# Potential of Photovoltaic Generation in the Putumayo Department of Colombia
## 4 Discussion  
Both at the beginning and at the end of the year, there are higher values of solar brightness, which decrease toward the middle of the year. The Amazon region has higher hbs values (Tres Esquinas station has the highest value with 123 hbs per month), while the Andean region has the lowest values (Michoacan station has the lowest value with 66 hbs per month). On the other hand, the radiation calculated from the Angstrom-Prescott method is higher at the end and beginning of the year and decreases toward the middle of the year (Leguizano and Tres Esquinas stations (in the Amazon region) with maximum values of 4.44 kWh/m\({}^{2}\)day and El Encano station (in the Andean region) with a minimum value of 2.33 kWh/m\({}^{2}\)day). This behavior is characteristic of Colombian regions. These results show that the solar brightness values directly affect the irradiance calculation values; however, the effects of altitude and latitude cannot be ruled out. To validate the calculated irradiance results with data from IDEAM meteorological stations, the NREL and NASA remote databases were evaluated. All irradiance data and results show the same monthly trend, with maximum values at the beginning and end of the year, and minimum values in the middle of the year. The NREL irradiance data, as well as the values calculated with the IDEAM data, show higher average irradiance in the Amazon region and lower in the Andean region. Although the data reported by NASA show a maximum average in the Andean region and a minimum in the Amazon region, these differences are possibly due to the difference in the resolution of the remote databases. The comparison statistics between irradiance values, taking as a reference the values calculated with IDEAM data, are acceptable (less than 10%) for both NREL and NASA in \begin{table}
\begin{tabular}{c c c c c c} \hline \hline \multicolumn{1}{c}{**Invoiced Value of Cost Per kWh Consumed (USD/kWh)**} & & & & \\ \hline
**Company** & **Municipality** & **2015** & **2016** & **2017** & **2018** \\ \hline  & Santiago & 0.13 & 0.15 & 0.16 & 0.17 \\ Empresa de energia del valle de Sibundoy EMEVASI S.A E.S.P & Colon & 0.13 & 0.15 & 0.16 & 0.17 \\  & Sibundoy & 0.13 & 0.15 & 0.16 & 0.17 \\  & San Francisco & 0.13 & 0.15 & 0.16 & 0.17 \\  & Mocoa & 0.12 & 0.15 & 0.15 & 0.17 \\ Empresa de energia del putumayo EEP S.A E.S.P & Villagarzon & 0.12 & 0.15 & 0.15 & 0.17 \\  & Puerto Guzman & 0.12 & 0.15 & 0.15 & 0.17 \\  & Orito & 0.12 & 0.15 & 0.15 & 0.17 \\  & Puerto Guzman & 0.13 & 0.15 & 0.15 & 0.17 \\  & Orito & 0.14 & 0.15 & 0.15 & 0.17 \\  & Puerto Asis & 0.14 & 0.15 & 0.15 & 0.17 \\  & Puerto Caicedo & 0.14 & 0.14 & 0.15 & 0.17 \\  & San Miguel & 0.14 & 0.14 & 0.15 & 0.17 \\  & Valle Del Guamuez & 0.14 & 0.14 & 0.15 & 0.17 \\  & Puerto Guzman (ZNI) & 0.35 & 0.35 & & \\ Empresa de servicios publicos domiciliaries de Puerto & Puerto Leguizano (ZNI) & 0.26 & 0.25 & 0.29 & \\  & Average cost in Putumayo & & 0.15 & 0.17 & 0.16 & 0.17 \\  & Average cost of the interconnected zones in Colombia & & 416.4 & 486.5 & 487.8 & 514.9 \\ \hline \hline \end{tabular}
\end{table} 
Table 11: Energy costs in Putumayo by company and municipality. the Amazon region, while the MPEs are higher than 10% in the other two regions: there is overestimation. The high errors of both remote bases in the Andean and Andean-Amazon regions are most likely due to their spatial resolution, since they cover areas of 4 km by 4 km for NREL and 55 km by 55 km for NASA, meaning that in these mountainous regions there is lack of precision covering small areas. Having on-site measurements, i.e., with meteorological stations, is advisable when performing radiation analysis for the installation of solar systems to avoid inaccuracies in data collection due to spatial resolution. To evaluate the effective potential of solar energy in Putumayo, an inclination angle of 10\({}^{\circ}\) was selected as the system would have losses of less than 1%. For maintenance reasons this angle is better than the smaller angles.