Hydro-Québec says that 1999 has been good for replenishing its hydroelectric reservoirs in northern Quebec, Canada. Hydro-Québec’s executive vice-president, Ghislain Ouellet, said that abundant winter snowfall and good spring rainfall had helped replenish reservoirs that last autumn had been at about 46% of capacity.
Hydro-Québec’s reservoirs can hold enough water to generate about 185.5TWh of electricity, but the usual storage capacity is some 171TWh. Its reservoir levels reach a low point in early spring before the snowmelt and after a long winter of peak consumption. The reservoirs usually reach peak levels by early fall, after a summer of much lower domestic consumption.
Under government-mandated criteria, Hydro-Québec must be able to deal with a loss of inflow to its reservoirs representing 64TWh over two years — equivalent to the two largest consecutive inflow deficits ever recorded.