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Sequestering carbon nature's way: in coal beds

Posted on 10 August 2012 by Sarah

One proposed solution to CO2 pollution is to collect the gas and sequester it away from the atmosphere. Nature has already done that for us in the form of vast reserves of coal.

Carbon sequestration must have some critical features to be a viable solution to prevent further climate change and dangerous ocean acidification:  

  • long lasting fixed carbon storage, at least a few thousand years, preferably millions.
  • will not contaminate ground water.
  • will not release carbon back into the atmosphere.
  • compact: able to store vast amounts of carbon in a small volume.
  • low energy process.

Amazingly, nature has already invented an ideal carbon sequestration substance: coal!

Coal is:

  • proven geologically stable for at least 300 million years.
  • completely insoluble in water.
  • unable to spontaneously convert to CO2 and escape into the atmosphere.
  • 60-90% carbon by mass, a very high carbon density.
  • no-cost sequestration: no energy is expended to leave it where it is! 

Owners of coal burning power plants continue to promote the idea that we can burn coal to extract its energy, then sequester the emitted carbon in a permanently stable repository. That proposal is the chemical equivalent of a perpetual motion machine. 

clean coal escher

The energy stored in coal originally came from the sun. Early plants used the sun's energy to convert carbon dioxide to lignin-rich wood and bark. Physical processes buried the carbon and converted it through heat and pressure to coal. That process sequestered over 10,000 gigatons of carbon (with its embedded energy) throughout geological time, especially about 300 million years ago during the Carboniferous period. The removal of that carbon from the atmosphere contributed to cooling the Earth to our present agreeable temperature range.

The reaction of coal with oxygen releases about 22.8 MJ/kg (19.6 million Btu per short ton, US EIA). To run this process in reverse and re-sequester the CO2 back into an ultra-stable chemically reduced form, such as coal (or maybe diamond), would require at least that much energy, and in practice much much more. 

Any sequestration plan that doesn't consume more energy than the coal produces means storing carbon in a less fixed form. 

And indeed, all carbon sequestration schemes proposed put the carbon into less fixed forms than coal. Several proposals leave the COas a gas or compress it to a liquid under high pressure without changing its chemical structure. These plans suggest storing the gas or liquid CO2 either (i) permanently underground, or (ii) in the deep ocean or in ocean sediments as COhydrates. Alternately, solar energy in the form of photosynthesis is used to chemically fix the carbon as biomass. To remove the carbon from circulation the biomass must then be premanantly stored somehow. The most viable proposal is to convert the biomass into biochar.

Of these, storage of CO2 in deep geological formations is considered to be the most technologically feasible (IEA). Since the carbon would be stored as CO2, not as fixed carbon, these reservoirs (and CO2 pipelines) will require continuous monitoring for leaks. Storage of CO2 as a liquid or hydrate in the deep ocean or ocean sediments is entirely unproven and has unknown long-term consequences (Vaughan, 2011, subscription required). Injection of CO2 directly into the ocean is not permanent as the carbon dioxide will slowly dissolve, contributing to ocean acidification, and ultimately re-entering the ocean-atmosphere carbon cycle. 

Carbon in biomass is chemically fixed, but is released again as CO2 when the biomass is burned or otherwise decomposed. Biochar is the most coal-like sequestration method yet proposed. In this method CO2 is converted to biomass by plants, then pyrolyzed (burned without oxygen) to capture about 50% of the carbon as charcoal (biochar) (Vaughan, 2011, subscr. required). Biochar is estimated to be stable for about 1000 years and could, with a major effort, perhaps decrease by 10% the impact of doubled atmospheric carbon dioxide (Vaughan, 2011, subscr. required). 

In the biochar sequence of coal-to-CO2-to-sequestered carbon, the energy to push some of the carbon back "uphill" to a fixed form comes from the sun by photosynthesis, but it's far from sufficient to close the circle. We can bypass the Escheresque carbon game entirely by collecting and using solar energy directly. 

None of the proposed methods stores carbon as safely and effectively as coal. Nature has already sequestered carbon for us. Let's leave it sequestered in those coal beds.

References

US Energy Information Administration (EIA), http://www.eia.gov/tools/faqs/

International Energy Agency (IEA), Technology Roadmaps: Carbon Capture and Storage, http://www.iea.org/publications/freepublications/publication/name,3847,en.html

Vaughan, N. E., & Lenton, T. M. (2011). A review of climate geoengineering proposals. Climatic Change, 1–46, doi: 10.1007/s10584-011-0027-7http://www.springerlink.com/index/351246645074460L.pdf (subscription required). See also  Lenton, T. M. & Vaughan, N. E. (2009). The radiative forcing potential of different climate geoengineering options. http://www.atmos-chem-phys-discuss.net/9/2559/2009/acpd-9-2559-2009-print.pdf.

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Comments 1 to 49:

  1. If you were to ask a 10 year old to solve the climate change problem the not so bright ones would come up with CCS technology.
    "I know we'll capture the CO2 from the smoke stacks of power stations, compress it to a high pressure liquid, pipe it 100's of kilometers and pump it underground. Where it will never, ever, ever leak out!"
    The stuff of fairy tails.
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  2. At last, an explicit explanation of the thermodynamic silliness that surrounds the notion that anthropogenic sequestration can balance unhindered fossil fuel combustion.

    I have lost count of how many times I've tried to explain to people that if we could put carbon into the ground at less financial and energetic cost than we obtain from diggin it up and burning it, we could save even more money and energy by not sequestering it in the first place and by reusing the nacently and magically-reduced carbon.

