Integration of Renewable Energies for Trolleybus and Mini-Bus Lines in Coimbra

Trolleybuses and electric mini-buses in the Portuguese city of Coimbra are one of the main forms of daily transportation of its many citizens. As part of CIVITAS MODERN European Project — MObility, Development and Energy use ReductioN, one of its main objectives for Coimbra is the integration of clean production electricity system owned by the City Council, able to supply the energy to the trolleybus traction lines, plus electric energy to charge the batteries of the electric mini-buses fleet. This electric fleet is undergoing a significant expansion in the near future. A study was carried out in order to evaluate the potential of renewable energy production to supply the electric fleet public transportation in Coimbra, reducing the necessity of fossil fuels and associated emissions, therefore improving the air quality. The electricity source will be a low head hydro potential, using an already existing dam-bridge, where a group of turbine-generators units can be placed, with modest operation costs and reduced civil works with small environmental impact. The optimization of the renewable energy generation is also assessed as a function of the load profiles.