## 4 Discussion  
Algeria is one of the most suitable countries for the cheap production of electricity from solar energy sources, especially from solar thermal concentration technology. Despite the great virtues of solar energy, the development of technologies that allow its use has been gradually slowed down by its disadvantages, including its high investment costs and the impossibility of generating energy at times when there is no solar radiation or it is intermittent due to the passage of clouds. This study researches the influence of solar normal irradiation on solar power plants and its efficiency. It simulates the electricity production, capacity factors, and surface area required for solar field versus solar multiples considering the effect of \(TES\) at different capacities. The study focuses on optimization of CSP heliostat field configuration. Prediction of the field area and solar multiple can directly increase the efficiency of the solar power plant and power production rate. Also, the accumulation of energy through molten salt systems is an adequate solution to promote the use of solar energy. According to study of the German Aerospace Centre (DLR), Algeria has with 1,787,000 km\({}^{2}\) of Sahara desert, the largest long-term land potential for concentrating solar thermal power plants. The insolation time over the quasi-totality of the national territory exceeds 2000 h annually, and may  
Figure 9: (**a**) Concentrated Solar Power (CSP) heliostats field configuration of Béchar region. (**b**) CSP heliostats field configuration of El Oued region. (**c**) CSP heliostats field configuration of Djelfa region. reach 3900 h (High Plains and Sahara) [35]. The daily obtained energy on a horizontal surface of 1 m\({}^{2}\) is of 5 kWh over the major part of the national territory, or about 1700 kWh/m\({}^{2}\) per year for the north and 2263 kWh/m\({}^{2}\) per year for the south of the country [36]. The solar thermal power plant is one of the promising renewable energy options to substitute the increasing demand of conventional energy [37]. The design of the solar towers allows the collector to reach a higher temperature than the cylindrical-parabolic ones. This higher temperature allows for more efficient conversion to electricity, as well as cheaper storage of thermal energy for later use. The position of heating head is an important factor for power collection. If the sunlight can be concentrated to completely cover the heating head with small heat loss, it can obtain the maximum temperature of the heating head of the Stirling engine. Therefore, the temperature of heating head can be higher than 1000 \({}^{\circ}\)C on a sunny day [38]. The choice of the solar field is a difficult exercise, for example, a choice of solar multiples between 1.4 and 1.6 is suitable for high-optical performance with a lower surface of the field, and the starting arrangement must be very close to the optimum configuration, based on the experience obtained from the plants already in operation [39]. The thermal energy storage capacity is insufficient for the whole night, it covers between two and four hours hence the obligation to use an auxiliary energy source. The starting layout must be very close to the optimum configuration (length of the tower, surface of the mirrors, dimension of the receiver), it is important therefore looking to design a cheaper and better performing heliostat concentrator. In terms of direct solar irradiance, a measure of the gross energy received per unit area, Algeria is one of the most suitable countries for the cheap production of electricity from solar sources, especially from solar thermal concentration technology [40]. On the other hand, a reduction of taxes decreases leveled cost of electricity generated by CSP solar technologies [41].