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Carbon capture technology—sucking excess carbon from the air and then storing it—has grabbed not only headlines, but billions of dollars in speculative investments. Ideas range from making giant air filters to stacking blocks of solid carbon in long-term storage to sinking giant bubbles of CO2 to the bottom of the sea.
Now research companies such as Captura and Equatic are working to take carbon out of the oceans, not put it in.
As the planet warms and carbon gas makes up a greater proportion of air, about 30 percent of that excess carbon is absorbed by the seas. The water warms, disturbing ecosystems and endangering populations of common sea creatures as well as current patterns that control weather.
Captura is completing a pilot test of its system on a barge anchored in the Port of Los Angeles. Its pumps, pipes, and tanks are taking carbon out of ocean water at the rate of 100 tons of the gas annually and returning clean water to the bay.
When its year-long test is completed, Captura expects to flip the switch on a 1,000-ton-per-year operation in Norway. The carbon captured there will be pumped into subsea rock formations.
Equatic will launch a 3,650-ton-a-year plant in Singapore later this year and other ventures have similar technologies in development.
The reason: taking CO2 from the oceans is far more efficient than trying to grab it from air.
Although the proportion is growing, carbon dioxide makes up only about 0.05 percent of the atmosphere. Removing carbon from air is costing pilot projects $600 to $1000 per ton of gas removed. In contrast, seawater concentrates CO2 about 150 times more than air does, making removal far cheaper.
SeaO2, a Dutch venture, estimates that its technology, when finalized, will be able to extract carbon for no more than $100 per ton, which the U.S. energy department has set as a 2032 target cost.
The cost depends on the efficiency of the technology used.
Captura zaps seawater with electricity to create ions—electrically charged particles—that react with sodium and chloride in the water. That creates hydrochloric acid that, in turn, reacts with bicarbonate ions in the water. That reaction liberates CO2 gas that is drawn off into storage tanks.
A byproduct of breaking up the seawater molecules is sodium hydroxide, which neutralizes the reaction’s acid in the water before it flows back into the sea.
After it uses electricity to break up ocean water, Equatic’s technology creates bicarbonate that can be used to make cement and other common industrial products. Its process also yields hydrogen gas, another favorite green fuel.
Boeing has contracted with Equatic to buy $50 million worth of hydrogen and CO2 over five years to make a cleaner aviation fuel.
The extraction companies also can sell carbon credits to polluting industries.
TRENDPOST: Researchers have calculated that five billion tons of carbon would need to be taken out of the air each year in order to limit the world’s temperature increase to 1.5°C. and avoid the worst effects of climatic disruption. While cleansing air and water of excess CO2 is a noble pursuit, it is unlikely to scale up fast enough to make a difference in meeting reduction targets.