    As Sarah so aptly notes, it's a belief akin to perpetual motion to imagine that reduced carbon can be sequestered as efficiently as we oxidise it.
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  3. There was also research into burying trees (mainly trunks) in the ground to sequester carbon. Don't know if it has been taken any further. It requires the right conditions in the ground to work correctly.
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  4. Very nice cartoon, Sarah. It gave me a healthy dose of laugh, especially the guy catching CO2 molecules like butterflies. That picture is doubling the informative value of all the words of the article.
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  5. Sarah is entitled to her opinion. But that is all it is, there is nothing remotely scientific about this post. A lot CH4 is stored safely under ground. CO2 can be too. Whether this will prove cost effective remains to be seen. Clearly, IMO, this is a long shot. Efficiency, conservation and non fossil fuel energy sources are our best bets, but we should keep all options open.
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  6. Mike @ 5- I understood the cartoon to not be focussed on the final storage of the carbon dioxide that is released from the burning of coal, but that the process, like a perpetual motion machine, can never be 100% efficient. The efficiency will be determined by (i) the percentage of carbon dioxide captured and (ii) the amount of carbon dioxide created by the various processes and equipment used to capture and store the gas.
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  7. Another method of sequestrating carbon not mentioned here is via the weathering of silicate rocks, particularly those of an ultrabasic composition, that is, those containing a relatively high percentage of iron, magnesium, calcium and other non-alkali metals. This occurs naturally, of course, but at a rate far too slow to counteract significantly the spike in atmospheric CO2 caused by human actions. However, ultrabasic rocks such as serpentinites, if finely ground and spread upon the ground will weather rapidly and moreover and are said to assist plant growth and possibly carbon storage in soils. Clearly, there will be substantial energy costs during the mining, crushing, transportation and spreading procedures, but the end result may be enhanced fertility, increased crop yields and a modest contribution to carbon sequestration. Unfortunately, I am unaware of any quantitative studies into this possibility.
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  8. I just registered, just to see that Mike had said most of what i wanted to say, but i will elaborate a bit. I usually enjoy reading SkS articles because they are well written and based on research but this one is mainly an opinion and the final conclusion isn't much more than wishful thinking.

    "Of these, storage of CO2 in deep geological formations is considered to be the most technologically feasible (IEA). Since the carbon would be stored as CO2, not as fixed carbon, these reservoirs (and CO2 pipelines) will require continuous monitoring for leaks."

    So, the most technically feasible way to store CO2, that could help reduce CO2 in the atmosphere and be one of the many combined ways we reach a carbon neutral future as fast as possible is dismissed because it would require monitoring? Really?

    Carbon capture and storage (CCS) is in my opinion not a goal, but a bridging technology. We have coal, natural gas and oil power plants now and as much as we want a non-fossil alternative, changing the entire system is not going to happen over night. While the system is changing we can use CCS to mitigate the damage of our current system by retro-fitting old plants or even burning bio-fuels in CCS-plants to reduce CO2 concentrations in the apmosphere.

    jimb @ 6 - CCS has never been about making fossile coal into a "renewable" as is shown in the picture. It is not recycling. Think of it more like nuclear waste management: We can either spread the nuclear waste in the atmosphere or we can bury it in the ground where it wont hurt us as much. The later alternative is more expensive but as it wont hurt society as much it is still more cost efficient, which is why we have regulations. The only difference is that nobody argues with the scientists when they say nuclear waste is dangerous.
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  9. Sarah is entitled to her opinion. But that is all it is, there is nothing remotely scientific about this post.


    Really?

    Perhaps you can demonstrate the validity of your claim and show your calculations for the energy required to sequester carbon in reduced form, compared and contrasted with the energy obtained by combustion of solid carbon. You must be aware of some thermodynamic loophole that has escaped most of the world's physical chemists, if you attach no scientific credibility to Sarah's discussion.

    For gaseous and liquid carbon, you might show similar calculations. And where you intend that carbon be sequestered as CO2 rather than as solid carbon, perhaps you will demonstrate numerically how successfully humans will return CO2 to subsurface reservoirs, both in terms of total energy return on energy expenditure and of centuries/millenia scales of effective reservoir integrity.

    The only way that carbon sequestration can work effectively in the short time period required is if humans have aburdly abundant renewable energy available: there is no way to drive effective sequestration with carbon-sourced energy. Without such spare energy sequestration is nothing like "an option" - the laws of thermodynamics don't permit cheating.
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  10. Hn... I'm somewhat startled to see the technotopian response to what is really a very straightforward consequence of accounting for thermodynamics. I'll repeat my earlier question, and note that it's the same question I put to those who think that humans can solve their planetary degradation problems by travelling to the stars...

    ...where are your energy-budget numbers that show that the concept(s) will work, in the face of thermodynamics?


    For reference, it's informative to consider some of Tom Murphy's BotE estimations. Tom himself admits that they're rough figures, but I have yet to see anyone who can demonstrate that Tom is off the mark, and that humans can efficiently put their carbon toothpaste back into the tube.

    And where the burial of vast quantities of naturally-fixed carbon is proposed as a solution, no-one has explained why it is not more efficient to use these as energy sources themselves, rather than the fossil carbon that they are to replace underground. Of course, the answer to that is rather obvious.

    No, the numbers simply do not add up in the context of humanity's current energy appetite. Sequestration in any way currently understood will be no more than tinkering at the edges of the problem.
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  11. Don't that CCS stuff reduce the efficiency of thos ethere powerstations meaning you have burn a hold lot extra of that there coal gas to get the same energy out?

    And as CO2 captured is always directly related to fuel in, isn't this slightly self defeating and mean that CCS captures not very much at all.

    2%?

    "Post-combustion capture

    Capture of carbon dioxide from flue gas streams following combustion in air is much more difficult and expensive than from natural gas streams, as the carbon dioxide concentration is only about 14% at best, with nitrogen most of the rest, and the flue gas is hot. The main process treats carbon dioxide like any other pollutant, and as flue gases are passed through an amine solution the CO2 is absorbed. It can later be released by heating the solution. This amine scrubbing process is also used for taking CO2 out of natural gas. There is a significant energy cost involved. For new power plants this is quoted as 20-25% of plant output, due both to reduced plant efficiency and the energy requirements of the actual process.

