The world’s largest ocean-based carbon dioxide-removal plant will be built in Tuas over the next 18 months.

Upon completion, it will be able to remove 10 metric tonnes (10,000kg) of carbon dioxide while simultaneously producing 300kg of carbon-negative hydrogen per day, according to a press release by the University of California (UCLA).

The plant, called Equatic-1, will cost US$20 million (S$26.9 million) and is a collaboration between Singapore's national water agency PUB, UCLA and its start-up Equatic.

At full scale, it is expected to remove as much carbon dioxide as what nearly 850 people emit annually.

In comparison, the average global annual carbon emissions per capita in 2020 was about 4.3 metric tonnes, according to the World Bank.

Pilot in Singapore has been successful

The project was announced on Feb. 27, 2024, following a successful launch and operation of two pilots in Los Angeles and Singapore in April 2023.

The technology was listed in various publications, such as TIME’s Best Inventions of 2023 and listed among Popular Science’s 50 greatest innovations of 2023.

According to UCLA, Equatic's pilot plant in Singapore, which can remove 0.1 metric tonnes of carbon dioxide per day, has proven to be successful.

The co-founder of Equatic, Dante Simonetti, said that the data from the Singapore pilot was crucial for the development of Equatic-1.

He said:

"The pilot plant commissioned in 2023 provided critical performance data to substantiate our carbon dioxide-removal efficiencies, hydrogen-production rates and energy requirements for the process.

The findings helped define the pathway for the design and engineering of Equatic-1 based on scaling performance confirmed by the pilot system."

How the carbon removal process works

The carbon removal demonstration plant will use four inputs — seawater, air, rock, and renewable electricity — to remove and store carbon dioxide while simultaneously generating carbon-negative hydrogen, according to Equatic's press release.

The plant will utilise electrolysis and pass an electrical current through seawater brought in from adjacent desalination plants operated by PUB.

The process induces a series of chemical reactions that break water into its hydrogen and oxygen constituents.

Atmospheric air will then be passed through the processed water.

These steps remove atmospheric carbon dioxide and carbon dioxide dissolved in the water by trapping them in the form of solid calcium and magnesium-based materials for at least 10,000 years.

Equatic will then use rock to neutralise the processed seawater and preserve the ocean's chemistry.

These calcium and magnesium-based materials can be stored on the ocean floor, or used for construction materials, The Straits Times reported.

Plant will be built in two phases

The first phase of Equatic-1's construction will begin in March 2024 and is designed to remove one metric ton (1,000kg) of carbon dioxide per day by late 2024.

The second phase will involve the installation of nine additional modules in early 2025.

With all 10 modules, the plant will be able to remove 10 metric tonnes of carbon dioxide per day from seawater and the atmosphere — 100 times more carbon dioxide than the amount removed by the pilot plant.

UCLA added that once the plant meets its projected carbon-removal goal, Equatic plans to launch a commercial plant designed to capture nearly 110,000 metric tons (110 million kg) of carbon dioxide per year.

This is equivalent to the annual carbon emissions of more than 25,000 individuals.

PUB aims to achieve net-zero emissions by 2045

The plant is part of PUB's broader efforts to achieve net-zero emissions by 2045 with a three-pronged approach to replace, reduce and remove carbon emissions.

Apart from capturing and removing carbon released into their atmosphere, PUB also aims to replace fossil fuel sources with renewable solar energy and invest in research and development to reduce energy required in water-treatment processes as part of its decarbonisation strategy.

"This collaboration with UCLA and Equatic is part of Singapore’s broader efforts to source novel technologies, such as carbon capture, utilisation, storage, which could contribute to mitigating the impacts of climate change," UCLA stated in its press release.

PUB chief engineering and technology officer, Chee Meng Pang, said:

"At PUB, we firmly believe that technological advancements, delivered in partnership with academia and the private sector, hold the key to addressing the complex challenges posted by climate change."

Top image by Charles Grace, courtesy of Equatic.