The storm that has spawned so many worst-ever superlatives managed a few more when it comes to electricity, with record-breaking power outages across 18 states stretching from Michigan and Indiana to Maine and North Carolina, according to a Department of Energy assessment.

As of Tuesday, Superstorm Sandy had left more than 8 million people without lights, heat, refrigeration, TV or Internet.

At least 2 million homes and businesses in New York state had no power. Consolidated Edison, which serves the New York City metro area, says 752,000 of its customers were in the dark Tuesday and that crews — some from as far away as San Francisco — will begin repairs once the damage is assessed.

Elsewhere, 2.5 million customers had no power in New Jersey, more than 1.2 million in Pennsylvania and 311,000 in Maryland. Some 625,000 also lost electricity in Connecticut and 300,000 in Massachusetts.

Massoud Amin, a power grid specialist and senior member of the Institute of Electrical and Electronics Engineers, says it could take up to two weeks before power is fully restored. After Hurricane Irene hit the East Coast last year, it took as long as 10 days for electricity to be fully restored to rural customers in Connecticut and elsewhere — and Amin notes that Irene was much smaller than Sandy.

Gregory Reed, director of the Electric Power Initiative at the University of Pittsburgh's Swanson School of Engineering, agrees it will take a week or more to turn the power back on.

"You normally will see a lot of major metropolitan areas get their power back in a short time, a matter of a couple of days in the case of a major event like this," Reed says, adding that rural areas are typically the last to see the lights come back on.

The storm couldn't have targeted a more vulnerable part of the power grid. "Pennsylvania, New Jersey, Maryland and New York are the oldest infrastructure," says Amin, who is also a professor at the University of Minnesota.

The grid in those states "is a marvel of engineering for the 20th century, but because of a lack of investment, it has been operating with diminished shock absorbers," Amin says, referring to backup lines and equipment as well as high-tech monitors to pinpoint problems.

A system of "mutual aid" among utility companies all over the country has been in place since the 1950s to help a crisis-hit power provider get the lights back on.

"As long as we get a heads up and know a few days ahead of time that something big is coming ... we can preposition crew, equipment, trucks, everything to a place close to where the event is going to be," Amin says.

Reed says because big, damaging weather events seem to be occurring more frequently, we may be heading into an era of "more activity and more significant impacts." Power lines are susceptible to strong winds and storm-tossed branches, and high waves can submerge substations and other critical equipment.

"The way [the grid] is designed and because so much of it is an overhead infrastructure, it is inherently vulnerable," Reed says.

Amin has run calculations on annual outages around the world. The most fragile part of the U.S. grid, in the Northeast, averages about 240 minutes of outages per customer per year. Compare that with the Midwest, where it's only 92 minutes, or Japan, where the outage rate is just four minutes per customer per year.

It costs anywhere from six to 12 times more to bury a power line than it does to put in overhead lines. But there has been a push in the past five to 10 years to put more infrastructure below ground, where it's safer, Reed says.

"This might not be justified everywhere, but there are certain parts of the country where" it might make sense, he says. "You do have to start looking more and more at the cost/benefit of spending that extra money on capital investment upfront instead of spending all the money on the back end to replace the damaged equipment and the cost of operations afterward."

Short of a massive investment to put wires below ground, Reed and Amin agree that other grid improvements and upgrades are possible. Some of them are already in the works, thanks to federal stimulus money aimed at moving toward a smart grid.

Before stimulus funds began flowing in 2009, there were only a few hundred smart-grid sensors, which help pinpoint exactly where a problem has occurred. With the government kicking in about 45 percent of the cost of these sensors and private utilities paying the rest, there should be 1,000 in place before the end of next year, Amin says.

Amin thinks building a system with almost 100 percent protection is possible, but it's just too costly.

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