World’s Largest Facility to Remove Ocean CO2 to Open in Singapore

SINGAPORE — The largest facility in the world that can help to remove planet-warming carbon dioxide (CO2) from the ocean, located in Singapore in Tuas, is expected to begin operations in the first quarter of 2026.

It uses technology to change the chemistry of seawater and remove dissolved CO2 so that the water can absorb more CO2 when released back into the ocean, The Straits Times had earlier reported.

The seawater is discharged back into the ocean only after it is processed to preserve the ocean’s chemistry.

READ: Singapore to expand ocean CO2 removal project as scientists call for more research

Efforts that manipulate natural processes to tackle climate change are known as geoengineering.

Tuas’ Equatic-1 demonstration plant is a collaboration between Singapore’s national water agency PUB and American start-up Equatic, which developed the technology.

ST finds out more about this nascent technology, as well as its benefits and challenges.

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What is marine carbon dioxide removal?

Marine carbon dioxide removal (mCDR) is a broad category that involves using the marine environment to take up and remove atmospheric CO2, said Dr Andrew Lenton, director of CSIRO’s carbon dioxide removal program CarbonLock.

CO2 is the main pollutant driving climate change.

READ: Global warming to continue no matter what we do: study

The ocean, which covers 70 per cent of the earth, is one of the world’s largest natural stores of carbon. It can store carbon more effectively and over longer periods than other natural ecosystems, such as forests.

Estimates show that the ocean absorbs around 30 per cent of CO2 emissions from human activity.

mCDR efforts such as the Equatic-1 demonstration plant seek to enhance or accelerate the ocean’s ability to absorb more CO2 from the atmosphere.

Why are countries looking to tap mCDR technology?

Climate change – driven by ever-increasing amounts of planet-warming gases being released into the atmosphere from human activities – is fuelling a rise in temperatures and more extreme weather events.

Investments are already being made into technology that can prevent the release of more planet-warming emissions, such as replacing fossil fuel plants with renewable energy.

But scientists have also said that novel solutions are also needed to draw down the CO2 already in the atmosphere.

Dr Asbjorn Torvanger, senior researcher at CICERO – Centre for International Climate Research, told ST that past pollution has left a “carbon debt”.

Given this, ambitious climate policy targets would require large volumes of CO2 to be removed, he added.

“Given the large volume of the ocean and the sizable absorption share of human CO2 emissions by the ocean, the ocean’s CO2 removal potential might be large,” he said.

What are the different approaches to mCDR?

CSIRO’s Dr Lenton said there are mainly two approaches to mCDR – chemical and biological.

The Equatic-1 facility will use the chemical method, he added.

An electrical current is passed through the seawater pumped into the plant from adjacent desalination plants.

This leads to a series of chemical reactions that split the seawater into hydrogen and oxygen. The dissolved CO2 is combined with minerals in seawater like calcium and magnesium to produce solid limestone – essentially trapping the CO2 for at least 10,000 years.

The process mimics the natural formation of seashells. The solid calcium and magnesium-based materials can either be stored on the ocean floor, or potentially be used as construction materials.

Biological methods include farming seaweed or restoring coastal ecosystems like mangroves.

Seaweed absorbs CO2 through photosynthesis. The seaweed may then be harvested or sunk to deep waters to store the carbon for a long time.

Blue carbon ecosystems such as mangroves, wetlands and seagrass, are natural carbon sinks. Restoring these ecosystems would enable them to take in large amounts of carbon.

Chemical approaches are currently the most technologically advanced and scalable techniques based on field trials to date, according to a blue paper commissioned by the High Level Panel for a Sustainable Ocean Economy (Ocean Panel) launched in June.

The Ocean Panel is an initiative of world leaders working together towards a sustainable ocean economy.

How does mCDR affect the marine environment?

The answer to this is not immediately clear, but scientists have warned that the environmental impact of mCDR technology warrants further study.

Dr Xu Haoxin, chief consultant of carbon capture at Ramboll, said that the long-term ecological effects of the removal processes on the marine ecosystems are not yet fully understood.

While the concept holds promise, this is a fairly new research field and much more work needs to be done, she added.

The Ocean Panel blue paper also noted that given the interconnectivity and interdependency of different oceanic environments, any intervention is likely to have environmental impacts.

For example, pH disruption to processes like photosynthesis can affect ecosystem services such as biological carbon sequestration (carbon dioxide removal by natural ecosystems), food production and water quality. pH is a measure of acidity and alkalinity.

Associate Professor Patrick Martin, Nanyang Technological University’s Asian School of the Environment, previously told ST that Equatic’s technology, if deployed at a large-enough scale, could represent a “major manipulation” of the ocean’s chemistry.

“When you start doing manipulations in the ocean, you change the ocean’s chemistry. Some species might be fine with that, other species might be harmed by it,” Associate Professor Martin said.

Some methods may change the concentrations and ratios of important dissolved elements such as calcium and magnesium, which are essential for marine species like corals to form shells and skeletons, he said. Other methods may increase the concentrations of harmful trace metals in seawater, which might be toxic for many marine species, he added.

Equatic told ST that its technology was “designed with the health of the ocean in mind”.

“Potential impacts on the marine environment are important considerations and our process directly addresses them through built-in safeguards,” it said.

“Years of ongoing research underpin our approach and we continue to run extensive laboratory-based, and full-scale simulation studies to evaluate environmental effects,” said Equatic.

The company added that ongoing studies have indicated no harm to the marine environment when processes are kept within the ocean’s natural limits.

What are the other challenges of mCDR?

Experts said that more research is needed to understand the permanence and scalability of the techniques, as well as their impacts on ecosystems.

While the natural processes upon which mCDR approaches are based are well understood, the potential to scale mCDR to climatically relevant scales is “highly uncertain”, according to the blue paper.

One challenge is the monitoring, reporting and verifying of the amount of carbon dioxide removed from the atmosphere and associated environmental impacts, said Dr Lenton. This may become more difficult when systems scale up, he added.

Dr Xu said that some mCDR methods, such as those that use electrochemical processes, may also require a lot of energy with the current technologies.

Another challenge may be the public’s attitudes towards these techniques – marine geoengineering may face skepticism due to perceived risks or lack of transparency, she said.

“Further development, rigorous testing, and public engagement are essential before it can be compared meaningfully with mainstream carbon removal solutions or considered for large-scale investment,” she said.

HSBC’s global head of carbon removal technologies Kash Burchett said that it is important for governments to support the development of carbon removal technologies.

This is because such innovations are essential in abating residual emissions that cannot be tackled via conventional methods like clean electrification.

“Not all approaches are equal and each needs to be assessed on its own merits,” said Dr Lenton. “Carbon dioxide removal is not a silver bullet. (But) it is clear that without carbon dioxide removal, there is no pathway to getting to net zero emissions.”

“The increasing urgency of the climate crisis makes it very important to conduct research on such technologies,” said Prof Martin.

“But it’s very important that we do not rely on such technologies instead of decarbonizing our societies. It is very important to reduce greenhouse gas emissions at a much faster rate than is currently being done.” /dl