'Champagne' technology to capture carbon dioxide via the oceans

The process – similar to capturing the CO₂ bubbles in a fizzy drink – makes use of natural processes and renewable energy to remove carbon from seawater, allowing that seawater to in turn take more CO₂ out of the atmosphere.

SeaCURE – led by the University of Exeter, in collaboration with Plymouth Marine Laboratory, Brunel University London and industrial partner tpgroup – has won a £250,000 grant for an initial study.

The funding comes from the Net Zero Innovation Portfolio, run by the UK government's Department for Business, Energy & Industrial Strategy.

"The challenge with capturing carbon from the atmosphere is that CO₂ makes up only around a 20th of one percent of the air around us, so you need to push vast quantities of air through capture facilities to extract a meaningful amount of carbon," said Dr Paul Halloran, of Exeter's Global Systems Institute.

"Our approach sidesteps this challenge by allowing the ocean’s vast surface area to do the job for us, tipping the natural process of CO₂ exchange between the atmosphere and ocean in our favour."

SeaCURE technology will temporarily make seawater more acidic, which helps get the CO₂ to ‘bubble out’, then delivers a concentrated CO₂ stream for utilisation and storage.

The CO₂-depleted water is released back to the ocean, where it takes up more CO₂ from the air.

The SeaCURE team will initially design a pilot plant to remove at least 100 tonnes of CO₂ a year.

"This is about combining and scaling up proven technology and solving problems," Dr Halloran said. 

"By optimising each stage of this process, we hope to develop a model that will make this commercially viable on a large scale."

The only input required by SeaCURE, apart from seawater, is electricity – and the team will use wind to power their process.

Dr Tom Bell, of Plymouth Marine Laboratory (PML), said: "Combining our understanding of the ocean with a scalable engineering approach fueled by renewable energy, SeaCURE has incredible potential to support the UK’s net zero carbon ambitions.

"PML’s research excellence and capability enables us to inform the design of the pilot plant, and we are excited to be able to apply our expertise to address the urgent issue of excess CO₂ in the atmosphere."

Dr Salman Masoudi Soltani, from Brunel University London, said: "In this project we will exploit our existing understanding of conventional amine-based absorption carbon capture processes to concentrate the low-concentration gas stream from the 'CO₂ removal' unit.

"The lower inlet gas temperature (and its variation throughout the year) is expected to impact the capture efficiency and the energy demand of the process – an aspect investigated in this project."

James Thomas, of tpgroup, said: "SeaCURE critically brings together a partnership of academic expertise with tpgroup’s pedigree in delivering carbon capture systems for maritime environments.

"We hope to make a difference by ensuring that we develop both a technical solution to this global challenge, and one that delivers long-term reliability and commercial viability."