*3.1. Data Collection*

The purpose of this stage is to collect objective information for the village necessary to perform the study. Since the case study is an existing project, sources for the collection of data are two-fold: most of the input data comes from equipment measurements developed in collaboration with utility UTE; on the other hand, public databases have been used to validate existing data, to gather data for optimization and, most important in this work, data for the inclusion of wind generation.

•Load demand data.

15-min records of active power consumption in the town have been obtained. Based on the data, the daily consumption curve, the annual profile, and the peak power have been calculated, as it was described in the previous chapter (see for example Figure 4).

•Solar resource.

The solar radiation is measured at the weather station installed. However, a validation with the following databases has been made: Meteonorm, PVgis, Tacuarenmbó, the nearest meteorological station, and TMY of Salto database. In the following graph in Figure 9, it can be seen how the data measured in the meteorological unit (Met Stat. 24◦) are higher than the values of the public databases consulted. This discrepancy was most probably due to the different slope but, thanks to the comparison of the energy produced vs. the estimated with the measured irradiance, it has been possible to rule out the discrepancy and validate the data measured by the meteorological unit for its use in the analysis. These data were summarized in Figure 5.

**Figure 9.** Comparison of measured data (Met. Stat. 24◦) with databases (Meteonorm, ERA5, Tacuarembó Met. Stat., and TMY from Salto). Discrepancy comes from the different slope.

• Wind resource.

It was obtained from ERA5 database and downloaded with WindPro software. The selected node is located in 21S UTX 523,741 UTY 6,514,956. It is the closest to Cerro de Vera, with a distance of 12.8 km. The series used includes the period 2010–2020, with hourly data for wind speed and wind direction at 10 m, pressure, and temperature. Data obtained are not influenced by the local effects of orography and roughness.

The quality of the data obtained in the meteorological unit has been evaluated. Since the meteorological unit is designed to measure the variables that affect the photovoltaic installation, they have not been sufficient for characterizing the wind resource. These data have been supplemented with re-analysis databases. In order to evaluate the wind resource, two specialized programs in wind energy have been used; they include WAsP and WindPro.

Based on the ERA5 time series of wind at 10 m height, orography, and roughness, WAsP was used to perform a horizontal extrapolation that allows obtaining a resource grid. The grid has a resolution of 100 m (as the resolution of the used Digital Elevation Model is 90 m), with 48,816 points calculated at 10 m height. In this manner, it is possible to identify areas with better resources and therefore with greater energy potential to place the wind turbine. The resource grid has been imported into Windpro to continue the analysis from that software. Figure 10 shows the resulting resource grid on Windpro, the location of Cerros de Vera and the location of the ERA5 node.

**Figure 10.** Resulting average wind speed at 10 m resource grid, with the location of Cerros de Vera on the bottom left and the location of the ERA5 node on the upper part.


The compilation of information on the existing system from the detail of the components to the costs (initial investment, operation and maintenance, fuel, etc.) and the operational experience as well. UTE has provided most of this information.

#### *3.2. Simulation of the Operation of the Current Electrification System*

This stage is particular of this case study, as it is an existing system. In order to simulate the future behavior of the system, the parameters for the simulation are adjusted so that they reflect the present performance in a more accurate manner. This stage seeks to determine the operation of the system, checking it against the simulation results system based on the information collected described in the previous chapter. Should there not be any existing system, only simulation results would be available, derived from estimated (not measured) information. At this point, the data from the monitoring system provided by UTE have been used.

Since Cerros de Vera has a photovoltaic installation, in order to determine the operating mode of the system, two software tools have been used: PVsyst® and HOMER Pro®. Since PVsyst® is a software specifically designed for photovoltaic systems, greater precision is expected for the simulation of photovoltaic production and for this reason the results of PVsyst® will be used as input data for HOMER Pro®. The simulation of all system components will be carried out with HOMER Pro® using 1 h average data. Windographer® has also been used to process this information. The visual review of these data has allowed detecting anomalies in the operation of the different parts that will allow the improvement of the electrification system.

