Crashing at friend’s houses, blessing our gas stoves and plugging into trees, New Yorkers are all wondering -- why does it take the power so long to go back on?
Con Edison’s said it could take as long as four days to restore power in Manhattan, and as much as a week in the outer boroughs. For many of us, desperately trying to preserve the flickering life of a laptop or cellphone battery, that seems too long to ponder.
Here’s why it will take that long, whether we like it or not.
According to Virginia Tech professor and infrastructure expert Saifur Rahman, an electrical grid like New York’s has several key parts, each of which are essential to getting electricity to homes. First, there’s the generator -- a power plant that generates electricity for large swaths of the city. That power is then pushed, at very high voltage, across transmission lines -- thick bundles of metal cables that handle enormous amounts of juice. Power from transmission lines is then sent into transformers, machines that bring down the voltage of the electricity, before sending it into small distribution lines, which transport that electricity into our homes.
All of these pieces are uniquely vulnerable. “Power lines are underground in cable trenches, and if they get flooded, you have short circuit possibilities,” says Rahman. Small or backup power generators, he continues, are often in basements which flood and short-circuit the generators when a storm hits, and “substations that contain transformers are open air and they’re subject to storm damage.”
Storm damage to transformer wires can prevent the machines from detecting spikes in electricity coming from the transmission lines. This in turn causes circuits in the machine to overheat and melt. In the best case scenario, this puts the transformer silently out of commission, robbing homes of power but causing no immediate catastrophe. In the worst case, sparks released by frying circuits can ignite coolant within the transformer, causing a massive explosion.
Unfortunately, electrical grids don't work like the web: “On the internet,” says Rahman, “there is a mesh of networks which has multiple alternate paths to get your data from point A to point B in various ways. Electrical power systems are not built that way for many reasons, one is cost, so in many cases you have one primary route and maybe a secondary route and that’s it.” If the primary distribution route for electricity to a cluster of homes is down, Rahman says, the secondary route can get overwhelmed very easily, “and sometimes, in the case of New York, you may have lost the primary and the secondary.”
So, to summarize: we have a grid with many vulnerable parts, and each piece between your power plant and your home must be working correctly for you to get electricity. In a storm like Sandy, every part of the system can be damaged, and Rahman says New York City’s grid is particularly at risk: “it’s very densely populated, a lot of power has to go through those underground cables.”
Given all this, it’s not surprising that multiple types of breakages are being reported all over the city, from downed power lines in the outer boroughs to exploded transformers in downtown Manhattan. And for any particular residence to get its power back on, electrical workers have to first determine where in the system the blackout to that particular residence was caused before they can even think about making repairs -- repairs which could be anything from fixing a massive substation to pinning up a particular local power line.
Also, we're not first on Con-Ed's list.
Disaster analyst Philip Jan Rothstein explains: Power companies "have to perform triage... they have their priorities set by things like military, emergency services, police, medical, fire, so forth.”
Further complicating matters, much of the badly damaged infrastructure is still inaccessible because of winds and flooding. “There’s no telling when a steam line’s going to rupture or a water main’s going to break or something’s going to back up or a pump’s going to fail," says Rothstein.
In other words, Con Edison probably wants the power on quickly, but not so quickly that it puts their workers at risk.
Bottom line, says Rothstein, there’s probably no quick fix. The power companies, he says, "are good at this. They’ve got all kinds of protective measures, they’ve got all kinds of detectors they’ve got all kinds of contingency plans and backups and so forth,” but in a Sandy-style situation, “sometimes something breaks, sometimes something fails.”
The Huffington Post is eager for insights from our community, especially people with experience in power, infrastructure and engineering, on the adequacy of emergency preparation in advance of Hurricane Sandy, and the degree to which past disasters have informed adequate planning and construction. Please send a note to email@example.com with insights and suggestions for the important questions that need to be asked of relevant private sector and government officials, and point us toward stories that need to be pursued.
SEE: PHOTOS OF HURRICANE SANDY'S AFTERMATH