The REAL problem with CCS?
Richter concluded that it could be done if we're willing to spend the additional money. HOWEVER, the CO2 has to stay sequestered for a very very long time: almost forever. That's where Richter is skeptical. Two scenarios are being discussed: first, depositing the CO2 in the deep ocean (by pipeline or as a liquid on a ship). "This one doesn't work", he says flatly. Second, in depleted oil and gas reservoirs or in deep saline aquifers. "This one might work".
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It would be great if we could just condense it out and store it at the poles as on Mars, but there are obvious uncomfortable side effects with that scenario as well. What the esteemed Mr. Richter doesn't realize is that the energy that was released by atmospheric combustion must be reapplied the the chemical equation to produce carbon back again, which can easily be stored forever in a variety of useful forms - consumer items if you will, most notably, structural products and insulating aerogels, so that we don't need to burn all that carbon in the first place.
That of course, requires space based solar energy and industry for the large energy consumers, and surface base solar energy on a large scale for the little people.
The interconnectedness of all things, and all that. So, as I have written extensively, we need the reusable rockets, we have the moon and geosynchronous orbit, the numerous Lagrange points and lots of hazardous asteroids to work with. But most of all, it will required regular breakthroughs in condensed matter physics, which for all practical purposes we already have. More importantly, it requires immediate reductions in carbon combustion, huge changes in attitudes and lifestyles and large investments in spectroscopy laboratories of every variety, which in turn requires a complete overhaul of our educational systems so that we produce scientists, engineers and naturalists and agriculturalists and not glorified babysitters.
In the short term, we need to seriously look at solar irradiance modification at Solar L1, because earth based geoengineering is simply not viable, as the current situation with the atmosphere clearly demonstrates. I must admit that I am not surprised at a Nobel laureate naivete in these matters.
Natural CO2 geological reservoirs exist (and are exploited to get pure CO2 for industrial and food producing purposes ...). So, geological CCS in aquifers is *possible*
However, there are unknowns :
- to get a good storage you need a place without cracks in the caprock. How many sites do we have ?
- if we inject CO2 in aquifers, we will displace brine ... somewhere. As such, this can disturb several other uses of deep saline aquifers : geothermy, temporary gas storage, etc. How will we manage different uses ?
- last point : how can we ensure that there will be no leakages during 1000 years ?
and there is a known : CCS is useful only for heavy industries and coal plants (meant to be phased out anyway). It will be useful, but it cannot replace LOTS of things to do to limit our emissions.
bratisla
Let's just treat carbon like nuclear waste so that the government takes over all responsibility to bury it "almost forever"*
That oughta work really well.
*Preferably in Nevada in case there is a "burp". You gotta wonder: do they write "almost forever" into the specification?
~@:>
Schellnhuber et.al. in his role as head of the German Advisory Council on Global Change, in this report, starting on page 77 discussed CCS.
Of interest is the assessment on how good the storage has to be. They did some "rough" calculations, they say. The calculation involved assuming how much CO2 would be stored in certain emission scenarios if civilization acted to limit warming to 2 C and various leakage rates. Obviously you can't have so much leakage that you can't emit CO2 in any other way.
"Therefore, sequestration can only be regarded as an acceptable climate mitigation technology if long-term CO2 storage for at least 10,000 years can be guaranteed". That'd be.... .01% per year.
Statoil discusses their pioneering facility at Sleipner here. And here They don't provide an estimate of how long they think the CO2 they are capturing will stay there.
Mills, in Capturing Carbon says natural CO2 emissions from volcanoes are of the order of 1% of anthropogenic, and states "even if we were to capture all [anthropogenic] emissions for a century, 0.01% leakage would be equal to natural levels. He notes that Texas regulations presently require 0.001% per year maximum. Mills calls this excessive. "It makes little sense to set excessively tough limits to save the climate in seven millenia if we thereby fail to save it in seven years". His sense of the situtation though is "as discussed above, storage sites probably can achieve even these strict targets". He also notes: "When considering the advantages of CCS versus biological carbon sequestration such as in forests, we should bear in mind that the retention time for underground CO2 is at least 1,000 times longer than for that in the biosphere", citing Zeman and Keith 2008.
