Energy efficiency in railways: Energy storage and electric generation in diesel electric locomotives

Diesel-electric traction is a well known and established technology for railways operators, but this alternative has a considerable uncerainty for the future because electric traction has a considerable superiority. Besides, diesel-electric engines waste energy when resistivebraking is used. This non-regenerative braking decreases the overall efficiency by 10–20%. With these premises it is important to develop new strategies to increase the energy efficiency of diesel-electric haulag.. To reach a better efficiency, a locomotive with energy storage (battery, super-capacitors) is theoretically proposed. Besides, the possibility of using a lower thermal engine (from other diesel locomotives out of use) with energy storage devices is considered too. This solution reduces diesel consumption and CO2 emissions while being economically viable. It supposes an efficient energy management because the diesel-electric locomotive could acts as a dispersed mobile generation (DMG) unit when working under electric overhead lines, and it can be used as a distributed resource for this specific electric power system.