Energy saving in metro-transit systems: Impact of braking energy management

In the urban mobility of big cities and metropolitan areas, the metro-transit system plays a fundamental role and it is one of the most energy-impactive. Considering the actual general upward interest for energy saving and sustainability in city transport, with the consumptions increasing and the technological evolution, new studies and projects on metro-transit lines are in progress. The aim is achieving new design proposals -including new technologies and management techniques -based on high-quality simulation models and software for energy evaluations. In this framework a study on a line of the metro-transit system of Rome has been performed. The study tasks are to provide future upgrading actions for energy saving with a reduced economic impact thanks to the maximum exploitation of existing electric power systems. The analysis principally regards the assessment of the impact of the braking energy recovering on the energy consumption. Its results point out the necessity of a revaluation of the choices on the power system design for its management, also according to the actual storage technologies, confirmed by a wide literature overview.