Having a battery could someday be compared to having gold mine. Take Southeastern Pennsylvania Transportation Authority, for example. They’ going to use a huge battery and charge it from the subway’s braking trains. The energy recovered thus will either be sold back to the grid or reused for acceleration.
Viridity Energy, a smart-grid company, is behind the project, having received $900,000 from the Pennsylvania Energy Development Authority for the pilot program costing $1.5 million.
One of the “hottest” lines in Philadelphia, Market-Frankford,will benefit the system, for the moment. 1.5 MW of energy will be recovered in much the same fashion that hybrid/electric cars and locomotives recover their braking force – by reversing the motors to work as generators.
Joseph M. Casey, general manager of the transportation authority, says the system will provide measurable gains in energy efficiency and voltage stability in a critical mass transit corridor. Audrey Zibelman, president and CEO of Viridity Energy, says the goal is to improve the transit agency’s operational efficiency, reduce its carbon output and cut its costs.
A $500,000 saving in energy costs is estimated after the system will go online in the spring of 2011. Plans of further expanding it already exist, but their accomplishment only depends on the results of the pilot project. Anyway, theory says that if the regenerative braking system would be applied at all of the 33 substations, a cut of 40 percent would be possible.
Another possibility is that the stations could recharge their batteries during nighttime, when rates are low, and use (or resell) the energy during daytime. If smart-grid companies will prosper and their services will be available to anyone, I guess any honest citizen could earn a living by having a larger battery at home…