Bersimis-1 Generating Station

The Bersimis-1 generating station is a dam and a hydroelectric power station built by Hydro-Québec in conjunction with Perini, Atlas and Cartier construction companies on the Betsiamites River, in Lac-au-Brochet, north of the town of Forestville, Quebec. Construction started in 1953 and the power station was commissioned in 1956 with an initial nameplate capacity of 912 megawatts.

It is the first plant ever built by Hydro-Québec and it has been described as a turning point in the history of electricity in province, paving the way for the takeover of all private utilities by the government-owned corporation in 1963. Three years later, the first plant was followed by a second one, built downstream. Bersimis-2 entered service in 1959.

With upgrades, a major overhaul in the 1990s and further river diversions, Bersimis-1 installed capacity has been increased over time to its current 1,178 megawatts.

Geography

The Betsiamites River, also known as the Bersimis, is located halfway between the Saguenay and Outardes rivers, on the north shore of the Saint Lawrence River, downstream from Quebec City. With the exception of an Innu reserve at Betsiamites, at the mouth of the river, the area is scarcely populated.

The word ''Betsiamites'' or ''Pessamit'' is from the innu language and means "the assembly place of the lampreys". ''Bersimis'' was not used by either the Innus, the French or the French Canadians, but was introduced by British admiral Henry Wolsey Bayfield, in his hydrographic surveys of the Saint Lawrence River of 1837. The Hudson's Bay Company used the name when opened a trading post in 1855, as did the post office in 1863. After 2 decades of efforts, residents and the Quebec government convinced the federal government to start using ''Betsiamites'' in 1919. But administrative use of ''Bersimis'' perdured for decades and Hydro-Québec used it in the 1950s to name its facility in the area.

Located in the Central Laurentians ecoregion of the Boreal Shield Ecozone, the hinterland is heavily forested and dominated by softwood species: black spruce (''Picea mariana''), balsam fir (''Abies balsamea'') and white spruce (''Picea glauca''). In 1937, the Quebec government granted a forest concession to the Anglo Canadian Pulp & Paper Co. to supply its Forestville mill, on the coast. The area is described as "a sportsman's paradise, where fish, moose, bear and a host of other game creatures abound".

The river is well suited for hydroelectric development. The river falls over , between Lake Pipmuacan, and the delta, including an initial drop of on the first . The site was also ideal because the river flow could be controlled very easily at the outlet of Lac Cassé. More development was also possible at a second location, approximately downstream, to capitalize from a further drop. The second site was developed between 1956 and 1959 and came to be known as Bersimis-2.

Background

The post-war boom in Quebec created an unprecedent increase in electricity demand in Quebec. Planners, at Hydro-Québec and other public utilities serving the province, were kept busy looking for ways to increase supply. In the Montreal area, the addition of 12 more units at the Beauharnois generating station would not be sufficient to meet the steady increase in demand as early as 1956.

Quebec's largest private utility faced the same problem. Although the Shawinigan Water & Power Company (SWP) added units at its Rapide-Blanc and La Tuque facilities while building the brand new 184-MW Shawinigan-3 (1949) and the 300-MW Trenche generating station in 1953, company executives were eager to increase capacity by getting the government to award new hydraulic concessions on undeveloped rivers.

SWP sets its sight on the promising rivers in northeastern Quebec. In 1948, its engineering subsidiary, Shawinigan Engineering, surveyed the North Shore rivers and started planning for the construction of a 1,000,000 horsepower (746 MW) generating station on the Betsiamites River, downstream of Quebec City. The drainage was easily regulated from its source, Lac Cassé, and according to preliminary calculations, developing the remote site would cost $125 per horsepower, a cost low enough to offset the cost of power lines to bring the power to Quebec's largest cities.

But the Quebec government decided otherwise. The hydraulic concession was granted instead to government-owned Hydro-Québec in September 1951. According to Claude Bellavance, an economic historian who wrote a comprehensive book on the rise and fall of SWP, this decision by the Maurice Duplessis government had major consequences on the future of the company, which was bought and merged by Hydro-Québec in 1963. In hindsight, writes Bellavance, this move represented a major step towards the re-appropriation of this economic sector by the State, making Hydro-Québec the main if not the sole entity in charge of hydroelectric development in the province.