Below, after some first general considerations, the results obtained in the simulation for each of the components are described: photovoltaic system, converters, batteries, and diesel generator.

•General considerations.

The data provided by UTE for the load characterization have been compared with the monitoring system data.

The active power of the cluster and the photovoltaic power generated at the inverter output have been used to estimate the village´s consumption. As a result, a difference of 1.54% has been obtained. In Figure 11, the comparison for 4 September with a minimum variation of 0.7% is shown.

**Figure 11.** Comparison of load profiles according to the information provided by UTE meters (real) and by the power converters (estimated) for 4 September.

The consumption obtained from the data sent by UTE has been used as load input to HOMER Pro®. Additionally, the components used and their respective costs have been defined.

• Photovoltaic system.

Since PV production in excess is curtailed, a simulation with PVsyst® has been carried out to obtain photovoltaic production capacity without the influence of curtailment. For this purpose, the parameters of the PV generator generation indicated in the previous section have been adjusted.

In order to estimate the operation of the installation without curtailment distortions, the average performance ratio has been calculated for irradiation values lower than 800 W/m<sup>2</sup> and a module temperature between 22 and 28◦. As a result, a PR of 80.4% has been obtained. This value has been used as a reference to estimate different parameters in the PVsyst simulation.

The simulation results show an energy production at the inverter output of 84,912 kWh/year, while the real energy produced was 64,403 kWh/year.

To verify if the parameterization carried out in PVSYST® corresponds with the monitoring system data, a comparison has been made showing a good correlation for the times without regulation, as shown in Figure 12.

**Figure 12.** Comparison between the measured and simulated PV power output (points out of the linear correlation correspond to solar PV curtailment).

In order to compare the behavior of the rest of the components of the system, the generation corresponding to the real behavior, affected by the regulation, was kept as PV generation. However, in Section 3.3, corresponding to the optimization of the system, the production without curtailment has been analyzed in order to evaluate the possibilities for improvement.

The following comparisons are related to the period from October 2018 to December 2018.

• Converters.

As the Sunny Island 8.0H converter was not present in the HOMER Pro catalog, it was created. The average efficiencies for the inverter and rectifier were of 92.33% and 89.71%, respectively, based on the current behavior calculated from the data of the monitoring system.

• Batteries.

Even though the installation was defined with a depth of discharge of 70%, the value of 40% detected in the monitoring system for the validation period has been used. The battery efficiency has been considered 77.1% as calculated and the initial state of charge has been established at 97.87%.

When comparing the results of the simulation in HOMER Pro with the monitoring system data, only a difference of 1.96% in the charge (battery + rectifier) and 2.94% (battery + inverter) in the discharge has been obtained.

• Diesel Generators.

Regarding the operating mode, the "Cycle Charging" option has been selected where the generator works at full load to supply the village's consumption and, in case of electricity surpluses, the battery charge is supplied. According to measured data, the diesel generator is automatically forced to work from 19 to 22 h, independently of the state of charge of the battery to prevent the gense<sup>t</sup> to automatically start during the night.

During the months from October to December, the energy delivered by the gense<sup>t</sup> at the Cerros de Vera facility at the hours where data were available was 22,329 kWh, while the simulated power was 23,761 kWh, giving a difference of 6.41%.

A summary of the results expressed above can be seen in Table 3:


**Table 3.** Differences between the simulated and the measured results for the different components and for the validation period.

Taking into account that the functioning strategy of the system is sometimes altered, according to measured data, these values are considered to be accurate enough, as it has been justified in this chapter.

#### *3.3. Analysis of Future Alternatives: Wind Generation*

An increase in the village loads and fuel consumption has been detected, triggering the following case study objectives: The analysis of the actual electrification system and the inclusion of wind energy in it. In this stage, the aim was to generate different electrification configurations considering what was evaluated in the previous points. Based on the technical and economic characteristics of the different alternatives obtained, this allowed the selection the optimal configuration. HOMER Pro has also been used at this stage. The design and analysis of the inclusion of wind generation to the current system in "Cerros de Vera" are detailed below.
