Power lines. (Nathaniel Robertson/Flickr Creative Commons)

Power lines. (Nathaniel Robertson/Flickr Creative Commons)

Increased demand for electricity and a diesel engine equipment failure factored into a recent power outage in Skagway and Haines.

On Monday, both communities went dark for about 15 minutes starting at 3:32 p.m.

Alaska Power and Telephone manager Darren Belisle says a diesel engine that supplements the main hydropower source suffered an equipment failure.

“A part wore out that let us know at the most inopportune time,” he said.

Skagway and Haines’s largest power source is the Goat Lake hydroelectric facility north of Skagway. It provides four megawatts of power. But when temperatures drop below freezing in the winter, Belisle says that isn’t enough to keep up with demand.

“With the increased power load due to the cold weather, it’s people having their heat on and Christmas lights — people don’t think about it, but Christmas lights add a lot of load this time of year. So Goat Lake doesn’t have the capacity to keep up with everybody so we have to turn a diesel engine on to help.”

Belisle says looking at last week, when it was a little warmer, and this week, when temperatures dropped into the teens and single-digits, power demand increased about 20 percent.

In the summer, AP&T supplements Goat Lake with run-of-the-river power from Kasidaya Creek near Skagway. But in the winter there’s not enough water in the creek to use for energy.

Belisle said AP&T turned off Kasidaya and switched to diesel support last week. He said AP&T usually has to run diesel engines during the winter and they have the capacity to handle increased demand.

When the equipment failure happened Monday afternoon, backup diesel engines in Skagway and Haines restored power after about 15 minutes.