Hey #EnergySky: on Wed., I am talking to @hausfath.bsky.social about everyone's favorite subject, rock weathering! Specifically, weathering rocks as a way of capturing & sequestering CO2. Apparently this is the carbon removal method that might actually work at scale. Got any questions? - ThreadSky

volts.wtf • 37 days ago

Hey #EnergySky: on Wed., I am talking to @hausfath.bsky.social about everyone's favorite subject, rock weathering! Specifically, weathering rocks as a way of capturing & sequestering CO2. Apparently this is the carbon removal method that might actually work at scale.

Got any questions?

Comments

aregitsky.bsky.social•37 days ago

Any studies on the effects weathering could have on a the flora/fauna in the dumping areas? Curious if there are any consequences (positive or negative) to mass intake of calcite, silicate, etc. on localized ocean ecosystems. Likely nothing compared to ongoing acidification, but still curious.

laurenkubiak.bsky.social•37 days ago

What’s the potential cost per ton of removal at scale? How do you pay for it? Who might be part of a coalition in support of it?

clasticdetritus.bsky.social•37 days ago

awesome, looking forward to this — I feel well-versed in the fundamental idea, the theory, and some of the lab-scale findings ... but, would love to learn more about the bigger-scale tests (what's the largest-scale test that's been done?, etc.) — sounds like you're already planning to address scale

mmullany.bsky.social•37 days ago

I wrote a primer on ERW with some good paper references in the bibliography.

https://www.linkedin.com/pulse/enhanced-rock-weathering-effective-michael-mullany-xwzxe

rgatess.bsky.social•37 days ago

Rock weathering is Earth’s natural way of sequestering carbon but it takes thousands of years. What would the energy input need to be from humans to accelerate this process?

mountaingoat.bsky.social•37 days ago

Have you read any research on Olivine being used?

mmullany.bsky.social•37 days ago

The research shows that most carbon captured from ERW is locally redeposited as solid carbonates in the subsoil rather than running off into rivers/oceans as bicarbonates as was hoped initially.

Until we know more re: persistence of these solid carbonates - how do we justify scaling up ERW?

volts.wtf•36 days ago

I don't entirely get it. Is the idea that solid carbonates in the subsoil are in some danger of re-releasing their carbon? If it's locked in rock why does it matter where it ends up?

mmullany.bsky.social•36 days ago

Two reasons:

1- when it deposits as a carbonate, it releases half its initial carbon as CO2

2 - there’s some evidence that additional deposited carbonates do accumulate - but the research on this is light.

mmullany.bsky.social•36 days ago

The C produced by ERW can turn back to bicarbonate or even CO2 if it encounters low or very low pH (like from N fertilizer if it percolates deeply).

This is a reason that initial ERW treatments on low pH tropical soils may not have much sequestration effects until the pH is raised.

mmullany.bsky.social•36 days ago

Remember the initial premise of land-spread ERW was that it captured CO2 as bicarbonates and these ended up in the ocean.

(Beach spreading and ocean based ERW is probably a better bet than land spreading.)

volts.wtf•35 days ago

Ah, thank you!

expansive.bsky.social•37 days ago

Please can you make this a quantitative discussion, e.g. how much CO2 needs to be sequestered? How fast? What volume of rock is required to sequester that carbon? What is the energy input required to mine the rock or inject the CO2? What are the energy requirements associated with that energy?

expansive.bsky.social•37 days ago

Sorry… should have been “What are the energy requirements associated with that activity?”

expansive.bsky.social•37 days ago

What are the geographic constraints (location and accessibility of the required minerals versus location of the carbon sources). Costs and risks of CO2 pipelines. Relative coats of emissions avoidance vs capture.

expansive.bsky.social•37 days ago

How fast could any of this be deployed? What successful projects exist? Can these or other technologies be scaled? What are the first order constraints to scaling up and reducing cost? Who is incentivized to funs this? What levers exists to influence this?

noeffoe.bsky.social•37 days ago

Please add biochar to your list. Interesting way to transfer wood residues and side streams into a persistent carbon storage form. How persistent depends on the application of the biochar - in soil biochar is persistent for hundreds of year.s

sillin.bsky.social•37 days ago

What (if anything) would it take to be economically viable on its own. A company I've heard of (UNDO) claims it boosts crop yields (i have no way of assessing the accuracy of this) but strikes me as potentially promising for standalone value assuming (our) govt wont pay for it (for a bit)

mmullany.bsky.social•37 days ago

It can boost crop yields - it raises soil pH so you can use it instead of lime. It also improves soil cation exchange capacity (nutrient retention) so helps for poorer soils in particular.

wormwood23.bsky.social•37 days ago

How much of the process relies on carbon fuel (I.e. the mining), and how much of that can be decarbonized?

bigskwigg.bsky.social•37 days ago

What kind of industrial base would you need for this? Sulfate injection gets brought up as something any nation with a couple tens of billion in cash could do. Is this a similar scale?

esgarchitect.bsky.social•37 days ago

Does any region or locality have an advantage of good conditions for power method (renewables - wind/solar/geothermal w batteries) and the rock type and the location/logistics to sell/deploy locally?

