Subways and the Smart Grid

As promised yesterday, Microkhan’s gonna continue with its week-long series of “extras” taken from the cutting-room floor of my Wired smart-grid essay. Today’s treat? How subways can become part of distributed-generation networks, along with rooftop solar panels and backyard wind turbines.

Beginning in the early 1970s, the Metropolitan Transit Authority began experimenting with flywheels that can capture the energy produced by subway braking. (About 60 percent of the heat in the subway tunnels st