The sizing is a very important step in the design of PV systems. It makes it possible to determine the size of the various components of the system. The installation of these systems offers more security to the environment and is an alternative to the disadvantages associated with the use of conventional energy sources. However, the high investment cost of these systems, and their limited technical performance, due to the environmental constraints, prompted researchers to deepen their research by making more accurate the optimization of the most expensive components, such as the storage device and the PV field. Several sizing and optimization methods have been used in the literature for the design of PV systems. The methods such as analytical, intuitive, numerical are used to obtain the optimum size of system components. A new analytical model has been developed by [
1] to determine the sizing optimum of a stand-alone PV system. Formulas have been used for calculating the capacity (Ca) of the photovoltaic field and the capacity (Cb) of the storage battery. The main drawback of the analytical method is the complexity of derivation of the equations, but it is simple and precise[
2].
With traditional optimization methods, it is not easy to find all the optimal solutions and are often constrained by the unavailability of meteorological data. However, to achieve better system sizing at minimum cost, several optimization techniques have been used but the most popular models have been revised in [
3], such as graphical construction model, probabilistic model, iterative optimization techniques, artificial intelligence techniques. However, artificial intelligence techniques offer an alternative for the sizing of photovoltaic systems in many areas that lack complete data and have been presented in [
4]. There are artificial neural networks (ANN), fuzzy logic (FL), genetic algorithm (GA) and hybrid systems.These methods each have their own characteristics but Genetic Algorithms are very effective for finding the global minimum, very suitable for optimization problems and overcome the unavailability of meteorological data [
5]. The performance of standalone photovoltaic systems has been analyzed by several authors through the sizing and optimization of the size of these systems. For example, Dhaker Abdes et al.[
6] study the total life cycle cost, embodied energy, loss of power probability for the optimal design of hybrid power systems. The proposed analysis uses a multi objective to minimize the total life cycle cost, stored energy and loss of system power probability. A multi-objective optimization based on genetic Algorithm has been used by [
7] for the minimization of the total cost of electricity (TLCC) and the Loss of Power Supply Probability (LPSP) of the load, simultaneously. In another work, a procedure has been developed by M Zagrouba et al. [
8], which identifies the parameters of solar cells and modules using genetic algorithms. The analysis shows that it is possible to perform a numerical technique based on genetic algorithms to identify the electrical parameters of photovoltaic solar modules and cells in order to find the maximum power point. Similarly, the work of Ami Sadio et al [
9] analyzes the performance of PV systems through a comparative study based on the method of genetic algorithms for the optimal sizing of an autonomous photovoltaic system in the Ngoundiane site. To minimize the cost while covering the load demand with a specified value for the loss of load probability a sizing optimization of a hybrid system using genetic Algorithm has been applied in[
10]. Effective analysis has been used to find the optimal PV/battery combination that satisfies load demand at minimal cost. Hence, D H Muhsen et al.[
11], developed a multi-objective optimization algorithm to optimize the size of a photovoltaic pumping system (PVPS) based on two technical (reliability) and economic (cost) objective functions. Genetic algorithms are also used by Muhammad Shahzad Javed et al.[
12], in their technical-economic evaluation study of a stand-alone hybrid solar-wind-battery system. In the literature, the use of genetic algorithms offers great performance in the studies carried out. In addition, the previous study of certain authors is based on simple sizing methods or on software like HOMER to solve their problems[
12]. Among these methods, we can note the intuitive method or the use of evolutionary algorithms. The objective of the optimization problem in this study is to simultaneously minimize the cost and the energy deficit of the system. The optimization must make it possible to achieve the best possible compromise between these two criteria. The resolution of this type of problem involving two objectives with the same weight, leads to the research for several solutions called Pareto solutions and not single optimal solution.
Thus, in this study an optimization algorithm to solve a multi-objective problem is be developed. The two objective functions used, are the total life cycle cost (TLCC) and the loss of system power probability (LPSP). The mathematical expressions of these functions are expressed according to the photovoltaic and storage capacities, which represent the decision variables. The objective is to find the optimal configurations of photovoltaic and storage capacities corresponding to satisfactory reliability and minimum cost. In the following, Matlab software will be used to run the optimization problem. Thus, the two objective functions is transformed into mathematical functions, dependent on two variables. All the constraints are be expressed as a function of these two variables. After, the terminals the limit of the "objective" functions and the properties of the genetic algorithm is defined. Finally, the obtained results is presented and commented.