On a remote stretch of coastline on the Big Island of Hawaii, a startup is pioneering “ocean-assisted” carbon removal—a process that can both permanently store CO2 and help reduce ocean acidification.
The startup, called Heimdal, pumps saltwater into a machine that uses electricity to rearrange molecules in the water, removing acid. It can then sell the acid it removes, which ends up in the form of hydrochloric acid. The process also produces hydrogen and oxygen. The de-acidified seawater can be returned to the ocean, where it will naturally capture CO2.
[Photo: Heimdal]“When the excess acidity is removed from the ocean, it shifts how CO2 exists back to how it was pre-Industrial Revolution,” says Erik Millar, coCEO of Heimdal, who began developing the technology with his cofounder Marcus Lima while both were students at Oxford University. “This moves it away from being carbonic acid, which causes ocean acidification, and toward bicarbonate and carbonate. These are stable forms of mineralized carbon dioxide that make their way down to the ocean floor, where they are stored for more than 100,000 years.”
The ocean has absorbed a third of the excess CO2 humans have put in the atmosphere—billions of tons per year (the ocean has also absorbed 90% of the excess heat on the planet). As the CO2 dissolves, it acidifies the water, making it harder for marine life like corals and shellfish to form and survive. The acidity in the Pacific Ocean, for example, has already started dissolving the shells of young crabs. The startup’s new process can help locally improve the pH of seawater. But the company’s main focus is to find a more affordable way to capture huge volumes of CO2.