Direct air capture: our technology to capture CO₂ • Hacker News Board

Re: Direct air capture: our technology to capture CO₂

#81

Post by johndunne » Sat, May 27, 2023, 1:52 PM UTC

onos wrote: post #73

dvh wrote: post #65

Earlier quoted context omitted.

That's 14kg per human per day. Seems about right.

And one tree does 25kg per year. So each person should plant 14 * 365 / 25= 204 trees. Seems very reasonable.

Consider UK; 204 trees * 65 million people = 13.2 billion trees. Woodland estimates there's approx 3 billion trees in the UK now. That's over 4 fold increase in trees every year. I doubt the terrain/nature could support such a significant increase in just one year, let alone a number of years. But I like the idea of more trees.

https://woodlands.co.uk/blog/woodland-economics/how-many-tre...

Re: Direct air capture: our technology to capture CO₂

#82

Post by thinkcontext » Sat, May 27, 2023, 1:52 PM UTC

jonplackett wrote: post #34

Explain like I’m 5: Why is this better than just growing trees and then cutting them down and burying them so the co2 never gets back into the atmosphere?

Burying trees is too unwieldy to be practical. Burning the trees and capturing the resulting co2 is more feasible. It's an example of BECCS, bio energy carbon capture and sequestration, some argue it's a practical solution.

Re: Direct air capture: our technology to capture CO₂

#83

Post by idlewords » Sat, May 27, 2023, 1:57 PM UTC

A similar technology (bed of amines that absorbs CO2 from ambient air) is being tested on the International Space Station, so it's worth reviewing how this stuff breaks:

1. Pipes and bearings clog up or corrode.

2. Trace contaminants irreversibly react with the sorbent material.

3. Stuff in the beds shifts around in unexpected ways, aided by the heat cycling.

4. The problem gets harder the more dilute the gas is. The older zeolite beds on ISS struggle to keep CO2 levels below 5000 ppm, vs. 400 ppm ambient on Earth. Submarines (which use amine sorbents) have the same problem getting below 5000 ppm.

I have no idea how Climeworks addresses these challenges, but they are kind of unavoidable when you're trying to remove a trace gas with a reversible process in thermodynamically unfavorable conditions. They will have to move vast quantities of air, and everything that is in it, through the system, and heat and cool the components thousands of times. I'm sure the problems are surmountable, but are they surmountable in a way that keeps total carbon used in the process (including manufacturing and repair) negative?

Re: Direct air capture: our technology to capture CO₂

#84

Post by somedude895 » Sat, May 27, 2023, 2:04 PM UTC

kmeisthax wrote: post #6

Lots of information about land usage, not so much about power usage beyond "it'll run on renewables". I imagine their cost benefit analysis boils down to "governments will pay for it to not die", which sounds rather optimistic.

And then wouldn't all that renewable energy production better be used to replace fossil fuel production? Maybe once we've replaced all possible CO2 emitting power generation it would make sense to start building out more to power these things?

Re: Direct air capture: our technology to capture CO₂

#85

Post by 14 » Sat, May 27, 2023, 2:15 PM UTC

vlovich123 wrote: post #66

MichaelZuo wrote: post #63

Earlier quoted context omitted.

The numbers don't look right, they would imply human CO2 generation of over 100 million tons per day.

Humans emit about 35 billion tons a year according to the reports which comes out to emit 100 million tons per day.

Then we will need to see these machines scale up over time like we see solar doing now.

I hope one day industry will be required to match their carbon capture with devices like this to their carbon output.

Perhaps someone will make a solar farm in tandem with these co2 capture devices with the fans from these devices cooling the solar panels as solar panels work more efficiently at cooler times (1).

1: https://www.solar.com/learn/do-solar-panels-work-less-effici...

Re: Direct air capture: our technology to capture CO₂

#86

Post by kitd » Sat, May 27, 2023, 2:18 PM UTC

johndunne wrote: post #81

onos wrote: post #73

Earlier quoted context omitted.

And one tree does 25kg per year. So each person should plant 14 * 365 / 25= 204 trees. Seems very reasonable.

Consider UK; 204 trees * 65 million people = 13.2 billion trees. Woodland estimates there's approx 3 billion trees in the UK now. That's over 4 fold increase in trees every year. I doubt the terrain/nature could support such a significant increase in just one year, let alone a number of years. But I like the idea of more trees. https://woodlands.co.uk/blog/woodland-economics/how-many-tre...