    No commercial-scale power plants are operating with this process yet. At the new 1300 MWe Mountaineer power plant in West Virginia, less than 2% of the plant's off-gas is being treated for CO2 recovery, using chilled amine technology. This has been successful. Subject to federal grants, there are plans to capture and sequester 20% of the plant's CO2, some 1.8 million tonnes CO2 per year."

    http://www.world-nuclear.org/info/inf83.html

    Sequesters at best 20% as of now, and reduces efficencies by 20%, so overall about 2% CO2 sequestered.

    CCS is however attracting lots and lots and lots of funding though and Biomass CCS is grwoing in popularity.

    Maybe in time.....Oh yeah we don't have any time do we!!

    And what about all those re-agents and all the process needed to make them?
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  12. Gustafsson @ 8- Who said anything about recycling or renewables?
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  13. Gustafsson,

    I understand your misconception in looking at the Escheresque picture (about renewables), but the intent is not I think to take out the same carbon, but rather to use sequestration as an excuse to keep taking out other carbon. In this way you are right, it's like nuclear fuel in that you burn it and then you're left with a nasty, hard to dispose of waste product.

    But the point was never to imply using up the same carbon as was sequestered, but instead to use the technology as an excuse to create an infinite loop (limited of course by FF availability) which keeps taking new carbon sources out of the ground and then burying them again.

    As far as Mike's and your sentiments... I think you are getting lost in a gray area. No one is saying "don't do it at all." Clearly every bit of sequestration we can manage will be needed just to draw down CO2 levels from the heights to which we've already pushed them.

    But using CCS as an excuse to keep burning FF and ignoring the problem is insanity. It is similarly ill-advised to keep pushing CC2 as a solution, rather than as a mere stop gap at first and maybe as a way back from the brink later, when we have our emissions under control through other means.
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  14. my take home was...
    It's silly taking out coal in the ground when we can use other energy sources and Coal is sequestered carbon. The article is quite clear and Sarahs 'vision' is quite clear and logical. I don't understand Gustafssons problem.

    Is the article scientific??
    Not exactly, but then it is logical if you detach energy from carbon. If the problem is carbon then it makes sense. If you are only interested in energy, then sure manipulate the worlds carbon and mess around with natural processes. But the point is you can get energy with the minimum impact on what nature has produced.
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  15. A further, slightly tangential consideration is whether or not massive coal deposits like those we mine now could ever be laid again - right now I'm reading through a really interesting article which attributes the end of the Carboniferous era to the evolution of lignin-digesting fungi. I wonder how this effects biomass sequestration - would it have been easier to bury carbon before the rise of white rot?

    http://www.sciencemag.org/content/336/6089/1715.abstract
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  16. I agree with Mike @5. There is nothing in principle about CCS that defies the second law of thermodynamics or implies the invention of perpetual motion.

    There is enough nonsense spouted about the second law by fake sceptics without SkS adding to it.

    I am extremely doubtful that CCS can be done economically, given that burning coal produces between two and three tonnes of CO2 for every tonne of coal burnt and the cost of transportation and pressurisation. However neither my doubts nor this article prove that it is impossible.

    Overall I think that this post detracts from the normal high standard of this site.
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  17. Concentrating flue gas CO2 thru membrane technology, purifying the CO2 for pipeline transport and pressurizing the CO2 to supercritical pressures for long-term underground storage (the most viable form of CCS technology) consumes 10 – 40% of the energy released from combustion of the fossil fuel (per source). Though this is not a perpetual machine, it certainly pushes the cost of coal or gas generated power up to or above current renewable cost levels (especially if this range is nearer the 40% mark which, as a combustion engineer, I believe to be more likely the case).

    It would seem to be ludicrous to divert investments away from renewable solutions in order to build 67% more fossil fuel power plants to make-up for the ~40% loss in output power due to CCS. But installing CCS technology on the EXISTING power plants deemed acceptable for “bridging the gap” is something I, personally, would have trouble finding fault in, all with the understood goal of not letting up on pushing toward ZERO GHG emissions.
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  18. @Skeptical Wombat #16:

    Neither the second law nor perpetual motion WRT the second law was invoked. The statement was meant as an analogy for the proposed chemical emit-sequester system, that's why the article said "chemical equivalent" and not "is perpetual motion." The thermodynamic points also still stand and have not yet been addressed by you or any of the other detractors to this article: if you want carbon that is stored in as reduced a state as it was when you oxidized it you will have to expend net energy.
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  19. Perhaps to clarify my last comment, the post did not invoke the second law to dismiss CCS but instead to dismiss the notion that you can simply put carbon that you emit into the atmosphere back into the ground in as stable and reduced a form as it was when you took it out, since that process would require more energy than we get out of coal burning in the first place. I suppose it is, in a way, an application of the second law (and I more or less retract my statement in the previous comment). But it's correctly applied, as opposed to the ridiculous arguments pseudo-skeptics make regarding the greenhouse effect.
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  20. There's been a bit of focus on the Second Law, but in the context of effective sequestering of carbon (which implies a solid phase as char or similar), it's the First Law that has rather a lot to say.

    As Alex C notes, no-one's saying that sequestration is thermodynamically impossible. It is, but when all costs are tallied it is apparent that sequestration comes at great expense - and the sort of budgeting that one might expect of a Ponsi scheme.

    Perhaps something to keep in mind is that the energy-availability/ease-of-execution relationship is not fractal: at small scales execution of sequestration is almost trivially attainable, but of course to no appreciable effect. At large scales the relationship heads more toward Escher territory, to the point where at the scale required to reverse global atmospheric carbon increase, the task requires a lot of energy other than that sourced from the combustion of carbon. To attempt it with only fossil carbon as an energy source would be in practice little different to expectation of perpetual energy, as the residual energy available for non-sequestration use would be abjectly insufficient to fuel humanity's current appetite.
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  21. First let me say I think the chances of getting an economically viable scalable CCS system are very small. However if one is developed it will certainly not be as a result of producing artificial coal.

