fluence ZE DYN, equipped with a 22 kWh (kilowatt-hour) lithium-ion battery bank and an engine with a maximum power of 95 hp (horsepower), corresponding to 70 kW. The main characteristics of the EV are summarized in Table 1.

Recollecting the information about the EVs market in Brazil, it still represents a small portion of the vehicle fleet, mainly due to their high prices. Under these circumstances, the presented car is the only data source available for this type of test in the university. The EV was recently purchased.

**Figure 1.** Analyses proposed for this study: (**a**) Carport maintenance and energy generation; (**b**) Renault Fluence ZE DYN energy consumption.



#### *2.2. Carport*

The generated energy from the carport is acquired from the online website of the installed inverter. The system is working connected to the grid since July 2019, and all the generated energy that is not used, the surplus, is used as energy credit in the deduction of the university's monthly energy bill.

The entire PV system of the carport was built by the donation from some companies that have business in the energy sector. From the academic point of view, it aims at the integration of photovoltaic energy generation with EV battery recharging. In addition to the energy generation and energy cost savings, it is an important source of information for research in the field.

The PV system contains 15 polycrystalline solar modules, arranged in 2 strings, one containing 6 modules from a manufacturer with 335 Wp each, while the other contains 9 modules from another manufacturer with 320 Wp each, totaling 4.89 kWp. The installation also includes a single-phase 5 kW inverter with integrated monitoring.

The carport was assembled aligned with the parking lot's geographical position, distant from shadows of trees and light posts, with a north orientation, a 10◦ inclination, and azimuth deviation of 22◦ to the west, allowing two vehicles to be parked simultaneously. Table 2 summarizes the main parameters of the PV system, and Table 3 presents the inverter electrical characteristics.

**Table 2.** Electrical parameters of the PV system strings [29].



**Table 3.** Electrical parameters of the PV system inverter [29].

For the electrical security of the PV system, there is a connection board in the DC (direct current) side, containing 4 inputs and 2 output pairs, supporting the connection of both strings into the MPPT (maximum power point tracking) channels of the inverter. It also contains, for every string, a set of SPDs (surge protection devices) model Dehn Type II for 1000 V (volts), a particular model for PV applications, and a disconnection switch of 1000 V and 25 A (amps). Regarding the AC (alternating current) side, there is a connection board with a circuit breaker and an SPD.

It was decided to build a wall in front of the carport, measuring 3.17 m × 1.63 m (meters), so that the fundamental equipment could be protected from the rainfall, but also exhibited to the community and other students from the university, contributing to the awareness of technologies and its benefits. In this wall, the inverter, both connection boards, a pair of standard AC outlets, and the vehicular charger were fixed.

The two standard AC outlets were installed for charging the EV in Level 1 Charge Mode or to use general electrical devices. The one and only vehicular charger so far, model ProEV1, was donated and installed by Egnex company and is illustrated in Figure 2. There is enough space for two more charges.

**Figure 2.** EGNEX ProEV1 charger.

This charger automatically communicates with the EV and starts charging it when there is an established connection with the vehicle, in accordance with current technical standards. To charge the EV, using the AC grid, the user can configure the equipment according to the local electrical installation, from 1 to 7 kWh in a single-phase and from 2 to 22 kWh in a three-phase network. The charger is available with a Type 1 or Type 2 connector,

which is the most accessible connector on the national market [45]. Figure 3 displays the carport's internal and external aspects, including the wall and the fixed equipment.

**Figure 3.** Current carport installations: (**a**) External; (**b**) Internal.

Each parking space has an area of approximately 15 m<sup>2</sup> (square meter). Knowing that two cars can be parked under the structure for simultaneous charging, the total area covered by the carport is 30 m2.

#### **3. Results and Discussion**

#### *3.1. Vehicle Energy Consumption*

In order to measure the energy consumption of the Renault Fluence ZE DYN, it was necessary to purchase and connect a specific scanner, "Konnwei OBDING BT 3.0", model KW902, to the EV's on-board computer. Using an Android smartphone to install the Fluence ZE Spy application, the device and the software establish communication via Bluetooth, exhibiting the required information. Figure 4 shows the scanner, and the application used to display the electrical consumption of the EV.

