Bird strike downs power grid early Monday

Early birds and night owls may have noticed a lack of power during the early morning hours Monday, after service for Wrangell, Petersburg and Ketchikan went down for several hours.

The grid went down at 2:48 a.m. after a mature bald eagle ran afoul of a section of line near Ketchikan’s Herring Cove.

“We’re very apologetic, especially when we cause problems in our neighboring communities,” said Andy Donato, manager of Ketchikan Public Utilities’ electric division.

He explained the power supply had been interrupted after the eagle struck the transmission line. The seafood processors that ordinarily would be operating were shut down for Sunday, and the low load meant there was not sufficient generation elsewhere to compensate.

In Wrangell, public utilities personnel were contacted by police dispatch at 3 a.m., and by 4:15 a.m. they had the diesel generators up and running, taking the island off the grid. The three communities have shared power since October 2009, through the Swan-Tyee Intertie managed by Southeast Alaska Power Agency.

By 5:32 a.m., Tyee Lake Hydroelectric was back online and most of Ketchikan was powered. Wrangell Municipal Light and Power then paralleled and rejoined the grid. By 7:32 a.m. power was restored to all parts of Ketchikan.

“The guys really did a good job, and everything went really, really smoothly,” said WMLP electrical superintendent Clay Hammer.

While quiet processors had contributed to the shutdown, he explained it was fortunate production was not in full swing when the temporary switch was made to diesel. To his knowledge, no processing operations were interrupted.

Donato explained bird strikes are a fairly common occurrence along the region’s power lines.

“We’ve taken measures to stop it,” he added, explaining the community last year approved installation of flight diverters. The diverters are visual indicators wrapped around the lines, alerting birds in flight. At the cost of around $20,000, they have so far been installed in two particularly strike-affected sections of line. Donato believes they have been having their intended effect; the eagle in Monday’s strike hit a line just beyond the diverters. He plans to have more diverters installed as resources become available.

But birds aren’t the sole strike risk in Ketchikan: last month service was interrupted after a transmission line was struck by a salmon. Rather than having made an impressive jump, the fish was likely dropped by an overburdened bird of prey.

 

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