Anyone who has stood next to a train pulling into a station can attest to the immense power it produces as it rattles along the rails. Scientists at Stony Brook University recently won a national award their mechanical motion rectifier (MMR)-based Railroad Energy Harvester – an invention that harvests electricity from the vibrations produced by railroad trains. The invention has the potential to save millions in railroad energy costs while reducing carbon emissions.
The U.S. has the longest network of railroad tracks in the world – it spans 140,700 miles in total. Many of these railways lie in remote areas where it is at times difficult to supply power to signal lights, cross gates, and railroad switches. The MMR-based Railroad Energy Harvester could capture the irregular oscillatory vibrations of railroad tracks and turn them into normal unidirectional motion, which can be harvested as electricity. The process is similar to the way in which an electric voltage rectifier converts AC current into DC. The invention could save the railroad industry a potential $10 million in trackside power costs in the state of New York alone while cutting CO2 emissions by 3,000 tons per year.
Stony Brook University team leader Lei Zuo says: “Our invention, the ‘Mechanical Motion Rectifier (MMR) based Railroad Energy Harvester,’ can harness 200 watts of electric energy from train-induced track deflections to power the track-side electrical devices. By using two one-way clutches, the innovative mechanical motion rectifier converts the irregular up-and-down vibration motion into unidirectional rotation of the generator, thus breaking the fundamental challenge of vibration energy harvesting and offering significant advantages of high-efficiency and high reliability.” The new technique can directly generate high-quality DC current using and electric generator rotating in one direction at a steady speed. “Such a design not only avoids the challenges of friction and impact induced by oscillation motion, but also enables us to make full use of the pulse-like features of track vibration to harvest more energy.” he added.
The team’s work won them a national award from the Energy Harvesting and Storage USA 2012 conference held earlier this month. The technology has been licensed to Electric Truck, LLC/Harvest NRG, Inc. and has garnered support from U.S. Department of Transportation’s University Transportation Research Center (UTRC-II), New York State Energy Research and Development Authority (NYSERDA), and SUNY Research Foundation.