Carbon capture promises to do the impossible and repent humanity’s climate sins. By absorbing our emissions out of the atmosphere and safely burying them back underground, this technology will not only be the find push we need to reach net-zero, but possibly even reverse the atmospheric damage we have already done. But the current reality of carbon capture is far from this holy grail of climate technology. Thanks to staggering costs and slow expansion, current carbon capture is barely making an impact. But, A new startup has a solution that promises to solve these problems and beckon in a new age of climate action. However, is this too good to be true?
This startup is San Francisco-based Vesta, and they want to use the mineral olivine to offset atmospheric carbon dioxide. The idea is that they would dump ground-up olivine on beaches and into seawater to speed up the ocean’s ability to absorb carbon dioxide. You see, the ocean already absorbs around a third of our emissions. When carbon dioxide dissolves into water, it turns into carbonic acid; as such, our emissions are making the ocean more acidic. Olivine reacts incredibly quickly with carbonic acid, breaking down and turning into dissolved carbonates. These carbonates settle on the ocean floor and can stay there for millions of years thanks to their chemical stability. What’s more, these carbonates are non-toxic and can even be used by animals to make shells, so they shouldn’t impact marine ecology. So, by pumping the ocean full of olivine, we can safely speed up the ocean’s natural ability to absorb carbon emissions and reliably store the carbon away as sediment and dissolved carbonates.
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This process is commonly known as enhanced rock weathering, as most natural rock weathering has the same carbon-sink ability, just at a much slower rate.
Vesta has already tested this idea in New York’s Hamptons, spreading ground olivine on the coast and mixing it with sand. This gave them the data they needed to know how effectively coastal olivine dissolves away and how it affects marine life. The tests were successful, and now they are setting their sights on a far larger site in the Middle East.
Tom Green, Vesta’s CEO, has said, “What we’re looking for is locations which have large amounts of the mineral [olivine] and the right oceanographic conditions.” The Hajar Mountains in Oman tick these boxes. They have easy-to-access olivine reserves of well over 100 billion tonnes, and the Gulf of Oman is only tens of miles away. Setting up a mining, transport and ocean dumping scheme in this location would be relatively easy. As such, Vesta aims to remove a billion tonnes of carbon dioxide from the atmosphere each year by 2050 using locations like The Hajar Mountains.
But is this feasible?
Well, estimates vary, but most experts agree that one tonne of olivine can capture and store away one tonne of carbon dioxide. So there is enough olivine in the Hajar Mountains to run Vesta’s operations for well over a century or completely offset a decade or two of our emissions at current rates. Olivine is also far from rare across the globe. For example, the Twin Sisters in Washington, USA, contains around 200 billion tonnes of mineable olivine reserves. So finding enough olivine to power Vesta’s plans is easy enough.
Once mined, olivine is also cheap at only $25 per tonne. This means that Vesta should be able to capture and store away carbon dioxide for under $50 per tonne once processing, shipping and monitoring costs are considered. This is literally a tenth the cost of current carbon capture technology, so funding such a massive project shouldn’t be an issue either. True, they would need somewhere in the region of $50 billion annually to reach their 2050 target of a billion tonnes of carbon sequestered per year. But for some context, that is roughly a 16th of the annual budget of the US military, and Vesta would meet the IEA’s 2050 net-zero global carbon capture capacity by themselves with this funding!
In other words, Vesta could easily be the crucial step final that enables humanity to go to net-zero.
But is such a wide-scale mining operation even possible? And wouldn’t the carbon emissions of the mining make the whole effort redundant?
Well, humanity currently mines 7.4 billion tonnes of coal yearly, a far rarer mineral than olivine. What’s more, mining limestone (a mineral with a similar density and harness to olivine) releases 440 kg of carbon dioxide per tonne mined. So, even with fossil-fuel-powered mining, this methodology can still capture carbon and function at a large enough scale. But, an olivine mine in Oman will likely be solar-powered (as it is one of the sunniest places on Earth) and use electric transport vehicles, taking these emissions per tonne way down.
On the face of it, this all seems incredibly feasible. But I can see three problems with Vesta’s plans.
Firstly, verification. Without knowing exactly how much carbon dioxide is sequestered, carbon capture is useless at best and, at worst, a painful greenwashing technique used by big polluters to legitimise more planetary destruction. That is why Climeworks getting its verification was a giant leap forward for them. Yet, as I said, experts aren’t even sure how much carbon is sequestered per tonne of dissolved olivine. What’s more, it is incredibly hard to verify how much of the olivine you have dumped on the beach or in the ocean has actually dissolved away. This is because waves, currents and tides can wash it away, making it appear as if it has dissolved when, in actuality, it is just somewhere else.
Moreover, olivine isn’t a pure mineral. It contains plenty of impurities. In particular, nickel and chromium, which are both toxic and potentially lethal to wildlife and humans. Different deposits have different levels, but nickel averages between 0.1% and 0.5% of olivine by weight, and chromium hovers around 0.3%. This means that Vesta’s billion-tonne-per-year operation could pump half a million tonnes of nickel and 300,00 tonnes of chromium into the ocean. If this happens in a concentrated area (which Vesta is implying is the case) or is concentrated by currents, it can poison marine ecosystems and any humans who subsist off them. Now, there are methods to extract these metals from olivine, but it is an expensive and energy-intensive process, and Vesta seems to have no plans to use it either.
Finally, the role of carbon capture in taking humanity to net-zero is now being played down. The IEA’s latest report found that the carbon capture industry has failed to get cheaper or expand fast enough. Moreover, they found that it is only being used to reduce emissions in areas where decarbonisation is easy with alternative technology. In other words, carbon capture is being used to legitimise delaying genuine decarbonising changes and legitimise oil expansion and further pollution. At the same time, the IEA has found renewables are cheaper and more profitable than they predicted they would be, while expanding incredibly rapidly. So, according to the IEA, our roadmap to net-zero now has to rely more on renewables and significantly less on carbon capture. As such, we might not need a billion tonnes of carbon removal by 2050, meaning Vesta might not have the funding available to meet its targets.
So, are Vesta’s plans too good to be true? Possibly. They have a long way to go to prove their methods can be reliable enough for solid carbon offsetting and not greenwashing, and they have a lot of work to do to ensure such wide scale olivine use won’t harm the ocean and, in turn, humans. These problems aren’t a dealbreaker, though; they are overcomable. If Vesta can solve them, then they could very well be the crucial step to not only net-zero but even enabling us to reach negative emissions and claw back our precious climate to where it used to be. So, keep an eye on this startup, they could be revolutionary.
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Sources: Japan Times, Vesta, Will Lockett, Dezeen, USGS, NOAA, US Senate Committee on Armed Services, Amsterdam Green Campus, MDPI, Gov.uk, Gov.uk, ACS Pub