As Hurricane Ida pulled away from New Orleans and its surrounding towns on Monday morning, August 31, it left miles of damage in its wake. Striking land as a category 4 hurricane, the storm had maximum sustained winds of 150 mph, approximately 25 mph greater than Hurricane Katrina’s maximum sustained winds.
As of Tuesday morning, Entergy, the electric utility serving the region estimated that around 1 million customers were without power and restoration was complete for 9% or 85,000 of them. The utility reported in an update that a storm response team comprised of more than 20,000 workers from mutual aid utilities across the country are working to restore service to the region.
Transmission lines down
The storm took out a transmission tower that had withstood Katrina and that, along with other with eight additional damaged high-voltage lines, cut power for New Orleans and Jefferson, St. Bernard and Plaquemines parishes, as well as parts of St. Charles and Terrebonne parishes. In all more than 2,000 miles of transmission lines are out of service in Louisiana.
Entergy explained in a statement that the transmission system is the backbone of the electric grid and helps move energy from the power plant to the lines serving neighborhoods. Without these lines in service, power cannot flow from generation to customers in affected areas. If the grid and the flow of power were compared to a highway system, transmission lines would be the interstates, substations would be the off-ramps, and distribution lines would be the streets and roads that lead to homes and businesses.
While these transmission structures are being repaired, engineering and operations groups are working closely, along with MISO, to ensure the safe and stable operation of the electric grid, said Entergy. Restoration crews are working in parallel to restore substations and the distribution system that feeds homes and businesses. The company said it is also aggressively exploring other opportunities to flow power into New Orleans by enabling generators located in the area to begin producing electricity without the need for a transmission source to provide start-up power.
Hurricane Ida’s fierce winds damaged some generating plants in the New Orleans area too, according to Entergy. By making generation repairs simultaneously with transmission, the utility will be able to produce power for New Orleans-area customers when the transmission system is able to deliver it. Entergy said it is now focused on identifying functioning transmission lines it can use to deliver power to customers in the area.
Is it time for undergrounding?
IEEE member Kyri Baker said in an emailed statement that Entergy may want to consider undergrounding some transmission lines as it considers grid modernization and improved resiliency efforts. Climate change is expected to bring more frequent, more destructive storms in the coming years.
“A higher number of interconnections in general would also be beneficial. Having some overhead and some underground, connected to geographically distinct areas, can help if one part of a region is hit hard by a disaster, but can still pull in power from another region. This is really challenging in an area like New Orleans, for example, which borders the ocean, but generally diversifying the source of power to a region is a good idea,” she said.
In addition, smaller-scale energy resources could also help in future scenarios. “Distributed energy resources, such as solar, can be advantageous in these situations, particularly if the solar panels are hurricane resistant,” she said.
Several utilities in the U.S. have begun undergrounding distribution lines in order to increase resilience in hard-to-harden areas. Dominion Energy’s and Wisconsin Public Service’s undergrounding projects are topics of discussion in a DISTRIBUTECH+ session later this month. But transmission lines are different and generally are designed to withstand ice, snow, high winds and other severe weather.
“Like any piece of infrastructure, towers can age, wind speeds can temporarily exceed what the towers were built to withstand, and things can go unexpectedly and, on occasion, disastrously wrong,” added Baker.
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