Posted January 7, 2023, 2:00 p.m
Drinking water from the evaporation of the oceans. Unfortunately, highlighted by climate change, this is a counterintuitive view of warming seas. In its origin, a group of American researchers from the University of Illinois (USA) explains the principle and virtues through research in the scientific journal “Nature”. Their process will take the form of extraction structures located off the ocean’s coasts capable of capturing and condensing water-saturated air, passing it through pipes for storage and distribution.
According to the researchers, the process has an advantage over conventional desalination: it will use less energy and have less impact on the environment. Desalination plants release pollutants such as salt water and wastewater laden with heavy metals.
Repeat the natural water cycle
The device proposed by American scientists overcomes this obstacle thanks to a natural chemical principle: seawater evaporates and turns into gas, naturally losing almost all its salt. Also, omitting this desalination step greatly simplifies the seawater conversion mechanism compared to desalination. In addition, generating stations could work very well using renewable energy produced by wind turbines.
“This technique replicates the natural cycle of water, the only difference is that we can direct the destination of water that evaporates from the ocean,” concludes study co-author Francina Dominguez, an atmospheric expert.
According to the authors of this study, a vertical catchment surface 210 m wide and 100 m high could provide sufficient moisture volume to meet the daily drinking water needs of an average of about 500,000 people.
They obtained this result through simulations in 14 water-stressed areas located near major population centers such as Los Angeles (USA), Rome (Italy) or Chennai (southeast India). According to models, this type of plant can produce from 37.6 billion to 78.3 billion liters of water per year, depending on the conditions of each site.
The price of a large cruise ship
How much would such an installation cost? “If the marginal cost of water does not increase, we assume that the cost of building an atmospheric vapor collection and condensation facility is $600 million, or the cost of building a large cruise ship or oil platform,” the scientists said. .
Three times the cost of the desalination plant, estimated to cost about $200 million. Aware of this gap, researchers argue that there is room for improvement to lower the cost of their installation. In particular, they guarantee that it will last longer and be more robust than a desalination plant.
For the driest regions
“As global warming continues, we will have to find a way to increase the supply of fresh water,” explains Praveen Kumar, a co-author of the scientific paper and a professor at the University of Illinois (UIUC). recycling water from existing sources, while important, will not be sufficient to meet human needs. We believe that the method we have just proposed can achieve this on a large scale. »
Afeefa Rahman, another co-author, emphasizes: “Our method provides an effective and necessary approach to climate change adaptation, especially for vulnerable populations living in arid and semi-arid regions of the world. »
According to a recent report by the World Meteorological Organization, a UN agency, 3.6 billion people do not have access to water for at least one month a year, and this number is expected to exceed five billion by 2050. increasingly long and frequent chronic droughts, especially in Horn of Africa countries such as Somalia and Ethiopia.