The UK is one of the least forested countries in Europe. It is very doable.

Re: Direct air capture: our technology to capture CO₂

#87

Post by wolfram74 » Sat, May 27, 2023, 2:21 PM UTC

mchannon wrote: post #55

thx-2718 wrote: post #3

"Our plants require less land than other techniques. E.g., on a land area of 0.42 acres, our Orca plant can remove 4,000 tons of CO₂ from the air every year, which is almost 1,000 times more effective than trees. The same land would host around 220 trees with an estimated capacity of 22kg each" How much land, in solar panels for example, is required to power this? Also what's the carbon waste that this generates? Is…

1000 kWh/ton (found it on google): 166 kW/ton in a sunny place: 1000 square meters/ton in a sunny place: 4 million square meters = ~1000 acres of PV to power. One unit. Yeah, that’s going to happen. /s “We’re too ashamed of our energy requirements to post them on our page and are well aware they’re dooming this technology until cold fusion comes out” is what I read between the lines on their fluff page.

two comments: they claim to sequester 1000 tons (1e6 kg) vs 22kg, so the sequestration space difference is on the order of 200000 difference. They may include the solar panel area in their stated efficiency calculation.

Secondly, the solar panels are a bit more liquid than a comparable area of trees, when industrial demand is high, you can route it there, when it's low, it can be working on sequestration. There are some advantages there. Especially considering the atmosphere is fairly homogeneous, but soil in proper condition for forests is less so.

Re: Direct air capture: our technology to capture CO₂

#88

Post by specialist » Sat, May 27, 2023, 2:25 PM UTC

shafyy wrote: post #59

Climate scientist David Ho has a good thread on CDR: https://mastodon.world/@davidho/109511745525784891 It's hard for people to visualize removing tons or billions of tons of #carbon #dioxide (CO₂). I propose we talked about CO₂ #removal (CDR) like a #time #machine (e.g., this machine will take us back 5 minutes). For example: Q: How far back in time does planting 100 million #trees take us? A: If one mature tree tak…

Time machine is neat metaphor. Thanks for sharing.

--

Net Zero is not enough. We must do Net Negative, a much bigger project than Net Zero.

The goal is CO2 350ppm, or lower.

Today is 417ppm. It will be >600ppm in 2050, our current global Net Zero deadline.

There is no either-or. We need all the solutions. To stop and then reverse emissions: solar, wind, geothermal, nukes (old and much more new), storage, transmission, carbon direct capture, solar reflection, etc, etc.

Renewables and electrification buy us a little bit of time.

Meanwhile, we need to over invest in CDR. Birth of Flight type thinking. Moonshot type efforts. Dump money onto every semi-plausible idea.

Any viable CDR solutions will take decades to scale up. So we must start today.

--

PS- Ditto methane and other GHGs. Ditto fusion and solar reflection (mirrors). And maybe even, god forbid, geoengineering.

Re: Direct air capture: our technology to capture CO₂

#89

Post by hef19898 » Sat, May 27, 2023, 2:32 PM UTC

thx-2718 wrote: post #3

"Our plants require less land than other techniques. E.g., on a land area of 0.42 acres, our Orca plant can remove 4,000 tons of CO₂ from the air every year, which is almost 1,000 times more effective than trees. The same land would host around 220 trees with an estimated capacity of 22kg each" How much land, in solar panels for example, is required to power this? Also what's the carbon waste that this generates? Is…

4000 tons of CO2 removal per year is at best a proof of concept. If it was one of the industrial giants, with the muscle and budget to scale it and the sales channels to sell it, I would be more optimistic about that.

But than I became so jaded regarding start-ups, especially "ddep" tech ones, lately that I tend to see even more negatively than I already do in general.

Re: Direct air capture: our technology to capture CO₂

#90

Post by the_third_wave » Sat, May 27, 2023, 2:32 PM UTC

If you insist on capturing CO₂ then capture it somewhere it is available in abundance instead of ~400 parts per million: at the source. Capture it at gas turbine exhausts, at coal-burning power station smoke stacks, maybe on board ships if the power is available to do so. Use some other process for capturing atmospheric CO₂, e.g. lime stone capture. Trying to actively capture airborne CO₂ is like creating needle-in-haystack-finding factories, it is possible but a waste of resources.