The paper describes a photovoltaic solar generator to supply a dielectric barrier discharge ozone generator employed for water treatment. This paper reports trials of the equipment and modelling the solar power generation system’s efficiency. The design methodology was used to obtain the optimal set point for the orientation of the solar panel during the passage of clouds which causes the decrease of sunlight and thus reduced ozone production. In Algeria, autumn is characterized by the passage of clouds almost every day which negatively affects the performance of the solar panel. The objective of this paper is to identify the set point and to set the robustness of the process in cloudy weather, by determining the optimal values of the orientation angles (north-south and east-west), in order to maximize the power produced by the solar system. Three ‘centred face-composite’ designs were performed on a laboratory experimental set-up and an optimal point was determined.