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Engineers find neat way to turn waste carbon dioxide into useful material

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Re: Engineers find neat way to turn waste carbon dioxide into useful material

#51

Post by readams »

perl4ever wrote: post #41
lykr0n wrote: post #3

Earlier quoted context omitted.

You can use Solar and other renewable energy to power the conversion process. Progress is still progress. I would much rather to pay more for net zero carbon fuel, then not do anything.

I do not understand the concept that a property of a sum of a bunch of numbers somehow applies to those components. Whether something is net zero depends on what you are adding it to; it's not inherent in that thing. It's like, if you have a pile of blue things, then the pile is also blue. But other characteristics do not work that way. If you have a pile of things that each weigh 1 lb, then the pile does not weigh 1…

If you make a hydrocarbon by taking CO2 from the air, and you use a carbon free energy source to do it, then burning that hydrocarbon is net zero carbon. That is, if all your hydrocarbons that you burn were made this way, then the atmospheric carbon doesn't increase because of your activity.

It acts just like a battery.

Re: Engineers find neat way to turn waste carbon dioxide into useful material

#52

Post by adrianN »

bit_logic wrote: post #10

Every time there’s a discussion about synthetic carbon fuels, there’s the same frustrating replies. I want to reply to those with one statement: the whole point is to use excess power from solar/wind. There’s always the same replies pointing out how it’s more efficient to use the power directly in EV batteries, laws of thermodynamics, and other similar things. Those completely miss the point. Solar/wind is going expo…

What's missing is a careful differentiation between doing what you said, storing excess energy, and approaches that are popularized, e.g. by carmakers unwilling to invest in R&D, where we keep on relying on hydrocarbons for things like transportation and heating and magically replace them with carbon neutral alternatives.

The first approach of using hydrocarbons as an energy buffer makes perfect ecological and economical sense and is most likely strictly necessary for a carbon neutral energy grid (barring battery breakthroughs), once we reach 60-70% renewable energy in our grids.

The latter approach however makes no sense at all, because we simply don't have enough space for wind and solar to feed our thirst for hydrocarbons with renewable power. The energy losses, both in the step creating the fuel, and in the step turning fuel to useful work, are just too great to fuel every car or heat every home in the world like that.

Re: Engineers find neat way to turn waste carbon dioxide into useful material

#53

Post by adrianN »

gpm wrote: post #24

Slightly offtopic, what's the easiest way to scrub CO2 from air (e.g. in a house) without using up consumable materials? Some form of pressure swing absorption?

Get a large amount of calcium hydroxide in a watery slurry. That absorbs CO2 to form calcium carbonate. Take the carbonate outside and heat it up sufficiently to form calcium oxide and carbon dioxide. Add water to go back to calcium hydroxide.

Re: Engineers find neat way to turn waste carbon dioxide into useful material

#54

Post by Godel_unicode »

ashtonkem wrote: post #34
carapace wrote: post #25

Earlier quoted context omitted.

Bucky Fuller had the idea to just connect the world's electricity grids together. He called it "World Grid" I think.

That’s more efficient, but difficult politically and logistically.

How would that be more efficient? The transmission loss would be outrageous between the summer and winter hemispheres. Compare that with transmission loss for LNG tankers at the moment, effectively 0 even with the occasional leak in transit.

Re: Engineers find neat way to turn waste carbon dioxide into useful material

#55

Post by namibj »

nine_k wrote: post #36
carapace wrote: post #25

Earlier quoted context omitted.

Bucky Fuller had the idea to just connect the world's electricity grids together. He called it "World Grid" I think.

Geography may also be a problem. Running a gigawatt cable from sun-soaked Australia anywhere in SEA is enormously expensive. Instead, packaging the energy into carbohydrates produced from waste water (cleaning it in the process) and waste CO₂ may be much more economical and convenient. You can likely produce the best quality Jet A fuel or octane 98 gasoline with little other fractions by tuning the synthesis process…

The need to fly commercial liquid-fuel planes beyond the near/medium future far from certain. To my understanding we could quite easily use electric ships for most trans-oceanic cargo, and supplement it with some rail tunnels/bridges crossing from the UK, over the Faroe Islands, to Iceland, Greenland, Baffin Island, and Québec. The only tectonic "issue" would be crossing the Mid-Atlantic Ridge on Iceland.

Sure, it'd be quite a large civil engineering feat, but the speeds would be hard to beat. It'd be just a 12h ride from London to NYC, assuming TGV's top speed of 575 km/h.

A potential alternative could be to use a low-flying plane and deploy a series of HVDC-fed buoys/platforms straight across the Atlantic for fast-charging.

You're right about the Falcon 9 though.

Re: Engineers find neat way to turn waste carbon dioxide into useful material

#56

Post by derriz »

bit_logic wrote: post #26
skybrian wrote: post #21

Earlier quoted context omitted.

