Among renewable energy resources, photovoltaic solar energy is the most important resource. For photovoltaic installation system, capturing the maximum solar energy is a challenge, because many factors influence the energy production of the system. Among these factors, there are: technology choice which is generally expensive, orientation of the panel, ambient temperature and weather, geographical location of the solar irradiances and the tilt angle. To carry out a good project for sizing photovoltaic system, a technical-economic study must be carefully done. Located in the heart of the Sahel, Niger is one of the sunniest countries in the world with an average daily sunshine between 5 and 7 kW•h/m2/day. Despite this enormous solar potential, the country does not sufficiently exploit this resource due to the increase in the price of raw materials which has led to an increase in the cost of installing a photovoltaic system. The objective of this work is to present a technical and economic analysis of a grid connected photovoltaic system in with a capacity of 11 MW in Niger. To do this work, PVsystem software was used for economical and financial data generation using methods like Levelized cost of electricity. During this evaluation, assumptions were made: the location of installation is free, taxes and duties during the purchase and transport of the equipment will not be considered and considering the start year of the project began in 2024 and the project lifetime is 20 years, after simulation of the results obtained: Levelized Cost of Energy is 0.0138 EUR/KW•h; Net present Value is 26 430 389 EUR; Internal rate of return is 40.92 %; Payback period is 2.8 Years; Return on investment is 606.2 %.