Energy transition has shaped the latest European economic and environmental policies to decrease CO2 emissions and contain the effects of climate change: since most of the emissions come from the energy system, this is the main focus of the latest policies. The decarbonization of the system is projected to be obtained through the integration of new technologies to increase electricity and renewable fuels share in the total final consumption. To reach the goal, pathways are traced through scenarios written at a national or supranational level. These scenarios speculate over the energy demand, the diffusion of existing technologies, such as PV systems, wind turbines, heat pumps and electric vehicles and the evolution of new ones, such as storages and electrolyzers.