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Suck carbon out of the atmosphere and desalinate seawater at the same time? This startup is trying.

Suck carbon out of the atmosphere and desalinate seawater at the same time? This startup is trying.

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There’s a new plan to suck planet-heating carbon dioxide out of the air while creating fresh water for petrochemical production.

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A mockup of an industrial plant layout for a facility that would desalinate seawater and take carbon dioxide out of the air.
A mockup of an industrial plant layout for a facility that would desalinate seawater and take carbon dioxide out of the air.
Image courtesy of Capture6

A startup developing technology to take planet-heating carbon dioxide out of the atmosphere just signed a deal with a state-owned water utility in South Korea to build a pilot project that combines the new climate tech with seawater desalination.

The first-of-its kind collaboration is intended to clean up some of the pollution from a giant hub for petrochemical production nearby, on top of supplying fresh water to heavy industries in the area.

Depending on how you look at it, partnerships like this could be an innovative way to minimize the environmental damage from very dirty business, or a way to keep fossil fuels flowing when the world needs cleaner alternatives. Either way, it’s an example of how the fossil fuel industry is cozying up with emerging technologies, like direct air capture (DAC), which are supposed to fight climate change but also have skeptics worried about whether it might become a crutch for big polluters.

The first-of-its kind collaboration is intended to clean up some of the pollution from a giant hub for petrochemical production nearby, on top of supplying fresh water to heavy industries in the area

“We actually kind of agree with the critique that if you do a DAC project, and that makes you more water insecure, or more climate vulnerable, or if that perpetuates fossil fuels on the grid, that’s a problem,” says Luke Shors, president of the California and New Zealand-based climate tech startup Capture6 that inked the deal. “We actually think these projects can accomplish multiple climate goals, and that’s why we should pursue them.” 

Shors’ company signed a memorandum of understanding (MOU) this week with South Korean water utility K-water and wastewater treatment company BKT. Together they’ll develop what they say is the world’s first fully integrated facility for carbon removal and water management using seawater desalination.

Capture6 plans to build Project Octopus, a carbon removal plant that it hopes will eventually remove hundreds of thousands of tons of carbon dioxide from the atmosphere each year — a feat that a growing number of startups around the world are trying to achieve.

What’s unique about Project Octopus is how it’s expected to work in tandem with a plant that turns seawater into fresh water. One downside with desalination plants is that they produce salty brine that can be harmful when released into the surrounding environment. Capture6 instead uses that wastewater in its carbon removal process, extracting salt that it then uses as a feedstock for a liquid sorbent that reacts with CO2 in the air.

The solution traps CO2 which, after mixing with calcium, produces a limestone or chalk-like mineral that keeps the greenhouse gas from escaping back into the atmosphere. Fresh water is another byproduct of the process.

This no silver bullet for climate change or drought, and these technologies come with their own costs. DAC and desalination plants both use a lot of energy. And since the pilot facility will be plugged into the grid, that means it will still be powered largely by fossil fuels and generating the same greenhouse gas emissions Project Octopus is meant to clean up.

Moreover, the facility is essentially being built to service the Daesan Industrial Complex that produces 40 percent of South Korea’s petrochemicals derived from oil and gas. “[The industrial complex] will exist, right? No matter what we do. So I think that’s why it’s very important for us to be at the same time realistic,” says Leo Park, vice president of strategic development at Capture6. “I think it’s important for us to reduce their carbon footprint any way we can.”

If it’s ultimately able to grow into a commercial-scale facility, Project Octopus could capture up to 500,000 metric tons of CO2 annually once fully completed. The pilot facility is supposed to draw down just 500 metric tons of atmospheric carbon dioxide a year, and the MOU also includes plans to filter another 500 metric tons of CO2 from smokestacks before it’s released into the atmosphere.

Altogether, that’s just a fraction of the 17 million metric tons of carbon dioxide Daesan pumps out each year. And to reach global goals of stopping climate change set under the Paris Agreement, polluters need to slash their CO2 emissions in half this decade. The plan at Project Octopus is to start construction on the $2-3 million pilot this year, but breaking ground on a potentially $100-200 million commercial facility might not happen until late 2026 at the earliest.