SeaCURE – the first marine carbon capture system in Europe

A groundbreaking project has been launched on the southern coast of England: SeaCURE – the first system in Europe designed to capture carbon dioxide from seawater. This innovative technology, currently being tested in Weymouth, could revolutionize climate change mitigation by harnessing the ocean’s natural ability to absorb CO₂.

What is the SeaCURE project about?

The SeaCURE project, implemented by the University of Exeter in partnership with Plymouth Marine Laboratory, Brunel University London, and the company Eliquo Hydrok, has received £3 million in funding from the UK Department for Energy Security and Net Zero. The aim is to test whether removing CO₂ from seawater could become a scalable and efficient method of emission reduction.

Oceans absorb around 25% of anthropogenic CO₂ emissions and play a crucial role in the global carbon cycle. The concentration of dissolved carbon in seawater is about 100–150 times higher than the concentration of CO2 in the air, which makes carbon capture from seawater, as in the SeaCURE project, more effective in terms of the volume of medium processed compared to direct air capture.

How does the system capture CO₂ from seawater?

The process begins with seawater being drawn in through a pipe beneath the beach. The water is then acidified, converting dissolved carbon into gaseous CO₂. In a special tank called a stripper, the CO₂ is released, extracted, and concentrated using carbonized coconut shells.

After extraction, an alkaline solution is added to neutralize the acid. The treated water, now with a reduced CO₂ content, is returned to the sea, where it immediately begins to absorb more carbon dioxide from the atmosphere. The water remains chemically neutral and environmentally safe – its pH complies with UK drinking water standards.

What sets SeaCURE apart from other carbon capture technologies?

The SeaCURE system differs from traditional carbon capture methods like Direct Air Capture (DAC), which focus on extracting CO₂ directly from the atmosphere. Instead, SeaCURE utilizes seawater – a medium with a significantly higher carbon content, allowing for greater efficiency with lower energy consumption.

Key distinguishing features:

– Higher efficiency – capturing CO₂ from 1 m³ of seawater is equivalent to extracting it from 150 m³ of air
– No land use competition – the system can be installed offshore, avoiding conflicts with agricultural or residential land
– Powered by renewables – the project aims to use renewable energy sources like solar panels, increasing its climate neutrality
– Practical implementation – the pilot system in Weymouth processes up to 3,000 liters of water per minute, which means it can remove up to 100 tons of CO₂ per year

As Dr. Paul Halloran, the SeaCURE project lead, emphasizes, the technology has the potential to operate autonomously on offshore platforms, without occupying valuable land resources. This makes it particularly promising in the context of global emission reduction strategies.

Environmental impact on marine ecosystems

One of the key aspects of the project is analyzing the potential impact of low-CO₂ seawater on marine ecosystems. Guy Hooper, a PhD student at the University of Exeter, is conducting laboratory studies to assess the effect of this water on marine organisms such as phytoplankton and mussels, which use carbon for photosynthesis or shell formation. Preliminary results suggest that large amounts of low-CO₂ water could have some environmental impact, but these effects can likely be mitigated, for example, through pre-dilution of the water.

At the current project scale, the amount of discharged water is minimal and does not affect the local ecosystem. All water parameters comply with the standards of the UK Environment Agency (EA).

Importance in the fight against global warming

Experts, including Dr. Oliver Geden of the IPCC, stress that carbon capture will be essential to achieving net-zero emission targets. However, SeaCURE does not replace reduction measures – it complements them, especially in the context of historical and hard-to-abate emissions.

UK Energy Minister Kerry McCarthy highlights that innovative projects like SeaCURE are crucial for the development of green technologies, supporting jobs and stimulating economic growth. The project is one of 15 pilot programs supported by the UK government as part of its greenhouse gas capture and storage strategy.

Challenges and potential

SeaCURE technology requires substantial energy input, making renewable energy supply essential. Further analysis will also be necessary to understand the effects on marine environments at larger deployment scales. Nevertheless, the potential is immense – estimates suggest that processing just 1% of the ocean’s surface could remove up to 14 billion tons of CO₂ annually. It’s an ambitious vision, but with adequate support and research, it could become a reality.

main photo: Belinda Fewings / Unsplash