You know, I'm not sure I really need to hear from any more non-experts thinking out loud anymore. We've had enough of that. I want to hear from experts giving their carefully considered views.
The impact of direct air carbon capture on climate change
121–130 of 147 posts
Re: The impact of direct air carbon capture on climate change
#122Not a word about the most effective, cheapest strategy: reduce emissions? Most Americans could reduce their emissions by 75% while improving their standard of living by buying less junk, wearing a sweater in the winter, eating more healthy, and other low hanging fruit that will make them more active, healthy, connected to their communities, etc. Reduce consumption by half. There, I just saved us $300 million. How is…
Personal choice is a very small aspect here. Americans can not choose to have lower carbon cement, steel, manufacturing, shipping, airliners, etc. Yes, we can do a lot by not flying ourselves, buying less items, eating less meat, but at the end of the day: MOST of our solutions are going to come from corporations and government.
Re: The impact of direct air carbon capture on climate change
#123I've been interested in these types of technologies lateley. > that many people are extremely pessimistic about climate change. They can’t imagine any solution – often, they become mesmerized by what appears to be an insoluble collective action problem – and fall into fatalistic despair. More and more, I find this description matches my thoughts on climate change. I'm really beginning to think the problem might requi…
I'm totally with you. Reducing carbon intensity is possible (and almost easy) up to a point, but once you've converted 80-90% of the power grid to renewable sources and electrified most transportation there is still significant carbon emissions occurring for high value operations, like air transportation. Plus we still have to deal with the elevated levels we are at today.
Having viable large scale carbon capture technology, gives us another advantage though- It gives us a really solid economic foundation for pricing those remaining carbon emitting operations. Entities can just regulate or tax carbon emissions at that point, and let the market figure out what activities and operations are still worth emitting for.
Re: The impact of direct air carbon capture on climate change
#124Earlier quoted context omitted.
I would aggressively vote and promote a us presidential candidate who stated they would negotiate an arrangement to do this for financial compensation on coastal equator countries- and failing that, a hostile military invasion to force it upon them. Probably no need for the latter, but having it on the table makes the former easier to negotiate. This process could release deadly nickel into the water. It probably wou…
> and failing that, a hostile military invasion to force it upon them. Eco-fascism! I mean, once you're willing to murder people to reduce carbon emissions, there are simpler ways to do it. But make sure you've got suitable carbon offsets for the invasion and the crematoriums. > optimistic message "Good news: America is going to improve the world at gunpoint again!"
I know people won’t like it, but the alternative is a Mad Max world. We’re told the whole planet will be either an ocean or a desert unless we return to the Stone Age. Therefore we need to follow the Georgia monument and reduce the global population to 500 million. Anything less than the total dissolution of human rights in the name of environmental protection is a death sentence anyways. At least we can use the benevolence of democracy to pick winners and losers.
Re: The impact of direct air carbon capture on climate change
#125Just plant trees. They're cheap, solar powered, and convert CO2 to building materials.
Interesting side effect is it makes the planet warmer because trees are dark.
Re: The impact of direct air carbon capture on climate change
#126I'm not sure if this article hammers home the key point: extracting carbon from the air always takes more energy that was gained by burning the fossil fuel to make that carbon. This is inevitable due to the entropy cost of de-mixing CO2 from the air, and from the limited efficiencies of thermal power generation (~33-40% for a coal power plant, perhaps 20% in an internal combustion engine), and limited efficiency of t…
> So it only makes sense to spend energy on sucking CO2 out of the atmosphere, once you've already de-carbonised everything which you possibly can.
The actual point is much narrower than that. It doesn't make sense to spend energy on sucking CO2 out of the atmosphere, unless:
1) You use an energy source that produces less carbon than the amount you're taking out; and
2) You're not displacing demand that must then be satisfied by an energy source that produces more CO2 than you're taking out.
In other words, it doesn't make sense to burn coal to capture CO2, but it doesn't also make sense to use nuclear power to capture CO2 if that means that some other demand will have to be satisfied with coal instead of nuclear power.