David Keith has been doing a lot of research into capturing CO2 from ambient air. Here he is at a Royal Society Geoengineering discussion meeting explaining why. He doesn't see CCS as useful only for heavy industries etc.
"Outta sight"
-- by Horatio Algeranon
Find yourself
Within a bind?
Out of sight
Is out of mind
Bury carbon
And be at ease.
Go on emitting
As you please.
Make diamonds :-)
The alternative is to solidify captured CO2 and sculpt the dry ice into earth art .
Works fine for Matt's coal mine !
"to get a good storage you need a place without cracks in the caprock. How many sites do we have ?"
Quite a lot, actually, based on the amount of oil and gas that's been trapped under these kinds of seals in many places for tens of millions to hundreds of millions of years.
The trick is to find a saline reservoir and then, when injecting, control the injection pressure so you don't fracture the overlying seal. Plus, the brines will almost always prefer to move sideways rather than up (they'll take the path of least resistance, which is to flow sideways through the same permeable formation rather than upwards through the impermeable formation).
Quite a lot is known about how fluids move deep underground, so it's not like a lot of this is a brand new and emerging science. It's just that the application of CCS tends to be.
I think CCS has its place, but is not a silver bullet (but it can play the part of a wedge in a big wedge strategy). That being said, it's costly and energy inefficient (at least currently), so it doesn't make a whole lot of sense unless we get a sizable carbon price.
A pessimistic article from June: http://www.thestar.com/news/canada/article/1208558--carbon-capture-and-storage-an-uncertain-future-in-canada
And Pembina Institute info: http://www.pembina.org/climate/carbon-capture-and-storage
Plankton eats CO2. Fishies eat plankton. Fishies die and their bones sink to the bottom of the ocean. Sequestration complete.
Joe Mamma
Oh dear. And on a chemist's blog, too.
(1) Check the geochemistry of adding modest concentrations of CO2 to dep saline formations; you will be pleasantly surprised.
(2) Consider in situ weathering of (ultra)mafic rock. In this case the CO2 reacts exothermically with the rock to form clay; CO2 gone forever.
Can you tell me where the carbon is in the 'clay'? Thanks in advance.
kT --- I don't understand the question, but here are links:
In situ peridotite weathering:
http://www.popularmechanics.com/science/earth/4292181.html
http://www.technologyreview.com/energy/21629/?a=f
http://www.pnas.org/content/105/45/17295
The IPCC talks about sequestration
Different mechanisms for trapping/holding the CO2 operate over very different time scales. The potential for leakage depends on the details of the storage reservoir and the stage of the process (in the case of a brine reservoir, it depends largely on whether the injected CO2 has (yet) become dissolved in the fluid of the reservoir)
Over the very long term, (some or all of) the CO2 may eventually undergo chemical reactions that produce carbonate minerals rendering it effectively "gone", but it has to first "get to" the stage where that happens -- and that can take a long time.
During the first stage when CO2 has not yet become dissolved in the surrounding fluid of the reservoir, it is subject to a buoyant force which makes it susceptible to upward movement. If, because of cracks in the cap rock, for example, the CO2 escapes, it will never even "progress" to subsequent stages of the trapping process (effectively rendering carbonate mineral formation a moot point).
In other words, it's not simply a "done deal" that when you inject CO2 into a brine reservoir it will remain there "forever". The IPCC (and others) understand that there are many considerations involved.
From an IPCC technical summary
"Once injected into the storage formation, retained depends on a combination of physical and
geochemical trapping mechanisms. Physical trapping to
block upward migration of CO2 is provided by a layer
of shale and clay rock above the storage formation. This
impermeable layer is known as the “cap rock”. Additional
physical trapping can be provided by capillary forces that
retain CO2 in the pore spaces of the formation. In many cases,
however, one or more sides of the formation remain open,
allowing for lateral migration of CO2 beneath the cap rock.
