Hurricane Sandy Will Put a Rickety Power Grid to the Test

The U.S. power grid is a 20th century technology powering a 21st century country. Why Hurricane Sandy will stress it to the limit

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A man walks his dog near downed power lines in Chevy Chase, Md., in the wake of Hurricane Sandy on Oct. 30, 2012

For most people in the path of Hurricane Sandy — save the hundreds of thousands who’ve already had to be evacuated from low-lying coastal areas and the occasional brave weather reporter — the biggest effect of the storm is the potential loss of electricity. As of Tuesday morning, after Sandy had made landfall, more than 6.5 million customers from North Carolina to New Hampshire had already lost power, including more than 1.9 million in New York alone. In New York City, the utility ConEdison shut down power in certain areas as a precaution to prevent greater damage to generating stations and other equipment in vulnerable areas. But that didn’t stop transformers in submerged parts of Manhattan from exploding in a burst of sparks.

It’s likely to get much worse. Experts estimate that power outages could affect as many as 10 million people along the East Coast, and it could take days or longer to fully restore service. That would be unprecedented; the number is a mark of just how destructive and widespread Sandy’s wrath could be. “The public should anticipate that there’s going to be a lot of power outages,” President Obama said Monday. “And it may take time for that power to get back on.” In other words: get ready to go dark — and stay dark.

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U.S. utilities haven’t had a sterling record recently when it comes to responding to storm events. The shock snowstorm that hit the Northeast last Halloween left some 3.2 million homes and businesses without power — some for more than a week — costing up to $3 billion, according to the Federal Energy Regulatory Commission. The derecho storm that soaked the mid-Atlantic states in June this year left 5 million people in the dark, while Hurricane Irene in August 2011 took out power for some 7 million people. For many of those households, especially in the remote areas of states like Connecticut and Vermont, power wasn’t fully restored for weeks.

The threat to the grid from a storm like Sandy is twofold. Massive storm surges will flood low-lying coastal areas as well as any power-generation equipment in the way of the water. That’s particularly worrisome for the more than a dozen nuclear plants that stand in Sandy’s projected path. The nuclear meltdown at Japan’s Fukushima plant was caused not by the earthquake itself but by the tsunami’s surge of seawater, which knocked out the plant’s electrical generators. U.S. plants have been receiving “enhanced oversight during the storm,” according to the Nuclear Regulatory Commission (NRC). The good news is that U.S. plants have been required to install backup electricity generators since 9/11, and they are required to shut down in the event of hurricane-force winds. The NRC says that all of the plants have flood protection “above the predicted storm surge.”

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If you live in the storm’s path, the other main threats to the grid are probably waving in the wind outside your home: trees. During the derecho, during Irene and certainly during Sandy, strong winds led to downed tree branches. Those have a habit of taking down power lines, which can then affect electricity access for thousands or more. It doesn’t take much; the great Northeastern blackout of 2003 began when a transmission line in Ohio sagged into a tree, touching off a cascading effect that led to the loss of power for more than 50 million people in the U.S. and Canada. Downed tree lines caused havoc with power lines during last Halloween’s snowstorm, which was intensified by the fact that most of the trees still had leaves, making them heavier and more prone to collapsing. That will likely be the case with Sandy as well.

Utilities had advance warning of Sandy — thanks, government scientists — and they’ve been sending out crews to trim trees near power lines. Connecticut Light & Power, which simply failed to have enough workers on the job after the 2011 Halloween snowstorm, began requesting 2,000 additional workers days before Sandy was scheduled to make landfall. The utility also doubled its tree-trimming budget to over $50 million this year. Other utilities have also had workers out early and often to get ready for Sandy. “We are far better prepared, particularly in coordination and communication, than we were last year,” said William J. Quinlan, senior vice president of Connecticut Light & Power, at a press conference last week.

Of course, it seems as if there could be a simpler solution than trying to keep wild trees trimmed: simply bury power lines to keep them out of harm’s way. But as Brad Plumer of the Washington Post wrote earlier this year, it is neither cheap nor easy to bury power lines underground:

On average, [the Energy Information Administration] found, underground lines can cost five to ten times more to build, per mile, than overhead lines. And that’s only construction. Utilities also have to dismantle the overhead wires when making the conversions. What’s more, repair costs can be higher for the underground lines — they don’t last as long and have to be dug up when they get old or break. The underground lines are also more vulnerable to flooding. But those costs need to be weighed against the (often steep) cost of blackouts. And overhead wires are more vulnerable during storms.

Altogether, just 18% of the U.S.’s distribution lines are buried underground, and only 0.5% of transmission lines are below ground. So utility crews will spend a lot of time cleaning up after downed lines and broken trees once Sandy has finally passed — which not be until much later in the week. Sandy’s sheer size will also stress those crews. Most disasters are limited to a few states, which means that neighboring states can send relief crews. But Sandy will hit almost the entire Eastern seaboard, leaving individual states struggling to take care of themselves.

The U.S. power grid is delicate even under the best of times: a 20th century technology charged with keeping a 21st century population charged. There’s hope that new smart-grid advancements, including distribution automation and smart meters that can keep utilities apprised of problems in real time, will make the grid more resilient in the future. But for now, as Sandy socks the East Coast, all we can do is hope that the lights stay on. At least for a little while longer.

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