Churchill Falls, 'here for many years to come,' has room to grow. Here's why

"Quebec is that way," says Walter Parsons, pointing toward a string of power lines spanning south across the Churchill River.

As he speaks, the high voltage wires – the beginning of a 1,200-pylon transmission network leading to the Quebec border – crackle softly, breaking the silence of an otherwise still morning in Labrador.

"That's where we send about 90 per cent of the electricity produced here at Churchill Falls. For Quebec, that's about 15 per cent of all their electricity," adds Parsons, Newfoundland and Labrador Hydro's vice-president responsible for transmission and business development.

For a few hours, Parsons serves as CBC/Radio-Canada's guide, giving a small camera crew a rare glimpse of the isolated Churchill Falls hydroelectric complex – the second most powerful in the country, whose future is currently being negotiated by the Quebec and Newfoundland and Labrador governments hundreds of kilometres south.

As Parsons walks through the quietly buzzing switchyard, some 300 metres below his feet, water from the Churchill River rushes through 11 spinning generating units.

Each one weighs about 800 tonnes. Together, they supply hundreds of thousands of homes with electricity.

"The plant is completely underground," Parsons says.

"Don't forget, Churchill Falls really started out as a mining project. We had to take out all the rock," adds Cyril Penton, who oversees day-to-day operations at the Churchill Falls plant, which first produced electricity in 1971.

Churchill Falls isn't just one dam, but rather a series of 88 dykes redirecting a watershed the size of New Brunswick toward a plant buried deep in the rock.

When it arrives at the intake level, the water plunges suddenly down 11 intake canals.

The rapid descent helps explain why Churchill Falls is an ideal place for producing hydroelectricity. The higher the drop, the quicker the water falls and the more force it exerts on the turbines, producing more electricity.

The plant's main elevator follows that vertiginous drop. After a few seconds, the doors open onto a granite tunnel, where the air is heavier and the sound – a heavy machine thrum – is everywhere.

A set of heavy doors swing open to reveal a vast tunnel stretching 300 metres and housing a row of transformers the shape of giant, high-tech dumpsters.

Each machine controls the voltage and intensity of the electricity being sent to the surface. Each one regulates some 550 megawatts of electricity – enough to power the entire Avalon Peninsula.