On a November day in 2007, Con Edison severed the last wire from the only remaining power plant Thomas Edison had established in New York City. Edison built the city's electrical framework based on a low-voltage direct current that could barely make it across the street, but many of the city's old buildings had remained wired for it. The shuttering of the old power plant at 10 East 40th Street meant the utility had finally finished converting the city to alternating current. It was, reported the New York Times, "a final, vestigial triumph by Nikola Tesla and George Westinghouse."

Then again, maybe not. For even as the city threw over Edison's current, its energy planners have begun installing microturbines in office towers, fueling them with digester gas and recycling waste heat to warm the city's buildings -- in other words, steadily returning to the inventor's distribution model, the one that required a power plant every mile or so. Had we followed that model all along, we might not now be wrangling with an invisible legacy of heat-trapping pollution.

Edison wasn't right about everything. He spent decades battling Tesla's technology, to no great purpose -- these days, even the hamsters generate an alternating current. But the debate over local versus long-distance power may have finally tilted in his favor.