The Blue Lake dam expansion is about seventy-five percent done, city officials told the Sitka Chamber of Commerce this week (Wed 5-14-14)
City engineer Dean Orbison and utility director Chris Brewton outlined progress on the hydroelectric project’s many moving parts. The city is raising the existing dam by 83 feet. Orbison told the Chamber that contractors are about three quarters of the way toward that goal. The city is also completing a new powerhouse, to house three newly-installed turbines.
The city is also building a new intake – the tunnel that brings water from Blue Lake to the city. Orbison reminded his listeners that the primary purpose of Blue Lake isn’t generating electricity – it’s providing drinking water.
“It runs through the mountain, through an unlined tunnel, just right through the rock,” Orbison said. “Blasted through there back in 1961. It was fantastic rock then, and it’s fantastic rock today…It’s unfiltered water. [It] comes straight from Blue Lake, we put a little bit of chlorine in it, and we drink it.”
So far, the city has continued to rely on Blue Lake for drinking water throughout the construction. But this fall, contractors will have to shut down the existing plant and switch over to the new one. For about two months, the city won’t be able to use Blue Lake for either drinking water or generation.
That outage is scheduled for September and October. During that time, the city will generate electricity from Green Lake, and it will rely on Indian River for drinking water.
Sitka used to get all of its drinking water from Indian River, before switching to Blue Lake. But the state has since tightened drinking water standards, and Indian River is no longer an approved source. So the city will rent a water filtration system for those two months, to the tune of $4-million.
After Orbison spoke, Brewton ran through the funding for the project. Sitka has received about $57-million in state grants and the city has borrowed about $82-million in the form of municipal bonds, he said. Sitka still needs to raise about $18.6-million, which city officials hope will come in the form of a low-cost loan from the Alaska Energy Authority.
Those might sound like big numbers, Brewton said, but he reminded his audience why Sitka relies on hydro power in the first place: A diesel turbine burns 24-thousand gallons of fuel a day.
“One day at the Blue Lake plant produced about the same energy,” he said. “And it uses 387-million gallons of water for one day of operation at Blue Lake. That will take about .27 inches of rain to replace that in the lake. We get about 131 inches of rain here a year, according to some NOAA charts, so that’s by far the best choice of fuel. It’s free and we get lots of it.”
Brewton said that even with recent electric rate increases to pay for Blue Lake, Sitka’s electricity rates remain relatively low.
“In 1993, a summer average residential was paying $113. Come July 1 of this year, when we implement our rate increase, they’ll be paying $118,” he said. “That’s remarkable that the rates have been relatively steady for that period time, and what that means is, [the] same thing [will happen] with Blue Lake. Once the project is done and all the costs are finished, we’re going to have essentially stable rates for the next 20 or 30 years, barring any unforeseen disasters.”
“So the folks that were wise enough to build Green Lake in the past really made an excellent decision,” Brewton said. “I don’t anyone that’s opposed to Green Lake these days that would rather us be running diesel for the past thirty years.”
The Blue Lake contractors are offering public tours of the project. The next tour will be this Sunday, May 18. You can sign up, and find more information and videos about the project, at bluelakeexpansion.com.