Darkness struck Kodiak around 7 p.m. on Thursday night after wind and ice disabled a transmission line running from the Terror Lake hydroelectric plant to the city of Kodiak.
Lights went off everywhere in Kodiak, Bells Flats, Chiniak and Pasagshak for varying amounts of time. Some places were without electricity for half an hour, some were dark for more than two hours.
Kodiak Electric Association President and CEO Darron Scott said there has not been an outage on the Terror Lake transmission line for eight or nine years, and the whole system hasn’t lost power in five years.
Power came back on in some places a half hour later when KEA’s diesel generators kicked back on. Others got power back a little later.
The issue on the line was rectified on Friday, and Kodiak’s power supply shifted back to hydro and wind.
The transmission line, Scott said, suffered a fault about halfway along it’s 17-mile length. KEA dispatched a helicopter to survey the line to try to find what exactly happened.
“It looks like we had some heavy icing combined with high winds that caused the lines to get too close and contact,” Scott said.
“But there was no significant damage or anything, so we were able to get to the line back on.”
The transmission line is actually three wires, all working independently of each other. If they get too close, then things malfunction.
Kodiak’s daily report from the National Weather Service on Thursday said temperatures were between 35 and 40 degrees Fahrenheit. Average wind speed was 35 miles per hour, with gusts up to 56 miles per hour.
At higher elevations, ice can build on the lines, sometimes several inches. Add the wind to the mix, and that’s a lot of strain on the wires.
Once power went out from Terror Lake, KEA had to call up its three backup diesel generators that are located around town.
But it’s not as simple as just flipping a switch. The generators have to heat up and there’s a whole process to start them safely.
Supply and demand also have to equal each other on an electric grid. When all the supply drops out, as it did on Thursday night, it takes some tinkering to restart it at the right levels.
“We have to make sure we’re matching. And that takes a while, to make sure we’re all stable,” Scott said.
That’s why some parts of town got power back before others.
KEA’s windmills still contributed to the mix. Operators cut them off at first and then reintegrated them into the power supply.
Usually Terror Lake supplies about 80% of Kodiak’s power, with the windmills kicking in the rest and the diesel generators as backup for times like this.
While the town ran on diesel, however, they were supplying slightly less than they usually do, for reasons Scott said would take an “essay” to explain.
“It’s providing power, but we don’t let it just kind of do its normal operations. We clamp it down to keep it more stable,” he said.
The big issue with running diesel generators is that they burn through money, too. A few days isn’t a big deal, but it’s a concern if it lasts much longer.
“It’s a very expensive process for us to run the whole town on diesel,” Scott said.
Thankfully, that wasn’t an issue as crews found and fixed the problem quickly.