# GIS-Based Site Suitability Analysis for Solar Power Systems in Mongolia
## 3 Methods  
### Selection of Criteria and Data Collection  
Selecting the criteria for rating is an important step in any site suitability assessment process for PV systems. Table 2 shows the criteria considered in previous studies that analyzed site suitability for PV systems. Among them, this study considered seven criteria to analyze the PV site suitability of Mongolia, in consideration of the availability of data at the national scale: global horizontal irradiance (GHI), temperature, elevation, slope, aspect, distance from a main road, and distance from a major power line (Figure 2).  
Figure 1: Map of Mongolia.  
GHI is the total amount of microwave radiation received by a horizontal surface on the ground. This value is interesting for light electrical installations, and includes both direct normal radiation (DNI) and diffuse horizontal irradiance (DHI). Figure 3 shows the GHI for Mongolia, generated using data from the Global Solar Atlas [24].  
\begin{table}
\begin{tabular}{c c c c c c c c c c} \hline \hline
**Reference** & **C1** & **C2** & **C3** & **C4** & **C5** & **C6** & **C7** & **C8** & **C9** & **C10** \\ \hline [PERSON] [9] & & & X & & & X & X & X & X & \\ \hline [PERSON] and Hudson [11] & & & X & X & & X & & & X & \\ \hline [PERSON] et al. [12] & X & & & & & X & X & X & & X \\ \hline [PERSON] [5] & X & X & X & X & X & & X & & \\ \hline [PERSON] et al. [13] & X & & & & & X & X & X & \\ \hline [PERSON] et al. [2] & X & X & X & & & X & X & & X \\ \hline [PERSON] et al. [14] & X & & X & & & X & X & X & \\ \hline [PERSON] et al. [15] & & & X & X & X & & X & X & X \\ \hline [PERSON] et al. [16] & X & X & X & & X & X & X & X & X \\ \hline [PERSON] and [PERSON] [17] & X & X & X & & & X & X & X & X \\ \hline [PERSON] et al. [18] & X & X & X & & X & X & X & \\ \hline \hline \end{tabular}  
* C1: Global horizontal irradiance, C2: temperature, C3: slope, C4: aspect, C5: elevation, C6: distance from a residential area, C7: distance from a road, C8: distance from a power line, C9: land use, C10: waterbody.  
\end{table}
Table 2: Criteria considered in previous studies for analyzing photovoltaic (PV) site suitability.  
Figure 3: Global horizontal irradiance of Mongolia.  
Figure 2: Selection criteria used in PV site suitability analysis in Mongolia.  
The efficiency of a solar panel depends on its temperature, which in turn depends on both the ambient temperature and the intensity of the incoming solar radiation. Mongolia's annual climate cycle involves four seasons, which are characterized by high temperature fluctuations, low precipitation, and conspicuous latitudinal and latitudinal differences. The average temperature varies between \(-4\) and \(10\)\({}^{\circ}\)C across the four seasons (Kang and Kang, 2018), and annual average temperatures are illustrated in Figure 4.  
The highlands receive more solar radiation than the lowlands. The Mongolian Plateau is the second-largest plateau in central and east Asia (Kang and Kang, 2018), surrounded by the Gobi Desert to the south and the southeast, at an altitude of 523-4318 m above sea level--as shown in Figure 5, which displays a digital elevation model (DEM) of Mongolia, with a resolution of 30 m.  
The slope and aspect of a site are considered important parameters for site selection for PV systems, as they determine the amount of radiation received by the solar panels. Figures 6 and 7 illustrate Mongolian slope and aspect data, as generated from the DEM of Mongolia.  
Figure 4: Annual average temperatures in Mongolia.  
Figure 5: Elevation of Mongolia developed using a digital elevation model.  
Proximity to main roads and major power transmission lines affects the cost of infrastructure construction and the associated environmental damage [12; 27]. The major Mongolian main roads and power transmission lines are illustrated in Figures 8 and 9, respectively.  
Figure 8: Main roads in Mongolia.  
Figure 6: Slopes of Mongolia derived from a digital elevation model.  
Figure 7: Aspect data for Mongolia, derived from a digital elevation model.