    The most likely way of making it work would be storage in saline aquifers. This is dismissed out of hand in the post on the grounds that it would require monitoring. The post then moves straight on to arguing that artificial coal is not going to work. To me this looks like switch and bait.

    Further while the second law would certainly preclude producing a product as reactive as coal, I don't see a theoretical reason why it is not possible to incorporate it into a non reactive solid and still have some energy left over.

    And before you write me off as a false skeptic I suggest you try googling my pseudonym.

    I think a very good argument can be made for believing that CCS is unlikely to work. I doubt that it is possible to prove that it cannot be made to work.
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  22. I saw a keynote address by Mark Zoback recently, and his assessment of the feasibility of large-scale CCS was sobering, to put it mildly. The scale of injection that would be required to offset the use of fossil fuels is simply mind-boggling and my impression is that he thinks it's completely impractical for it to make a meaningful contribution.

    On top of that you have the very real problem that there simply aren't that many "good" places available to inject it, and even when you do have a "good" one, the extremely large changes in pressure you get when you first deplete an oil or gas reservoir and then again when you inject CO2 back in trigger seismicity; if a large reservoir's containment was compromised by ongoing fracturing -- which he seemed to think was only a matter of time -- then what? Not only have you wasted all the energy spent putting the carbon in there in the first place, you now have to deal with the consequences of it coming back out again all at once.

    My take from the post-talk discussion I had was that the experts in the field -- which is who these guys were -- saw CCS as a very high-risk solution to the problem.
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  23. First, i think the article could benefit from having it's context more clearly described. The context seems to be (from comments above) that coal companies are portraying CCS as the only solution needed and that is what the article is "debunking". This article was actually the first time it was put forward to me as such. From my personal experience talking to people working with CCS this has never really been the goal. CCS is rather seen as a step in the right direction. The tone of the article together with the picture and without that context (it is only mentioned very briefly) makes the article feel like it is ridiculing all uses of CCS.

    Bernard J @ 20
    I agree with you that storing carbon in a solid form after burning it would probably give very litle energy (if any) for any other process. I however do not agree with you that effective sequestering of carbon implies a solid phase. Note, I am not talking about a permanent solution but one for the next hundred years or so.

    sauerj @ 17
    yes CCS will definitely reduce the "efficiency" of coal power (or increase costs if you wish), but the possible rate of change of our system using CCS is also very high compared to alternative technology.

    Widespread CCS (i assume by regulation) would drive up marginal prices, making renewable alternatives more competitive and increasing rates of investment without making the companies previous investments into coal completely without value. If we didn't have coal plants CCS wouldn't make much sense, but we do and that forces us to take that into account.
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  24. Bernard J @20: Case in point: I worked at Biosphere II during the summer of 1997, as a NASA-funded intern, and student at (then) Columbia University's "Earth Field systems" classes; as such, I got to see the entire 'underpinnings,' literally and figuratively, of the area, plus insight to the first "Biospherians" woes w.r.t. dealing with excessive CO2 build-up.

    To battle that, they had installed a rather large CO2 sequestration system in the basement (the "technosphere") which required the biospherians to manually mix bubbled air through a large tank of (IIRC) sodium hydroxide, by using for all the world what looked like electric outboard motors. Needless to say, it didn't work well, and we're talking a miniscule "atmopshere" of ~6 million cubic liters.

    On planet Earth? I agree: so far, I've not seen a single CO2 sequestration proposal that comes anything ~near~ acceptable in terms of EROI.
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  25. Gustafsson at #23.

    JasonB and vrooomie encapsulate well in their comments some of the serious problems with sequestration of even non-reduced carbon. Harking back to Tom Murphy's analogy, it's akin to having to extract the dissolved toothpaste from your sewer, and patching up a split tube rifled from the garbage dumpster behind the local supermarket, before you can put the toothpaste back.

    There's a serious numbers problem involved: specifically, the numbers don't and won't add up. I spoke with a renowned planktonologist about the feasibility of iron fertilisation following the small kerfuffle that accompanied the publication of the Smetacek et al paper last month, and he said the same thing in the context of that route to fixing carbon.

    A lot of 'solutions' are not feasible solutions when it comes down to it. Certainly, they deserve to be investigated - that's how we determine their feasibility in the first place - but for many it doesn't take much to figure out that they're not actually solutions after all. It's no different to the situation where it didn't take too much work to figure out that homeopathy was indistiguishable from placebo, even though many folk still think otherwise... and I'll go out on a limb and say that one might as fruitfully develop a homeopathic remedy for the problem of excess carbon, as sequester it rapidly using any of the currently understood anthropogenically-energised mechanisms.
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  26. So, in a nutshell, nuclear power is the only answer.
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  27. Uncle Pete,
    The nuclear argument has been beaten to death several times here at SkS. Please take it somewhere it is on topic and not here. Suffice it to say there are many renewable energy sources that compete with nuclear.
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  28. After reading the comments above I realise, the context of this article is not clearly specified. My original thought of it as the excuse for FF induustry to dig and burn more stuff promoted as "clean coal" because it's CCSed, is reinforced by the cartoon.

    But when you change the context to apply it to existing coal plants because you cannot dump them as it's economically unreasonable, totally changes the meening. And even people like Jim Hansen suggest that CCS would be helpful here. However, does anyone know any plans to apply this context, i.e. retrofitting existing plants with CCS? I hear about "new modern plants coming with CCS" only...

