Energy

Seawater plant will capture 10 tons of CO2 and make 300 kg of H2 per day

A rendering of the world's largest ocean-based carbon dioxide removal plant, slated to be built in Singapore
Charles Grace, courtesy of Equatic
A rendering of the world's largest ocean-based carbon dioxide removal plant, slated to be built in Singapore
Charles Grace, courtesy of Equatic

After successful pilot programs, UCLA has partnered with Singapore’s national water agency and others to build the world’s largest ocean-based carbon dioxide removal plant capable of removing 3,650 metric tons (8,046,873 lb) of the greenhouse gas per year while producing 105 metric tons (231,000 lb) of carbon-negative hydrogen.

According to the World Bank, average global carbon dioxide (CO2) emissions in 2020 were 4.3 metric tons (9,500 lb) per capita. With this figure in mind, researchers from the UCLA Samueli School of Engineering have been working to trap atmospheric CO2 from the oceans in an effort to reduce it.

Following the successful launch of two seawater-based CO2-removal pilot systems in Los Angeles and Singapore in 2023, UCLA and its start-up company Equatic, are eyeing the next phase of the project: a US$20-million full-scale demonstration plant called Equatic-1. They’re supported by Singapore’s national water agency, the Public Utilities Board (PUB), Singapore’s National Research Foundation (NRF), and UCLA’s Institute for Carbon Management (ICM).

“Scaling carbon removal solutions requires technology, bold and committed partners, and a focus on timely and measurable success,” said Gaurav Sant, Professor of Sustainability at UCLA Samueli and ICM director. “We have been very fortunate to create this shared vision with our partners in Singapore to scale Equatic’s solutions to the commercial scale and around the world.”

The Equatic process uses electrolysis, passing an electrical current through seawater from adjacent desalination plants. It causes chemical reactions that break water into its constituents, hydrogen and oxygen, while securely storing dissolved and atmospheric CO2 as solid calcium and magnesium-based materials for at least 10,000 years. The process activates and expands the ocean’s natural CO2-storing ability by removing dissolved CO2 while enabling it to absorb more of the greenhouse gas.

A team of researchers and tech-scaling experts from ICM and Equatic will head out to PUB’s research and development facility in Tuas, western Singapore, to begin building the world’s largest ocean-based CO2 removal plant over the next 18 months.

Equatic-1 will be built in two phases. Beginning in March, the first phase is designed to remove one metric ton (approximately 2,205 lb) of CO2 per day by late 2024. In early 2025, installing nine additional modules will complete phase two. With 10 modules in operation, it’s expected that Equatic-1 will be able to remove 10 metric tons of CO2 per day from seawater and the atmosphere. The Singapore pilot plant was deemed successful after removing 0.1 metric ton (220 lb) of CO2 per day; Equatic-1 could remove 100 times more. The technology could also simultaneously produce nearly 300 kg (660 lb) of carbon-negative hydrogen daily.

“The pilot system commissioned in 2023 provided critical performance data to substantiate our carbon dioxide-removal efficiencies, hydrogen-production rates and energy requirements for the process,” said Equatic co-founder and ICM’s associate director, Dante Simonetti. “The findings helped define the pathway for the design and engineering of Equatic-1 based on scaling performance confirmed by the pilot system.”

PUB has set a target of achieving net-zero emissions by 2045 by adopting a three-pronged approach: replacing fossil fuels with renewable solar energy, investing in research and development to reduce the energy required in water-treatment processes, and capturing and removing carbon released into the atmosphere.

“We are pleased to further our collaboration with UCLA and Equatic to develop a solution that has potential synergies with PUB’s desalination plant,” said PUB chief engineering and technology officer Chee Meng Pang. “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 posed by climate change.”

Equatic-1’s modular design reduces the risks usually associated with scaling technological innovation. The system will also use selective anodes, newly developed with the support of the US Department of Energy’s Advanced Research Projects Agency-Energy (ARPA-E), to produce oxygen while eliminating the unwanted chlorine byproduct created during seawater electrolysis. This opens a new pathway to carbon dioxide removal at the gigaton scale with the co-production of hydrogen – a clean fuel vital to decarbonizing transportation and industrial applications.

Source: UCLA Samueli School of Engineering

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11 comments
Oirinth
its a good start, but removing an actual 0.1 ton a day vs. aiming to scale to 10 ton's is a long way to go to combat the 37.15 billion metric tons annual global emissions of carbon dioxide
Ric
Sounds like this plant cancels out about 4000-6000 peoples worth of carbon emissions. Can’t someone design a stationary bike that extracts small amounts of carbon directly from the air? It might be cheaper and could be distributed to millions if not billions of people…
martinwinlow
I must have missed the bit about what happens to all the Na… and just how many litres of horribly expensive - in both energy and financial terms - desalinated water is needed to make just one litre of H2? Yup, missed that, too (it’s 9).
TechGazer
I'd like to see an overall assessment of CO2 sequestration, including the carbon cost of electricity production and providing the calcium and magnesium in the forms required, including lifetime costs of producing the solar panels, water pumps, etc.
SussexWolf
Those criticising the concept and making assumptions on how it works, should read the original paper which explains it. This process works directly on seawater, not desalinated water. It’s colocated with desalination plants to take advantage of their associated infrastructure.

https://newsroom.ucla.edu/releases/using-seawater-to-reduce-co2-in-atmosphere
Jinpa
The claim: "...while securely storing dissolved and atmospheric CO2 as solid calcium and magnesium-based materials for at least 10,000 years." Mankind has had writing for about 5,000 years, so in what language(s) will future people be able to read the writing on the storage facility? Where is this storage going to occur? Paid for and maintained by whom? Secure against what threats?
Karmudjun
Decent write-up Paul, but you left so many questions unanswered in your synopsis of the Samueli School's article. I think everytime the "public" reads about steps to lower the CO2 in seawater or CO2 in the atmosphere, they focus on how little impact a proof of concept process will have, and then when scaled up, how little impact a scaled up processing plant will have. And then they focus on cost and energy consumption, and timeline until the system is removing more CO2 than it took to build and operate and so forth. From reading New Atlas comments - I would presume no action would be desirable compared to mitigating actions that are only "drop(s) in a bucket". But thanks for writing about actions in place to mitigate our impact on the environment!
Sean Kerr
So it's a huge facility that off sets CO² for 750 people per year and creates 300 liters of water per day? Wouldn't it be better to just Plant trees and not flush 100 toilets per day?
DJ
hmmmmm where to start......H2 production .... good thing but is the cost economic? stuffing CO2 into the oceans, do we really want for acidify the oceans this way? what's the power usage at scale, and what are you using to provide said power? anything else usefully here like fresh water?
175mws
So once again the California costal committee is allowing projects to get done, without regard to the microbiology and fish losses that was a big push to close ocean water cooled power plants that were doing the exact same thing with sea water.. money grab green energy and environmental science backed by junk science and private and government funding..