Why it’s taking so long to restore power after Sandy

Daily News Article — Posted on November 5, 2012

Utility crews work on power lines in Ship Bottom, NJ. “We had massive damage to our infrastructure,” said a spokesman for Jersey Central Power & Light Co.

(by Lorenzo Franceschi-Bicchierai, Mashable) – After the wrath of Superstorm Sandy hit the Northeastern coast of the United States [on Monday, Oct. 29], towns and communities have been left without power for days. Even New York City hasn’t been spared. Since Monday night, a large part of lower Manhattan from roughly 30th Street down to the tip of the island, [was] shrouded in darkness.

The question that is on everybody’s mind is: Why is it taking so long to restore the power?

The simple answer is that Sandy was one of the worst storms the Northeast has ever endured and it damaged the whole electrical grid. “The severity of the storm hit us so bad that it really took a beating on both our underground and overhead systems,” Alfonso Quiroz, a Con Edison spokesman, told Mashable.

Sandy’s strong winds knocked out trees and overhead power lines, and the water surge flooded underground substations. According to Con Edison estimates, as many as 930,000 customers were left without power at a some time during the last few days due to the “the most devastating storm in company history,” as Con Edison referred to it.

According to Sakis Meliopoulos, a professor of electrical energy, systems and controls at Georgia Tech, it takes a lot of time to restore the power in every part of the grid after such a damaging disaster, because before turning on the switch in the affected areas, “each circuit has to be checked” to make sure it’s in good shape.

The New York electrical grid is complex and made of a lot of parts that play an essential role in bringing electricity to homes. Generators [power plants] produce power and push it at high voltage through distribution lines [transmission lines], which can be both overhead or underground. That electricity then passes through substations, often open air, that contain transformers and other equipment that reduce the voltage. From there, the electricity moves into smaller distribution lines that reach single homes or buildings.

[In New York City] Sandy knocked out distribution lines, damaged open air substations, flooded basements with transformers and backup generators, and inundated underground substations and subway lines, which often host electrical cables. It even caused some transformers to explode.

Moreover, all these single parts of the system must be checked with limited personnel . [Con Edison] hired more than 1,600 external contractors to conduct repairs and inspections.

In Manhattan, flooded substations are the problem. Quiroz said first water needs to be pumped out, then technicians need to clean all the equipment to get rid of the saltwater before drying everything off with fans and blowers.

Cleaning up everything is key. “If you re-energize the system without cleaning, you could cause more widespread damage,” says Vijay Vittal, a professor of electrical engineering at Arizona State University.

Once that’s done, some equipment might have to be repaired or even replaced and then, finally, everything needs to be tested and checked before putting it online.

This can be a painstaking process, but for Meliopoulos, “comparatively it’s a smaller problem than the bigger problem of the trees and the damage in the distribution system” in suburban areas with overhead lines.

In fact, as many as 100,000 wires were downed by Sandy, according to Con Edison. These all need to be put back in place or replaced to put power back on in the areas affected. The task is complicated by the fact that access to some lines is blocked by trees or other debris. That explains why suburbs in Long Island or New Jersey will remain without power longer than some areas in New York City, which only have underground lines affected.

Sandy could also have a long-term effect on the system, because of the salt in the water that flooded the substations. In the long-term, salt can corrode and deteriorate wires, switches and other electro-mechanical equipment.

“We’re going to pay the price later on when the corrosion starts progressing.”

“The problem with saltwater is something that we’re going to see later on, the effect of the saltwater is not immediate. Basically [some of] the salt … is going to remain on the equipment and it’s going to start corroding,” Meliopoulos tells Mashable. “We’re going to pay the price later on when the corrosion starts progressing.”

So what can be done to prevent these kinds of problems? First of all, says Meliopoulos, Con Edison should make sure that no cables in the system are easily exposed to water. Also, the grid could be improved by investing in new equipment like waterproof transformers, and transitioning from overhead cables to buried ones. Obviously, he warns, all these solutions are very expensive. “So it’s probably out of the equation to redo the whole system.”

Another possibility would be to upgrade the system to a so-called “smart grid,” installing sensors throughout the system to monitor the state of the equipment. That way the utilities would be able to know exactly where the problem is in real time, which would make repairs quicker and more efficient. This is also expensive, but given New York City’s high concentration of customers, says Meliopoulos, it would probably be more cost-effective than in other places.

Considering all the circumstances and the magnitude of the storm, both Meliopoulos and Vittal agree that it’s not taking that long for the power to come back. For Vittal, who praised Con Edison’s precautionary measures and response to the storm, the power in some areas was actually restored “quite fast.”

Con Edison said Thursday [Nov. 1] that power for 228,000 customers in Manhattan should be restored by Saturday morning [Nov. 3]. After that, there will still be 400,000 customers elsewhere potentially in the dark, almost a full week after Sandy.

Background

Hurricane Sandy Power Outages: Why it its taking the power companies days to get the lights back on:

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. “[In New York City] 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. [This is what happened in a transformer substation in New York City.] (from huffingtonpost.com)

Problems faced by the power companies:

Several utilities described massive mobilization efforts coordinated with utilities across the country. Con Ed (as of Oct. 31) was waiting for new crews from California utilities to arrive any day and help with the effort of draining water from flooding, repairing equipment, removing trees and completing other tasks needed to restore power, a spokesperson said.
Connecticut Light & Power imported about 600 workers from utilities as far away as Texas and Washington state to assist with power restoration.
Kathy Fitzgerald, a spokeswoman at New Jersey’s Public Service Electric and Gas Company, said the company’s biggest challenge has been “major flooding” at its substations, the facilities that redirect power to customers. The company shut down six substations along the Passaic, Raritan and Hudson Rivers before the storm hit as a pre-emptive measure. Only three have returned to service due to flooding.
“The magnitude of that flooding was unprecedented,” Ms. Fitzgerald said. In order to restore the substations to service, she said the utility has to “manually dry” the equipment using toothbrushes to remove debris.
She said the utility has assembled a “virtual army” of more than 1,550 technicians to repair infrastructure and 600 contractors to cut and remove trees. The storm knocked down 50 transmission lines across its service areas, of which 25 have been restored. But several challenges remain.
In Hoboken, N.J., across the Hudson River from New York, the company has repaired the transmission line and the substation that supplies power to the city. But the utility has yet to connect homes to the substation due to flooding.
“There are a lot of things to be done in the city of Hoboken, including waiting for the waters to recede,” she said. (from wsj.com)

Why progress seems slow:

Pennsylvania power companies said Thursday they have restored service to a majority of customers knocked out by Hurricane Sandy, while 1.6 million electricity customers in hard-hit New Jersey are still off the grid.
"We had massive damage to our infrastructure," said Chris Eck, a spokesman for Jersey Central Power & Light Co., which had restored service to only 31 percent of the 1.2 million customers that were knocked out by the storm.
Pennsylvania utilities said nearly all of their customers would be restored by this weekend. But JCP&L and Public Service Electric & Gas Co. in New Jersey are warning customers that many will remain powerless until the middle of next week.
The New Jersey utilities lost numerous substations to floods, in addition to losing power lines and pole-top transformers. The substations, which serve large areas of customers, must be drained, dried and cleaned before they can be reenergized.
Ralph A. LaRossa, PSE&G's president, said Thursday that cleanup crews were engaged in "hand-to-hand combat" with filth in substations, using toothbrushes and rags to remove dirt. (from philly.com)