
20 Years Since the Great Blackout of 2003
- Monday, August 14th, 2023 - 9:56 pm
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Today is the 20th anniversary of the great North America blackout, a day when over 50 million people across the continent found themselves without power.
On August 14, 2003, just past 4 p.m. ET, numerous cities, including Guelph, New York, Cleveland, and Ottawa, experienced a sudden halt as the blackout spread. Traffic lights stopped working, office buildings were plunged into darkness, subways came to a grinding halt, and airports closed. The outage spread over 24,000 square kilometres, from Chicago to the Atlantic coast, encompassing most of Ontario.
Energy analyst Tom Adams remembered the immediate aftermath filled with “wild speculation, often political in nature” regarding the reason for the blackout. Initial guesses ranged from a terrorist attack to the failure of a nuclear power plant.
The eventual investigation traced the root cause to Ohio’s FirstEnergy Corporation. Power lines from a FirstEnergy plant in a Cleveland suburb came in contact with overgrown trees, leading to a shutdown.
A technical malfunction prevented the appropriate alarms from displaying on the control system, causing FirstEnergy to be unaware of the issue until it was too late. This resulted in a cascading effect, ultimately leading to the shutdown of over 100 power plants in Ontario and the northeastern U.S.

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