Interesting seeing this thread at midnight PST on HN -- assuming this is the Europe crowd, hello!
Curious for people's thoughts about perception of these technologies around the world. Have you heard about carbon removal outside of this article?
Yes, Carbon sequestering and storage underground is something that brings out all the usual tin-foil hatters from Greenpeace to the alt-right who fantasize about "gassing the population".
What I am wondering is why we are not planting billions of trees, harvest them, make charcoal and stuff it underground. Or grow algae on roofs and use them to harvest carbon.
I would love to have a good clean home biochar solution to increase the carbon content of the soil of my farm. Something I can stuff prunings and grass and brush cuttings and leaves into, flip a switch, and get carbon out of.
But right now it's mostly DIY solutions that look of varying quality and still generate some smoke.
Wouldn't it be great if every suburban neighbourhood had an efficient pyrolysis chamber that processed the organic waste from the surrounding area?
You use plants to concentrate carbon. You make biochar. And then you put it back in the soil, so you're not depleting it of nitrogen, phosphates, and minerals.
The waste heat that you get from making the biochar is useful energy -- solar energy, really -- that you can use to heat homes, make hot water, and run heat engines.
Maybe even the Haber process too?
The chief challenge I see is how to reduce human labor requirements without increasing capital requirements too much.
I'm also a little concerned about eventually diluting the soil with too much biochar. Because you're sucking carbon out of the atmosphere, but the amount of phosphates and such is remaining constant.
The solution space is large. Lots to work on.
Aside from growing then burying cellulose or cooking it off into carbon, you could also pyrolize it into a liquid form via a self-feeding process if your preferred form of sequestration is to pump it back underground i.e. into previous extraction fields.
Direct air capture is something that makes me doubly wary - Aside from the carbon-density-in-air issue, return-on-energy-invested is a key metric I don't see enough emerging encouraging information about. Incorporating the acres of wind, solar, or hydro required to power a DAC solution, the usual land-use objection to a forestry-based carbon removal approach would seem to evaporate pretty quick.
for (int i = 0; i<= 100000000; i++) { Tree t = new Tree(); t.plant(); }
You need specific types of trees for specific microclimates, otherwise they won't thrive and might die. You need a healthy species mixture, otherwise you are creating monocultures vulnerable to mass pest infestation. You need the right amount of rain. You should not reforest good arable land, because we are almost 8 billion now and everyone wants to eat.
Israelis are very good at reforestation, but it took them over 100 years to recreate some modest forests there.
As far as pure sequestration goes, fast growing plants like hemp are better candidates.
Make charcoal. Use the waste heat. Put the charcoal back in the soil, so you're not depleting it of phosphates, minerals, or nitrogen. Repeat.
Maybe you can even use the waste heat to run the Haber process.
That, and the idea that it's a pipe dream that is sold as an excuse not to make some really tough choices about decarbonising other things seems to be the prevailing thought about from cynical environmentalists.
Personally I can only feel that those arguments make some sense but I don't understand the potential enough.
Also, a more personal thought is that it seems really hard to collect such a diluted chemical from thin air?
As Alan Kay says, the best way to predict the future is to invent it.
Learn more about building carbon removal solutions at: http://bootup.airminers.org
Like, would a coal power plant combined with carbon capture be more economical viable than a nuclear plant?
Yeah it's an interesting line of thought but is it really possible to ask that? If you scale up one technology you will hopefully find incremental improvements that will turn that initial calculation on its head. My guess is that any such calculation would be so speculative it wouldn't give you any actionable information.
So my guess is that the best we can do is try scaling up all possibilities until we have a clear winner?
(Although in your example nuclear should already be scaled up enough to give us some idea.)
Question that Vaclav Smil had raised as a potentially fatal obstacle to large scale carbon capture. All is nice and well when we're trying to sequester 1000 tons of CO2 per year as a pilot project. But once we scale up to ~100Mtons or even ~Gton per year - we'll very quickly run out of places to safely store it. How much is this a real physical constraint vs. Smil's skepticism being cranked up to 11/10?
The only real path to avoiding the worst effects of climate change is stopping emissions.
Sucking carbon out of the air while also pumping it up there doesn't make too much sense unless the cost of carbon capture drops well below the cost of de-carbonizing.
No I haven't heard of carbon removal at all.
I guess I'll have to start reading the article, without immediately resorting to comments ;-)
however I have grave concerns. This facility removes 4000 tons of carbon a year. Great, but how much power does that take?
save for france, iceland and bits of sweden, most places emit >200grams of co2 per kwhr. In the uk 1kw for a year is ~2.5 tons of carbon.