[LUM#19] Alice, age 12: “With the drought, will we still be able to generate electricity using dams?”

[LUM Magazine, Podcast] - Published on July 27, 2023 in Science and Society

Alice, age 12, future headmistress of Hogwarts.

Not all the dams you see are designed to generate electricity; some are used to support agriculture or regulate river flow. In France, dams thatgenerate electricity account for between 11 and 12% of the country’s total electricity production—less than nuclear power but more than wind and solar power. Globally, hydropower is the world’s leading source of carbon-free energy. It’s called that because it doesn’t 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 there’s no economically viable way to store electricity on a large scale.

There are three main types of dams: run-of-river dams that generate power continuously on a river; reservoir dams that have a large water storage capacity and thus allow for inter-seasonal storage; and pumped-storage plants, which 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 for the optimization of when electricity is generated.

There is still significant potential for hydroelectric power generation worldwide, but this potential remains limited in France. Global warming could indeed jeopardize the use of hydropower due to water shortages in rivers, as well as reduced snowfall in the mountains, since snowmelt is a major contributor to river flow. Furthermore, competition between energy and agricultural uses is likely to 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 to allow for irrigation, particularly in the summer. However, the water that is released is then no longer available in the winter, which reduces electricity production.

Jacques Percebois – Professor Emeritus at the University of Montpellier.

An article in partnership with The Conversation.

Keywords: Energy, LUM Junior, LUM#19, LumLu, Science, Company, The Junior Conversation