On Aug. 14, 2003, the lights went out across a large swath of North America. A power company in Ohio was slack in tree trimming, and a local transmission line problem cascaded into a 61,800-megawatt blackout, leaving 50 million people in the dark in eight states and parts of Canada. In some areas, it took four days to restore power, which, according to some estimates, cost the American economy between $4 billion and $10 billion.

The blackout highlighted the vulnerability of the electric grid to massive failures and to potential attacks by terrorists, giving new impetus to calls for more regulatory standards and enforcement in the utilities industry. On Aug. 8, President George W. Bush signed the Energy Policy Act of 2005, which helped change the way the utility industry is regulated. "This bill," said President Bush, "will strengthen our economy, and it will improve our environment, and it's going to make this country more secure."