This article aims to study different configurations of renewable energy sources in order to propose viable power plants, with maximum power production that compensating for the country's energy deficit. To do this, first, after determining the appropriate software for our study, isolated systems are studied and compared with each other. Hybrid systems are then analyzed and compared with each other. Finally, a comparison between optimal hybrid and isolated systems is made. The simulation is performed with Lomé’s site characteristics, located in the south of Togo. This simulation result of isolated and hybrid configurations using HOMER software, reinforced by a feasibility study of optimal systems using RETScreen Expert software, make it possible to conclude that the PV-biodiesel hybrid power plant is the best alternative energy production on this site. This power plant of 32 MW photovoltaic panel field coupled with a 30 MW biodiesel generator, can supply an electricity demand of 408 MWh per day (17MW) with a peak of 48 MW. The cost per KWh of electricity generated by this hybrid power plant is 0.185$.It also comes out that, this systemis viable due to its internal rate of profitability(18.3%)higher than the discount rate (8%), the net present value is positive, and is strongly involved in the reduction of greenhouse gases.