The Oil Drum | DrumBeat: November 7, 2008

199 comments on DrumBeat: November 7, 2008

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zeroworker2 on November 7, 2008 - 9:39am

Hi Leanan,

I didn't see this article anywhere in the Drumbeat recently, so I thought I'd provide a link.

http://www.eurekalert.org/pub_releases/2008-11/teia-rc110508.php

The article talks about how to store CO2 underground in rocks that react with CO2 and create carbonite. I'd be interested to see what TOD crowd thinks of it.

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Leanan on November 7, 2008 - 9:41am

Look up. :-)

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zeroworker2 on November 7, 2008 - 9:44am

You're good Leanan. I scanned the article list and obviously missed the link. Sorry 'bout that.

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elwoodelmore on November 7, 2008 - 9:59am

the doe has a publication on sequestering co2 in the basalt flows of the colombia river basin. and i think it was referenced on tod a few months ago. maybe a good idea, but at what cost ? and will power plants, for example, actually do so, or just talk about it ?

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doug fir on November 7, 2008 - 2:04pm

It's been talked of for quite some time, the link I posted a while back:

http://www.inlander.com/topstory/290133035477934.php

The main impetus behind it anymore seems to enable coal generation plants there, making the area an energy hub-nuke, hydro and coal.

The more I learn, the more I'd prefer the wind farms of Horse Heaven Hills, also talked about, and the ag and sagebrush.

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ROCKMAN on November 7, 2008 - 10:04am

Interesting article zero. But disposing of CO2 underground has never suffered from a lack of suitable reservoirs. There are numerous potential disposal formations in almost every area of the USA. Most would be sandstone formations containing salt water. CO2 would be trapped in these formations for millions of years with no potential harm to aquifers or any other human interests. The difficulty, as the article mentions, has always been the energy requirements. Besides the effort to separate the CO2 it requires a significant (and costly) amount of compression to raise the pressure sufficiently for injection regardless of the target reservoir. There has never been significant technical difficulties sequestering CO2…it’s really all about the expense.

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zeroworker2 on November 7, 2008 - 10:24am

Hello Rockman,

I'm aware of the cost problems around sequestration, but this article claims the costs would be greatly reduced (although it doesn't really talk about why that's the case). I'm wondering if anyone has any specific knowledge as to whether this technique really would be cheap, or if it's just hype.

I'm skeptical because you would still have dissolve the CO2 in the water, trasport it to the burial location, and then pump it down, which seems comparable to simply pumping the CO2 into underground reservoirs.

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ROCKMAN on November 7, 2008 - 11:46am

The most important fact I found missing was exactly how they would inject any amount of liquid or gas into a rather impermeable formation as they describe. The reaction might produce a solid but as I mentioned that's not any big advantage. As far as finding that same type of rock in the USA it would cost 100's of million of dollars to just drill one well deep enough in most areas of the country. But there already many coal-fired plants sitting over potential injection reservoirs.

As far as transport goes, every analysis I've seen of proposed CO2 sequestering projects requires the injection site to be adjacent to the source. Even then the economics seemed questionable without a gov't mandate. IMO, as coal becomes increasing more important in electrical generation in the US we'll see mandated sequestration required and rolled into the rate base. It's the only way I can see future energy needs being met while still minimizing green house gas emissions

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Gwydion on November 7, 2008 - 12:51pm

My 2¢:

As ROCKMAN points out, the problem isn't reservoirs for the storage sites, nor is it stripping the CO2 from the emission source, it's that you have to pressurize the CO2. In order to pressurize that CO2 enough to that you can inject it deeply enough in the subsurface so that it will stay there, you have to liquify it, which means something like at least 1000 psi. The number I was told IIRC was that this will effectively double the cost of coal if you want to strip and pressurize the CO2 coming off the smokestack.

One possible solution is to react the CO2 with something at the surface to make a carbonate mineral precipitate, thereby effectively sequestering your CO2 as a solid phase and don't have to pressurize it as much. I haven't looked into it as much as I should have, but you basically want a Mg or Ca rich mineral that will dissolve in the presence of the acidic CO2 solution and cause MgCO₃ or CaCO₃ to precipitate thermodynamically favorably. Thus far, that I know of, most people have been looking at serpentinite Mg₃Si₂O_6.8(OH)_0.4 and some others like Brucite Mg(OH)₂ and the olivenes Fayalite and Forsterite (Mg,Fe)₂SiO₄. You also want the rock to be cheap cheap cheap.

