Optimal Site Selection for Solar Photovoltaic Power Plants: A Case Study of the Nakhchivan Autonomous Republic, Azerbaijan

This study is concerned with optimally selecting sites for solar photovoltaic power plants, an important research objective because electrical energy generated by converting total solar irradiance on a horizontal surface of direct and diffuse components of photovoltaic (PV) cells of solar panels has a low power output; therefore, more efficient power generation can be achieved by identifying areas with a high power factor. Moreover, it is known that, due to the low efficiency of PV panels (14-18%) and the low intensity of total solar irradiance on a horizontal surface, achieving a certain satisfactory power level requires a large installation space. Additionally, due to the high cost of installing solar power plants, site selection must be based on a comprehensive systematic assessment of the region's geographic factors. The Nakhchivan Autonomous Republic was chosen for this case study because the irradiance level in the region is higher than in other regions of Azerbaijan (1220-1699 kW h/m(2)/year) and sunshine duration exceeds 2500 h per year. Since the installation of solar power plants in regions with high levels of total irradiance on a horizontal surface depends on technical, economic, and environmental criteria, descriptive criteria are used to determine optimal installation areas. Suitable installation sites for solar power plants are identified using an analytical hierarchy process (AHP) model based on multi-criteria decision making (MCDM) methods. The first phase of the study involves an analysis of seven site selection criteria: total solar irradiance on a horizontal surface; slope; land use; buffer distance between the areas with high annual solar power potential and residential areas; and proximity to substations, highways, and power lines. The second stage involves assessing the accessibility and suitability according to certain criteria using the Weighted Overlay tool in a Geographic Information System (GIS). This GIS tool was also used to determine the suitability level of the territories according to certain criteria. The conclusion reached as a result of the analysis is that 9.5% (510 km(2)) of the territory of the Nakhchivan Autonomous Republic is highly suitable, 12% (645 m(2)) has medium suitability, and 24% (1290 km(2)) corresponds to low suitability for the installation of solar power plants. The remaining 54.5% (2930 km(2)) of the region is unsuitable due to low irradiance levels; steep slopes; the presence of specially protected, residential, or agricultural areas; or poorly developed infrastructure. Optimal locations are found mainly the southern and eastern parts of the region.