Hydro-Québec | A rejuvenation treatment that brings power

(Baie-Comeau) “The current is strong in places! », says a Hydro-Québec employee on this cool September morning. His words have nothing to do with any electrical charge; rather, they refer to the power of the eddies downstream of the Manic-2 complex. Sitting in a container, in front of a quilt of screens, this submarine operator maneuvers the small Hydro-Québec submersible with a control lever that looks like a video game controller.

The film-like device Titanic skillfully navigates the cold, dark waters of the Manicouagan River and attempts an incursion into an exit from the power plant, called Jean-Lesage. “For security reasons, we now prefer the submarine to the divers who had to do this job,” explains Marc-André Marcoux, power plant power development project manager at Hydro-Québec.

The operation aims to assess the condition of the components of the large pipes with a view to replacing six of the eight turbine-alternator groups of the power station in the coming years. Because Manic-2 is preparing to host a large-scale project which will allow it to add 20% power (245 MW), the equivalent of what is needed to power 88,000 homes. “But changing the turbines requires preparation. Let’s say that it’s not like opening the hood of a car, removing the engine to put in a new one,” says Mr. Marcoux.

The entire site must be adapted. “When the power plant was built, the turbines were installed before the walls and roof of the power plant were raised,” recalls Steeve Gagnon, production and maintenance manager of the power plant. Result: to change these immense structures, the teams will have to maneuver in a limited space.

Already, outside, dozens of employees are busy adapting the structures for the preparatory work. Inside, the new machinery needed to lift, manipulate, remove and insert huge structures is functional. “In fact, we must prepare the site before the real preparatory work begins,” continues Mr. Gagnon. The operation to increase the power of the plant will be spread over eight years: two years of preparatory work followed by one year of work to replace each of the turbines.

More electrons with the same facilities

Manic-2 is not the only complex that will undergo a rejuvenation in the coming years to increase its power. To meet the growing demand for electricity, Hydro-Québec will revisit seven hydroelectric power stations. The objective: to increase the number of electrons produced from the same quantity of resources.

To enhance the power of existing installations, several options were on the table. “We could have increased the height of the fall or organized ourselves to increase the flow of water entering the turbines,” explains Marc-André Marcoux. In the first case, however, it would have been necessary to increase the height of the dam and drown more territory. The second option would require the replacement of significant pipes.

Hydro-Québec has instead decided to replace turbine-alternator groups with new, more efficient technologies. In its strategic plan, it also underlines the importance of investing substantial sums to restore luster to a network and infrastructure “operated at the limit of their capacity”.

By 2035, the state-owned company estimates it will be able to add 2,000 MW of power to its network of existing installations. A substantial gain which represents 5% of its current capacity (37,000 MW), or the equivalent of the average consumption of 720,000 homes.

Work in progress

Replacement work has begun at three power stations, Carillon, La Trenche and Rapide-Blanc. At the Outardes-2 power plant, about twenty kilometers from Baie-Comeau, preparatory work is also well underway. “We expect that there will be between 150 and 200 employees on the site during the replacement phases,” says Karine Gagné, in charge of the replacement project at the Outardes-2 power plant, located about twenty kilometers from Baie-Comeau.

Electricity consumption predicted by 2050

Decarbonization and economic growth will rely on electrification, particularly in the energy-intensive sectors of transport and building heating. Quebec’s electricity consumption is expected to increase by 60 TWh within 10 years and more than double by 2050, according to Hydro-Québec forecasts. To meet this demand, the company plans to add 9,000 MW of power by 2035, the equivalent of three of its largest structures: Robert-Bourassa (LG-2), Manic-5 and the complex of the Roman. Nearly 2000 MW will come from the replacement of turbine-generator groups.

Already, a Hydro-Québec team is coordinating the activities of subcontractors working to prepare the site. Trailers are piled up about a hundred meters from the power station and a parking lot has been built near Route 138. “From there, shuttles will be able to bring workers to the site,” says Mr. Gagné.

Somewhat behind, Hydro-Québec has erected a huge white dome equipped with a heating and ventilation system. This is where employees of the turbine manufacturer, GE Renewable Energy, will assemble the final components to the structures which will be transported by barge from Montreal.

In total, more than 400 people will converge on the three repair sites not far from Baie-Comeau: Outardes-2, Manic-2 and Manic-3. “We try to hire people from here, but it’s certain that some will come from outside,” says M.^me Gagné, emphasizing that housing is scarce in this North Shore city. The housing vacancy rate there has hovered around 0.5% for years.

The replacement of turbine-alternator groups in seven power plants over the next decade signals, for Hydro-Québec, the return of major projects which will mobilize hundreds of workers.

The state-owned company plans to add up to 2,200 additional MW by building “new hydroelectric power stations, including pumped storage power stations”. Hydro-Québec launched a preliminary study in the spring of 2023 to assess the potential of the Petit Mécatina River.