Peridot = olivene rich igneous rock.

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enemy of state on November 7, 2008 - 1:45pm

I wonder about the possibility of simply pulverizing the rocks, and just letting them absorb the CO2 from the free air over time. I saw an article a few years back, that claimed that an examination of old hard rock mines, showed that they had absorbed about as much CO2, as had been released during their active lifetimes. Perhaps we don't need do anything fancy, just find the right rock formations in desert areas, and break them up enough that they absorb CO2 over say the next century. Perhaps we cab absorb at least a few percent of current emissions by such deliberate geo-engineering?

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Gwydion on November 7, 2008 - 2:14pm

Yeah that's right. It's not just newly exposed rocks from mines that are absorbing CO2 but all silicate soil and rock minerals will weather faster as you increase CO2 in the atmosphere. What happens is the increased CO2 dissolves in water and converts to carbonic acid or bicarbonate and lowers the pH in rainwater. The lower pH rainwater then dissolves the silicates it comes in contact with. Finally, the water makes it's way to the oceans where it eventually precipitates calcite (e.g., in coral reefs or in the little critters whose skeletons eventually form limestone). Here's the sequence of reactions from my former office mate's dissertation:

CO2 dissolution in rainwater: 2CO2(g) + 2H2O(l) → 2H2CO3(aq) → 2H+(aq) + 2HCO3-(aq)  
silicate dissolution:         CaAl2Si2O8(s) + H2O(l) + 2H+→ Ca2+(aq) + Al2Si2O5(OH)4(s) 
carbonate precipitation:      Ca2+(aq) + 2HCO3-(aq) → CaCO3(s) + CO2(g) + H2O(l)

The difficulty is the natural rate at which it's happening is too slow to keep up with the rate at which we're increasing our emissions. So for example, minerals like olivene that they're looking at as a sequestration possibility will respond to the increased CO2 concentration relatively rapidly, say in some decades. So the active sequestration schemes increase the CO2 pressure locally by trapping the CO2 emissions from a coal-fired power plant to get that reaction to go much faster. More common minerals like feldspars and quartz won't react under natural conditions for 10k to millions of years though, so they won't start dissolving fast enough to save us from the permafrost or ice sheets melting. On the rough scale, net mineral weathering rates controls CO2 levels in the atmosphere on the million year cycle.

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enemy of state on November 7, 2008 - 7:59pm

On the rough scale, net mineral weathering rates controls CO2 levels in the atmosphere on the million year cycle.

Thats why I was asking if mechanical disturbance of the right sort of surface deposits would be sufficient to make a dent in the problem. It might be somewhat affordable to break up the deposits, as in current open pit mining, but simply leave the material in place. Would the increased surface area from being busted up be sufficient to increase the overall rate of absorption enough to be interesting. The timespan for emissions to double CO2 is roughly a century. A century timescale for absorption, if it can be engineered would be a decent match.

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HFat on November 9, 2008 - 12:10pm

This was discussed on realclimate:
"In order to reach a new balance, we must speed up the weathering of olivine by a factor of 10. This can be done by opening new olivine mines in tropical countries, where weathering is fastest. There the olivine rock must be ground and spread in the wider surroundings of these mines. These new olivine mines will be larger than existing olivine mines, so the economy of scale will drive the price down. Transportation cost will be low, because the material will not be transported more than a few hundred kilometer from each mine. Calculations show that the price will be around 10 to 15 US$ per ton of captured CO2, say 5 to 10 times cheaper than other proposals like carbon capture and storage. Moreover, this approach will bring new employment to developing countries.
The reaction is often misunderstood. The products are not solids, but dissolved Mg- and bicarbonate ions, that will find their way by passing through groundwaters and rivers. They will help the oceans to counteract the ongoing acidification. We are developing now a simple technology to keep fine-grained olivine floating on the surface of the sea. A large field test with olivine has started this week in the Netherlands. The theory behind the enhanced weathering concept can be found in:Schuiling, R.D.and Krijgsman (2006) Enhanced weathering; an effective and cheap tool to sequester CO2 . Climatic Change, 74, nrs 1-3, p.349-354."

