More than 485,000 without power after Sally, Laura hit the Gulf Coast

Houston — Four weeks after Hurricane Laura and one day after Hurricane Sally made landfall, almost 485,000 power customers lack service in Alabama, Florida, Georgia and Louisiana, which has weakened power demand and power prices across the South.

Meanwhile, a tropical disturbance in the southwestern Gulf of Mexico has a 90% chance of forming into another tropical depression, storm or hurricane, according to the National Hurricane Center.

Post-tropical depression Sally was "still producing torrential rains over the Carolinas" with maximum sustained winds near 30 mph and "little change" forecast through the morning of Sept. 19, the NHC said in one of its final public advisories about the storm on Sept. 17.

As of about 4 pm CT Sept. 17, Sally had left more than 232,000 customers offline in Alabama, more than 188,00 offline in Florida and almost 16,000 offline in Georgia, according to PowerOutage.US.

Around the same time, Louisiana had 48,655 customers offline after Laura, which slammed into the area around the Louisiana-Texas state line on Aug. 27 as a Category 4 storm with wind speeds up to 150 mph.

Power demand

In the Southern Company balancing authority footprint, which covers utilities in Alabama, Florida, Georgia and Mississippi, the total power demand through 2 pm ET on Sept. 17 averaged down about 7.6% from the forecast and down about 14.2% from the same period on Sept. 10.

Bilateral day-ahead on-peak prices for Sept. 18 delivery Into GTC and Into Southern were basically flat in comparison with the previous day, with Into GTC bid at $18/MWh and offered at $20.50/MWh on the Intercontinental Exchange, and Into Southern trading around $21/MWh.

The S&P Global Platts Index for delivery Sept. 17 Into GTC was $19/MWh, and the Into Southern index was $18/MWh.

It should be noted that the Southern Company balancing authority demand on Sept. 16 was down an average of 13.9% from forecast and 17.9% from Sept. 9.

Kent Berthoud, an S&P Global Platts Analytics energy analyst, acknowledged that Sally's wind damage was less severe, but "the extensive flooding does appear to be having a broader [natural gas power] demand response than we saw from Laura."

"Our power burn sample has declined by 1.5-2 Bcf/d in the last couple of days (looking on a per degree basis," Berthoud said.

NextEra Energy's Gulf Power, which serves the western Florida Panhandle, had the largest number of customers – 177,155, according to PowerOutage.us -- offline around 4 pm ET Sept. 17, and the company's website said it has about 7,000 people working to restore service. The number offline equals about 38.7% of its customer count.

Southern Company's Alabama Power had the next largest total offline around 4 pm ET Sept. 17, almost 109,000 or about 7% of the total.

"We positioned extra crews in the Mobile area prior to the storm, with more than 1,800 additional resources from across the state now helping local crews with restoration," Alabama Power spokesman Michael Szajderman said in a Sept. 17 email. "We are coordinating with our Southern Company sister companies and with investor-owned utilities through the Southeastern Electric Exchange for additional personnel to aid restoration efforts. Approximately 4,000 resources are ultimately expected to be on the ground to assist with the restoration process, which we do expect will take several days."

Restoring service in Louisiana

Substantial portions of Lake Charles, Louisiana, have waited more than four weeks for power to be restored after Hurricane Laura destroyed the area's electricity grid.

Platts Analytics' Berthoud said that the gas demand drop from power generation has been sharp in response to "the acute phase of Sally, but it remains to be seen whether Sally will be as damaging to power generation once it passes" as Laura has been in Louisiana.

"Entergy is still working on replacing the transmission line damage from Laura, so even if it was more concentrated, the effect has far exceeded the storm itself," Berthoud said.

Entergy Louisiana now projects most of the area to be restored to service by Sept. 30, with substantial stages restored Sept. 20, Sept. 21-23, and Sept. 24-27.

"The 25,314 workers brought over time to restore service comprises the largest restoration effort we have ever mobilized," Entergy said in a Sept. 17 news release. "Our crews, contractors and mutual-assistance partners continue working long hours restoring service to customers as safely and as quickly as possible."

And the hurricane season continues, with a low pressure system over the southwestern Gulf of Mexico showing upper level winds that "are gradually becoming more conducive for development, and a tropical depression or a tropical storm could form within the next day or so," the National Hurricane Center said in a Tropical Weather Outlook issued at 2 pm ET Sept. 17.

"The low is expected to meander over the southwestern Gulf of Mexico through tonight before moving slowly northward to northeastward on Friday and Saturday," the NHC said.