"Shortly after midnight, attackers armed with Molotov cocktails almost simultaneously disabled electrical substations in at least nine cities and towns in Michoacan, plunging an estimated 1 million people into darkness. The power was out for 15 hours." From the LA Times, Oct. 27
In the 1970s some of the San Francisco Bay Area antiwar protestors decided to knock out power to Berkeley. One group tried to pull down a tower with a winch and would have if the cops hadn't shown up. That incident created enough commotion for PG&E to take a very brief look at system vulnerability to physical attack. Then the war ended, the hubbub died down and the issue went back to sleep.
Twenty years later, in the 1990s, I was on a secretive committee that was asked to pretend it was a saboteur and figure out the best way to shut down power on the west coast. It didn't take us long. We determined that two guys with hunting rifles, strategically placed, could shut down the entire Pacific Intertie with a few rounds and casually escape. The impact would be to destabilize and island areas throughout the western states, perhaps for weeks.
Well, our report was passed up to the top floor and we were told to keep everything hush-hush. Don't want to give the terrorists any ideas.
More recently system security has gotten a lot of attention again. But it has evolved almost totally into cyber security. A lot of money is being spent on very smart specialists meeting and eating in some of the finest establishments in the world and trying to figure out the best way to protect against digital dynamite tossed into the system by sophisticated hackers.
In the meantime a bunch of ordinary goons in southern Mexico figured out that they didn't need no stinkin' cyber-whatever. They just tossed burning bottles of gasoline over the substation fences. I don't know the details of the damage. But I can imagine transformer and breaker flashovers and fire damage that at least required some equipment replacement.
The biggest damage to our industry is the precedent set, the object lesson to terrorists that shutting down the grid is pretty easy. Hopefully the incident is also a wake-up call to focus more on the mundane physical protection of substations and other assets.
Whatever the lasting impacts, the cat is out of the bag and nobody's going to put it back in.