## 3 Results
### Main Outcomes of the Top 20 Highly Cited Articles from Each Thematic Area
#### 3.2.7 Energy  
The majority of the top 20 highly cited articles in the energy thematic area focus on the spatial assessment of the energy potential and on the location selection for energy plants [150; 151; 152; 153; 154; 155; 156; 157; 158; 159; 160; 161; 162; 163; 164; 165; 166]. Thirteen of these studies focus on solar energy (photovoltaics, concentrating solar power), two studies focus on wind energy, and two studies focus on bioethanol/biogas. The three remaining studies focus on techno-economical assessment of energy resources [167; 168] and on the design optimization of off-grid hybrid renewable energy systems [169]. The geographical focus of the studies was on Iran (nine studies), Morocco (four studies), Egypt (two studies), Turkey (two studies), Algeria (one study), and Saudi Arabia (one study).  
In their study on the spatial assessment of solar energy potential at a global scale, [PERSON] et al. [157] analyzed the solar radiation distribution and intensity based on global horizontal irradiation (GHI) and direct normal irradiation (DNI) data. They found that most of the countries located in the EMMENA region (Saharan countries and countries located in the Arabian Peninsula) present superb (maximum) solar potential, thus there are opportunities for developing solar energy at a national or international (regional) level. However, there are additional factors that can affect solar power generation in this region, such as dust particles and dust storms, high air temperatures, insufficient financial resources, and political instability or war conflicts.  
Eleven studies in the spatial assessment of the energy potential and on the location selection for energy plants combined GIS and multi-criteria decision models (Table 5). The assessment of the energy potential and the location of energy plants includes a range of criteria such as climatic (e.g., solar radiation, sunshine, land surface temperature), morphological (e.g., slope and aspect), locational (e.g., distance from cities, roads, and electricity grid), land cover, and hydrological (e.g., distance from dams and groundwater) criteria [150; 151; 152; 153; 158; 159]. The criteria for the assessment of the offshore wind energy potential include, among others, wind characteristics, water depth, soil substrate, and distance from the shoreline, military areas, parks, submerged cables, shipping routes, and fishing areas [155; 156]. Finally, the criteria for bioethanol facility location selection include social (e.g., policies, work force, societal impact, quality of life), environmental (e.g., ecologically sensitive areas), and economic (e.g., investment, maintenance, and operation costs) criteria [154].  
\begin{table}
\begin{tabular}{c c c c c c c} \hline \hline \(\mathbf{N}\) & **Ref.** & **Energy Resource** & **Focus** &
\begin{tabular}{c} **Methods** \\ **Used** \\ \end{tabular} & **GIS** & **Satellite Data** & **Country** \\ \hline
1 & [166] & Solar/hydrogen & OL & HE & Yes & n/a & Iran \\
2 & [165] & Biogas & P & & Yes & n/a & Iran \\
3 & [164] & Solar & OL & BF & Yes & ASTER DEM & Iran \\
4 & [168] & Solar/hydrogen & TE & & Yes & CAMS-Rad & Morocco \\
5 & [167] & Solar/wind/hydrogen & TE & & Yes & n/a & Iran \\
6 & [169] & Diesel/solar/wind/battery OD & SO & Yes & n/a & Algeria \\
7 & [163] & Solar & OL & MCDM & Yes & SRTM & Morocco \\
8 & [162] & Solar & OL & MCDM, MC & Yes & n/a & Iran \\
9 & [161] & Solar & P & MCDM & Yes & n/a & Iran \\ \hline \hline \end{tabular}
\end{table}
Table 5: Energy resource and research focus (OL: Optimized Location/Site, P: Energy potential, TE: Techno-Economical, OD: Optimal Design) of the top 20 highly cited papers in the Energy thematic area (Ref.), the geographical focus (Country), the methods used (MCDM: Multi-Criteria Decision Model, BF: Boolean-Fuzzy Logic, SO: Swarm Optimization, HE: Heuristic, MC: Monte Carlo), and the satellite data used.