CasdraBlog

Believe it or not, this is a question I've been asked before. Many people wonder how key parts of civilized society might continue after a post-apocalyptic Dawn of the Dead / Night of the Comet / Omega Man / Teletubbies Go to Paris scenario. Your question has two possible answers depending on which scenario of zombie conquest you envision.

In Dawn of the Dead, the zombification process doesn't happen all at once. We can imagine a gradual scenario in which the infrastructure systems controllers plan ahead for shortages of personnel and try to keep the power going as long as possible. Alternatively, zombification could happen fairly quickly – say, over a few hours. I'll address the second, more dire scenario in detail first, then the first, slightly less alarming one briefly.

How long the power supply would last in the most critical zombie situation depends on two key factors – first, how long a given power plant can operate without human intervention, and second, how long before enough power plants fail to bring down the entire transmission grid. I'll ignore the side issues of whether the zombies would want to try to run the power plant themselves, or if they would be a union or non-union shop.

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Focusing on individual plants doesn't give us the whole story, though. The North American power grid is a classic illustration of a chain being only as strong as its weakest link. As we saw during the blackout of August 2003, a relatively minor event or series of events can, under the right circumstances, bring down large portions of the whole system. During the August blackout, despite massive non-zombified human intervention, enough parts of the system failed to result in the loss of more than 265 power plants and 508 generating units within a few hours. As bad as the blackout was, without human intervention to shut down plants safely, balance load, transfer power to different lines, and disconnect salvageable chunks of the system from those that had totally collapsed, it could have been much worse. Quick intervention allowed isolated "islands" of power to remain in service – one large island in western New York supplied nearly 6,000 megawatts and was used to restart the power grid days later. But without humans working to isolate it, that island would not have been formed in the first place.

Bottom line? My guess is that within 4-6 hours there would be scattered blackouts and brownouts in numerous areas, within 12 hours much of the system would be unstable, and within 24 hours most portions of the United States and Canada, aside from a rare island of service in a rural area near a hydroelectric source, would be without power. Some installations served by wind farms and solar might continue, but they would be very small. By the end of a week, I'd be surprised if more than a few abandoned sites were still supplying power