In a Friday, Aug. 15, 2003 file photo, the Empire State Building towers over the skyline of a blackout-darkened New York City just before dawn. Power lines from Jersey City, N.J., are in foreground. Ten years after a blackout cascading from Ohio affected 50 million people, utilities and analysts say changes made in the aftermath make a similar outage unlikely today, though shifts in where and how power is generated raise new reliability concerns for the U.S.