[gustaf]

Carbon Engineering and Climeworks are two incredible companies working on Direct Air capture and Air-to-Fuel and we'd like to fund more companies like them. There are less than 5 companies worldwide that are serious about getting Direct Air Capture to scale. The world need more bets that that on such a promising technology

[dharma1]

If Carbon Engineering can really scale (and they can reduce costs to below $100 / tonne of CO2) - why not just pour money into them?

[gustaf]

People are. But that's just one bet. There are lots of components in the ecosystem needed to make everything succeed

[dereke]

One of the things I find interesting about Carbon Engineerings process is that it requires a lot of heat to separate the captured carbon from the fluid (I forget what the fluid is called). Last I heard they were using natural gas for this (with more carbon capture tech attached).

I wonder if they have considered using concentrated solar as the heat source instead? The temps are pretty high and obviously there is no carbon capture needed so it might be a cheaper way of doing it. Also you already build those plants out in the desert so you probably have a lot of cheap land available to put the units nearby.

[state_less]

You could put compressors next to windmills so that on days there is too much wind, you could start up the compressors and make dry ice, liquid nitrogen or some liquid air feed stock.

Cheap energy seems like the key ingredient. The compressor equipment to do the task seems within reach.

One could reverse the process and feed the air (de)compressor gas to make energy on low wind days. I'd be interested to know what the round trip efficiency could be. You could optionally use the compressed products as feed stock in some other industry. Perhaps use blocks of CO2 to make methane or a room temperature liquid gas.

[gustaf]

Yes, you are correct. Cheap energy is the main input to Direct-Air-Capture. Overflow energy from Solar and Wind is a great source of that.

[state_less]

Yes, solar seems like it will continue to drop in price and you'd probably want to leverage that savings too.

A mass produced portable compressor unit could also be neat. Something for around the home. A 1kw to 3kw unit could be nice to make dry ice. You practically need to have AC if you want to work in Florida or other tropical climate. There is a big market for AC combined with solar in the U.S. since folks want AC and a good chunk probably also want to use solar. Given that you want cooling at night, a solar powered dry ice maker might be able to compete with solar + battery + AC. The panels can feed directly into the compressor to make the night's dry ice rather than storing the energy in a battery and running the compressor at night.

The bonus is that any efficiency gains in the dry ice maker could be applied to processes further down stream that make methane or heavier hydrocarbons. You get a solar cooling solution and something that could be helpful when bootstrapping synth gas production.

Here are some small high pressure projects / products:

Liquid nitrogen https://makezine.com/2010/06/07/diy-liquid-nitrogen-generato...

Shoebox compressor https://www.shoeboxcompressor.com/

Not sure how you'd separate the CO2 out of the liquid air though.

[aoner]

Hi Gustaf, I read earlier that you are more interested in Direct Air Capture technologies than others. Do you have any specific reasons?

I think another way we could look at things is finding "cheap" forms of carbon that would have otherwise been burned/left to rot and reprocess those into building materials.

[gustaf]

The reason I'm so interested in Direct Air Capture is:

- It's primarily a tech solution which allows for scale. If you build one Machine you can build a million. It won't actually require very much space, it need access to cheap energy and abilities to store/sequester the CO2 captured.

- Technology have the benefit that can be optimized and optimized and optimized to the point where the cost is not very high. The less tech the less changes for optimization

- There is a big risk many countries won't meet their responsibility. Getting wealthy democracies onboard is hard enough. We need a scalable way to solve this that doesn't require everyone to help because they prob won't after all

- Any negative emission solution that requires a large land-mass will create other problems (dealing with land-owners etc).

[yazaddaruvala]

I'm not Gustaf, but I'll try to answer this.

The return on investment for a lot of Carbon capture/sequestering is not lucrative (or at least the business models are not yet apparent). The long term VC angle for air to fuel seems straight forward.

- Mars alone will be a huge market for such technology. Driving a lot of demand 100-200 years out (if not a big market in 20-40 years).

- Shanghai, et-al, need air filters. Now imagine a filter which also generates a sellable resource; fuel. I imagine that machine would sell quite well in those markets.

- With the right level of efficiency, a new era of "sail" boats could be powered by reclaimed fuel from air. Imagine the market for a cargo/cruise ship leaving port with an empty fuel tank, and days later reaching the destination port with a full tank and its goods delivered.

- With the right level of efficiency, this only improves the efficiency of coal plants. Burning coal for electricity but also reclaiming the CO2 for fuel.

[Xixi]

I don't see how you could make a "sail" boat powered by reclaimed fuel from air, as there is no fuel in the air. You will need a source of energy to convert the CO2 to fuel. In nature the most common (to my knowledge) CO2 -> fuel process is called photosynthesis, and is powered by the sun.

CO2 -> fuel consumes energy (that is stored in the fuel). Fuel -> CO2 releases it.

[yazaddaruvala]

Sorry, in the case of "sail" boats, I worded it poorly before. Wind turbine-like "sails" could act as a propulsion source when the wind direction is correct, and generate energy and funnel the air into the CO2 -> fuel machine when the direction of wind is non-optimal for propulsion.

I agree in all of the cases I mentioned there would always need to be some energy source.

[tempestn]

Also other greenhouse gasses, like methane capture from landfills.