## 4 Urban Population and Urban PV Generation vs. Energy Sustainability
### Photovoltaic Generation in Cities and ETI 2017
The results of the variation in the concentration of electricity generation divide the countries into two groups: A first group of countries that increases the diversity of their electricity generation and a second group of countries that concentrate it. Countries that diversify their electricity generation (green columns with negative results in Figure 11): A total of 87 countries that, on average, vary the concentration of electricity generation by \(-42.44\%\). This means that the initial concentration value of electricity generation decreases due to the increase in PV generation. Within these countries are the 25 countries with the best energy sustainability in the ETI ranking, and with a variation in the concentration of electricity generation (\(-42.49\%\)) above the total average. On the contrary, the last segment of the ranking is made up of only seven countries and with the lowest value in the variation of the concentration of electricity generation (\(-32.7\%\)). Countries which reduce the diversity of their electricity generation (green columns with positive results in Figure 11): This group is made up of 38 countries that on average focus their electricity generation on one single source by \(97.57\%\). This group is comprised of countries in the last segment of the ranking. The diversity of its generation is concentrated in generation from renewable resources, mostly from hydroelectric energy. Although in terms of the energy security ranking, this low level of diversity leads to a lower position in the ETI, the concentration of generation from renewable resources would lead to a reduction in the emissions of GHG and; therefore, a higher position in the environmental sustainability ranking. \begin{table}
\begin{tabular}{l c c c c c c} \hline \hline  & & \multicolumn{6}{c}{**ETI Ranking Segments**} \\ \cline{2-7}  & **Total** & **1** & **2** & **3** & **4** & **5** \\ \hline Number of countries analyzed & 125 & 25 & 25 & 25 & 25 & 25 \\ \hline Average concentration (reduced diversity) of & 66.41 & 44.92 & 65.40 & 71.76 & 76.76 & 73.20 \\ \hline After the urban PV generation (0–100) & 55.16 & 28.23 & 44.98 & 55.53 & 61.37 & 85.71 \\ \hline Average variation & \(-15.94\) & \(-42.49\) & \(-32.33\) & \(-20.91\) & \(-14.29\) & 30.32 \\ \hline Number of countries that have diversity & 87 & 25 & 21 & 18 & 16 & 7 \\ electricity generation & & & & & & \\ \hline Average variation of concentration (reduced & \(-42.44\) & \(-42.49\) & \(-43.30\) & \(-45.08\) & \(-42.51\) & \(-32.70\) \\ \hline Number of countries that concentrate electricity generation & 38 & 0 & 4 & 7 & 9 & 18 \\ \hline Average variation of concentration (reduced & \(44.73\) & \(0.00\) & 25.25 & 41.25 & 35.90 & 54.83 \\ \hline Average variation of the consumption of fossil & \(-56.31\) & \(-30.93\) & \(-50.24\) & \(-51.08\) & \(-57.88\) & \(-91.41\) \\ \hline Average variation in CO\({}_{2}\) emission [\%] & \(-64.00\) & \(-40.72\) & \(-59.62\) & \(-61.09\) & \(-65.29\) & \(-93.29\) \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Average results of the effect of the diversification of the electric generation with urban PV generation in the ETI 2017 countries.