**Figure 4.** Required gadget and software: (**a**) Scanner Konnwei OBDING BT 3.0, model KW902; (**b**) Fluence ZE Spy application.

After installing the scanner hardware and the application to display the required results, the energy consumption of the EV was measured in the urban environment in June 2021, the winter season in Brazil. We executed two measurements with the same driving distances, with the objective of obtaining a reliable result. The driving tests were performed in the central area of the city, around 11 a.m., facing a light traffic jam. Eco mode was enabled.

The total driving distance was 42.9 km (kilometer), and both attempts ended up with approximately the same outcome, with 15.75 kWh/100 km (kilowatt-hour per a hundred kilometer) for the first trip and 15.55 kWh/100 km for the second drive, both presented in Figure 5.

**Figure 5.** Energy consumption measurements for the Renault Fluence ZE DYN in the urban environment during the driving tests.

To perform the evaluations proposed in this article, the highest obtained result from the two-driving tests has been used; therefore, in the following scenario calculations, it will be considered that the EV energy consumption, considering the urban traffic of the city of Curitiba, is 15.75 kWh/100 km.

#### *3.2. Carport Energy Generation and Performance Ratio*

Based on the mass memory of the inverter, Table 4 presents the monthly energy generation of the PV system from July 2019 to June 2021, totaling 24 months of analysis. Summing the data from all operational months, the PV system has already generated 11,168.77 kWh. The monthly average energy generation is 465.37 kWh, and it is the value that will be used in the scenario analyses, taking into consideration the local renewable energy regulation.

One way to evaluate the generation of a photovoltaic system is by analyzing the merit indices. These are important indicators that show whether the energy is being generated by the systems in an optimized way and enable the comparison between other photovoltaic installations or other energy sources [46–48].

Among the merit indices, only the performance ratio (PR) will be analyzed here, which is the relation between the generated energy (kWh), the reference irradiance (kW/m2, kilowatt per square meter), the incident irradiation in the plane of the photovoltaic panel (kWh/m2, kilowatt-hour per square meter), and the installed PV power (kWp), according to Equation (1).

$$PR = \frac{Energy\,\,Generation \times \,Reference\,\, irradiation}{Irradiation \times PV\,\,Power} \tag{1}$$


**Table 4.** Monthly Energy Generation of the Carport (kWh).

It is impossible to achieve an efficiency of 100%, as photovoltaic installations present losses that are typical, and among them, panel degradation, temperature, dirt, internal network failures, cabling, inverter, transformer, and system availability can be highlighted. For the dimensioning of photovoltaic systems, it is common to adopt a PR between 70% and 80% [47].

Due to the dirt conditions that can be identified by visual inspection and the calculated low-performance ratio indicator, a cleaning service was executed on the photovoltaic modules on 1 June 2021 in order to verify its impacts on the generation of electricity. A comparison between the electricity generated in June with the previous months is performed. Figure 6 illustrates the conditions of the modules before and after cleaning them.

**Figure 6.** Comparison of the PV modules conditions: (**a**) before washing; (**b**) after washing.

The irradiation data were acquired from a solarimetric station called EPESOL—Solar Energy Research Station, located in the university's campus, the same site where the carport system is installed. However, the installation of the carport was prior to the solarimetric station, which has been in operation since March 2020. The previous irradiation values were obtained from the INMET (National Institute of Meteorology). Originally, these measurements are acquired for the horizontal plane and later converted to the plane of the

carport, according to the inclination and azimuthal deviation, through software, and are presented in Table 5.


**Table 5.** Monthly average irradiation in the plane of the carport (kWh/m2/day).

With the acquired data and Equation (1), it is possible to calculate the monthly performance ratio for the entire period of operation of the system.

In Table 6, the results of the performance ratio for the 24 months of the carport's operation are presented. For the periods when the calculated outcome is below 70%, it can be understood as a warning signal, which may indicate that the PV system is experiencing long periods of shading, the modules are dirty, or there are electrical problems.


