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Different energy resources that have been used during human history were based on knowledge and ability of man to produce; control and transfer the energy involved. Accordingly, human ability in energy production from these different sources has played an essential role in each period of history in which one or more sources have been more essential. Nowadays, rapid development of the global economy and population increase are accelerating the consumption of fossil energy; therefore governments, and human society in a broader sense, are facing energy crisis issues all over the world. In addition to political and economical issues, since fossil fuels are known as the most severe cause of the environmental pollution and ecological imbalance, they are increasingly becoming undesirable resources. These are considered as essential constraints to social and economic development and even a serious threat to human society and national security of countries. As a result, application of new energy sources is becoming a global hot issue (Honglian & Ding, 2011).
Although fossil energy resources are playing a vital role in current civil and industry issues, economic analysis shows that continuous rise in their prices are inevitable in the first decades after the end of 2010, especially for oil (Azad & Panahandeh, 2000). Among all replacements for fossil energy resources, solar energy, as the oldest and the biggest energy source of the plant, has been one of the most important choices since early 1970 (Azad & Panahandeh, 2000). Unlike some non-fossil energy resources such as nuclear power, devices and technologies for power production from solar energy source are reliable and available all around the world (Hayashi et al., 2000; Nakamura, Sakurai, Suzuki, Hayashi, Enoeda, & Tobita, 2006; Yamanishi et al., 2008; Song, Huang, & Ni, 2010). Therefore, the general popularity of these technologies depends mainly on the economic feasibility and the proper sizing of the components in order to avoid outages and ensure quality and continuity of supply.
Photovoltaic (PV) technology has become one of several promising alternatives for energy technology (Winter, Sizman, & Vant-hull, 1989; Markvart, 1994; Sukamongkol, Chungpaibulpatana, & Ongsakul, 2002; Rajapakse, & Chungpaibulpatana, 1994). This endless source of energy, unlike fossil or nuclear resources which are associated with environmental risk and are not trustable in long term, is absolutely clean and free from any pollution. In a large area of our planet, the average density of solar radiation which reaches the earth is more than 2000 KWh/m2. In these cases, the use of solar energy is not only necessary but inevitable. The geographical extent and circumstances, social context, frequency and extent of villages, often as a point in mountain and plain zones are located and also lack of advanced technology and independent production and distribution of today’s conventional methods of energy and many other scientific and technical reasons should be taken into account to come to a conclusion whether solar energy can be a reliable and sustainable resource of energy for a country or not (Azad & Panahandeh, 2000).