Commuter trains run by SEPTA, the Southeastern Pennsylvania Transportation Authority, are becoming “virtual power generators” thanks to new technology that captures the energy from braking and feeds it back to the grid. CleanTechnica first reported on the regenerative braking system when it was in development a couple of years ago and we’re happy to pass along news that the system has hit an important milestone on the path to completion.
Trains that capture kinetic energy
Regenerative braking systems are ideal for just about any kind of mechanism that involves frequent braking. That includes elevators, school buses, trucks, shipping cranes and yes, commuter trains. SEPTA partnered with the company Viridity Energy to develop a system that not only captures the kinetic energy from braking, but also stores it for later use.
The pilot program for the new system is situated on Philadelphia’s heavily used Market-Frankford line, and with the help of a large-scale lithium-ion battery from the company Saft it is now capturing and storing energy.
Another company, transit energy specialist Envitech Energy, is on board to provide power conversion, control and integration. When fully operational, the new system will enable SEPTA to sell energy to the grid, just like any other power generator.
A regional transmission organization, PJM, has dibs on the electricity, which enables it to add another element of alternative energy to its portfolio while providing SEPTA with the kind of revenue stream that other commuter rail systems can only dream about.
Sustainable energy in a built environment
The new system is another great example of the potential for alternative energy to piggyback on environments that are already developed for other purposes, rather than impinging on virgin lands. Rooftop solar panels and building-integrated solar technologies are of course two other obvious examples.
New developments in piezoelectric technology (the same trick behind that push-button starter on your barbecue grill) may some day make it possible to harvest energy from any surface under stress, such as floors and even highways.
Along similar lines, the U.S. EPA is aggressively promoting the use of brownfields and other abandoned industrial sites for wind and solar power installations, the Department of Agriculture is looking into the potential for growing biofuel crops on the grounds of airports, wastewater treatment plants are emerging as multi-purpose alternative energy generators and sports venues from baseball to football, hockey and even NASCAR are getting into the act.
And when those possibilities are exhausted, there’s always you: wearable solar gear and human-powered kinetic energy are just around the corner.
Follow Tina Casey on Twitter: @TinaMCasey.
Tina Casey specializes in military and corporate sustainability, advanced technology, emerging materials, biofuels, and water and wastewater issues. Tina’s articles are reposted frequently on Reuters, Scientific American, and many other sites. You can also follow her on Twitter @TinaMCasey and Google+.