**Table 6.** Performance ratio (%).

The performance ratio measures the efficiency of the photovoltaic panel in a given location, deducting the losses, measures the onsite quality, and compare PV installations in other locations. Considering the 24 months studied, an average performance ratio of 68.04% was reached.

As mentioned earlier, scheduled cleaning of the PV modules was performed with the objective of exploring its effect on the performance of the system. According to the results presented in Table 6, it is possible to verify that there was an improvement of approximately 10%, comparing June 2021 with May 2021, which can be assigned to the executed maintenance.

Analyzing the abrupt variation between the months of April and May 2021 (Table 6), it is possible to indicate two climatic factors that had a positive influence on the improvement of efficiency. Rainfall rates collected from the same solarimetric stations indicate that the month of April 2021 was extremely dry, recording only 7 mm (millimeters), in contrast to the month of May 2021, where 115.8 mm were registered. The rainfall collaborates with the self-cleaning of the photovoltaic modules, eliminating superficial layers of deposited dirt.

Another determining factor for the improvement in the performance was the decrease in the temperature, which, according to the datasheet of the PV modules, results in an increase in the PV power. Comparing May 2021 with April 2021, the daily maximum temperature dropped by more than 1 ◦C (degree Celsius), and the daily average temperature decreased by more than 2 ◦C. It may seem that the temperature variation is not very significant, but the two climatic factors combined are strong contributors to an increase in photovoltaic energy generation.

#### *3.3. Vehicle Energy Consumption and Carport Energy Generation*

According to [49], at the end of 2020, there were 1,099,979 vehicles registered in the city of Curitiba, capital of the State of Paraná, whose population is 1,751,907 inhabitants. To make the calculations simpler, it was considered that the fleet is composed of 1,100,000 vehicles. According to [50], the population of the city travels, per day, an average of 13.7 km to get to work, totaling 27.4 km considering round trips. Adding 10% as a margin for supermarkets, gas stations, restaurants, or other emergencies, an average distance of 30 km per day is used, resulting in 660 km in a month. Only the working days of each month are included, which will be set at 22, considering that on weekends generally there is no associated driving pattern. Table 7 presents a summary with the main values.

**Table 7.** Main parameters.


After defining the variables, it was calculated that under these conditions, the electric vehicle would consume 103.95 kWh of electrical energy per month. Therefore, with the electricity generated by the carport, it would be possible to charge the battery of approximately 4 vehicles like the one used in the example.

Expanding the analysis scenarios, the simulations do replace a percentage of the city's vehicle fleet with EVs, based on the results obtained with the Renault Fluence ZE DYN, and compare with the electricity generation data from the presented carport. For each case that the number of EVs is increased, the amount of required charging energy, the number of identical carports, and the necessary available area for the installation of the PV system also increase.

The work presented by [51] analyses the impacts in the electric power system for the city of Curitiba in the case of a substitution of 15%, 30%, or 50% of the internal combustion vehicle fleet with EVs.

The scenario analyses follow the same replacement rates and define the average electric power generation of the carport as the basis for comparisons. The first two suppositions can be considered as a condition for 15 to 30 years in the future. The main obtained results are shown in Table 8.

**Table 8.** Comparison of the results.


#### *3.4. Economic Analysis*

According to [52], the price of photovoltaic systems in 2021 increased compared to 2020. In the study, it is stated that the low-power residential installations are costing approximately USD 0.95 per Wp. Reminding that the installed PV system has 4.89 kWp; as a result, the considered cost is USD 4645.00.

As stated previously, the metallic structure of the carport was donated to the university. However, the cost to purchase the product is about USD 2000.00. Another USD 200.00 is required for the electrical devices, like the SPD, cabling, connection board, disconnection switch, circuit breaker, and the construction expenses like the foundation and walls. Finally, the total expenditure of the carport is summed as USD 6845.00.