Construction

Preliminary work began in June 1953. The first step involved building infrastructures to deliver 500,000 tons of equipment, food and supplies to the 5,000 workers on site, including a wharf and a warehouse in Forestville and of roadwork in the hinterland. Everything, from sundries to cement, was shipped to Forestville, then unloaded at the Hydro-Québec wharf in Forestville and loaded into trucks for the trek to the interior.
The 2-lane road from Forestville to Labrieville is now part of the Quebec highway network and is now known as Route 385.

Labrieville

But even before starting work on the dam and power station, a stable supply of electricity was required. Hydro-Québec built a temporary hydroelectric plant at nearby Lac Cassé between November 1952 and July 1953. The 15,000-horsepower (12 MW) hydroelectric generating station supplied the construction sites and camps. The equipment used for the temporary plant came from the Saint-Timothée generating station, a small hydro plant in the Montreal area dismantled by Hydro-Québec in 1949.

Construction of Labrieville, a village named in honor of Napoléon-Alexandre Labrie, founding bishop of the Gulf of St. Lawrence Roman Catholic Diocese, began in June 1953. Besides temporary quarters for workers, an 8-classroom school, a 400-seat church, inn, an administrative and commercial center and 117 homes were built. The first tenant took possession of a dwelling on November 16, 1953, and the village was completed in 1955.

Described as a "jewel set in the ruggedness of wild country", the village was located in the Betsiamite River valley a short distance from the generating station. Improvements in telecommunications and remote-controlled operations made it redundant, and the company chose to close Labrieville in 1974.

Dam

The actual construction of the dams and power plant kicked off in October 1953. Two rock-filled structures were built to create the Pipmuacan Reservoir, increasing the surfaces of lakes Pipmuacan and Cassé: the first, long and high, is built between two mountains surrounding the Lac Cassé, the second, long, curtailed the release of water into the Desroches River.

Vast quantities of clay was required to make the impervious cores of the rock-filled dams. A sufficient quantity was found nearby by surveyors with the assistance of native guides, who recalled seeing beavers fetching the material for their own dams.

A mountain between the two dams was cut down to build a spillway for the reservoir. Both dams are similar in conception to the Kenney Dam built in 1952 by Alcan as part of their Kemano, British Columbia generating station.

Generating station

The underground powerhouse is located from the dam. A diameter, concrete-lined water intake was dug in the Laurentian Plateau granite to bring water to a manifold, where individual penstocks feed the plant's 8 units. Work on the tunnel was carried out at an average speed of per week.

The surge tank has been carved from rock and is located from the first penstock. A shaft rises vertically , connects to the bottom of the surge tank, in diameter and deep, and opens on to a hilltop overlooking the village.

The powerhouse was carved inside the mountain and is accessed through a tunnel. Inside the long, high and wide cavity were installed eight 150,000-horsepower Francis turbines, connected to 13.8 kilovolt generators. Parallel to the powerhouse, a tailrace tunnel discharges the water to the river channel below.

Power lines

Construction of the 2 double-circuit high voltage overhead power lines built to carry power to Quebec City and Montreal attracted considerable interest in the engineering trade press and contributed to raise the profile of Hydro-Québec's engineers internationally. From the power station, the 315-kilovolt (kV) power lines, among the first to be built in North America at this voltage, follow a westerly direction to reach the Sault-aux-Cochons River, where they turn south following the valley. Near the mouth of the river, the line takes a south-westerly orientation, parallel to the Saint Lawrence River and crosses the Saguenay River fjord near Petit-Saguenay. Two sets of crossing pylons, separated by a span width of were built on each side of river in order not to interfere with shipping.

A third 315 kV power line to Baie-Comeau was built to bring power to the Gaspé Peninsula, via 4- submarine power cable

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