A problem with processes based on using excess power is that they use equipment inefficiently. If cheap power is only available for a quarter of the time then it would take 4x as long to pay for the investment in the equipment. Whatever scheme you set up to use excess power needs to be pretty cheap to make it worth running only a small part of the time, or it needs to be doing something especially valuable. Compare t…

Solar produces only during the day, but wind is at any hour. And these days, the idea of massive over-provisioning is being discussed to overcome the intermittent problem since solar/wind keeps getting cheaper and cheaper. The idea is simple, how to overcome the cloudy winter day issue? Simply overbuild a lot of solar/wind so it can still provide enough on a winter day. Then during summer, shutoff the excess power ge…

If BEVs capture even a fraction of the market then you've effectively a massive distributed battery which could help soak up the excess renewable electricity. Quick estimate - if 1% of the US passenger vehicles were BEV each with 50KWh batteries on average is 100GWh of storage.

It would require dynamic pricing to the consumer to work as off-peak prices would need to be low or very low to encourage all BEV owners to take on the excess power at particular times of the day.

By the way, unfortunately dynamic pricing seems to be a very unpopular idea as far as I can see.

Re: Engineers find neat way to turn waste carbon dioxide into useful material

#57

Post by namibj »

gpm wrote: post #24

Slightly offtopic, what's the easiest way to scrub CO2 from air (e.g. in a house) without using up consumable materials? Some form of pressure swing absorption?

Not really without consumables, unfortunately. But it's easy and costs about 50-200$ per human and month when you just buy the required substance, granular CaOH treated with 1~2 NaOH (by pouring a concentrated solution of it over the CaOH), from Alibaba once a year. That stuff is e.g. used for re-breathers in anesthesia. CAS 8006-28-8 is the "magic" word/number.

The potential alternative, which would not use consumables, would be to just freeze it out. It's not _that_ hard, I believe an ammonia-based single-stage chiller should still suffice. Make sure to use counter-flow heat exchangers to not loose insane amounts of power. Handling the water condensation might not be that trivial, though.

Re: Engineers find neat way to turn waste carbon dioxide into useful material

#58

Post by namibj »

gpm wrote: post #48
marcosdumay wrote: post #46

Earlier quoted context omitted.

If you are concerned about indoor CO2 concentration, the answer is to ventilate the place. No reasonable amount of plants will keep a house stable. If it's just really curiosity, well, people have been scrubbing CO2 since space travel is a thing. Wikipedia was completely unhelpful to me, but I remember there is a mineral with high CO2 selectivity that you can simply push the air though it.

98% curiosity, 2% lack of faith in our long term ability to keep CO2 levels down to healthy levels (1000ppm is enough that we can detect minor negative effects... I have to wonder if really minor ones exist even at 400 ppm). Wikipedia was similarly not useful for me. Scuba divers and the like apparently use a one-time-use non-regenerative mineral that absorbs CO2. The space station has something that regenerates but…

If you figure out some concrete setup, let me know. I am fairly certain that there are measurable cognitive effects at "just" 500 ppm, and good luck staying below that when you can't just sit at an open window outside of a city.

1000 ppm is btw. enough to feel uncomfortable. Cognitive impairment will be much more subtle.

Re: Engineers find neat way to turn waste carbon dioxide into useful material

#59

Post by jfkebwjsbx »

adrianN wrote: post #52
bit_logic wrote: post #10

Every time there’s a discussion about synthetic carbon fuels, there’s the same frustrating replies. I want to reply to those with one statement: the whole point is to use excess power from solar/wind. There’s always the same replies pointing out how it’s more efficient to use the power directly in EV batteries, laws of thermodynamics, and other similar things. Those completely miss the point. Solar/wind is going expo…

What's missing is a careful differentiation between doing what you said, storing excess energy, and approaches that are popularized, e.g. by carmakers unwilling to invest in R&D, where we keep on relying on hydrocarbons for things like transportation and heating and magically replace them with carbon neutral alternatives. The first approach of using hydrocarbons as an energy buffer makes perfect ecological and econom…

How big are the losses to make such a big impact as to say there is not enough space for enough solar/sun farms?

99% or what?

Re: Engineers find neat way to turn waste carbon dioxide into useful material

#60

Post by usrusr »

skybrian wrote: post #21
bit_logic wrote: post #10

Every time there’s a discussion about synthetic carbon fuels, there’s the same frustrating replies. I want to reply to those with one statement: the whole point is to use excess power from solar/wind. There’s always the same replies pointing out how it’s more efficient to use the power directly in EV batteries, laws of thermodynamics, and other similar things. Those completely miss the point. Solar/wind is going expo…

A problem with processes based on using excess power is that they use equipment inefficiently. If cheap power is only available for a quarter of the time then it would take 4x as long to pay for the investment in the equipment. Whatever scheme you set up to use excess power needs to be pretty cheap to make it worth running only a small part of the time, or it needs to be doing something especially valuable. Compare t…

Yes, you can't do your price calculations based on 24/7 utilisation. But that's true for almost every other bit of technology as well. What's the average utilisation of a theatre? Of a plough?
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