Electricity conservation still urged to refill Southeast hydro lakes

Recent photo of the Tyee reservoir. (Courtesy Southeast Alaska Power Agency)

Petersburg’s utility director doesn’t foresee the need for more diesel power generation this spring but says the community’s conservation measures will continue to help hydroelectric reservoirs refill this spring.

The community this month is on hydro power from the borough’s plant at Crystal Lake on Mitkof Island as well Tyee Lake near Wrangell, owned by the Southeast Alaska Power Agency, or SEAPA.

“The term that SEAPA uses is we’re almost close to making the turn, which is a seasonal change to warmer temperatures, not only more rainfall instead of snow, but snow melt in the watersheds,” said Karl Hagerman, Petersburg’s utility director. “And we are very close,” he added.

Both Wrangell and Petersburg ran diesel generators this winter to make up for dwindling hydro reservoirs in the midst of an ongoing drought. This past week has seen several weather systems with significant rainfall.

“It did help on the south end a little bit better,” Hagerman said. “Swan Lake is responding to a better degree than Tyee is from the recent rainfall. Tyee is not drafting down continuously like it was before those rain events so it did take a jump up by a half, three-quarters of a foot for both of those rain events. But then as temperatures come down at night and the loads go up, we see less water coming in during periods of colder temperatures and also the increased loads in the morning peak of the system in Wrangell and Petersburg really draw the lake down quite dramatically.”

Swan Lake is one of Ketchikan’s hydro power sources and it’s not currently providing any power to Wrangell and Petersburg. Likewise, Tyee Lake is only powering Wrangell and Petersburg. That lake this month is up more than three feet from its low point in March but continues to fluctuate daily.  The level of the Petersburg borough’s Crystal Lake meanwhile is climbing slowly.

Hagerman said historically lakes start to refill rapidly at the end of this month and the beginning of May but that has not started yet. His message: conserving electricity is still a good idea.

“It’s always a good idea I think to push conservation until we’re absolutely positive that the lakes were on the rise and the turn has actually come upon us,” Hagerman said. “So I would just encourage folks to if you’ve created new habits in conservation to continue those for the short-term anyway.”

Hagerman does not anticipate having to run the backup diesel generators again in the short-term in place of hydro generators. He said SEAPA is drafting a plan to keep Wrangell and Petersburg off diesel except for maintenance work. However, diesel power could still be needed again if this summer is dry like last year’s.

Joe Viechnicki is a reporter at KFSK in Petersburg.

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