    Needless to say the change of context does not change my skepticism: i.e. I see PV technology already successfully competing with old C plants in Australia (without CCS but with carbon tax) in terms of $/kWh within next 2-3y (certainly this decade), so why even looking at still doubtful and largely uncertain CCS? PV has already reached the state when the energy put into production is returned within 1-2y (check Martin Green video here) while CCS remains very doubtful, almost pointless.
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  29. The new report Australian Energy Technology Assessment by the Bureau of Resources and Energy Economics has some interesting figures for the cost of electricity from coal power stations with and without CCS. In most cases adding CCS roughly doubles the cost of the electricity, making it a relatively expensive option.

    Importantly, "the cost associated with CO2 injection wells, pipelines to deliver the CO2 from the power plant to the storage facility and all administration supervision and control costs for the facility" were excluded from those figures. Given the points I relayed earlier suggest the storage itself is a far from trivial problem to solve, I can't see how CCS will be competitive on purely economic grounds alone. I also think that transportation of the CO2 will be a big cost because I don't like the chances of there being a suitable storage location "near" each of the existing coal-fired power plants.

    For this reason, chriskoz, your original thought might be more accurate. The "marketing" for CCS is around retrofitting existing power plants, which makes it seem like a good idea because they're already there and they're already polluting, so why not clean them up? But I suspect the reality is that very few existing power plants will be economic to retrofit because of the costs of dealing with the CO2 once it's captured at the plant, whereas new plants could potentially be located with that being taken into account -- in which case CCS gives us an excuse to build more coal-fired power plants.
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  30. Oops, posted too fast -- should have read ahead a little rather than just doing a keyword search. The costs associated with sequestration were not included in the direct and indirect costs, but an estimate of the cost of sequestration was included in the levelised costs. The table of assumed costs is on page 23. The lowest is $14/tonne of CO2 in WA, the highest is $72/tonne in NSW. Without a very high carbon price I guess it'd be cheaper for NSW generators to just emit the CO2 and pay the tax.
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  31. Well my 2c (disclosure - my department is involved with CCS research) is that it is still too early to making judgments on CCS. CO2 doesnt have to collected at point of emission though you would need incredibly energy-efficient process to extract from raw atmosphere. Even if it doubles the cost (or more), there can still be situations where this may be economic. While I would agree that it is high-risk research, I am amazed that at such sweeping judgments on whether storage can work given the state of knowledge so far. If a seal can hold methane for 60 million years or so, then I dont think you can dismiss out of hand, the possibility of it holding CO2 for tens of thousands of year.
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  32. scaddenp @31, storage is my key issue on CCS. There is little gained, IMO, if we bury the CO2 now, but it returns to the atmosphere within a couple of hundred years.

    In that context, the analogy to natural storage of methane is misleading IMO. First, it is misleading because geological processes can result in the release of methane, and does so all the time. Of the methane formed within the Earth 60 million years ago, a significant fraction has been released. How large a fraction? I suspect we don't know because the areas in which methane has escaped are of no economic interest, and do not get recorded. Of course, I am not a geologist. For all I know some geologist may have done a study of the proportion of the surface in which methane is likely to have been formed and trapped 60 million years ago which has since been eroded (thus releasing the methane), and the proportion in which methane is likely to have been formed and trapped, but which have been fractured by seismic activity, or had the cap eroded through, etc. From such a study we can truly estimate the stability of long term storage. Are you aware of any such study?

    More importantly, from my point of view, every proposed area of CO2 storage differs from areas of natural storage of methane in one crucial area - we have already breached the seal. We have breached the seal to provide a means to pump in the CO2. So the question of stability resolves not on that of the geological formation, but of the concrete seal we place afterwards to prevent leakage. This makes me think the stability of storage has been way oversold.
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  33. scaddenp: like Tom, storage is my key issue, too. It hasn't always been -- I previously had a fairly simplistic view that if those reservoirs had managed to contain fossil fuels under high pressure for millions of years then it made sense that we could use the same reservoirs we are tapping for fossil fuels as secure repositories of carbon dioxide.

    However, following that talk by Zoback and subsequent discussions with others in the geomechanics field I have come to realise it's not quite as simple as that. As Tom mentions, the first point is that the reservoir that may have been sealed for millions of years is, of course, no longer sealed -- and that could be a weak point. Even more importantly, the stresses in the rock mass have changed enormously -- firstly by unloading, in the case where the reservoir previously contained fossil fuels that were tapped, and then by re-pressurising. Changing stress fields induces fracturing, and fractures have a nasty habit of propagating in unpredictable ways, potentially intersecting with larger-scale geologic structures that are relatively porous and allow the gas or liquid to traverse large distances. There have been some interesting studies where the chemical tracers from fracking operations have ended up in various wells in surprising configurations (e.g. contaminating a nearby well and a relatively distant well but leaving an intermediate well clean) that highlight how difficult these things are to predict.

    The scale of injection required to make a meaningful difference is also truly mind-boggling. It's difficult to see it being economic to construct infrastructure on that scale even if suitable sites can be found rather than simply not emitting the CO2 in the first place.

    Tom's point about the bias inherent in only looking at the "winners" is well made, too. If you only ever interviewed lottery winners you would think everyone wins the lottery -- it won't give you any information about the likelihood of winning a lottery with your next ticket. We simply don't know how many "potential reservoirs" there have been over that period that failed the test of time.

    I do agree with your point that it's still too early to be making judgements -- and I include the estimate of a doubling of cost in that. There has to be an enormous range of uncertainty associated with cost estimates, but even at double the cost it's not terribly attractive for new coal (but, of course, would be better for existing coal than simply leaving them running as-is). It should certainly still be pursued (although I would argue at a lower priority than it currently is in Australia) as it may lead to options for geoengineering in the future if it comes to that.
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  34. Sarah @ Article

    Now that it seems pretty clear from the article and the above comments that storing C02 in such a manner as to negate human emission problems is practically, if not physically impossible, are there any other threads that discuss a solution to the problem of human-activity-driven-global-warming-via-CO2-production anywhere(questionmark)

    I am a very recent skeptic-cum-convert, who was of the massive population that believed global warming may be true, but humans probably had very little to do or say with or about it. It is, embarrassingly enough, clear from even the first few argument refutations that I was in error. My bad.

