2. Electroshock

Icon: Bryan Christie Design; Background: Brian Staufffer

It’s a lazy late-summer afternoon in New York City. So when the whole metropolis suddenly goes dark, everybody remembers the day seven years previously when a cascading blackout paralyzed much of the U.S. Northeast, Midwest, and southeastern Canada. Just as they did on that day, hundreds of thousands of office workers stumble down the dimly lit staircases of skyscrapers and brace themselves for the long walk home.

With most communications down, there is no way of knowing that the blackout had originated in the same region as the 2003 episode, but this time it’s the result of a mysterious and concerted series of attacks on high-voltage transformers and a few well-selected transmission towers. Though monitoring and supervision of the grid had greatly improved since the earlier blackout, this time too many failures happen simultaneously for the system to cope.

As thousands of homeward-bound pedestrians surge onto the Brooklyn Bridge, a young man suddenly tosses a grenade into the heart of the crowd. Pandemonium breaks out, as people attempt to escape the jammed walkway. In the horrifying stampede that ensues, hundreds are trampled and a few dozen jump or fall to the river below.

And it isn’t just the Brooklyn Bridge. The ferries and all five of the major bridges connecting Manhattan to its neighboring boroughs are attacked by ­grenade- and assault-rifle–toting terrorists. The eventual toll far exceeds 9/11’s. The parties responsible? A cluster of white supremacist groups, some with access to sophisticated weaponry and military training, who decided to attack the most multicultural of U.S. cities.

Not much would prevent terrorists from taking down the North American power grid. With about 300 000 kilometers of transmission lines and countless vulnerable nodes crisscrossing the United States and Canada, “it is impossible to secure the whole system, and thus a determined group of terrorists could likely take out any portion of the grid they desire,” a group of experts concluded in a recent issue of IEEE Power & Energy Magazine.

Especially vulnerable are the high-voltage transformers that step voltage down from transmission levels, typically above 100 kilovolts, to distribution voltages in the tens of kilovolts. There are about a thousand of these units in the United States, most of them located at substations that are secured by nothing more than a chain-link fence. Any one of these transformers could be knocked out of action quickly and easily with rocket-propelled grenades or improvised explosive devices. To be sure, perimeter security could be bolstered, and transformers could be encased in bunkers, but it would be a very expensive proposition to do so nationwide.

The Edison Electric Institute, in Washington, D.C., has worked with the utility industry to develop an inventory of large transformers as well as agreements about how they could be shared in emergencies. There’s also been a concerted effort to design generic power transformers that could quickly replace severely damaged transformers.

Engineers from the Electric Power Research Institute, in Palo Alto, Calif., and the Zurich-based electrical manufacturing giant ABB have produced a set of criteria for such replacement transformers. They got some initial encouragement from the U.S. Department of Homeland Security. But the DHS has since shown little interest in following up with that effort. And even if such transformers now existed, they could not be delivered and installed fast enough to prevent the second punch anticipated in this scenario.

In the best case with the least damage, the system recovers quickly, and critically needed components like traffic lights start functioning again almost immediately, according to an article published four years ago in Issues in Science and Technology. “No one can prevent a terrorist from taking down a transmission pole,” wrote Alexander E. Farrell, Lester B. Lave, and Granger Morgan, all associated with the program in electrical engineering and public policy at Carnegie Mellon University. “However, the system can be configured so that although the failure of single elements may lead to discomfort, the electric power system will still be able to fulfill its mission in a timely manner.”

As for a bombing attack aimed at civilians, the United States has been blessedly free of such tactics since 9/11. But there is no guarantee this will always be so, and public complacency is a real danger. Almost everywhere in Europe, there is a much higher level of public and police vigilance. In Paris, for example, every unclaimed package or suitcase is immediately put into a special container and blown up.

Outside the United States, private ownership of weaponry is often much more tightly regulated. Militias found in many U.S. states provide opportunities for weapons training. Terry Nichols, who with Timothy McVeigh plotted the Oklahoma City bombing in 1995, had contact with one such group.

In the final analysis, old-fashioned gumshoe police work has the best chance of preventing bomb attacks. Ever since 9/11, the New York City Police Department has had highly trained and well-armed plainclothes officers patrolling high-risk target areas constantly and unobtrusively. But those patrols could get scaled back if the city fails to make up for lost federal funds. Citing the high cost of the extra police patrols and investigation, among other things, the DHS cut the city’s counterterrorist funding by 40 percent for 2006–2007.

—William Sweet