Hydro-Québec - Power Generation


	Nuclear
	Fossil fuels
	Biomass, hydrogen and solar

Other sources of power generation

Because they burn fossil fuels, thermal power plants cost more to operate and emit more pollutants in comparison to hydroelectric generating stations.


The role of thermal generation at Hydro-Québec

While these facilities represent only a small portion of Hydro-Québec's overall generating capacity–about 3% in 2002–they play a vital role in meeting Québec's baseload and peak energy requirements. They're also useful in supplying power to remote, off-grid regions such as the Magdalen Islands.

Diesel

Diesel-powered stations are used mainly in remote areas. For the most part, they supply electricity to isolated communities in Nunavik, on the Lower North Shore of the St. Lawrence and in the Haute-Mauricie region. Diesel generating stations power off-grid systems. The facility shown below is Hydro-Québec's largest diesel generating station, located on the Magdalen Islands. Îles-de-la-Madeleine generating station		This type of power plant has no turbine; its diesel engine (A) creates mechanical energy that drives an alternator (B).

Heavy oil

Conventional thermal generating stations burn coal or heavy oil. Hydro-Québec's power plant located near Sorel-Tracy uses heavy oil as fuel. The power station has a strategic role because it is operated when reservoir water levels are low or when demand peaks in the winter. Tracy generating station		The boiler (A) of a conventional thermal power plant turns water into steam. As it expands, the steam (B) spins the turbine (C) , which drives the generator (D) that generates electrical energy. Condensers (E) return the steam to a liquid state; the water is pumped back into the boiler and the cycle is repeated.

Light oil and natural gas

Gas-turbine generating stations generally burn light oil or natural gas. They are called "gas-turbine" because their combustion process produces gas that drives the turbine. Given the relatively high cost of fuel needed to run these facilities, they are used only during periods of peak demand.

These generating stations have the advantage of taking only minutes to start and stop operations, compared to the longer time frames required by other thermal power stations.

Bécancour generating station

In a gas-turbine generating station, light oil (D) is ignited in compressed air, forming a gas mixture that expands (C) and strikes the turbine blades. This force drives the turbine (B), which drives the alternator (A).


Combined-cycle gas turbine generating stations Effective technology

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Combined-cycle gas turbine generating stations

Effective technology

These power stations are named after their combined gas cycle and steam cycle. Each cycle generates electricity. The required fuel—natural gas—is used only to drive the gas turbine, which in turn propels the alternator. Exhaust gas from the turbine is then used to produce steam without burning any other fuel; the steam then drives another turbine to generate even more power. All things considered, a combined-cycle generating station is more efficient than a gas-turbine facility. It’s also the least polluting type of thermal generating station after nuclear power plants. In comparison, combined-cycle generating stations produce 2.5 times less greenhouse gases than conventional coal-fired facilities.

Thermal Generation at Hydro-Québec

Some thermal power stations operate continuously to meet baseload energy needs; for instance, diesel generating stations and Gentilly-2 nuclear power plant. Others, such as gas-fired facilities and the oil-fired conventional thermal generating station located near Sorel-Tracy, operate only when demand is high and hydroelectric facilities are working at maximum capacity.