Siemens has developed a hybrid electric truck that draws power from overhead wires but without the need for rails embedded in the road. Power is transmitted directly from the overhead contact lines into the vehicle, enabling an optimal efficiency level of more than 80%. The trucks are also able to recover braking energy and feed it back into the grid. The 670 V DC power system requires DC/DC conversion for the energy transmission and recovery. The system reduces fossil fuel consumption and existing highways can be easily retrofitted. In this case, the German government spent €70 million ($77 million) to develop trucks that can use the system. Siemens has filed numerous patent applications around power conversion, although their filings have slowed dramatically since 2015.