The energy tariff charged by the local power distribution concessionaire is USD 0.18 per kWh. The PV system average energy generation data from the past two years is reported as 465.37 kWh, resulting in an average avoided cost of USD 83.76 per month. The calculations are based on the average energy generation considering the renewable energy regulation of the country.

Performing a simple payback calculation for the carport and indexing the inflation and increasing in the energy tariff in the variation of the dollar exchange rate results in 81.7 months, approximately six years and nine months.

According to the technical data presented in [53], the same vehicle, a Renault Fluence, powered by a combustion engine and gasoline, presents a final consumption (in the city) of 9 L/100 km.

Considering the same usage scenario of 660 km/month, the car would consume 59.4 L to complete the entire drive. Taking into account that the average price of gasoline in the city of Curitiba is USD 1.05 per liter, the vehicle would generate a fuel cost of USD 62.37 per month.

If the same electric vehicle, used on an identical route, was recharged without the photovoltaic system, using only the energy made available by the local utility, the consumption of 103.95 kWh/month would generate an average extra electricity cost of USD 18.71 per month.

In the last comparison, when the EV is recharged by the electricity generated in the carport, after the payback period of the PV system, it no longer has a recharge cost.

#### **4. Conclusions**

The selected EV is a Renault Fluence ZE DYN, whose driving consumption tests in the city resulted in an average of 15.75 kWh/100 km. Investigating the responsible agencies, the number of vehicles registered in the city is determined, making it possible to simulate scenarios of the replacement of internal combustion vehicles by EVs.

The article presents the complete electric energy generation records of a PV system constructed as a carport to cover two parking spaces of the parking lot of the Federal University of Technology—Paraná, Brazil, with 4.89 kWp of installed power. Along with the electricity generation, the irradiation data was collected from a solarimetric station installed in the same area of the university, making it possible to calculate the system performance ratio, both for monthly and annual analyses.

Calculated performance ratio values were lower than what is commonly accepted as normal, and with high dirt accumulation, all the PV modules were cleaned, aiming for an overall performance improvement of the PV installation. The task had a positive effect, increasing the performance ratio by more than 10% when compared to the previous month, demonstrating that the PV systems demand periodic maintenance, which is simple and can improve efficiency.

Investigating the performance ratio of the other months, it was detected that after a month with very low rainfall records, the rain performed a natural cleaning on the photovoltaic modules, which, combined with the lower temperature due to the winter season, there was an increase in the PV system performance ratio. The rain has the capacity to perform superficial cleaning and reduce the rate of deposition of dirt on the modules.

Defining the daily drive based on the distance to work, returning home, and a margin for extra activities, while limiting it to weekdays, it was calculated that the EV energy consumption was 103.95 kWh per month, and the average energy generated by the carport was enough to charge the battery of approximately 4 EVs. The study does not define a specific charging routine and also does not analyze the impact on the electric power system. The energy balance is linked to the resolution of the National Electric Energy Agency, where the credits from the months with high PV generation can be used within 60 months.

The economic analyses compared the monthly expenses of an internal combustion vehicle and the EV for the same driving scenario. The EV presented approximately 3.3 times less expenditure. Purchasing and maintenance costs were not compared.

The EV used in the driving test was recently purchased and is the only source of energy consumption available at the moment. Future research should use larger driving samples during different periods of the year and hours of the day.

**Author Contributions:** Conceptualization, A.C.K., A.K.S., J.E.d.S. and J.U.J.; Data curation, J.E.d.S. and J.U.J.; Formal analysis, É.A.T.; Investigation, É.A.T., J.E.d.S. and J.U.J.; Methodology, A.C.K. and J.U.J.; Project administration, A.C.K.; Resources, J.E.d.S.; Software, É.A.T.; Supervision, J.U.J.; Visualization, A.K.S.; Writing—original draft, A.C.K. and A.K.S.; Writing—review & editing, É.A.T. and A.K.S. All authors have read and agreed to the published version of the manuscript.

**Funding:** This study was financed in part by the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior—Brasil (CAPES)—Finance Code 001.

**Conflicts of Interest:** The authors declare no conflict of interest.

#### **References**

