"Net Zero"

[JohnW2]

The main idea, as I understand it, is to pump it I to empty gas fields, which is somewhat ironic IMO

Yes, I've heard of that plan and, as you say, it's rather ironic!

CCS will only work when captured at source, and then, only when CO2 is produced in significant quantities, so power stations, and hydrogen production sites. ...

As I implied, it's the sheer magnitude of the issue that boggles my mind. If the "back of my ciggie packet" is correct, then with a total mass of atmosphere of about 5.15 x 10^18 kg and CO2 currently at about 414 ppm (about 50% higher than at the start of the 'industrial era'), that seems to equate currently to about 2.1 trillion tonnes of CO2 (about 0.6 trillion tonnes of carbon, or about 4.8 trillion tonnes if converted to, say calcium carbonate)

If that's all correct, and if one converted the CO2 to calcium carbonate for 'storage', then if one wanted to store say, an amount of carbon equivalent to, say, 10% of the present atmospheric CO2 content, it looks as if one would be having to 'store' something approaching 0.45 trillion tonnes of calcium carbonate - and I'm not at all sure how realistic that would be In passing, that same process would also result in the 'storage' (removal from the atmosphere) of about 0.24 trillion tonnes of oxygen, and I'm not sure whether that would be of any relevance.

The idea is that if we can capture carbon at source, and use it to produce non carbon producing fuel, such as electricity or hydrogen, we can decarbonise significantly, which along with tree planting and other more "natural" measures will lead to net zero

If I understand correctly, you're not now talking about "Carbon Capture and Storage" but, rather, of continuously re-cycling the carbon - in other words, repeatedly 'burning' the carbon to generate electricity, then recovering the carbon from the CO2 created by the 'burning , and then burn it again (to generate more electricity) ... and so on, ad infinitum. Is that what you mean?

Kind Regards, John

 

[mikeey84]

If I understand correctly, you're not now talking about "Carbon Capture and Storage" but, rather, of continuously re-cycling the carbon - in other words, repeatedly 'burning' the carbon to generate electricity, then recovering the carbon from the CO2 created by the 'burning , and then burn it again (to generate more electricity) ... and so on, ad infinitum. Is that what you mean?

No, and sorry if I wasn't clear.

We can't capture carbon from most users of natural gas, as they are too small. However, if we can capture the carbon from large scale producers of it, ie power stations, and hydrogen plants, who in turn produce carbon free energy, that carbon can be captured and stored much more efficiently.

Nb a hydrogen plant strips the hydrogen from natural gas, pumps that into the network, and captures the remaining carbon.

10% of the present atmospheric CO2 content

Ah, that won't be carbon neutral, that would be carbon negative. We don't produce that much carbon (I hope!) I doubt, with current tech, we will ever be able to be carbon negative. (To be honest, without significant investment, I doubt we will be carbon neutral in my lifetime, and I'm not quite 40!)

 

[mikeey84]

re-cycling the carbon - in other words, repeatedly 'burning' the carbon to generate electricity, then recovering the carbon from the CO2 created by the 'burning , and then burn it again (to generate more electricity) ... and so on, ad infinitum.

This is pretty much the theory behind biomass generated electricity. Few problems with that however!

 

[ericmark]

It seems people don't understand carbon and carbon dioxide are not the same thing.

Chlorine is deadly, but we can't live without sodium chloride.

 

[mikeey84]

It seems people don't understand carbon and carbon dioxide are not the same thing

You are obviously correct, but if you remove the carbon from carbon dioxide, it becomes much less harmful, hence why its referred to as carbon capture, and not carbon dioxide capture. I'm not actually sure what form the carbon is captured in, so carbon dioxide capture maybe more accurate if oxygen isn't a byproduct...

 

[JohnW2]

No, and sorry if I wasn't clear. ... We can't capture carbon from most users of natural gas, as they are too small. However, if we can capture the carbon from large scale producers of it, ie power stations, and hydrogen plants, who in turn produce carbon free energy, that carbon can be captured and stored much more efficiently.

Maybe I wasn't clear, either. because I was talking about large-scale operations such as power stations. My point was that, if they recover 'carbon' from the products of combustion, why 'store' the recovered carbon, rather than repeatedly ('for ever') re-burn it, to produce electricity again?

Is the problem perhaps that it is not easy (or perhaps not cost/energy-efficient) to recover something 'burnable' (e.g. pure carbon) from the emissions?

Ah, that won't be carbon neutral, that would be carbon negative.

Sure, but I only )lazily) pulled "10%" out of the air for illustration. However, even if one sought to capture carbon (and store it as, say, calcium carbonate) to the extent of being equivalent to just 1%, or even 0.1% of the current atmospheric C)2 content, one would still be needing to store countless billions of tonnes of calcium carbonate (or whatever) - which is what I suspect would not be realistic.

We don't produce that much carbon (I hope!) I doubt, with current tech, we will ever be able to be carbon negative. (To be honest, without significant investment, I doubt we will be carbon neutral in my lifetime, and I'm not quite 40!)

I'm in my early 70s, so it's probably more than just 'doubts' in my case

Kind Regards, John

 

[JohnW2]

It seems people don't understand carbon and carbon dioxide are not the same thing.

Undoubtedly true. "Carbon" seems to have become shorthand for CO2 - or, indeed, more generally to include other carbon-containing 'greenhouse gases' such as methane.

