Since 1970, the waters of the Churchill River have been diverted into the nearby Churchill Falls hydroelectric power plant. Today water flows down the falls less than once a decade, during spring thaw or periods of exceptional rains. The Churchill Falls power station has the second largest hydroelectric-generating capacity in North America (5,428 MW (7,279,000 hp) installed, expandable to about 6,300 MW (8,400,000 hp)) and is also the second largest underground power station in the world, after the Robert-Bourassa generating station in northern Quebec.

In August, 1949, Joey Smallwood, Premier of Newfoundland, had the opportunity to see Churchill Falls for the first time and it became his obsession to develop the hydroelectric potential of the falls. In 1953 British Newfoundland Development Corporation (Brinco) was formed to do extensive exploration of the untapped water and mineral resources. With the development of the iron ore mines in western Labrador and the construction of the Quebec North Shore and Labrador Railway (1954), development of Churchill Falls as a power source became feasible.

After years of planning, the project was officially started on July 17, 1967. The machine hall of the power facility at Churchill Falls was hollowed out of solid rock, close to 1,000 ft (300 m) underground. Its final proportions are huge: in height it equals a 15-storey building, its length is three times that of a Canadian football field. When completed, it housed 11 generating units, with a combined capacity of 5,428 MW (7,279,000 hp). Water is contained by a reservoir created not by a single large dam, but by a series of 88 dikes that total 64 km (40 mi) in length. At the time, the project was the largest civil engineering project ever undertaken in North America.

Once all the dikes were in place, it provided a vast storage area which later became known as Smallwood Reservoir. This reservoir covers 2,200 sq mi (5,700 km2) and provides storage area for more than 1,000,000,000,000 cubic feet (2.8×1010 m3) of water.

The drainage area for the Churchill River includes much of western and central Labrador. Ossokmanuan Reservoir which was originally developed as part of the Twin Falls Power System also drains into this system. Churchill River's natural drainage area covers over 23,300 sq mi (60,000 km2). Once Orma and Sail lakes' outlets were diked, it added another 4,400 sq mi (11,000 km2) of drainage for a total of 27,700 sq mi (72,000 km2). This makes the drainage area larger than the Republic of Ireland. Studies showed this drainage area collected 410 mm (16 in) of rainfall plus 391 cm (154 in) of snowfall annually equalling 12.5 cu mi (52 km3) of water per year; more than enough to meet the project's needs. Construction came to fruition on December 6, 1971, when Churchill Falls went into full-time production.

The generating station is owned by the Churchill Falls (Labrador) Corporation Ltd. — whose shareholders are Nalcor (65.8%) and Hydro-Qu├ębec (34.2%) and operated by the Newfoundland and Labrador Hydro company.

The government of Quebec considered the inland watershed of Labrador to be part of their province and fought a long but losing legal battle to prevent granting the territory to Newfoundland at the Judicial Committee of the Privy Council.

The Churchill Falls hydroelectric power plant development was undertaken in the absence of any agreement with the aboriginal Innu people of Labrador. The construction involved the flooding of over 5,000 km2 (1,900 sq mi) of traditional hunting and trapping lands. A recent agreement signed between the government of Newfoundland and Labrador and the Innu offered the Labrador Innu hunting rights within 34,000 square kilometres of land, plus $2 million annually in compensation for flooding.

Project facts of Churchill Falls Power Plant

  • Churchill Falls power plant is the second largest hydroelectric plant in North America, with an installed capacity of 5,428 MW (7,279,000 hp).
  • Churchill Falls was, at the time of its construction, the largest underground power station in the world. (The Robert-Bourassa power station in Quebec currently holds the record, both for installed capacity and volume of the main underground hall).
  • The powerhouse is 972 ft (296 m) long, up to 81 ft (25 m) wide and 154 ft (47 m) high from the bottom to the top. The height would be equivalent to a 15-storey building or almost as long as three Canadian football fields (990 ft (300 m) and is hollowed from solid granite. To strengthen walls and ceiling, more than 11,000 rock bolts (steel rods 15 to 25 ft (5 to 8 m) long) were used in the three major chambers.
  • To move the 2,300,000 cu yd (1,760,000 m3) of rock that was excavated from the underground caverns, it required 5,000,000 lb (2,300,000 kg). This material was used in roads, building the town site, and as dike material.
  • The turbine wheels are cast of stainless steel and weigh 80 short tons (73 t) which is a world record for the largest stainless steel casting ever made.
  • During construction, 730,000 short tons (660,000 t) of material, equipment and fuel were moved to the site.
  • The natural catchment area for the Churchill River covers over 23,300 sq mi (60,000 km2).
  • By diverting the water from the Ossokmanuan Reservoir the total catchment area became 27,700 sq mi (72,000 km2).
  • Total natural drop of the water starting at Ashuanipi Lake and ending at Lake Melville is 1,735 ft (529 m). As a comparison, the water starting 30 km (19 mi) upriver until it enters the power plant drops over 1,000 ft (300 m).
  • There is no big dam associated with this hydropower plant. There are 88 dikes to contain the reservoir, the longest is 6.1 km (3.8 mi) and the highest is 36 m (118 ft). The total length of all dikes is 64 km (40 mi) and contains 26,000,000 cu yd (20,000,000 m3) of embankment material.
  • After five years of non-stop field work by approximately 6,300 workers and costing $950,000,000 (1970) construction culminated on December 6, 1971 when the first two generating units began delivering power, five months and three weeks ahead of schedule.
  • Currently Churchill Falls makes almost 1% of the world's hydroelectric power.
  • Newfoundland and Labrador recently announced a call to develop the Lower Churchill Project. This is, in fact, a number of small projects which includes a 2,000 MW (2,700,000 hp) dam at Gull Island, an 824 MW (1,105,000 hp) dam at Muskrat Falls, 1,000 MW (1,300,000 hp) upgrade to the existing facility at the Churchill Falls power plant. This would increase the present power production capability by an extra 4,000 MW (5,400,000 hp) for a total of 9,252 MW (12,407,000 hp) for the entire Churchill River hydroelectric complex.

Churchill Falls Hydroelectric Power Plant Spesification

Churchill Falls generating station
Year commissioned: 1971
Installed capacity: 5,428 MW (7,279,000 hp)
Annual energy output: 35,000 GWh (130,000 TJ)
Number of turbines: 11
Turbine capacity: 493.5 MW (661,800 hp)
Type of turbine: vertical Francis type, 200 rpm
Generators: 15 kV, 526,315 kV·A
Transformers: 14.75 kV/240 kV, rated at 5,500 MV·A
Net rated head: 312.4 m (1,025 ft)
Maximum tailrace discharge: 49,000 ft³/s (1,390 m³/s)
Powerhouse: 296 m (971 ft) length, 25 m (82 ft) width, 47 m (154 ft) height, 310 m (1,020 ft) below ground
Tailrace tunnels: 2 × 1,691 m (5,548 ft), 14 m (46 ft) width, 19 m (62 ft) height
Penstocks: 11 × 427 m (1,401 ft) length, 20 ft (6.1 m) diameter
Cable shafts: 11 × 7 ft (2.13 m) diameter, 263 m (863 ft) deep
Dikes: 88; 64.4 km (40.0 mi) total length, 9 m (30 ft) average height, 36 m (118 ft) maximum height
Size of reservoir: 6,988 km2 (2,698 sq mi)
Total catchment area: 71,700 km2 (27,700 sq mi)