“Several companies are exploring the possibility of desalinating water on the ocean floor. At those depths, the water is often cleaner, leftover salt can be expelled with less harm to wildlife, and the high pressure can help push seawater through desalination membranes, making the process less energy-intensive,” notes The Doomslayer.
The Wall Street Journal reports:
For decades, desalination has been the only reason that many places, from the Caribbean to the Emirates, have been habitable. But it’s always been a solution of last resort, for one big reason. “Desalination is the most expensive way to make water, and there’s no getting around it,” says Tom Pankratz, who has been in the industry for 45 years, and has consulted on many of the world’s biggest desalination projects.
Up on land, engineers would literally boil the ocean, creating steam that would become drinking water and, on its way, drive some power-generating turbines to pay back a bit of its cost. It was so energy intensive that in the 1960s, some proposed using nuclear power to do it. The world’s largest desalination plant, in Ras al-Khair, Saudi Arabia, produces much of its water through evaporation.
Around the year 2000, reverse-osmosis changed everything, says Pankratz. In this process, water is forced across a plastic membrane with holes so tiny only water molecules fit through, leaving behind salt and other impurities. This process requires about half the energy, making it a credible option for Trinidad, which in 2002 got a plant that now produces 40 million gallons of water a day, and Israel, which got one in 2005 that now produces 85 million gallons of water daily. Many more plants followed, and this is now the standard way to desalinate water…
Oslo-based Flocean, Netherlands-based Waterise and Bay Area-based OceanWell are among the companies that seized on this idea of desalination—then submerged it to a depth of at least 400 meters.
The principle is easy to grasp: Instead of expending huge amounts of energy to pump seawater onto land, and then pressurize it inside a plant, why not take advantage of the ocean’s extreme natural pressure? At depth, seawater naturally wants to cross a desalination membrane, so long as the fresh water on the other side of it is being pumped to the surface. The result is a net energy savings of up to 40%.
Many arid or dense countries, such as Malta, Israel, and the United Arab Emirates, now rely on desalinization to provide water. A couple years ago, researchers discovered an additional way to get fresh water from the sea, due to the creation of floating desalination machines that use “no electricity” and are “100% mechanically driven”:
Oneka’s floating desalination machines – buoys anchored to the seabed – use a membrane system that is solely powered by the movement of the waves. The buoys absorb energy from passing waves, and covert it into mechanical pumping forces that draw in seawater and push around a quarter of it through the desalination system.
The fresh, drinking water is then pumped to land through pipelines, again only using the power provided by the waves.
In some places, drinking water could come from thin air:
Cody Friesen, an associate professor of materials science at Arizona State University, has developed a solar-powered hydropanel that can absorb water vapor at high volumes when exposed to sunlight. It is a modern-day twist on an approach been used for centuries to pull water from the atmosphere, such as using trees or nets to “catch” fog in Peru, a practice that dates back to the 1500s and is still being used today….Friesen founded his own company Zero Mass Water in 2014 following his research on solar-powered hydropanels. Today the company is called Source Global, operates in more than 50 countries and has a private valuation of more than $1bn (£800m).
The panels work by using sunlight to power fans that pull air into the device, which contains a desiccant material which absorbs and traps moisture. The water molecules accumulate and are emitted as water vapor as the solar energy raises the temperature of the panel to create a high-humidity gas. This then condenses into a liquid before minerals are added to make it drinkable.
“That’s how we’re able to create water in most places in the world, even when it’s very dry,” says Friesen. “We’re headquartered in Scottsdale, Arizona, which is sub-5% relative humidity in the summer and we’re still making water. It’s a uniquely efficient and low-cost approach that enables us to go places where nobody else can go.”
The air, even in relatively dry climates, can hold a surprising amount of water. The Earth’s atmosphere as a whole contains about six times as much water as the planet’s rivers.
Friesen’s goal is to expand access to water for people with few options, such as rural communities that don’t have electricity, and regions afflicted by natural disasters. Among Source’s customers is a school in Africa where students once had to trek for hours a day to find fresh water. A panel costs about $2,000 and lasts at least 15 years. But advances in artificial intelligence have boosted yields, able to monitor changing conditions, humidity, temperatures, and sunlight to extract the maximum amount of water, says Adam Sharkawy of Material Impact, an investor in Source Global. “These panels are constructed to create four to five liters of drink per panel per day. But with AI and machine learning algorithms, these numbers can go much higher, maybe aspiring towards seven, eight, nine. That makes it even more effective and more cost efficient.”
Water’s perceived scarcity has led to stupid federal regulations in the U.S., where water is plentiful in most areas. Dishwashers and washing machines take much longer to run than they used to, and get clothes and dishes less clean, due to federal regulations that make washing machines use ridiculously little water, too little water to get many clothes and some dishes clean. As a result, some people run their washing machine or dishwasher multiple times rather than just once, increasing energy use. A a recent study in England suggests that people compensate for showerheads that emit less water by taking longer showers, rather than reducing overall water use. The fist Trump administration attempted to roll back these regulations to the extent that they were counterproductive and actually increased energy use. But the Biden administration undid the Trump administration’s steps toward fixing this situation. Recently, the second Trump administration rescinded the Biden administration’s counterproductive regulations, which will probably lead to a lawsuit against the Trump administration by groups that seek to restrict water use.
