The Southeastern Pennsylvania Transportation Authority (SEPTA), which runs the transit system in Philadelphia, is piloting a smart electrical grid technology that could cut its electricity bills by up to 40 percent and generate millions of dollars a year.
A massive battery installed at one of the authority’s substations will store electricity generated by the braking systems on trains (as the trains slow down the wheels drive generators). The battery will help trains accelerate, cutting power consumption, and will also provide extra power that can be sold back to the regional power grid. The pilot project, which involves one of 38 substations in the transit system, is expected to bring in $500,000 a year. This figure would multiply if the batteries are installed at other substations.
The project shows how cash-strapped public transit agencies that operate major subways and electric rail systems could find a new source of income by tapping into the smart grid. It also highlights one way that the smart grid could save energy, avoid blackouts, and incorporate more renewable power.
Several energy utilities are already experimenting with using large batteries to help smooth out fluctuations in electricity supply, keeping the grid operating at the correct frequency and preventing blackouts. In the new pilot project, this kind of battery technology will be paired with software from a Philadelphia-based smart grid company called Viridity Energy.
Read more here Technology Review: Subway Trains to Generate Power for the Grid.