In these cases, additional mechanisms are important for the
long-term entrapment of the injected CO2.
The mechanism known as geochemical trapping occurs
as the CO2 reacts with the in situ fluids and host rock. First,
CO2 dissolves in the in situ water. Once this occurs (over time
scales of hundreds of years to thousands of years), the CO2-
laden water becomes more dense and therefore sinks down
into the formation (rather than rising toward the surface).
Next, chemical reactions between the dissolved CO2 and
rock minerals form ionic species, so that a fraction of the
injected CO2 will be converted to solid carbonate minerals
over millions of years."
~@:>
Joe Mamma.
A few weeks ag,o following the release of Smetacek's et al latest paper, I spoke to one of the scientific grand poobahs of plankton research and asked him about the possibility of serious carbon sequestration through oceanic fertilisation.
Between the facts of Sprengel's Law of the Minimum, the oxidative lability of the fixed carbon, the marine physico-chemical and biodiversity confluences required, and the very scale of the problem, his answer was an emphatic "no chance".
"At all".
Anyone who tells you otherwise is trying to sell you a pup.
Bernard J. Hyphen-Anonymous XVII, Esq.
David, having glanced at these articles it appears to me they are just speeding up the carbonate precipitation process using a catalyst, heat and salt water, which are all naturally occurring resources. Wouldn't that process be better industrialized at the source (presumably the smokestack) where heat is readily available and the catalysts could be manufactured or shipped in, and the resulting product could be stored, isolating it from a rapidly acidifying wet and inaccessible environment?
Also, I still fail to see how clay could have anything to do with it, other than perhaps supplying the cations or isolating the reaction products, or how the carbonate 'disappears forever'. Nature has already provided us with hundreds of millions of years of carbon sequestration in the form of coal and carbonate plateaus and sediments, although I can readily see how carbonate would be a better sequestration medium than coal or dry ice. I would prefer and indeed advocate however that the carbon would be better sequestered as coal (as in left in the ground) rather than converted to carbon dioxide and subsequently carbonate, and rather the more pressing problem is the removal of the excess carbon dioxide directly from the atmosphere returning it to preindustrial levels, thus reducing the evolutionary and adaptation stresses on our existing biota, and fast tracking the obvious alternatives of solar, wind and space based solutions.
But in the long term pure carbon products such as diamond (which indeed are forever, until you burn them apparently), and innovative carbon matrices (as opposed to the technologically messy and toxic composites), will go a long way towards solving the legacy technology problems we have created for ourselves. These are condensed matter physics problems that if you were alert you would understand we are very close to solving, pending the massive educational and research funding changes required to fast track them to success and implementation.
Jim Hansen in one of his helpful incarnations has proposed combining biomass power generation with CCS, resulting in a net removal of carbon from the atmosphere. While CCS right now is mostly about coal, it may have another future.
The real problem with CCS seems to be it's more expensive than doing nothing.
Jay Alt -
Nah, the real problem is that (high-tech) CCS is more expensive than doing just about anything else to mitigate against global warming - and likely less fruitful, too.
Bernard J. Hyphen-Anonymous XVII, Esq.
I still don't know if this is actually workable, but if I had to pick some sequestration method that I'd want to work, it would be Calera, since it could actually produce useful outputs (building materials) in which to sequester carbon.
Back to CCS and such:
I assume everybody here knows there are thousands of miles of CO2 pipelines in US, for EOR (Enhanced Oil Recovery, as per SciAm.
Basically, they "mine" the CO2, send it through pipeline to an oilfield, and put it back.
John Mashey --- Even if it works (which it doesn't seem to) its too specialized to apply on a large scale.
Worse, from inside knowledge (2rd hand reaching me) the company appears to be a form of scam.
Well I know a little bit about carbonate precipitation and while indeed it can be a slow process, if you are talking about using ultramafic rocks as a deep sea catalyst under uncontrolled and disruptive conditions then certainly something like this can be reproduced in the lab. Have you looked at the literature yet?
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