Alaska Electric Light & Power lost all power from the Snettisham Hydroelectric Project, causing an area-wide power outage this morning, the company said.
Scott Willis, AEL&P’s power generation engineer and spokesman, said line crews discovered damage to the support system of three tower structures on the Snettisham transmission line. Each tower, located about three miles from Snettisham, is supported by four guy-wires, which are tensioned cables fashioned to the tower and anchored to the ground. Two of the steel anchors that are cemented into the ground broke, causing one tower to fall and to lean against a neighboring tower.
“When the guys failed, the uphill structure started to lean downhill,” Willis said. “The conductor on that tower came to rest on the guy-wire of the center tower. This provided a path to ground — conductor to guy-wire to ground — and was actually what caused the short circuit.”
Willis estimated it would take approximately three to seven days to repair.
He added the cause of the damage is unknown at this point, “but there is no sign of any avalanche activity at this tower, so it probably wasn’t that.”
Power went out in Juneau around 6:30 a.m. and could not immediately be re-energized, so AEL&P began running its backup diesel generators around 6:45 a.m. Power was fully restored to all 15,844 customers by 7:45 a.m. At that point, AEL&P began turning on hydropower generated from the Lake Dorothy, Annex Creek, Salmon Creek and Gold Creek hydroelectric projects, and easing off the diesel. Those four hydroelectric plants were running at full-capacity by 11:30 a.m.
AEL&P is currently running 60 percent diesel and 40 percent hydropower. That equates to using about $10,000 of diesel an hour, Willis said, “maybe a bit more during the day and less at night.”
AEL&P customers will not see an immediate charge for the diesel on their bill, he said. The fuel cost will be recovered through the normal quarterly Cost of Power Adjustment to begin in January, he added.
“It is still too early to tell exactly what that COPA charge will be,” he said, adding an estimate will be provided early next week.
The cost of fuel is one of the main factors that determines how much customers will be charged for the use of the diesel units, which has the potential to energize all of Juneau when hydropower is cut off.
The good news in this case is the tower structures and cables are still intact, unlike in April 2008 when avalanches destroyed three structures and damaged two others on the Snettisham transmission line, Willis said. Diesel generation cost the community $1.5 million per week, and customer bills skyrocketed up 400 to 500 percent during the month-long outage.
Consultants from City Electric Inc., an electrical and telecommunication contracting company in Anchorage, will be coming to Juneau to help assess the damage and help plan how to move forward, Willis said. Crews are expected to begin working at the site on Friday, he added.
“Today we’re making plans and we’re gathering materials, supplies and equipment,” he said on Thursday. “Tomorrow we’ll mobilize personnel crews to Snettisham.”
About 70 percent of AEL&P’s power comes from the Snettisham Hydroelectric Project, and the remaining 30 percent is generated from the Lake Dorothy, Annex Creek, Salmon Creek and Gold Creek hydroelectric projects.
• Contact reporter Emily Russo Miller at 523-2263 or at firstname.lastname@example.org.