Ten years ago, a sagging power line hit a tree near Cleveland, tripping some circuit breakers. To compensate, power was rerouted to a nearby line, which began to overheat and sink down into another tree, tripping another circuit. The resulting cascade created a massive blackout in the Northeast U.S., affecting power in eight states and part of Canada.
Some 50 million people were left without power for days after the lights went out around 4 p.m. on the sticky summer day. New York seemed transformed with a flip of a switch. On the Upper West Side, strangers, who moments earlier had avoided eye contact, started chatting. They now had something in common. There was a mix of excitement and fear.
Many New Yorkers were trying to get home from work. There were no subway trains, so competition was fierce for buses and cabs.
"Just get us to Washington Heights, man," a man on the street said. "I'll give you a lot of money for Washington Heights."
Meanwhile, Rick Gonzales was in the Albany control room of the New York Independent System Operator, or NYISO — the air traffic control for the state's power grid.
"The lights in the control room dipped," Gonzales says. That's not a good sign when you're in charge of the power. Soon, it looked like a scene from a movie. "There were hundreds of alarms going off. All the transmission lines that had tripped were flashing red."
Gonzales, the chief operating officer of the NYISO, says that unlike during a big storm like Sandy, his team had no time to prepare for this emergency.
That night, when a chunk of the country was still dark, Terry Boston got a call. He was a vice president of the Tennessee Valley Authority, a government utility corporation that provides electricity for 9 million people in seven Southeastern states. Boston was asked to be part of an official investigation into what happened.
He says the causes came down to three things: "tools, training and trees."
Beyond trees that were too close to power lines, the cascading blackout was fueled by failing computer systems and poorly trained operators who didn't talk with each other.
Today, hundreds of new sensors have been installed across the U.S. electric grid system. They're called phasor measurement units and can help investigators figure out problems after things go wrong. But they also monitor in real time, and Boston says that if the devices had been widely used a decade ago, there would have been an early warning.
"There was about an hour of operator time that could have been used," he says.
The power outage was also an industry wake-up call. The voluntary operating standards that utilities had been using were no longer good enough, so Congress beefed up regulations, ultimately giving some teeth to an organization called the North American Electric Reliability Corp., or NERC.
NERC CEO Gerry Cauley says his organization has already punished utilities hundreds of times, including a Florida power company it hit with a $25 million fine.
"We have the authority to enforce penalties up to a million dollars a day," Cauley says. The tougher rules and new technology have many in the industry feeling good about preventing blackouts in the future.
But Paul Hines at the University of Vermont is not so optimistic. He says the industry is looking backward.
"We've done some things that will reduce the risks of the blackouts that happened last time, but haven't done things that would prevent the next blackout," Hines says.
Yes, he says, we have new sensors installed in the grid, but utilities don't totally understand what to do with all the data. And sure, trees are being trimmed and new regulations are in place, but we still had a cascading blackout in the Southwest two years ago.
"We haven't come up with the technology or policies that will prevent these things entirely," he says. And Hines says we could do more, like promoting something called distributed generation, which is basically lots of little, local power plants.
The Durst Organization, a commercial realty firm in New York City, put one of these facilities in its 55-floor office tower in Midtown Manhattan. The natural gas plant generates two-thirds of the building's energy.
"It takes stress off of the grid," says spokesman Jordan Barowitz. "When the grid is stressed on very, very hot days, anything you can do to lessen the amount of traffic on the grid is good for the system and avoids power loss."
But for the rest of us, the question for now is: What's reliable enough? The average American loses power for less than two hours a year. Improving that even more could cost a lot of money, a cost that the ratepayers would ultimately pay.