Subterranean Power Station Blues: A underground tour of Aishihik

The undisturbed wilderness surrounding Aishihik Lake is an illusion. Buffalo graze at a leisurely pace, the mountain peaks are hidden behind a…

The undisturbed wilderness surrounding Aishihik Lake is an illusion.

Buffalo graze at a leisurely pace, the mountain peaks are hidden behind a shroud of clouds and the first heavy snow of the year blankets an endless forest of dark pines.

But all is not pristine wilds.

Beneath nature’s calm, a man-made ruckus roars through tunnels, turbines and canals at an unforgiving speed. Aishihik’s two-turbine power station thunders relentlessly at 115 metre’s underground.

There’s no rumble on the earth’s surface, just a two-storey home, a small warehouse and an electrical switch yard to mark the site. It looks more like a gated hunting cabin with exceptionally high electrical maintenance needs than an underground dam.

Jim Petelski is the maintenance engineer currently living in the two-story home. He’s nearly done his eight-day stint here.

This isn’t his regular job with Yukon energy, he said, but sometimes he needs to fill in. One of the engineers who usually monitors the station hurt himself while playing on his ATV, he said.

Does it get lonely or boring?

“A bit of both.”

What do you when you’re not working?


Looks like someone’s got a case of the Subterranean Power Station Blues.

It’s too bad Yukon Energy won’t let engineers bring their families when it dispatchs employees to this outpost. A tiresome whine coming from the basement isn’t the best company.

And besides, Aishihik is a great place for kids. The hydro facility evokes thoughts of an underground lair and secret missile silo in one — a mix of James Bond and Doctor Evil. It’s buckets of fun — just remember to bring your steel-toe Uggs, kiddies.

And be prepared for two things – earplug dispensers and safety posters. They’re everywhere.

In fact today, Petelski gets to share his infinite knowledge of hydro station safety precautions with a gaggle of clumsy reporters. The goal is to keep their camera straps, tripods and loose clothing from accidentally plunging the Southern Yukon into a blackout.

Even kids would be easier to guide on a tour of Aishihik. At least they know how to pack light.

There are three ways to descend into the bowels of the power station. You can take the basement-only elevator down 36 floors. You can take the stairs with its rest landings at every six metres. Or you can throw yourself 115 metres down a giant vertical shaft used to lower new parts into the power station.

We took the elevator.

After taking our crowded elevator to the station’s second-lowest floor, we arrived at the surge chamber. It’s sealed by air-tight doors in case of an emergency.

The walls are not covered, so condensation drips from the jagged walls of rock and puddles on the floor. It’s an underground equivalent to a panic room with food and life jackets to sustain its terrified inhabitants.

In the event of an emergency — and if you’ve got a thing about being buried alive in a wet closet — there’s another way to escape this claustrophobic nightmare.

In front of the main turbine room, the water being used to generate electricity jets out into in an underground cave.

This gigantic rush of water flows down a 1.5 kilometer-long canal. It’s called a tailrace in hydro station jargon, and it’s basically a watery tunnel which takes you into broad daylight at the West Aishihik River.

In the giant cave a small white dingy hangs from a platform. If the panic room is getting crowded, or you missed the fire alarm because of those infernal earplugs, you can lower the boat, fall into the river, follow the light and end up more than a kilometer away.

It’s one smooth exit.

And if you’re a parent who’s said no to a McDonald’s request one too many times, a trip down the tailrace would make everything up. Your kids would love you forever.

Just when you think you’re actually in a safety precaution museum and not a power station, Petelski brings the reporters to the “power house.”

It is dominated by the two giant green generators, creatively named Aishihik One and Aishihik Two.

Each generator can produce 15 megawatts for the grid which spans from Haines Junction to Whitehorse.

Only Aishihik One is running today. Haines Junction is using 1.3 megawatts while Whitehorse is receiving 10 megawatts.

Both generators are controlled in Whitehorse, but someone always needs to be at Aishihik in case the communications shut down.

That scenario actually happened the night before, said Petelski, but he assured one of the reporters from Porter Creek that it had nothing to do with the outage that interrupted his TSN sports center.

Petelski also needs to be there to do manual inspections. Some of the information goes to Whitehorse, but some of the monitoring needs to be done with a human eye.

“We’ve got 2000 technology and we also got 1950s technology. And the 1950s technology is sometimes more reliable,” he said.

Next, we go to the lowest room in the station, the turbine room. Just beneath the generators, water flows through the turbines. A giant gold shaft spins at 720 rotations per minute just below the water intake into the turbine.

Aishihik Two’s gold shaft is completely still, but Petelski warns us to keep clear. All it takes is one more toaster on the grid and, bam! A reporter could be dragged in by the pant leg and spun like a human gyroscope.

Aishihik was built by carving a canal from Aishihik Lake to a manmade underground waterfall.

The water drops 174 meters, building up speed over almost a kilometer before it reaches the turbine.

The power station harnesses the power of that water.

The rock encasing the Aishihik plant is ideally suited to withstand the pressure of all that water.

And the pressure is immense.

When the water enters the turbine, the pressure is 286 psi. Aishihik is about mastering the uncontrollable, and it’s a wonder every screw stays in place.

Canadians are pretty good at building these plants.

The Robert-Bourassa underground generating station in north-western Quebec, named “La Grande”, is the biggest generating site in North America and can produce 5,619 megawatts.

And Aishihik is more than 90 per cent Canadian made.

Once outside, Petelski checks the water levels at the lake. The extra snow means the water levels are high and the current going into the run-off river needs to be increased.

Near the control latch there’s a campsite where visitors can go fishing and hiking.

But how can you enjoy the outside world when there’s a hydro station nearby?

“In the summer, I come right back out here with my kids to the campground after work,” he said. The fishing in the rivers isn’t bad either.

In the wilderness above Aishihik’s power station, humanity’s work is hidden. A secret.

Unless you put your ear to the ground.

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