I had a difficult time swallowing that story of the tree branch in rural Ohio that caused theblack-out the whole NE US and parts of Canada a few years ago.
That was one mighty Oak or Elm.
No; that wasn't hacking.....it was incompetence of the operators who were kept dumb by the corporate leadership there, to save money. The cost of the move by that particular company was to end up costing others (and all consumers) BILLIONS and the Congress stepping in to whitewash the facts in the report, and creating another Regulatory monstrosity to oversee "The Grid". Transporting electricity across boundaries of former service territories, on paper, is a simple method of financial trading. Electrons move acording to Kirchoff's Law, and Ohm's Law, neither of which can ever be repealed or amended via Congress. The purported sales and delivery of power from a point 1000 or more miles from the generator, over typical transmission systems, is an un-natural act....the electrons can't go that way when a generator was built and the transmission supporting it was to transport the power to a load center nearby.....it wasn't designed to pump power from California to New York, no matter who wants that to happen.
Yes; hackers could knock out large areas of power supply, but so could strategic placements of explosives at key transmission and generator sites. Unfortunately, as demonstrated in your example, the current crop of System Operators rely on the Computers to make decisions, and would be poorly prepared to operate through experience and operating knowledge as in the past. The retirements of veteran system operators and the regulations in place today will make a complete regional blackout a simple matter of knocking out a few systems' energy management systems, or even just disrupting their data communications....no matter what the regulators say.
There was a major internet worm that appeared a few days before that caused the pc to reboot. It is assumed in most IT circles that the blackout was caused by the blaster worm.