# Potential of Photovoltaic Generation in the Putumayo Department of Colombia
## 3 Results
### Calculation and Analysis of Solar Radiation Data for Different Regions and Stations  
Figure 4 presents the average sunshine for each month of the year considering the data series from the weather stations. Two important facts can be highlighted: first, there is more sunshine in the summer months and less in the winter months for the three geographical areas under study. Second, in all the stations of the same zone there is consistent data; for example, in the three stations located in the Andean zone, there are fewer hours of brightness than in other regions. Third, there is a higher value of brightness in the Amazon region, and this value of solar brightness decreases as we approach the Andean region. In Figure 4b we can see the results of the average monthly daily irradiation, which were obtained with Angstrom--Prescott method and the Gopinathan formulas explained in the methodology. It is evident that as a tendency of the solar brightness the behavior of solar irradiation is greater in summer and less in winter, and there is greater irradiation in the Amazonian zone and less in the Andean zone. In addition, in Figure 4b, it is observed that three groups of irradiation values are marked which correspond to the three regions of Putumayo. This behavior of the irradiation values is because the irradiation, besides depending on the solar brightness, depends on the zone's altitude and latitude, as observed in the Angstrom-Prescott equations and the equations proposed by [PERSON]. Taking the above irradiation values, the average daily irradiation of each weather station was calculated with a 95% confidence interval (CI) and is presented in Figure 5. As can be seen, the stations in the Amazon region have the highest irradiation values with an annual daily average of 4.35 kWh-day/m\({}^{2}\) while the Andean region has the lowest irradiation values with an annual daily average of 2.60 kWh-day/m\({}^{2}\). The Andean-Amazonian region, as a transition zone, has an annual average daily irradiation of 3.67 kWh-day/m\({}^{2}\). The large differences in solar irradiances depending on the site are given by the different geographical conditions of Colombia, as well as by the location of the stations. Some stations are in the valley and others in the mountains; however, both topologies can be in the same region. In addition, as the meteorological stations are scattered throughout the department, which presents these different topologies, solar irradiations will differ greatly from one site to another. \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline
**Region** & **Name of the Station** & **Latitude (°)** & **Longitude (°)** & **Altitude (m)** & **Years of the Series** & \begin{tabular}{c} **Average** \\ **Temperature (°C)** \\ \end{tabular} \\ \hline \multirow{3}{*}{Andean} & El Encano & 1.16 & \(-\)77.161 & 2830 & 1985–2017 & 11.67 \\  & Michoacán & 1.198 & \(-\)76.961 & 2100 & 1978–2017 & 15.73 \\  & Primavera & 1.168 & \(-\)76.933 & 2067 & 1984–2014 & 15.53 \\ \hline \multirow{3}{*}{\
\begin{tabular}{c} Andean- \\ amazon \\ \end{tabular} } & Mocoa & 1.157 & \(-\)76.652 & 650 & 1985–2017 & 23.01 \\  & Villagarón & 1.034 & \(-\)76.619 & 440 & 1969–2017 & 24.32 \\ \hline \multirow{3}{*}{
\begin{tabular}{c} Amazon \\ \end{tabular} } & Umbria & 0.839 & \(-\)76.570 & 362 & 1986–2012 & 24.96 \\  & Valparaiso & 1.195 & \(-\)75.704 & 270 & 1969–2017 & 25.88 \\ \cline{1-1}  & Tres Esquinas & 0.738 & \(-\)75.236 & 219 & 1977–2015 & 25.65 \\ \cline{1-1}  & Tagua & \(-\)0.06 & \(-\)74.665 & 153 & 1974–2017 & 25.76 \\ \cline{1-1}  & Leguizamo & \(-\)0.18 & \(-\)74.776 & 147 & 1978–2017 & 25.68 \\ \hline \hline \end{tabular}
\end{table} 
Table 1: IDEAM stations with solar brightness data in the department of Putumayo. Figure 3: Location of IDEAM’s weather stations with sunshine data in the department of Putumayo. Following the analysis of the databases with remote sensors, the NREL data series were taken.