Petersburg experienced a power outage on Monday, Oct. 19, after a regional hydropower supplier’s system went offline. The town ran on diesel generation until around 8:00 p.m. once the supplier’s feed was available again.
Petersburg gets much of its electricity from Southeast Alaska Power Agency, or SEAPA, which also supplies power to Wrangell and Ketchikan. Those two communities also reported outages Monday morning.
SEAPA was working on its Tyee hydro project and needed to take its power feed offline on short notice, according to Petersburg’s Utility Director, Steve Harbour.
“They gave us a call [this morning] and said, ‘Hey can you shut down, can you go on diesels at 9:30?’ That was the plan,” Harbour told KFSK around 9:40 a.m. on Monday.
However, the power went out several minutes before planned.
SEAPA experienced a system-wide outage. Harbour noted he hasn’t yet heard from SEAPA about the cause, “and it will probably be a day or two before we receive their report.”
He said Borough staff were in the process of switching the town onto diesel-generated power when the SEAPA feed went offline, and lights went out across town.
“It’s a holiday for us,” Harbour said Monday morning. “But we got a decent crew to come in, and we should be restored like normal.”
But, in the hours following that interview, staff faced a number of mechanical issues and capacity constraints while working through options to restore power.
During an outage last month, two of Petersburg’s generators had mechanical issues. One was quickly repaired. The other, located at Scow Bay, still requires servicing.
Harbour said the Borough’s own Blind Slough hydroelectric plant, south of town, goes offline when Petersburg experiences a system-wide outage. So, Petersburg was without both the Blind Slough hydro plant and the Scow Bay generator during Monday’s outage.
Staff were able to get the Borough’s hydro plant back online, until an old valve tripped and shut it down again.
“When we lost the hydro generation, the electrical demand exceeded our available diesel generating capacity,” Harbour wrote in a message to KFSK Monday afternoon.
To prevent losing the entire system, he said staff reduced the load by opening a breaker that serves, namely, “the Sandy Beach and Silver Bay areas, along with other customers on that line.”
Then an old generator, dating back to the 1950s, was brought online, allowing staff to close the breaker and restore power to those areas.
“At that point, we were in reasonably good shape. We didn’t have a lot of extra generating capacity, but we felt comfortable with where we were,” Harbour wrote. “Unfortunately, the 1950s generator then experienced a mechanical problem and shut down.”
He said that was when Petersburg experienced a longer, widespread outage.
With just a couple of options left given the limited available generating capacity, Harbour said the utility department contacted the largest customer on that particular circuit: Silver Bay Seafoods, a processing plant downtown.
“We really appreciate [manager] Don [Spigelmyre] and Silver Bay working with us on that,” Harbour wrote. “Their cooperation made a significant difference in our ability to stabilize the electrical system and restore power to the community.”
Harbour said the series of events during Monday’s power outage “underscores our need to finish the new generator project” at Scow Bay, “and look forward at the next.”
KFSK reached out to SEAPA on Tuesday and did not immediately hear back.
This story has been updated.
