How Much Energy Would It Take to Pull Carbon Dioxide out of the Air?

jeffw@lemmy.world to Technology@lemmy.world – 151 points –
How Much Energy Would It Take to Pull Carbon Dioxide out of the Air?
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Algae does it for free all the time. Physically trying to capture carbon dioxide is dumbassery. We need more investment in algae production.

It could be beneficial for densely populated areas, though. Because you have predictable airflow and low-hanging regions to implement physical capture and sequestering. We can do more than one thing at a time and targeted approaches combined with generalized approaches will yield faster results.

In order for that we need more renewable energy, otherwise we're just burning fossil fuel, producing carbon dioxide, and then capturing it. Solar, wind, algae biofuel, renewable diesel, green hydrogen, etc. We have to be careful how we use energy otherwise we're just producing carbon dioxide to capture carbon dioxide.

People keep complaining that solar and wind give us “too much electricity at the wrong time”, causing power prices to go negative (as if this is a problem). Having a beneficial process like co2 removal that you can do at any time of day (the co2 isn’t going anywhere) that would soak up all that energy seems like a win win.

Yea, and one of the best ways to sequester carbon dioxide is by using algae. Algae biofuels are a great way out of the climate crisis. Use excess energy to produce algae biofuel, net negative emissions.

But if it's used as fuel, wouldn't that typically return the CO~2~? Just about all fuels are burned, which creates the CO~2~, and you have to make sure the energy you use to make and transport the fuel is clean, too.

Yes, but overall it would be net negative carbon dioxide emissions.

How does it stay net negative? Carbon goes into the fuel, which is good, but doesn't like all of it come back out when burned for fuel? My understanding is that these fuels can only really achieve neutrality, and that assumes clean energy used to make the fuel.

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Algae doesn't capture it for long. Trees do it for longer but not long enough to be more then a speed bump. Unless we start dumping algae and trees into giant pits and sealing them up three is no long term carbon capture.

Biochar (created in a retort) is how you sustainably sequester carbon for the long-term using trees (and similar biomass).

Good point. I'm curious how the total amount of energy and resources utilized to grow, harvest, and char algae compares to direct CO2 removal. Ultimately, I just want something that works without generating another issue.

I think the key would be to not use any additional resources to grow, harvest, etc.

This could be done for example by landscaping companies that put their waste through a retort (which could be anything from a stove made of mud bricks, to a mobile trailer that does on-site pyrolysis and use the resulting biochar to fertilize their customer's plants. Farms could put their waste through it, innoculate the biochar with animal waste, and use it as fertilizer.

I make biochar from my backyard waste in my firepit using a can like this guy.

Any other method of carbon capture I've ever heard about makes no sense. Having hundreds of engineers and workers drive to work for years to engineer and build giant metal and plastic factory/machines with parking lots that require staff that has to drive and park there, etc is nonsense. And even if they work, what would they do with the carbon? Biochar provides a cycle that is accessible to everyone, can be done on-site, uses no fancy technology, nothing is patented, and doesn't require all this nonsense.

Algae doesn’t capture it for long.

Not true, it depends on how it's contained. Drying algae and removing the water will stop it from decomposing. Think of seaweed used for sushi except ground up into a very dense powder. Algae will decompose if left hydrated in the sun though.

Where you getting the energy to capture and dry algae that results in a total positive capture?

Solar, wind, nuclear, green hydrogen, hydro, geothermal.

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Techbros were pitching how we'd invent self replicating carbon capture nano machines in the future

That's so annoying about motorsports in recent years. Commentators are tasked by the race series owners to hype up that BS. Researching the technology is fine. Scientists may find ways to capture carbon at a better rate at acceptable energy cost but shouting that an inefficient combustion engine is somehow better for the environment than EV because "batteries bad, carbon capture great" is just stupid.

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