But it goes too far to say that the above criteria only hold "once you've already de-carbonised everything which you possibly can."
For example, if you build a surplus of renewable power (which we have in some cases, where instantaneous generation exceeds what the grid can use at that moment), it makes sense to use that to suck out CO2, even if, for example, you haven't replaced ICE vehicles with electric vehicles.
As a practical matter, we need carbon capture much earlier than 2050 or 2100 to keep below 1.5C or 2C. For example, China plans to ban EVs by 2040: https://www.forbes.com/sites/energyinnovation/2018/05/30/chi.... Even if they stick to that plan, they will put out hundreds of millions of ICE vehicles on the road until that time. Even by 2025, official goals will leave 60% of new Chinese vehicles as ICE.
If you look at the mitigation pathways for 1.5C, they require the whole world hitting net zero emissions by 2050 and often going net negative soon after that: https://www.ipcc.ch/site/assets/uploads/sites/2/2019/05/SR15...
That will not happen. Indians and Chinese aren't going to stop building high-speed rail (which puts out a huge amount of carbon due to the concrete used), skyscrapers, etc. Nigeria's population is going to balloon to 400 million. We're going to need to build a large number of nukes and offshore wind to capture all that new CO2.
Re: The impact of direct air carbon capture on climate change
#127I'm not sure if this article hammers home the key point: extracting carbon from the air always takes more energy that was gained by burning the fossil fuel to make that carbon. This is inevitable due to the entropy cost of de-mixing CO2 from the air, and from the limited efficiencies of thermal power generation (~33-40% for a coal power plant, perhaps 20% in an internal combustion engine), and limited efficiency of t…
Sure, but does it matter? If we decide that's a better use for the energy, then we spend it that way. And can't we capture any carbon generated through that process instead of releasing it as further emissions?
Re: The impact of direct air carbon capture on climate change
#128Earlier quoted context omitted.
> Burning methane is even better Actually, burning is probably the best way to deal with any excess methane. Methane has a significantly higher warming potential than CO2 does. So if there's any methane we're venting into the atmosphere, we should burn it to convert it into CO2. Bonus points if you can use the generated energy to capture the CO2 as well.
From what I can see, yes, methane is abstractly a worse greenhouse gas. However its absorption band is within that of water vapor. Since water vapor is plentiful around the blue marble, methane doesn’t really cause any problems.
This is incorrect, it’s well established that methane is a more potent GHG. See the reply here: https://news.ycombinator.com/item?id=21485738
Re: The impact of direct air carbon capture on climate change
#129Earlier quoted context omitted.
From what I can see, yes, methane is abstractly a worse greenhouse gas. However its absorption band is within that of water vapor. Since water vapor is plentiful around the blue marble, methane doesn’t really cause any problems.
This is incorrect, it’s well established that methane is a more potent GHG. See the reply here: https://news.ycombinator.com/item?id=21485738
What’s not taken into conservation with that comment is that methane at those altitudes does not impact much because the energy is radiate back to space.
Re: The impact of direct air carbon capture on climate change
#130Earlier quoted context omitted.
There is a well known relationship summarized in the Sherwood plot. https://www.pnas.org/content/pnas/108/51/20428/F1.large.jpg related paper: https://www.pnas.org/content/108/51/20428 Your basic intuition is correct in that the more dilute something is, the more costly it is to extract/purify it.
A properly engineered DAC system will be much less expensive than the number they found. https://www.cell.com/joule/fulltext/S2542-4351(18)30225-3
That paper only looks at the energy/cost balance of the plant, not the chemical feedstock. Production of that feedstock is energy intensive, the recycling is not 100% efficient per the paper (i.e. it will constantly have to be replenished), and the industrial infrastructure to produce those chemicals at the necessary scale to materially reduce atmospheric carbon simply doesn't exist.
Any cost model for large-scale DAC must include the capital and operational costs of new feedstock factories to keep the DAC supplied at scale. It won't be cheap. The pilots can ignore this because they rely on the excess capacity of existing industrial infrastructure.