The state of California has dedicated $34 million for eight desalination facilities across the state amid growing concerns about water scarcity in the U.S.
Desalination is when saltwater is converted into freshwater. Though 71% of the Earth is made up of water, extreme weather linked to climate change is adding to concerns about water scarcity.
Scientists estimate that by 2071, nearly half of the 204 freshwater basins in the U.S. may not be able to meet the monthly demand for water, according to a study published in the journal Earth’s Future.
Extracting salt from water seems like an easy fix to a global problem, but the process of desalination can be expensive, and it can also have a huge impact on the environment. That’s why some researchers are looking into how to lower the cost and improve efficiency.
Desalination technology can cost anywhere between two to 10 times the cost of traditional freshwater sources, says Meagan Mauter, research director for the National Alliance for Water Innovation and an associate professor of civil and environmental engineering at Stanford University.
“I think it's very important to think about seawater desalination as one part of a much broader water portfolio,” she says. “In the same way that we don't rely solely on solar panels to provide electricity, we shouldn't be thinking about relying solely on next-generation desalination facilities to provide water.”
Mauter says desalination costs so much because of the amount of energy needed to separate salt from water, she says.
“The National Alliance for Water Innovation is really built on the premise that to drop costs and to reduce energy intensity, we need to look at the broader network of water management in order to drop those costs,” Mauter says. “So broadly, the costs of managing water are the combination of the costs of treating water, plus the costs of distributing water and collecting wastewater.”
The amount of energy needed for the desalination process also negatively affects the environment. Most of the current technology is tailored for large scale desalination projects, but building technology on a smaller scale could offset the financial and environmental impacts, Mauter says.
“It'll drop the overall energy intensity of that combined treatment and distribution,” she says. “And second, novel ways of managing concentrate at smaller scales will help us avoid the need to do lots of seawater desalination to augment supply.”
Climate change is not only expected to affect the amount of available water, but it will also impact “the timing at which that water is delivered or naturally stored,” Mauter says. Making the electricity system more energy efficient is also “deeply connected” to the water supply.
“The process of decarbonizing our electricity system or our energy system is itself going to require lots of water treatment capabilities,” she says. “Underlying that is a tremendous need for new desalination technologies that integrate well with the electricity system.”
While desalination is more costly and energy intensive than some other water sources, it does provide water resilience for municipalities because it is not subject to drought, changes in precipitation or snowpack, Mauter says.
“I think it's also critically important for municipalities to think about other sources of resiliency,” she says. “That could be through water conservation, that could be through ensuring the safety and longevity of water storage, and that could be through supporting water reuse inside of the municipalities.”
This segment aired on February 18, 2020.