Editor's Note: CNN Films' 'Blue Carbon: Nature's Hidden Power' takes viewers from the mangroves of Vietnam to the salt marshes of France to explore a powerful new ally in the fight to slow climate change. The premiere is Sunday, April 21 at 9:00 PM ET/PT.
On a patch of ocean frontage in western Singapore, a startup is building a factory to convert carbon dioxide from the air and seawater into the same material as seashells, in a process that will also produce 'green' hydrogen - a much-hyped clean fuel.
The cluster of low-slung buildings starting to take shape in Tuas will become the "largest" ocean-based carbon dioxide removal facility in the world when it is completed later this year, according to Equatic, the startup behind it that spun out of the University of California. in Los Angeles.
The idea is that the plant takes water from the ocean, zaps it with an electric current and passes air through it to cause a series of chemical reactions to capture carbon dioxide and store it as minerals, which are returned to the sea can be brought or used. on the land.
It's a compelling vision of a possible solution in the face of a worsening climate crisis that has fueled unprecedented heat and devastating extreme weather. Efforts to curb global warming are vastly lacking, and many scientists now warn that, in addition to rapidly cutting back on fossil fuels, the world will also have to remove the carbon pollution that humans have already pumped into the atmosphere.
This factory in Singapore is one example of a slew of recent projects using the oceans, which already absorb nearly 30% of humanity's global warming pollution, as a tool to do this. Other projects include sprinkling iron particles into the ocean to stimulate CO2-absorbing phytoplankton, sinking seaweed into the depths to lock up carbon and spraying particles into marine clouds to capture some of the solar energy. reflect energy away.
But carbon removal projects are controversial and criticized for being expensive, unproven on a large scale, and a distraction from fossil fuel reduction policies. And when they include the oceans - complex ecosystems already under great pressure from global warming - the criticism could become even louder.
There are "major knowledge gaps" when it comes to ocean geoengineering in general, says Jean-Pierre Gatusso, an ocean scientist at Sorbonne University in France. "I'm very concerned that science is lagging behind industry," he told CNN.
How it works
Equatic's technology, which has been tested in small pilot projects in LA and Singapore, requires three main ingredients: seawater, rocks and electricity.
It works like this: the plant pumps in seawater and passes an electric current through it, separating it into four components: two liquids, one acidic and one alkaline, and two gases, hydrogen and oxygen.
The acidic water is mixed with crushed rock to bring the pH back to the same level as seawater and then sent back into the ocean.
Fans pump air through the alkaline flow, causing carbon dioxide to form solid calcium carbonate, the material from which seashells are formed, which looks like fine sand, as well as dissolved bicarbonate.
The solid and dissolved minerals, which Equatic says can store carbon for at least 10,000 years, will be returned to the ocean or used on land. The seawater will also be sent back into the sea, ready to absorb more carbon dioxide from the atmosphere.
None of the processing takes place in the open ocean, says Gaurav Sant, founder of Equatic and professor of sustainability at UCLA, "this is important because it allows you to perfectly measure everything you do." This includes the electricity the factory uses, as well as the amount of carbon trapped.
The $20 million facility will be fully operational by the end of the year and can remove 3,650 tons of carbon dioxide annually, said Edward Sanders, chief operating officer of Equatic, which is working with Singapore's National Water Agency to build the plant. That amount is equivalent to taking approximately 870 average passenger cars off the road.
The ambition is to scale to 100,000 tons of CO2 removal per year by the end of 2026, and from there to millions of tons in the coming decades, Sanders told CNN. The plant can be replicated virtually anywhere, he said, stacked into modules "like Lego blocks."
As the factory grows, they must ensure there are no negative impacts, Sant told CNN. "It makes a big difference whether you do this on a scale of one ton, versus a million tons, versus a billion tons. You have to measure, you have to monitor, you have to adapt."
The upfront costs are high, but the company says it plans to make money by selling carbon credits to polluters to offset their pollution, and by selling the hydrogen produced in the process.
Equatic has already signed an agreement with Boeing to sell 2,100 tons of hydrogen, which it plans to use to create green fuel, and to finance the removal of 62,000 tons of CO2.
Fragile oceans
For some critics, however, the risks far outweigh the benefits.
Lili Fuhr, deputy director of the Center for International Environmental Law's Climate and Energy Program, criticized the use of "speculative technology" at a time when "climate change is already killing our oceans."
Processing large amounts of seawater could kill marine life, Fuhr told CNN. "We already know that power plants kill fish larvae and other marine life. Equatic would process much more seawater per plant than a power plant," she told CNN. "And thousands of such plants would be needed to have any meaningful impact on the global climate."
The impacts should be closely monitored, says James Niffenegger, a researcher at the National Renewable Energy Laboratory, who wrote a report on the removal of carbon from the ocean. The "artificial movement of water on this scale will be enormous," he told CNN.
The process could also potentially upset the delicate balance of ocean chemistry, Niffenegger said. While there has been a lot of research on the negative impacts of ocean acidification, much less research has been done on what might happen if the ocean becomes more alkaline.
There are indications that the impact may be small, he added, but "we won't be able to understand the potential of this solution until we actually deploy these kinds of things."
Then there are energy needs: as the world turns away from fossil fuels, the demand for clean energy is increasing exponentially. "Moving seawater would require enormous amounts of renewable energy, which would be better used to replace fossil fuels," Fuhr said.
This point is echoed by Gatusso, who said: "Justice must be taken into account when precious electricity is used to remove carbon rather than providing it to populations in need."
Equatic said it filters seawater to ensure marine life does not enter the system, and the water released back into the ocean will have the same composition as normal seawater and will comply with Singapore's environmental guidelines.
The company also said that the production of hydrogen, which could be used to power the process, means that overall energy consumption is lower than other carbon removal methods.
Equatic's project encapsulates a broader debate between those who fear that the rush to geoengineering could cause untold damage to ecosystems, versus those who believe that the climate crisis is so acute that this technology should be an option.
It is clear which side Equatic is on.
"Inaction is not a climate strategy," says Sant of UCLA, adding that being able to make decisions with uncertainty is critical. "If we are serious about limiting the trajectory of climate change," Sant said, "we must be willing to move, and quickly on a large scale."
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