Tuesday, July 21st, 2009 | Author:  | 7,883 views - starting Aug 9/09

in my previous post, i listed 3 general CO2 gas storage geotechnology strategies … i’ll discuss the pros & cons of each individually in the upcoming posts …

protestors dressed in CO2 molecule costumes to demonstrate in essen (1 june 2007) as part of the anti-CO2 pollution initiative, 'byebye CO2' ... photo from reuters

protesters dressed in CO2 molecule costumes to demonstrate in essen (1 june 2007) as part of the anti-CO2 pollution initiative, 'byebye CO2' ... photo from reuters

1.  CO2 stored in gaseous form and pumped or injected deep below the ground, into various geological formations such as saline aquifers, exhausted gas fields, coal beds, etc.

PROS:

* currently, this option is considered the safest … the injected CO2 gas is expected to react with the local bedrock and naturally form inert mineral carbonates via a process known as mineral carbonation … this is a natural geological process which, under normal conditions, occurs over a span of thousands of years … hence, the injected CO2 gas will theoretically exert no detriment to the local and regional geology while becoming permanently stored below the Earth’s surface …

* injecting CO2 into oil fields is 1 currently popular method of enhanced oil recovery

* CO2 injected into coal beds is also an apparently safe method of enhanced coal bed methane recovery … the injected CO2 adsorbs superficially to the coal, which causes methane gas to be released …

* saline aquifers are currently assumed to provide no overt benefit to, or have any important (i.e., economic) use for, humans and therefore are seen as ideal CO2 storage sites … moreover, saline aquifers have been used as sites for storage and disposal of chemical wastes with no obvious negative effects; therefore, industries, geoengineers, and governments assume that CO2 injection will have little or no observable impact to saline aquifer hydrological cycles … [ok i admit it -- i am biased ... this is point has an obvious sarcastic bent ...]

CONS:

* currently, the cost of CCS (CO2 capture & storage) technology is comparatively high and potentially prohibitive for some coal plants … realistically however, high cost can be a moot point if the option is a sound, effective, and long-term solution … all new technologies are expensive as prototypes and when in “beta” form … operational and logistic costs will decrease to an affordable level if and when this technology becomes more common and more refined … therefore, to assess an accurate risk-to-benefit ratio, the focus needs to be on larger scale and on higher impact drawbacks such as risks to local and regional human and wildlife health, ecosystem integrity, and natural geological processes … i.e., shift the focus away from calculating solely the economic costs & benefits of this technology to assessing the long-term costs & benefits to regional and global ecosystems …

* prior to injection into the ground, the CO2 gas must be compressed to a near-liquid (supercritical) state and mixed with water … this requires energy, and may increase the fuel requirements of a coal plant by up to 25-40%  … therefore, increasing CO2 gas emissions to attain the goal of decreasing the overall CO2 gas emissions of a coal plant seems a little inefficient and counter-intuitive …

* the site of CO2 gas injection may be located at a great distance from the site of CO2 capture … therefore, extensive pipelines spanning several hundred or thousand kilometers must be built … the CO2 emissions yielded from the building of these pipelines, as well as the materials used to construct them, must be factored into the cost-benefit analysis of CCS …

* building pipelines almost always exerts some degree of disturbance (and sometimes destruction) of ecosystems … the roads, vehicles, equipment, drilling, noise, and subsequent waste that are part-and-parcel of building and maintaining pipelines may have significant impact on the local and regional hydrologic cycles, pedosphere processes, wildlife behaviour (e.g., mating) and movements (e.g., foraging and migration patterns), and plant ecology … generally, the smaller the organism, the greater the impact on it (e.g., sessile herbaceous plants and ground-dwelling insects may be affected to a greater extent than large trees and terrestrial vertebrates that have a relatively broad home range) …

supercritical CO2g -- marc jacobs* long-term consequences are difficult (if not impossible) to accurately assess … no one actually knows what the potential repercussions of human intervention into geological processes may be … geologists and geoengineers may extrapolate and estimate the outcome based on the knowledge they’ve garnered from decades of research into Earth’s terrestrial cycles … however, those data are still relatively incomplete, superficial, and potentially ambiguous … injecting supercritical CO2 gas into the Earth’s crust is a previously untested experiment — this is not how natural CO2 geosequestration works … the outcome of our experiment could be innocuous, moderately catastrophic, or completely disastrous; we don’t yet know which 1 of these it will or could be … frankly, this is a risk i would rather not explore …

* the potential for CO2 leakage into the atmosphere from, for example, pipeline leaks or breakages, can be devastating on a local or regional scale … in december 2008, a small pipeline leak in Berkel en Rodenrijs, Netherlands, proved fatal to a number of nearby ducks … while the incident overall may not be calamitous, it does attest to the potential dangers of a large CO2 pipeline leak …

* environmental assessment for potential CO2 gas storage sites is driven largely by the motivation of governments and corporations to complete projects rather than on the ecology of the ecosystem and its resident wildlife … additionally, the primary focus appears to be on locating geological formations and assessing rock type … arguably, all ecosystems have the potential for being irreversibly damaged by CO2 storage; however, some ecosystems are more vulnerable than others … i would be curious to know exactly how ecosystem resilience and wildlife habitats are factored into site assessments and selections …

* very little is known about saline aquifers — their ecology, hydrology, and importance to terrestrial, marine, and freshwater ecosystems … injecting CO2 gas will drastically change aquifer pH (i.e., it will decrease pH/increase acidity via increasing formation of carbonic acid) … the impacts on associated ecosystems will undoubtedly be significant and negative, as pH levels can completely alter biochemical processes (e.g., respiration and osmoregulation in aquatic species) …

*   *   *   *   *   *   *

a slight digression:

1 of the aims of this website is to provide encouraging insight and easy-to-follow tips for ‘greening your life’ … i suspect there is little in this blog entry that satisfies either of the said objectives … to be completely honest, i think the most important and effective  “thing to do” about CO2 storage is to find out whether or not this is occurring in or around your living space …

social and political action on a community scale is probably your best chance for learning more about the technology and about its potential impact on your health and the integrity of local ecosystems … i’ve tried to highlight some points that will hopefully raise some questions about the purported safety of CO2 ground storage …

in my next post, i’ll write about CO2 storage in oceans … this is an even more disturbing option and 1 that i am quite adamantly against …

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6 Responses

  1. 1
    Scarlett Johanson 

    Nice to know how the heck this C02 process works.. This explanation makes it pretty clear. And yes, activism is key.

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