[LUM#19] Alice, 12 years old: "With the drought, will we still be able to generate electricity with dams?"
Alice, 12 years old, future headmistress of Hogwarts.
Not all dams are used to generate electricity; some are used to supply agriculture or regulate river flow. Dams thatgenerate electricity account for between 11 and 12% of the electricity produced in France, which is less than nuclear power but more than wind and solar power. Globally, hydropower is the world's leading source of carbon-free energy. It is called this because it does not emit CO2, even though carbon is produced during the construction of the dam. These structures are primarily a means of storing electricity: water is stored because we do not know how to store electricity on a large scale in an economical way.
There are three main types of dams: run-of-river dams that continuously generate electricity on a river, lake dams that have a large water reservoir and therefore allow for inter-seasonal storage, and pumped storage plants that consist of two dams, one upstream and one downstream of a penstock. Water is pumped from downstream to upstream during off-peak hours, and electricity is generated during peak hours by turbining the water from the upstream dam. This allows the timing of electricity generation to be optimized.
There is still significant potential for hydroelectric power generation worldwide, but this potential remains limited in France. Global warming may compromise the use of hydroelectricity due to a lack of water in rivers, but also because of reduced snowfall in the mountains, as melting snow is a major source of river flow. In addition, competition between energy and agricultural uses may intensify if water becomes scarcer. River water is also used to cool nuclear power plants, which is why new plants are likely to be built near the coast. Dams sometimes have to release water for irrigation, especially in summer. However, the water released is then no longer available in winter, which reduces electricity production.
Jacques Percebois – Professor Emeritus at the University of Montpellier.
An article in partnership with The Conversation website.
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