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DaveMart on November 7, 2008 - 2:17pm

Some mine tailings have the potential to absorb CO2:
http://lablemminglounge.blogspot.com/2007/06/carbon-sequestration-in-min...

It won't solve the problem, but it might help.

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metalman on November 9, 2008 - 1:29am

Desert areas are not good - these processes only happen in the presence of liquid water (that is, in solution). Dry olivine and dry (gaseous) carbon dioxide can be left together essentially forever without reacting. As mentioned by other posters, kinetics is the key to this sort of process, and the kinetics are generally poor (slow).

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woodychuck on November 7, 2008 - 1:09pm

Rockman,

Why are you projecting that it would cost "100's of millions to drill just one well deep enough in most areas of the country" ? Is this an estimate for the total outlay for all of the wells, or each well? If each well, why so much?

Also, not being familiar with the mineral itself, I would ask why is it so impermeable?

Sorry for the density, just do not understand.

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ROCKMAN on November 7, 2008 - 3:08pm

woody,

I actually just pulled that number out out my butt. The reality is that the type of rock they're talking about is many 100's of thousands of feet below most portions of the US. There isn't even drilling technology to reach those depths. I was just making a short-hand point that such an effort isn't feasable. But drilling the shallower wells to sandstone formations underlying much (but not all) of the country wouldn't be cheap either but are doable.

I'm not a geochemist but I have to guess that and solid rock, crushed or not, would absorb CO2 at such a slow rate that there's really no practical application. Planting a few hundreds trees might accomplish more than a mountain of powdered serpentinite.

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metalman on November 9, 2008 - 1:37am

And planting a few hundred trees on top of a mountain of powdered serpentinite might be best of all from a kinetic standpoint - carbonate nodules commonly grow in the soil around tree roots. Many weathering processes are sped up immensely by biological agents. This fact is utilized in, e.g., having "bugs" clean up after leaking underground storage tanks, and in leach mining of metals.

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Geckolizard on November 7, 2008 - 11:06am

Better yet, inject it in Cantarell, or even better Ghawar, and kill two birds with one stone... Prop up oil production and get rid of CO2 at the same time.

/sarcasm

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puhkawn on November 7, 2008 - 11:50am

Actually CO2 injection is a popular method of secondary recovery for older fields. The limiting factor is a nearby supply of cheap CO2. Denbury oil company is one of the leaders in using CO2 injection in older fields.

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woodychuck on November 7, 2008 - 5:33pm

Puhkawn - The problem arises when the CO2 is not PURE CO2, but has some oxygen in with it. The most effective CO2 floods actually compress the CO2 to a liquid form before injection, typically 2000 PSI plus, where it will go into solution with oil and force the oil out of the pore spaces. It is not practical to use oxygen due to the need for the liquid CO2 and due to corrosion created by any oxygen with which it might be mixed.

Flue gas from you local, neighborhood, coal fired electric generating plant will not work without purification. Such purification is the next problem, using both BTU's and equipment. CCS is a very complicated process, and will take a long time to get it right.

It is of course possible to use old, FULLY DEPLETED reservoirs, preferable next to somebody else's production (and not mine) to simply inject the CO2 directly into the ground, at whatever level of purity, but that reservoir would for all practical purposes, be totally ruined with respect to further production.

CO2 is easy to get in an impure state, but hell to get rid of in the best of circumstances.

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puhkawn on November 7, 2008 - 6:35pm

Thanks, but I am on top of CO2 injection in old reservoirs. As far as CO2 injection just to get rid of it; my humble opinion is it is something not even remotely ready for prime time.

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Apuleius on November 7, 2008 - 12:53pm

The fact remains that the easiest way to sequester CO2 is to grow hemp and bury it.
Do it in a sinking polder and you also get the benefit of landfill.
(Hybrid poplar or jute would also work.)

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