    Now I want to know how to FIX it. I don't care amymore about the bad arguments from the deniers (who I was until 3 hours ago one of). Now I care about a solution to the argument that, socioeconomically, politically, and practically speaking, there's not a damn thing we can do about it, as long as the 'powers that be' don't want us to do anything about it (which they don't, and I don't mean any of the three branches of government people normally refer to when they speak of powers that be, but pick whichever powers that be you recognize), cause you should all be smart enough to recognize that they operate FAR too slowly to fix a problem like this in time, despite their ability to severely exacerbate a problem like this in time for it to matter for anyone but the mutants living in caves to escape the heat.

    This disturbs me, and coincides with my hopelessness regarding the availability of social security funds when i reach the appropriate age, the value of my dollar, and the erosion of my civil liberties.

    Educating the populace would be nice, but what do they do about it once they know. Stop using cars (questionmark) Right, my minimum wage job allows me to stop using fossil fuels as I struggle to provide for my family, let alone the rest of the wage slaves that comprise the majority of the world's population, as 30% of my paycheck is gone before i get it, and 15% of that (made up number) goes to pay for bullets, billionaires, and blow.

    Solar power won't cut it, it's just not efficient enough, and given the amount of money being put into researching making it more efficient (or how about even, potential money available TO put into researching it and still pay for things like food) it wouldn't be ready before we all fry like bugs under a microscope anyway.
    Same with tidal power, wind power, etc. etc.

    As the son of a nuclear engineer who actively oversees nuclear reactor operations, including refueling, decommissioning, testing, and maintenance, am I alone in thinking that massive and immediate conversion to Nuclear Power across the board is quite possibly the only solution that we have time to implement (questionmark)

    It is CLEARLY the best combination of safe, clean, VIABLE, efficient, and available energy, especially with the emergence of breeder reactors as an option, so can someone point me in the direction of a thread that talks about the effects of an energy-industry wide conversion to nuclear energy that includes informed discussion from actual nuclear engineers and nuclear reactor operators on the overall C02 emissions problem. What effect does fuel production have on CO2 emissions. What about manufacture, transportation, storage, etc. If global warming is in the top 3, or even top 30, list of problems most needing solved, then this seems like a reasonable solution, and a reasonable topic of discussion, doesn't it (question mark)

    That would be a really cool discussion, I think. Pardon the newbie mistakes in violation of perhaps the 'no politically charged' comments. And I know it's BARELY on topic, but I couldn't really find another topic that even discussed the skeptical argument that "it's too damn late anyway, so it is irrelevant that we are, in fact, the cause of global warming" Admittedly I only looked for the better part of a couple hours, which isn't very long, and I'm really NOT trying to trivialize the whole discussion or be sarcastic.

    Thanks for converting me. I'm still a skeptic, but only in the same sense that I'm skeptical that this website exists at all, or that I'm in fact typing anything.
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  35. @8

    I think part of the point is, don't even waste money furthering the project as it can't possibly even come close to making enough of a dent in the problem to matter and spend that money on something else. Like nuclear power conversion efforts =-D.
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  36. Onceaskeptic,

    You're overwhelmed because you're trying to find one solution. There is no magic bullet.

    That said, reducing carbon emissions to a notable degree would be trivial, and would have a serious impact if we do it soon enough. The longer we delay, the more difficult the problem becomes. The waste of the last ten years is going to be looked on by history as a huge, huge black mark against our generation.

    First, there is a lot of total waste. Cars could be far more efficient, yet moms drive pickup trucks to go to the store for a loaf of bread. There are a million other examples where simple behavior changes will make a difference. Our vehicles are unnecessarily inefficient, and our personal habits are foolishly wasteful.

    Secondly, our power infrastructure is inefficient and needs revision.

    Third, there are many, many alternate power sources, and they are all getting cheaper by the day. If man tried to go to the moon the way we're addressing renewable energy, waiting for it to be so economical that it is not only painless but foolish to do otherwise, then we wouldn't get to the moon in a thousand years.

    Each of these things by themselves won't do a lot, but in concert they can make an impact, one that will not solve the problem, but will at least slow the speeding train and give us more time get further (cheaper, better vehicles and renewables, more social progress, etc.).

    Delay is the only real problem.

    [That, and as you pointed out, that so much of the public is fooled by climate disinformation, so there is no broad-based popular will to solve the problem -- yet. Things are only going to keep getting worse, and it's just a question of how long people are willing to remain stupid, and how evil the deniers who think they will benefit from delay are going to be.]
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  37. @36

    Thanks, and I know there are a lot of little steps to take. Two steps forward and 1.9 steps back is still progress definitely! I didn't mean to be so doom and gloom, I guess. I recently looked into hyper-miling as a driving method, bumping up from 32 to 50 MPG in my civic for instance, but it's hard to know which widely endorsed solutions ARE actually solutions... like the big recycling myth-hap.

    I used to think recycling plastic was the way to go, even though I didn't really believe in global warming as a human phenomenon, but it turns out it's actually worse for the environment than making new plastic, given that the energy requirements are higher and the energy comes from burning the very oil that would make new plastic anyway. (the evidence is there, don't take my word for it)

    speaking of plastics, let's consider CO2 and plastics manufacture alone;

    Does the manufacture of brand new plastics from oil contribute to C02 emission assuming a world where the electricity for that manufacture doesn't come from a CO2 emitting source?. Or, is there something we have to burn off or heat up that would produce CO2 to make the plastic out of the oil even if we had a truly clean source of energy?

