With the ongoing decarbonization of energy systems, the share of renewable energy sources (RES) is rapidly increasing, posing significant challenges for Transmission Power Systems to be operated while maintaining their adequacy and security. This thesis analyzes the main impacts and challenges posed by the new RES plants and the concrete solutions currently implemented by the Italian Transmission System Operator (TSO). The aim of this study is to analyze how the Italian transmission grid will evolve in the medium term due to the increasing penetration of renewable energy. Simulations are performed using the calculation software WinCreso, where newly authorized renewable energy plants scheduled to be operational by 2025 were modeled.