Solar energy is an important source of renewable, sustainable, and accessible kind of energy in the world. Halting environmental degradation, this kind of energy is what can reduce the damaging consequences of fossil fuels. Iran or other counties located in the arid area can use this type of energy.
In fact, the geographical position of Iran in word's dry belt makes this country a proper land for constructing facilities of using solar energy. One of the most usual facilities, which use solar energy are photovoltaic power plants. Photovoltaic power plants need special situations to get the best efficiency. First of all, they need the highest portion of sunny days in a year. Moreover, to reduce the cost of construction, they must be built near the roads and power transmission lines. To find the places which include the best conditions, GIS is a useful system. GIS is able to prepare maps of the desired conditions and then combine them using various approaches to find the best locations. Many researches have already been done around the world for site selection of photovoltaic power plants. There are some researches in Iran, as well. However, the criteria used in these researches seems not to be comprehensive enough for such a sensitive site selection. Thus, this research aims to take as much as possible criteria for site selection of photovoltaic power plants into account.
The goal of this research is to find the potential area for constructing photovoltaic power plants in Iran. This purpose contains four main sections such as assessing effective factors on the operation of photovoltaic power plants, preparing factor maps (criteria maps) in GIS environment regarding the spatial nature of the effective factors, the maps conversion into fuzzy form and proper combination, and finally, classification of result into four levels.
Using fuzzy logic helps us to consider unavoidable uncertainty that exists in spatial data. In this study, the prepared factor maps are first converted into a fuzzy form using fuzzy membership functions. Then, using fuzzy overlay, the maps are combined. To set the most strict situation, among the fuzzy logical operators, fuzzy AND was selected. Thus, we will be sure that the final selected sites will have the best possible conditions.
The results indicate that six provinces, including Kerman, South Khorasan, Fars, Yazd, Hormozgan, and Sistan-o-Baluchestan, achieved the highest score for constructing photovoltaic power plants in Iran. Overlay, more than 557000 square kilometers of Iran have a high potential for gaining solar energy. The results also show that north and north-west of Iran in compare to the other areas, achieve less suitability for constructing photovoltaic power plants. The most important criterion that causes these situations is the portions of sunny days. While in the north side of Iran, as well as the mountainous areas such as Zagros Mountains, the precipitation is higher than the other regions, the number of sunny days in a year is less. This study detects the proper sites in a general form. The scale of the study covers the whole country. Thus, most fine-scale studies must be performed on the selected regions to find the best specific sites.