These researchers from Canterbury University have come up with an idea that they say can cheaply remove 3 million tonnes of CO₂ from the air each year. And it utilises existing infrastructure.
The TLDR is that geothermal water contains CO₂, and the stations here have systems that capture and dissolve that CO₂ into the water before it’s reinjected. This CO₂ rich water is heavier than the surrounding water, so it sinks to the bottom.
The heat from geothermal wells is not replenished at the speed it’s taken by the stations, so eventually the water coming out isn’t hot enough and new wells need to be drilled.
The scientists are suggesting that instead of simply drilling a new wells, we burn biomass from forestry to heat the warm water up the last bit. The carbon in this fuel has been gathered by the trees, and if it was released into the atmosphere it would be carbon neutral. But if you use the station’s existing CO₂ capture and dissolve systems, the carbon goes underground permanently. The operation becomes a carbon sink that also enables the use of geothermal energy that would otherwise be unusable.
They say, “in terms of buying ourselves out of an emissions liability, geothermal carbon removal is one of the cheapest options out there.” They compare it with the cost of switching from a petrol to electric car - US$700 for each tonne of CO₂ saved. With the existing infrastructure, they say their plan would remove CO₂ at a cost of about US$55 a tonne.
Their papers and a bunch more evidence and info is linked in the article.
This is the first time I’ve seen carbon capture that is not a crock of shit.
…well I hope it is.
Check out [https://news.mit.edu/2023/carbon-dioxide-out-seawater-ocean-decorbonization-0216] it seems like a far more efficient way to capture CO2.
Awesome to see ideas like this come out of nz. People may scoff at 600,000 cars but that’s a sizable chuck of the cars on our roads
I’d like to know more about the actual process behind capturing CO2 from combustion and sequestering it into water. It sounds like a fascinating process.
Here you go
It sounds like a technology that actually works, whether it’s cost effective will remain to be seen. I certainly hope for the best.
Love this idea, but need a better explanation than “goes back underground”. Does it change the acidity of our water tables, get slowly released back into atmosphere, or what else?
The dissolved CO₂ reacts with reactive rocks, like basalt, forming solid, stable carbonate minerals. It’s essentially permanent on a human timescale. But you’re asking the right questions.
The scientists link to this page, which explains it in more detail.
Thanks for the insight - as much as climate change is going to be/already is a massive issue we need to make sure we’re not exchanging one disaster for another.
Permanent on a human time scale gives us time.
Yes, it works GW made an amz report on carbon capture .
Isn’t a solucion, but it sure as hell can buys us time while we transition, that would probably involve keeping the pannic. Or we’ll just use this extension to post bone on the change from fossils to renewables.
Gw report also has other methods, but I found the carbon capture one to be the most interesting.
We absolutely need to stop putting it into the air as soon as possible. If these kinds of technologies delay transitions then they’re counterproductive. I’m inclined to think that reducing atmospheric CO₂ at every possible opportunity is important at the moment.
Even if the world becomes carbon neutral, we’ll need to remove the excess CO₂ from the atmosphere if we want the heating to stop. This is one of the most practical systems for doing that that I’ve seen so far. We’ll need it to happen on a much larger scale, but it’s important to be researching it now.
600,000 cars sounds like a lot but it really isn’t. Better than nothing I guess.
