Braking Trains to Generate Electricity for Philadelphia
Philadelphia to Capture Kinetic Energy generated by Braking Trains and return to electric grid
The Southeastern Pennsylvania Transportation Authority (SEPTA), in conjunction with Viridity Energy, is planning to test a system that will capture the kinetic energy generated by braking trains and use it to power other trains, or to sell back into Philadelphia's electric grid. The new project will be piloted in the city this spring.
The proposed mechanism is very similar to the regenerative braking already found in many electric vehicles, but on a much larger scale. Although some of the kinetic energy from braking trains is already captured by the third rail, more than half of it is lost as heat. This new system will use a large battery, capable of holding a megawatt of power, to capture and store that lost energy until it can be used or sold back into the electric grid.
SEPTA is planning to pilot the system on its busy Market-Frankfurt line. Energy created from this test will save SEPTA an estimated $500,000 on electricity per year, as it can use the kinetic energy captured from the braking trains to power its other electric needs. SEPTA can sell the energy back into the city's electric grid or it can choose to store that energy to sell it into the electric grid at night, when it costs more. If the new kinetic energy system is installed throughout the entire railway, it could save SEPTA up to 40% of its total electricity costs.