    If so,
    Given that
    i. the likelihood that the amount of plastic we need to manufacture all the materials for most, if not all, of the forms of alternative energy that we know about (alternative to fossil fuels and nuclear power I mean, I suppose) is gargantuan, and
    ii. that plastic just is spun fossil fuel or sometimes bio oil in the first place, and
    iii. we still would need a VAST amount of plastics for everyday life, even if we did away with bags and bottles (think even just healthcare, let alone household items, etc.)
    are there even enough resources to convert to all those various forms of alternative energy even if we do get the popular will?

    I'm still pushing for nuclear energy discussion I guess, and REALLY considering EVERY way humans emit CO2 above the threshold the natural carbon cycle can handle, from cars to plastics to agriculture to 'homeland security'/war to SO MANY other things.

    I mean, the only real answer still seems to be stopping all fossil fuel use as soon as possible, except for what is necessary to convert to a system where we use NO fossil fuels at all (even like, the plastics for fiber-optic lines). There's only one crop I know of that even has a hope of creating enough bio-oil to make enough plastic, and still be renewable and not destroy the land and it's currently illegal to grow on most of the planet (hemp, of course... corn and soy and sugar cane and linseed, cotton seed just don't make enough per acre).

    With conversion to nuclear power though.... no CO2 for plastic and other oil based synthetics potentially. What, if any, are the direct CO2 worries with regards to nuclear power that outweigh the incredible efficiency it provides? even taking into account nuclear disaster potential (which becomes less and less likely as new reactors are designed).

    I mean, we've been using fossil fuels for a pretty large chunk of time compared to nuclear power, and think of how much less polluting in terms of CO2 natural gas is per amount is used now compared to when we first started burning coal in an industrial capacity. With all that effort put towards nuclear power couldn't we completely solve the CO2 problem alone with that alone?
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  38. Onceaskeptic, I think nuclear certainly has to be part of the solution mix but I don't think it can be the whole solution. Even if you ignore the political and practical problems of dealing with the waste there is the simple problem of fuel availability.

    Currently there are about 85 years proven supplies of uranium at current usage rates, but only a 13% of the world's electricity comes from nuclear. If the whole planet converted their electricity generation to nuclear then the uranium would only last about 11 years, and that calculation doesn't take into account other uses of fossil fuels e.g. fuel for cars.

    Breeder reactors (e.g. thorium) sound like a solution but as far as I understand it the breeding is too slow to be of much use. Simply not economic.

    Humanity desperately needs an easily exploitable, plentiful, non-polluting and free energy source. That's the only way I can see we can meet our energy needs *and* start pulling CO2 out of the air so it can be buried again.
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  39. I think there is one point - possibly - overlooked:

    it is true - CCS is now heavily discussed. however there are other ways of elimination of CO2 from the atmosphere:

    the transmutation of CO2 into CH4 or CH3OH with the help of H2 generated by electrolysis (the current stemming from PV, wind or other sources of electrical energy). there are some interesting projects here in Germany carried out recently at the Fraunhofer Institute (IWES in Kassel) by Michael Sterner, now professer at HS-Regensburg. Very promising.

    However:

    The big technical problem is the effective filtration of CO2 from the rest of atmospheric gases. From a very reliable source here in GErmany I became the following information (filtering is performed by selective membranes):

    1. normal atmospheric filtration (390 ppmv of CO2) just yields a filter result of 3000 ppm for one stage of filter. It is simply not effective enough.

    2. filtering of fluegases from carbonic power plants results in an effectiveness of about 15 % and if you do it in a two stage version you will get about 90 %.

    This procedures result in enriched CO2-concentration. Then the next step could be the process of physico-chemically forming the methane or methanol products ... Methane could be put into the gas-pipelines. Methanol could be treated as normal fuel ... on the long run ..

    To sum up: CCS might be an interesting issue for the coal industry - but with all the negative issues - cited above - this is only a political point and does not solve the problem ... There must be emphasis on developping other procedures like the one above described ...
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  40. Onceaskeptic, the following is a good thread to read for solutions to the problem:

    http://www.skepticalscience.com/global-warming-too-hard.htm

    You'll note that nuclear power certainly is one of the options available, although as Sphaerica notes it's but one avenue -- any plausible expansion of nuclear by itself won't be anywhere near enough.

    One of the dangers of insisting that any particular technology must be the magic bullet is that it's an unrealistic expectation -- after all, we have always used a mix of technologies with different characteristics. Some, like coal and nuclear, have large capital costs but relatively low marginal generation costs, so we run them constantly at high capacities to provide so-called "baseload power". Wind, OTOH, has medium capital costs and zero marginal generation costs but is intermittent, so we use whatever we can get when we can get it. Gas turbines, however, have low capital costs, high marginal generation costs, but very quick response times, so we run them only when needed to fill the gap. A grid that was 100% reliant on any one technology would be expensive and inefficient. Integrating renewables (and nuclear) would mean changing the mix of technologies to optimise costs but the need has always been there -- what makes it more challenging is the intermittency issue, which I believe is not beyond our capabilities to overcome.

    I will add that China, South Korea, and India are still actively pursuing ambitious nuclear programs so even if we don't build any in Australia, the world as a whole derives the benefit in CO2 reductions.

    I also think you dismiss solar power and wind power too quickly. If you read the report I linked to in #29 above I think you'll be surprised by the actual costs relative to other technologies, and the growth in wind power worldwide in the past decade has been phenomenal:


    (Source)

    Divide by three to get an "equivalent" capacity for comparing to fossil fuel and nuclear; that means that in the five years to 2011 the world added wind generating capacity equivalent to about 55 GW of nuclear power generating capacity. That's about half as fast as the peak rate of growth in installed nuclear capacity, which occurred during the 80s, so it's nothing to sneeze at:


    (Source)

    The decline in solar PV prices has been phenomenal, too. Solar thermal is still very expensive, which is a shame, because it has the advantage of relatively cheap energy storage and night-time operation, but hopefully that will come down.
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  41. Tom, edging closer to my field here. Most of the generated oil/gas in a basin is going to be lost because there is not a suitable trap at the time of expulsion or because subsequent tectonics destroys the cap. My modelling software would tell you how much was generated and when, but it wouldn't interest an oil explorer unless the quantities are at least 10 times greater than an economic target, because they would assume 90% was lost. However, once a trap is formed and oil/gas accumulated, there is every reason to believe that trap can be stable for very long periods. (Evidence would include secondary cracking products consistent with trap conditions).

