# Potential of Photovoltaic Generation in the Putumayo Department of Colombia
## 3 Results
### Calculation and Analysis of Solar Radiation Data for Different Regions and Stations
Therefore, between one geographic point and another close to it in this zone, which contain the Umbria and Valparaiso stations, are different climatic conditions. The MPEs exceed 10%, i.e., comparisons between the two databases are not acceptable. For the other three stations, the MPEs are less than 10%, i.e., the data are comparable, although the t-statistic is high. The errors obtained between NASA and NREL were up to 22%, which can be explained by the different scale resolutions between both databases, and by the different topographic conditions in the Putumayo department. A possible way to resolve these discrepancies may be to identify the variations in geographic relief, before using the NASA data. An average or interpolation calculation could then be performed between areas with different heights above sea level. However, if the study area is very heterogeneous, it would be best to use data from weather stations or NREL. After statistical comparisons were made between the irradiation results from the NREL and NASA remote sensor databases, these irradiation results were compared with those from the IDEAM weather stations. The average radiation values and statistics for each station are presented in Tables 3 and 4. In Table 3, it is observed that according to the comparison statistics between IDEAM and NREL, the NREL irradiation values are overestimated for all zones. In addition, for the Andean region, MPEs are not acceptable as they are above 10%. This behavior can be explained by taking into account that the Andean region has a particular topography that, as mentioned above, generates diverse microclimates even in areas close to each other, so on-site radiation measurements are required. The best adjustments and the least error between IDEAM and NREL occur in the Amazon region's stations. This may be because this zone has more homogeneous climatic conditions that do not vary abruptly as in the Andean zone. Table 4 shows the comparison between the IDEAM and NASA data sets. It is evident that all the irradiation data from the Andean and Amazonian-Andean region are overestimated, and according to the MPE, not acceptable as they have an error greater than 10%. However, the Amazon region has a lower error with a better adjustment. In general, it can be observed that for the Amazon region the results of NREL and NASA compared to IDEAM have better fit and less error. This is because the region is characterized by similar geographical and climatic conditions as a plain with a tropical climate in all its extension. \begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline \multirow{2}{*}{**Region**} & \multirow{2}{*}{**Station Area**} & **IDEAM \(G_{da}\)(0)** & **NREL \(G_{da}\)(0)** & **MBE** & \multirow{2}{*}{**MPE \%**} & **RMSE \(\mathbf{\mathbf{\mathbf{\mathbf{\mathbf{\mathbf{\mathbf{\mathbf{\mathbf{ \mathbf{\mathbf{\mathbf{\mathbf{\mathbf{\mathbf{\mathbf{\mathbf{ \mathbf{    }}}}}}}}}}}}}}\) \\  & & **(kWh/m\({}^{2}\)day)** & **(kWh/m\({}^{2}\)day)** & **(kWh/m\({}^{2}\)day)** & **(kWh/m\({}^{2}\)day)** & **(kWh/m\({}^{2}\)day)** \\ \hline \multirow{4}{*}{Amazon} & Leguizamo & 4.44 & 4.75 & 0.31 & \(-\)7.28 & 0.33 & 9.40 \\  & Tagua & 4.34 & 4.84 & 0.50 & \(-\)12.09 & 0.53 & 9.33 \\ \cline{1-1}  & Tres-Esquina & 4.44 & 4.73 & 0.29 & \(-\)6.80 & 0.31 & 9.75 \\ \cline{1-1}  & Valparaiso & 4.41 & 4.85 & 0.44 & \(-\)10.18 & 0.45 & 14.92 \\ \cline{1-1}  & Umbria & 4.13 & 4.52 & 0.39 & \(-\)9.71 & 0.41 & 10.10 \\ \hline \multirow{2}{*}{\
\begin{tabular}{c} Andean- \\ Amazon \\ \end{tabular} } & Villagarzón & 3.64 & 4.21 & 0.57 & \(-\)16.18 & 0.58 & 14.40 \\ \cline{1-1}  & Mocoa & 3.71 & 4.08 & 0.37 & \(-\)10.17 & 0.39 & 10.43 \\ \hline \multirow{2}{*}{
\begin{tabular}{c} Andean \\ El encano \\ \end{tabular} } & Primavera & 2.71 & 4.02 & 1.31 & \(-\)49.95 & 1.32 & 22.50 \\ \cline{1-1}  & Michoacán & 2.48 & 3.66 & 1.18 & \(-\)50.79 & 1.21 & 14.80 \\ \cline{1-1}  & El encano & 2.33 & 4.24 & 1.91 & \(-\)85.76 & 1.93 & 20.82 \\ \hline \hline \end{tabular}
\end{table}