In order to make up its energy deficit and reduce its energy imports from neighbouring countries, Benin is opting for the construction of photovoltaic solar micro-power plants in the sunniest regions and to consider injecting it into the existing electricity grid if this locally produced energy is not entirely consumed. With this in mind, a decentralised electricity production project has been initiated. In particular, the project, which is the subject of this presentation, aims to simulate and analyse the impacts of injecting 25 MW of photovoltaic energy production into the existing national electricity grid of the Société Béninoise d'Energie Electrique (SBEE). For this purpose, the dimensioning of the 25MW power plant has been carried out and injected at a specific point of the 20kVA line of the existing electricity network in the NEPLAN software environment, while respecting the requirements for injecting photovoltaic energy into an existing electricity network. Only extreme operating configurations have been studied: the synchronous hollow and synchronous point configuration. Simulation results showed overloads on certain transformer stations in the network, which indicates that adjustments must be made before the actual injection of the electricity produced. Besides, the power grid did not experience any disturbance in the voltage plan and power flows. Finally, the simulations carried out led to the conclusion that the integration of solar PV plants will make it possible to limit the import of energy from Ghana and Nigeria.