    Jason's point is a valid one - extracting gas alters a reservoir and depending on the nature of the seal, it could lose integrity. However, this to me is a reservoir engineering problem and I cant see how you assume a priori that it was insoluble, or that the problem would affect every reservoir. (eg a thick plastic, mudstone seal could still retain gas despite deformation and cracking in the underlying reservoir rock).
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  42. scaddenp, I wasn't assuming a-priori that the problem was insoluble (in fact I had originally assumed quite the opposite), but rather relating the impression I got from listening to the geophysicists and geotechs who's job is to solve it, and the impression I got was that it's unrealistic to expect to be able to find suitable sites and build the necessary infrastructure on a scale large enough for it to make a meaningful difference and the risk of containment failure was high.

    Speaking of modelling, this is somewhat related to the topic at hand so you may find it interesting. (Disclaimer: We've worked on projects with these guys.) The PDF fact sheet you can download at the bottom has more details. As I'm sure you're aware from your own experience, this kind of physics-based computer modelling is both extremely powerful and well accepted by industry -- something that "skeptics" would no doubt be surprised to learn.
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  43. @ onceasceptic
    http://bravenewclimate.com/
    Count me in also re nuclear power. France is the great example.
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  44. Onceaskeptic,

    There are lots of answers to the plastics problem. First, we use it too much because it's so cheap, because it's a byproduct of the distillation process. It's there, why not use it? But if it's not there... do we really need to coat magazine pages in plastic, or use plastic straws (straws were once made of rolled paper, you know). Do children need to live a childhood dominated by heaps and heaps of plastic toys? Would it really be that unacceptable to actually have well-crafted, real wood trim some things (instead of plastic, which is sometimes colored to look like real wood)?

    Similarly, yes, with today's infrastructure we burn more FF collecting recyclables than we do just creating new things. But what if vehicles were electric, and drew their power from a grid whose source is not fossil fuel based? We're light years from there now, yes, but we have to get there.

    I think you are trapped too much in the moment, without recognizing the myriad possibilities. Think of the major lifestyle and technological differences just fifty or a hundred years ago. The USA did not have an interstate highway system. Think about rail and air transport, communications and electricity, manufacturing and more. It's not like things have been this way for centuries. Our current "lifestyle" is a blip in history. Things don't have to be this way, and they don't have to stay this way.

    "Thinking outside the box" means eliminating false assumptions -- and I think a lot of your pessimism is based on a number of false assumptions.
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  45. @All,
    I have communicated much with Jeffrey Michel (engineer who lives in Germany), who has researched (power-plant based) CCS for many many years. I will forward his research to SkS, potentially for a follow-up post. He has not yet attempted to publish it I think (its too long for a journal article), but extracts can be found in various of his writings and testimony in German parliaments. The conclusions are sober, some of which have been hinted to above, such as, e.g., the required excess energy:
    To extract CO2 from the flue gas stream, you need 20-30% more energy (CC only!), which means you have to burn MORE coal per plant and therefore also use more cooling water (a problem often overlooked), which is already limited in some locations. And, BTW, the effectiveness of CC is around 90% (target value used by the industry), not 100%.

    Economically, CC makes currently sense only for enhanced oil recovery (EOR), which actually leads to increased carbon emissions (at current recovery rates) as a result of that oil being burned. The question then about why CCS gets pursued lies in the simple fact that the industry is trying to protect its assets, the FFs in the ground. Most of us indirectly benefit from that as our pension funds invest in FF and related industries ... On the other hand, I think the industry knows well that the carbon problem cannot be solved by CCS. Even if you equipped all FF power and cement plants around the world with CC, you'd only have "covered" the large stationary sources, maybe 20% of all anthropogenic emissions ... Andy Revkin once had a post Smil on Hummers in which Vaclav Smil sums up this sysiphos task in a few sentences.

    Some realistic statements can be found through this site (if you bypass the advertisement video).
    Also: The Carbon Capture Journal makes for interesting reading and updates.

    My simple conclusion: It may be a dumb idea scientifically and economically, but there is so much capital in it already that it is going to go ahead. Eventually, it may become useful to remove most CO2 out of waste streams that are not FF related, such as cement production or biomass fuel plants, assuming a product is developed to store the CO2 (some Texas company developed a carbonate I think).
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  46. @Sarah
    BTW, it should be 22.8 MJ/kg, not J/kg, if converting from the Btu number. This comes (roughly) from 393 kJ/mol / 12 g/mol * coal carbon content
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  47. Carbon capture could also be used to drive CO2-enhanced algal farms though this is by no means "storage". However, using CO2 in this way would at least improve MJ/tonne CO2 emitted for the energy production.
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  48. scaddenp @47, I do not know about the economics, but that is one form of CCS that I do consider safe. The idea is that having harvested the algae, it is converted to charcoal by combustion with limited oxygen. That process burns of much of the hydrogen, leaving carbon behind, and is desirable to prevent the formation of methane after burial. The resulting charcoal is then buried in deep, anoxic conditions. This is effectively a coal to coal CCS storage sytem. It does not violate any law of thermodynamics because of the additional solar energy absorbed by the algae (which then becomes an upper limit on energy harvested). Of course, photosynthesis is not an efficient means of capturing solar energy, so I doubt this is economic.

    Without the burial, as you note, it is not CSS, and hence not a solution to the problem of excess CO2 emissions.
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  49. For my money, I think it should be used for emissions from steel works and cement - we cant easily avoid use of coal, especially for steel, but it does increase carbon efficiency.
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