Your question was a little challenge to our experts – just how they like it!
The answer is: 72 litres of water.
To answer your question, we established the following hypothesis:
• A cup of water (237 mL) at room temperature (20°C) is brought to boiling point (100°C) in a 1500-watt electric kettle.
In this scenario, the energy required to boil a glass of water is 80,000 joules.
To produce this much energy, 72 litres of water have to go through one of the units in the Robert-Bourassa generating station (formerly known as La Grande-2).
Although 72 litres may seem like a lot of water just to boil a cup of water, it is important to remember that this water is neither wasted nor consumed. This volume of water would eventually go into the river even if there were no hydropower facilities in place. This means that we use the water, but we don’t consume it!
Note that in our scenario, we didn’t take into account the heat loss or the efficiency of the water heating device.