The use of renewable energy sources is a topical direction in the development of the energy industry in the modern world. However, when investing, choosing the optimal strategy is essential to keep costs down. The goal is to evaluate the efficiency of using solar panels parallel to the electric grid for the plateau municipality, the Republic of Cote d’Ivoire. The objectives of the study in this regard are to determine the strategy to the greatest extent, affecting the reduction of the investment cost when introducing a solar battery project, the calculation of economic indicators that allow us to assess the risks when making decisions to implement the investment. For the assessment, a technique is presented that differs from the existing complex taking into account specific indicators (average annual insolation, efficiency of solar panels, temperature coefficient, price of 1 M ^ 2 solar panels, transportation costs, cost of installation work, depreciation period, maintenance costs, property tax, the cost of training employees. The methodology includes the author’s recommendations, taking into account the specific features of determining the indicators of the annual economic effect, NPV. IRR, DPP for a solar battery project. A comparative analysis of an autonomous SES and operating in parallel with the electric grid. Conclusions: SES in parallel with a network of solar power plants. reduces the cost of the project investment, and also hinders the payback period of the project.