In a pivotal step toward tackling climate change, a groundbreaking project aimed at extracting carbon from the sea has officially commenced operations along the picturesque south coast of England. This pilot initiative, dubbed SeaCURE, is being funded by the UK government as part of its broader strategy to explore innovative technologies that combat climate change. The project underscores a growing consensus among climate scientists regarding the urgent necessity to reduce greenhouse gas emissions, which are predominantly responsible for global warming. However, there is also recognition that capturing some of the already-released gases will be essential in addressing this global crisis.

The SeaCURE project stands out in the realm of carbon capture technologies, which traditionally focus on either capturing emissions directly at their source or extracting carbon dioxide from the atmosphere. What makes SeaCURE particularly intriguing is the exploration of whether it could be more effective to remove planet-warming carbon directly from seawater, where carbon is found in significantly higher concentrations than in the air.

Located at the Weymouth Sealife Centre, the SeaCURE facility employs a unique method that begins with the extraction of seawater via a pipe that extends under the rocky beach and into the English Channel. This innovative approach aims to determine if the removal of carbon from seawater could serve as a cost-effective strategy for diminishing atmospheric CO2 levels. Once the carbon is extracted, the processed seawater is then discharged back into the ocean, where it resumes its role in absorbing additional CO2 from the atmosphere.

Our team was among the first broadcast journalists granted access to this pioneering facility, where we were guided by Professor Tom Bell from the Plymouth Marine Laboratory. As we toured the premises, Professor Bell explained the intricate process that begins with treating the seawater to increase its acidity. This alteration encourages the dissolved carbon in the seawater to convert into gas and subsequently escape into the atmosphere as CO2. Professor Bell humorously referred to the facility's carbon extraction apparatus as the "seawater stripper," which is a large stainless-steel tank designed to maximize contact between the acidic seawater and the air.

Professor Bell likened the process to the way a fizzy drink froths when opened. "When you open a fizzy drink, that frothing is due to CO2 escaping," he elaborated. The SeaCURE method spreads the seawater across a vast surface area, akin to pouring a drink on the floor, allowing the CO2 to evaporate swiftly. The released carbon dioxide is then captured and concentrated using charred coconut husks, making it ready for storage. The now low-carbon seawater has alkali added to neutralize the previously increased acidity and is then returned to a stream flowing back into the sea. Once reinstated in the ocean, it begins the process of absorbing more CO2, contributing, albeit modestly, to the reduction of greenhouse gases.

While there are more established carbon capture technologies that focus on extracting carbon directly from the air, Dr. Paul Halloran, who leads the SeaCURE project, highlighted the advantages of utilizing seawater. "Seawater contains approximately 150 times more carbon than air," Dr. Halloran pointed out. However, he also acknowledged that there are significant challenges, particularly regarding the energy requirements needed to produce the outputs necessary for this seawater-based process.

Currently, the pilot project is able to extract a modest amount of CO2around 100 metric tonnes annuallyan amount that pales in comparison to the carbon emissions produced by a single transatlantic flight. Nonetheless, the advocates of SeaCURE see vast potential in this approach. In its proposal to the UK government, the project outlined a vision of scaling up the technology to potentially remove as much as 14 billion tonnes of CO2 per year, provided that just 1% of the worlds surface seawater could be processed. Achieving this ambitious target would rely on the entire carbon stripping process being powered by renewable energy, with the possibility of using solar panels installed on floating platforms at sea.

Dr. Oliver Geden, a member of the Intergovernmental Panel on Climate Change and a carbon capture expert, emphasized the necessity of carbon removal in reaching net-zero emissions, which is vital for halting further global warming. "There are various options for carbon capture, including direct air capture and seawater extraction. Ultimately, the choice of method will depend on cost," he stated.

The SeaCURE project has been allocated 3 million in government funding and is one of 15 pilot initiatives being supported in the UK to advance technologies that capture and store greenhouse gases. Energy Minister Kerry McCarthy highlighted the importance of projects like SeaCURE in the journey toward achieving net-zero emissions. "Removing greenhouse gases from the atmosphere is essential in helping us achieve net zero," McCarthy remarked. "Innovative projects like SeaCURE at the University of Exeter play a critical role in creating the green technologies needed to make this happen while also supporting skilled jobs and promoting economic growth."

In addition to its focus on carbon capture, the SeaCURE project is also engaging in research regarding the impact of low-carbon seawater on marine life, spearheaded by Guy Hooper from Exeter University. This research aims to understand any potential environmental effects stemming from the introduction of treated seawater back into the marine ecosystem.