All of Petersburg experienced two power outages Thursday morning.
Utility Director Steve Harbour leads Petersburg’s power department.
“Yeah, there were some gremlins in the system,” he said. “I don’t know where they came from.”
Petersburg buys most of its electricity from a regional hydropower provider called Southeast Alaska Power Agency, or SEAPA.
Harbour said a planned outage with SEAPA around 5:30 a.m. required them to temporarily put the town’s power feed on diesel generators. Petersburg has a fleet of generators, used when local loads are high or hydropower is lost.
But one of the town’s main generators had a sensor failure that shut the engine down.
“ It had two megawatts of power it was generating,” Harbour said. “When that much power goes away, it causes a cascading effect, and it shuts everything down.”
The power was out across town for just over an hour, until staff got the diesel generators back online by 7:00 a.m.
Then, when switching back to hydropower later that morning, another big generator south of town in Scow Bay wouldn’t shut off on its own.
Harbour said the generator is designed to gradually slow down once the town’s electric grid is back on hydropower, and then shut off.
But it didn’t slow, so they had to manually shut it down, which caused a whole system crash — and another hour-long outage.
That second outage happened right before 11:00 a.m. and also affected all of town.
But, “gremlins” aside, Harbour said residents shouldn’t worry about planned SEAPA outages, “Because we slowly take the load from SEAPA and put it on our generators, and then we disconnect seamlessly — 99 times out of 100.”
By noon, all power was restored and Petersburg was back running on hydropower.
