Green Lake dam awaits replacement part to get back up and running

The failed hydraulic ram, at the bottom of a 160 ft shaft at the Green Lake power plant. The ram – which is essentially a water-powered pump – failed while the Green Lake Tunnel was being drained for a planned inspection. (File photo courtesy of Utility Director Bryan Bertacchi)

A breakdown in the Green Lake hydroelectric plant has forced Sitka to temporarily switch fuel sources this winter.  The city – which normally runs on hydropower – has been using diesel since October to meet energy demand on the coldest of days. As the Electric Department waits for the new part to arrive. KCAW’s Emily Kwong visited the dam to see the work in progress.

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Audio transcript:

Bryan Bertacchi is Sitka’s Utility Director.

“Where we’re going is we’re going to Green Lake Dam, this is a side view of the dam right here,” Bertacchi said.

It’s 8 a.m. The temperature is below freezing, and has been for several weeks. But before throwing on our coats to head out Green Lake Road, we take a moment to look at a diagram of the dam’s inner workings.

“This is the single most important safety feature in the powerhouse,” Bertacchi said.

That being the intake gate.

“If there’s a leak or something goes wrong in the powerhouse, the first thing you do is you close that gate because you can imagine the amount of water going down there,” Bertacchi said.

The gate is opened and closed by a giant hydraulic cylinder, 11-feet-long. The problem is that it’s made of carbon steel, which corrodes easily in fresh water. Bertacchi shows me a picture of the old part. It’s rusted red and chewed up, like a Slim Jim.

“Last time it was operated was 1989,” Bertacchi said. “And it’s underwater when it’s running, so all the fish stuff…this was really a mess.”

Now FERC, that’s the Federal Energy Regulatory Commission, requires that the whole system be inspected every five years. But that didn’t happen in Sitka. Decades went by, with no inspection of Green Lake. I asked Bertacchi, who started on the job last year, why.

“I think there were a lot of other distractions they were working on overtime,” Bertacchi said. “Funding was kind of tight for a lot of years on the Electric Department. They weren’t doing much. They weren’t doing tree trimming. There’s a lot of stuff you just can’t do. But I can’t speak to why the decision was made not to do that. All I know is my job is make sure we’re in compliance with all the rules and regs. And it’s a safety issue. It’s a $50 million asset on the other end of this pipe.”

So, to get system back into compliance, the Electric Department decided to schedule the inspection on October 17th.

“We didn’t want to do this in the middle of summer, with our tourist season, fish processing, when we needed all the energy for sure,” Bertacchi said. “We picked this time of year to go do it, we thought it would work okay but it didn’t.”

What happened is that the gate closed, that went fine, but red oil appeared in the water. The seal on the hydraulic cylinder had broken. Coast Guard was called in to contain the leak, about five gallons of oil. The dam shut down. And Bertacchi, who was then acting city administrator, authorized an emergency procurement of $60,000 for a replacement cylinder to be built out of stainless steel, which should fare underwater much better. When it arrives, it will be installed inside the belly of a dam, at the bottom of a 160 foot shaft.

We’re at the Green Lake Dam. Water is spewing over the top in a furious cascade. And I’m peering over the edge of the shaft, where Adam Charlton, Tony Balovich, and Trevor Webb have been working six days a week, twelve hours a day, to clean out the muck and prepare the area for the new part. Here’s Balovich and Webb.

“When you get down there it’s like working in a muddy ditch, laying a pipe,” Balovich said.

“With no light,” Webb said.

“With very little light,” Balovich said.

“They’re having their lunch down there,” Bertacchi said. “It’s amazing.”

Safety is Bertacchi’s #1 priority. There’s a ladder and when the mechanics descend, they wear a harness that they can hook onto the side. They’re also clipped to a cable, that would automatically stop them if they fall. And on standby is a crew of emergency and search and rescue personnel.

“It’s the unsung heroes in all this too,” Bertacchi said. “Because with the wind up and it’s snowing, they’re getting out there and they’re doing this job.”

Temperatures plummeted in December and the cold has forced the electric department to fire up the diesel generators during peak use. So far, they’re within their $166,000 budget for diesel. There likely won’t be a fuel surcharge for the community. But it’s very likely that major components of Sitka’s electrical infrastructure will continue to fail. Here’s City Administrator Mark Gorman.

“It’s reaching the end of it’s life and we have not put in the bank what we have needed to put in in terms of taking care of it and we’re seeing those consequences now,” Gorman said.

Like the Marine Street substation, which provides power to 80% of the city, and the 69 kilovolt line, which delivers a huge amount of power to downtown. The Sitka Assembly recently approved a 10 year capital plan to fix these and other problems. But that will take money, which is scarce within a city also tasked with paying off the $150 million Blue Lake Dam. For Bertacchi, the key is identifying what the city is not going to fix and focus on the big things that ensure reliability.

“We’d hate to have a two month outage in the middle of our summer season impacting fish processing and everything else,” Bertacchi said. “So that’s where our focus is and that’s why we’re here today.”

Not here yet is the hydraulic cylinder, but it’s scheduled to arrive on Tuesday. The city hopes that the Green Lake Dam will be back in operation before the new year and the next cold snap.

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