The desalination industry is in boom times: Dwindling supplies of freshwater coupled with rising demand are driving annual growth rates near 10 percent. 

The industry, however, consumes large amounts of energy and produces significant amounts of salty wastewater, which isn’t good news for the environment. But an emerging trend — integrating carbon removal into desalination plants — offers hope of blunting those negative impacts.

The trend is visible at a desalination facility in Ma’agan Michael, Israel, where local startup CarbonBlue announced this month that it has begun capturing dissolved carbon dioxide from water flowing through the facility’s inlet pipe. It has multiple rivals in the race to commercialize technology that can be integrated with desalination and other water treatments facilities. These competitors include startups Captura and Ebb Carbon, as well as Capture6, which has plans to work with a desalination plant in South Korea to capture up to half a million tons of CO₂ annually. 

Emissions from desalination plants could exceed 400 million metric tons this year, according to projections made in 2022. The theoretical upper limit for carbon removal at desalination plants is more than twice that, noted a recent report on the approach from nonprofit RMI. But limits on the availability of renewable energy to power the process, along with other constraints, mean that carbon removal is unlikely to completely decarbonize the industry. Still, technology from CarbonBlue and others could, if scaled globally, remove hundreds of millions of tons of CO₂ annually.

Capturing carbon and cutting costs

CarbonBlue’s approach is well positioned to scale because it also saves money, the company said. The installation at Ma’agan Michael is an initial test designed to capture up to 400 tons annually. The removal takes place in a reactor that uses lime to pull CO₂ from the water. Desalination operators already know that lime can reduce the accumulation of organic matter on membranes, alongside other benefits. CarbonBlue’s reactor controls this process and can cut operating costs by almost 8 percent, said Dan Deviri, the company’s co-founder and CEO.

“Our approach is to provide industry with tools to decarbonize, not only without harming the value chain, but actually to make it more profitable,” added Adam Etzion, the startup’s director of marketing and communications.

CarbonBlue’s competitors are pursuing diverse approaches. Captura is headed by Steve Oldham, a carbon removal veteran who previously led Carbon Engineering, a direct air capture company that was acquired by Occidental, a U.S. oil and gas major. The startup uses electricity to trigger reactions that release CO₂ from seawater, which is then captured and stored. Capture6 takes the salt extracted during desalination and generates a solvent for use in direct air capture facilities, while Ebb Carbon uses electricity to create alkaline water, which naturally pulls CO₂ from the atmosphere.

Credits are critical for some

In addition to saving money for desalination plants, CarbonBlue plans on selling carbon credits. Frontier, a coalition of carbon removal buyers founded by Shopify, Google and