AISHIHIK - Underground hydroelectric facilities are not uncommon. When the Aishihik Power Plant was built in the early '70s, however, it was the first of its kind North of 60.

On the surface, it looks like just another building, with a garage door, some windows, and a bunch of big wires strung out back.

But far below - 36 storeys below - are two of the territory's main hydroelectric generators, sitting in a cavernous structure carved out of bedrock.

It"s something of a James Bond movie.

The rock walls ooze groundwater, in contrast to the banks of sophisticated panels of dials and knobs surrounding the generators and related equipment.

It looks more like an underground hideout for a diabolical psychopath than the essential piece of electrical infrastructure that it is.

With a vertical drop of almost 180 metres, the force of the incoming water from the Aishihik Lake system creates 20,500 of horsepower, spinning the turbines at 720 r.p.m.

Through the winter, its the heartbeat of the Whitehorse-Aishihik-Faro grid.

System monitors detect the slightest vibration in the turbines, or variations in operations at Aishihik.

Hydro-mechanic Jim Petelski can watch what"s going on down below from his office topside, as can Whitehorse.

The system control centre at the Whitehorse Rapids Dam sees all, and controls all, though the Aishihik plant is staffed 24-7 in case there's a need to switch to onsite operation of the facility.

Once a day, the local Aishihik operator takes the 90-second elevator ride down to the generator floor. (On his best day, Petelski can make the climb up the emergency ladder in 8 1/2 minutes.)

With all the electronic monitoring that goes on, it's still a good idea to check things out first-hand, Petelski explains in an interview Tuesday during a tour of the subterranean facility.

Should a fire break below, there is an isolated chamber, outfitted with emergency food and survival equipment, where personnel can take refuge until help arrives from Whitehorse.

"But there's not a whole lot that can burn,"Petelski quips. "Everything's made out of rock."

In the event smoke did breach the shelter, there's a dingy that can be lowered into the discharge tunnel for a 1.5-kilometre Disney-like ride through rock to the beauty of the West Aishihik River.

How James Bond is that?

The splendor of the Aishihik was once featured on the back of the Canadian $5 bill with a picture of Otter Falls.

While some believe the falls are not what they use to be since the Aishihik dam was built, Petelski points out Yukon Energy is compelled by its water licence to maintain minimum flows over the falls to ensure a stable ecosystem.

Down below, a team of engineers is also touring the plant, as the publicly-owned corporation advances its plan to add a third turbine to the Aishihik plant.

Directly above the two main generators, at the top of the large 111-metre shaft, is a 38-tonne crane which will be an integral piece of equipment to install the new unit, with its total weight of 100 tonnes.

The intake and discharge channel for a third turbine were blasted out during the original construction of the Aishihik facility, which became operational

in 1975. It was a time of growing demand, particularly from the huge electric equipment at Faro"s burgeoning lead-zinc mine.

Demand is on the rise again, from domestic and industrial users.

Currently, the Whitehorse-Aishihik-Faro grid has a surplus of hydroelectric energy. That surplus will all but disappear later this month when the Minto mine and the community of Pelly Crossing plug into the WAF grid.

The third Aishihik turbine is a feature of Yukon Energy's 20-year plan to build hydroelectric capacity.

Though half the size of the two larger generators, the new seven-megawatt unit is meant to provide flexibility in conserving water stored in Aishihik Lake, explains Yukon Energy spokeswoman Janet Patterson.

Half the size, she says, requires half the water.

The WAF grid is largely dependent in the summer on the 40 megawatts of hydroelectric capacity at the Whitehorse dam. But the role is reversed in the winter, when Yukon Energy relies on the water stored in Aishihik Lake through the summer to help power the grid.

Patterson points out Yukon Energy is hoping to have the new turbine ready for installation during the summer of 2010.

The Aishihik facility, she notes, will have to be taken off-line for a few months during the installation, though it will be available in case of emergency.

She says Yukon Energy is planning to go out to tender for the new unit by the end of this month, as delivery is expected to take 18 months or so.

In the meantime, other work will be focused on expanding the rock tunnel and additional electrical work.

The cost of adding the third turbine is estimated at $8 million, of which $5 million is coming from the federal Eco-Trust Fund.