Let's face it, virtually all of the current concerns relate to 'climate change', hence greenhouse gases' in general, regardless of what they are.

Kind Regards, John

 

[JohnW2]

You are obviously correct, but if you remove the carbon from carbon dioxide, it becomes much less harmful, hence why its referred to as carbon capture, and not carbon dioxide capture. I'm not actually sure what form the carbon is captured in, so carbon dioxide capture maybe more accurate if oxygen isn't a byproduct...

I'm not at all up on this but what little I have read about 'CCS' seems to relate primarily to conversion of the captured CO2 to calcium carbonate (in one form or another) - which, if commonly the case, adds to the 'storage problem' - since 1 unit weight of carbon equates to about 8.3 units weight of calcium carbonate.

Kind Regards, John

 

[mikeey84]

Is the problem perhaps that it is not easy (or perhaps not cost/energy-efficient) to recover something 'burnable' (e.g. pure carbon) from the emissions

I'm sure it would be possible, but efficiency is key for all of these choices, and I reckon there would just be too many losses during that process

needing to store countless billions of tonnes of calcium carbonate (or whatever) - which is what I suspect would not be realistic.

Not sure how much space our oil and gas extraction has left, but I reckon there is a fair bit of space down there.

I think the real hope is for the generation of low carbon electricity to get to a point that efficiency becomes less of an issue, and we can afford to pour excess electricity into processes that produce useful things from the carbon, in whatever form, whether atmospheric or captured at source

 

[JohnW2]

I'm sure it would be possible, but efficiency is key for all of these choices, and I reckon there would just be too many losses during that process

As I said, I suspected that might be the case. Otherwise, they would surely being do it, since it is 'so obvious' - and, apart from 'top up' becauses of losses, would be heading in the direction of a 'perpetual motion machine'

Not sure how much space our oil and gas extraction has left, but I reckon there is a fair bit of space down there.

Obviously quite a lot, although I have no idea of how much - but, as I said, the magnitude of the 'requirements' essentially boggle my mind! I imagine that the 'space' to which you refer has probably filled up with sea water (or something), but I guess that would 'come out' if one started pouring 'solids' in!

I think the real hope is for the generation of low carbon electricity to get to a point that efficiency becomes less of an issue, and we can afford to pour excess electricity into processes that produce useful things from the carbon, in whatever form, whether atmospheric or captured at source

Sure, but I fear that most of that will be beyond my lifetime, and quite possibly even yours If we ever get to the stage of most electricity being produced by the current 'renewables' and nuclear (particularly if/when nuclear fusion becomes viable), the goalposts will obviously have totally moved - but I (and perhaps you) are not going to see that.

Kind Regards, John

 

[mikeey84]

Obviously quite a lot, although I have no idea of how much - but, as I said, the magnitude of the 'requirements' essentially boggle my mind! I imagine that the 'space' to which you refer has probably filled up with sea water (or something), but I guess that would 'come out' if one started pouring 'solids' in!

No idea of the veracity of this, but I found this in a press release from ICL:
"This is far less than leading estimates by academic and industry groups of what is available, which suggest there is more than 10,000 Gt of CO2 storage space globally."

Now that is a mind boggling figure!

 

[chivers67]

I've been reading so much in the way of Hydrogen production, as long as it's produced by a Green source it should be zero carbon and only produce H2O/Water as a byproduct. The only thing is to produce the equipment that provides the "green" you use energy sources reliant on carbon in the process of making it Turbines/Solar/Hydro/Electrolysis plates

Once there is an abundance of green hydrogen then perhaps there will truly be Net Carbon output if it is also used to produce Green energy producing products. If Hydrogen production takes off as quick and efficiently as some other products like mobile phone improvement it's only a matter of time.

 

[JohnW2]

No idea of the veracity of this, but I found this in a press release from ICL: "This is far less than leading estimates by academic and industry groups of what is available, which suggest there is more than 10,000 Gt of CO2 storage space globally." Now that is a mind boggling figure!

Mind boggling, yes, but (in terms of the big picture) not dramatically greater than what I was suggesting might be required.

However, none of this is as straightforward as might at first seem to be the case. How much energy would, I wonder, have to be expended in order to process, say, 1 Tt of CO2 and shift into into 'storage' (mostly in the middle of the North Sea)?

Kind Regards, John

 

[JohnW2]

I've been reading so much in the way of Hydrogen production .... If Hydrogen production takes off as quick and efficiently as some other products like mobile phone improvement it's only a matter of time.

One thing to consider is that a widespread shift to hydrogen use might be associated with an increasing number of reports of 'big bangs' on the 6 o'clock News!

Kind Regards, John

 

[mikeey84]

However, none of this is as straightforward as might at first seem to be the case. How much energy would, I wonder, have to be expended in order to process, say, 1 Tt of CO2 and shift into into 'storage' (mostly in the middle of the North Sea)?

About 250-300 kwh per tonne apparently, and I guess the left over infrastructure in the North Sea from the oil and gas extraction would be quite useful.

CO2 compression uses about a third of that, so in suitable strata, the gas could be pumped in directly. CO2 is pretty soluble, so you wouldn't even need to displace all of the water, and if it's impermeable to gas, as gas fields would be, its not going anywhere