Thursday, Aug. 14, 2003, started out as a typical hot summer day in Toledo.
It was 69 degrees at 6 a.m., and by noon it had risen to a sizzling 84, although according to the RealFeel Temperature it felt like 99 degrees to anyone forced to be outside.
By 2 p.m., the thermometer reached 88, the high for the day, and practically everyone in Ohio was scrambling to find ways to keep cool, including millions who cranked up their air conditioning.
But over in northeast Ohio, scrambling of a different kind was about to start.
Just two minutes after 2 p.m., a 345-kilovolt transmission line, which is among the highest-capacity power lines running through Ohio, began to stretch and sag because of the day’s heat and the large amounts of power it was required to ferry on such a hot day.
Eventually, a segment of that power line that runs through the village of Walton Hills, east of Cleveland, dipped low enough to touch a tree.
The line overloaded and then, as it was programmed to do, shut itself down.
That should have sent a computerized alarm to power grid operators at FirstEnergy Corp.’s control room in the small city of Wadsworth, about 15 miles west of Akron.
But a programming bug in the system’s software kept the utility’s grid operators from ever seeing the alarm.
Blind to what was happening, control operators also didn’t notice when another 345-kilovolt line — this one in Parma, south of Cleveland — overloaded and shut down just 63 minutes after the first line shut down. Twenty-seven minutes later, a third 345-kilovolt line sagged into a tree and shut down.
Over the next hour, three more high-voltage lines shut down, and by 4:10 p.m., with the outside temperature still 88 degrees, nearly 55 million people living in eight Great Lakes and northeast states and the Canadian province of Ontario were caught up in the second-largest power blackout in history.
The largest power outage occurred in Brazil in 1999.
In Toledo, the blackout’s full effect left most of the city without power at 34 seconds past 4:10 p.m.
Three seconds after Toledo went dark, the blackout hit Detroit and southeast Michigan, and one second later, Cleveland went dark. Northwest Ontario, New York, and northern New Jersey followed quickly.
By 4:13 p.m. the blackout was complete and utilities were left trying to figure out what happened and how to restore power.
Many areas had restored power by 9 p.m., but several parts of the northeast did not get power back until the next day, and some continued to have rolling brownouts.
Six months later, a joint U.S.-Canada investigation attributed much of the problem to Akron-based FirstEnergy, asserting that the utility failed to “assess and understand the inadequacies” of its system, and that during the day of the blackout it “did not recognize or understand the deteriorating condition of its system.”
The utility also was singled out for failing to adequately manage tree growth along the right-of-way of its transmission lines.
Lastly, the report faulted the electric grid’s reliability organizations for not interconnecting with FirstEnergy to provide it with effective real-time support that might have allowed it to understand that it wasn’t aware of critical events as they were happening.
But as U.S. Energy Secretary Spencer Abraham noted at the time, there was no way to punish FirstEnergy for its role in the blackout because U.S. law at the time did not require electric-reliability standards.