snoozebuttonben.bsky.social•37 days ago

Really curious about Metalplant

andrewstyan.bsky.social•37 days ago

Like any innovation, there’ll be some low hanging fruit (low cost, high benefit) that may actually happen with low effort. What proportion of global emissions might that represent? Too many big claims with little reality.

oleanders.bsky.social•37 days ago

It would be useful to get a comparison to the transportation of other bulk commodities. Eg would it require more or less transport than fossil fuels? If more how much more.
Being told we need "a gigaton per year" (or something) just doesn't tell me anything I can relate to.

elliej.bsky.social•37 days ago

We looked at this, and for 2.7gtons co2/yr of removal we’d need equivalent of about 2x global coal production in rock https://en-roads.climateinteractive.org/scenario.html?v=25.1.0&p208=2&p72=100&g0=77&g1=119

oleanders.bsky.social•37 days ago

Which is useful to know! But transporting that rock could need less transportation work than 2x coal, or more (seems likely), perhaps much more.

maerlande.bsky.social•37 days ago

Well... coal is usually used right at the mine. Build the coal powered plant right there. It's easier and cheaper to move the electricity.

materialsdan.bsky.social•37 days ago

What would we use those rocks for, if we weren't weathering them?

pineapple-king.bsky.social•37 days ago

Bimsstein Cleaners for feet skin removal

wolfmercury.bsky.social•37 days ago

not so much a question as please tell him thank you for all he does. I greatly appreciate it

dominiclavelle.bsky.social•37 days ago

I second that 👍

ecomigrant.bsky.social•37 days ago

I third that 🤩

elliej.bsky.social•37 days ago

Can removals be measured/verified? Like…how to ensure the rock was definitely not going to have this normal chemical reaction happen w/o us?? And be sure the co2 gets captured durably?

pyth-of-samos.bsky.social•37 days ago

For carbon sequestration it is always about can you verify that the carbon is actually removed and is the removal durable. So how do you quantify removals so that it can be financed. My daughter was working in this space for deep sea sequestration and that is the challenge for a lot of good ideas.

robertbobbington.bsky.social•37 days ago

Many questions....but firstly how does this work? Is there a link to a paper of some back ground?

econundertow.bsky.social•37 days ago

It only takes 100,000 years (or more).

nathanmesser.bsky.social•37 days ago

Way way less than that

@volts.wtf has there been any follow up or development after this paper? I haven't seen anything but it sounds so promising
https://iopscience.iop.org/article/10.1088/1748-9326/abc217

ecomigrant.bsky.social•37 days ago

Somewhat off-topic but I'm particularly curious about adding limestone powder to waterways to restore the pH of rivers, and carry that to the ocean. https://www.carbonrun.io

thetruemichael.bsky.social•36 days ago

I'll probably never understand how people can believe that there is any easier way to limit global warming than ending emissions as rapidly as possible.

People say "we can do it all at once" but using fossil fuels to truck rock around while people continue to use fossil fuels is doing nothing

achuck-ten.bsky.social•36 days ago

So happy to see Volts here on the blu! Would like to know if my favorite capture idea is feasible: Identity exposed appropriate rock formations (basalt?)on the seabed, with a strong ocean current flowing over it. Reduce large areas the rock seabed to rubble (boom!) Repeat as needed.

davidho.bsky.social•37 days ago

Is enhanced rock weathering just ocean alkalinity enhancement in a muddy trench(coat)?

sorenhave.dk•37 days ago

What is his view on the rock flour from Greenland?

I understand you guys in the US have taken a special interest in Greenland 😵‍💫

https://da.uni.gl/forskning/gletsjermel/

judy3t.bsky.social•37 days ago

I think of weathering as the wearing away of rock. So that would still leave the CO2 in the atmosphere. I thought they were talking about layering it between rocks to trap it. Would that cause those rocks to weather? Curious use of terms. So what am I missing?

nathanmesser.bsky.social•37 days ago

Some rock chemistries interact with ambient CO2 to form calcium or silicon carbonate on their surfaces, which is stable. Crush up the rock to increase surface area, layer it on trays and blow fans across, then dispose of the result in abandoned mines, use as concrete aggregate, land reclamation etc

nathanmesser.bsky.social•37 days ago

Alternately dump the crushed rock in the ocean so it can take up co2 from the water, giving the water more capacity to pull CO2 from the air

annarose75.bsky.social•37 days ago

I was contacted recently and told the solution is to spread this rock on farmland, but farmland needs tiny amounts of minerals, this isn’t a sensible approach.
We need to work on not emitting CO2, rather than these nonsensical ‘solutions’ which just delay the inevitable

pineapple-king.bsky.social•37 days ago

I used volcano rock dust for farming, and its pretty big bags you need of those tiny amounts of minerals.

Volcanic rock dust is very lightweight.

Just my personal experience

annarose75.bsky.social•37 days ago

Yes but you do it once, and it lasts for many years. This might be a technical solution for a short time, but it doesn’t take into account the social issue of farmers being asked to take responsibility for what is pollution being created by massive corporations with no accountability

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