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The need for carbon removal -

When it comes to tackling climate change, in particular rising temperatures, many scientists believe that it will be necessary to capture and store more of the Earth’s excess carbon.

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Various options -

Experts have made various proposals on how to do this, including sequestering the carbon and injecting it into rocks far below the Earth’s surface.

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Ocean-based carbon removal -

One option of particular interest is how the ocean can be used to capture and store carbon in the long term. Indeed, the ocean already absorbs an estimated 25% of carbon emissions.

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Hydrogen production -

A separate but equally important challenge when it comes to climate change is how to produce green hydrogen on a large enough scale that it can replace fossil fuels.

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The status quo -

As it stands, we are able to produce green hydrogen, but production is tiny. In order for it to become a viable alternative to fossil fuels, a massive scale-up is needed.

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Introducing Equatic -

There has been a lot of buzz recently around LA-based start-up Equatic, which claims to have built a machine that can store carbon in the ocean while at the same time producing green hydrogen.

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How it works -

The process of the Equatic machine is complex, but in a nutshell, it works as follows. Firstly, it pumps seawater into an electrolyzer.

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The electrolyzer -

An electrolyzer is basically a machine that splits water into hydrogen and oxygen. In the case of Equatic, it runs on clean electricity, such as that produced by wind, solar, or hydro.

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Four products -

The electrolyzer turns the seawater into four main substances: hydrogen gas, oxygen gas, an acid stream, and an alkaline slurry that consists of calcium and magnesium-based materials.

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How the CO2 is trapped -

It is the alkaline slurry that is important when it comes to carbon sequestration: when exposed to air, the alkaline slurry pulls out the CO2 and traps it, ready to be discharged into the sea.

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How the CO2 is stored -

The CO2 that is captured by the Equatic machine ends up in the ocean as dissolved bicarbonate ions and solid mineral carbonates.

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Immobilized indefinitely -

In these forms, it is immobilized for 10,000 years and billions of years respectively. Unless heated to very high temperatures of around 900°C, the CO2 will not be released.

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Final step -

In the last step, the acid waste stream produced by the electrolyzer is neutralized (so as not to acidify the ocean) and is discharged into the sea as well.

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Plans to scale -

As it stands, the Equatic project is small. However, the company has plans to scale and they are already underway.

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The pilots -

In early 2023, it started operating two pilot plants from barges in Singapore and Los Angeles. Each machine removes around 30-40 tons of CO2 per year (that is equivalent to the annual emissions of around eight cars).

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Singapore machine -

It is now focusing on constructing a machine that will be the world’s largest ocean-based CO2 removal plant. The machine will be based in Singapore.

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Machine 100 times larger -

Sources suggest that the new machine will be 100 times larger than the pilots and that it will remove around 4,000 tons of CO2 from the atmosphere per year.

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Growing concerns -

At the same time, it is expected to produce around 100 tons of hydrogen per year. Not everyone agrees that scaling these machines is a good idea, however.

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Impact on marine ecosystems -

Many experts have expressed concerns about ocean-based carbon storage, in particular about how it may impact the surrounding marine ecosystems.

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Impact on marine ecosystems -

There are concerns, for example, that ocean-based carbon storage machines could alter the ocean chemistry, which in turn could cause changes in nutrient levels and species abundance.

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Viability -

Another key concern is about the viability of marine carbon removal and whether it will actually make enough of a difference.

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Viability -

Indeed, the scaling of ocean-based carbon removal technology will require a huge investment in infrastructure, equipment, and operations.

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Viability -

Many skeptics are worried that we do not have enough evidence that there will be a good enough return on the investment.

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Ignoring the root cause -

There is also the more general concern that focusing on ocean-based carbon removal does nothing to address the root cause of the climate crisis.

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Ignoring the root cause -

Indeed, it could be argued that instead of solving the problem, this would give the illusion of a quick fix, which would only delay the process of finding a real solution to the problem of climate change.  

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Hurdles to clear -

It seems, then, that Equatic and other similar companies have a few hurdles to clear when it comes to convincing both experts and non-experts of the benefits of their technology.

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Regulatory frameworks -

Couple this with the strict regulatory frameworks they must adhere to and marine carbon storage companies will have their hands full over the next few years.

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Final thoughts -

Only time will tell whether this technology will eventually offer a viable solution to two of the main climate challenges: carbon storage and green hydrogen production. 

Sources: (BBC)

See also: How to reduce your carbon footprint while saving money

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