Carbon Sequestration
Carbon sequestration is a collection of techniques
for the capture and long-term storage of carbon dioxide or other forms of
carbon using combinations of biological, physical, or chemical processes. It is
proposed as a means of reducing or reversing current and future accumulations
of GHGs released from burning fossil fuels. Carbon could be captured for
sequestration during either energy production or refinery. Natural biological
processes that sequester carbon include ocean mixing, photosynthesis and soil
sequestration. Since plants and soils naturally absorb carbon dioxide,
preventing outright deforestation and managing forests and agricultural lands as
carbon sinks can remove significant amounts of GHGs. In Northern California, certain
agricultural practices (e.g. reduced tillage, cover cropping and manure
management) have been demonstrated to increase the value of farmed lands as
carbon sinks, at least temporarily (De Gryze 2009, Howitt et al. 2009). If
large-scale algae farms become viable, they would also act as biological carbon
sinks. Physical means of sequestering carbon include landfilling of waste (provided
garbage-generated methane and other GHGs are captured for fuel and do not
escape to the atmosphere) and the burying of bio-char (inert, pyrolysized
biomass) or tree parts directly into the soil (Lehmann et al. 2006).
Technology exists to capture carbon dioxide from coal plants and physically inject it into old wells or the deep sea. Chemical techniques to increase oceans’ carbon absorption capability and chemical scrubbing processes have been proposed to remove carbon dioxide directly from the atmosphere. One patent has been awarded for a technique that could use captured atmospheric carbon to produce electrical and chemical energy (Olah and Prakash 1999). Cap-and-trade programs (such as in Siskiyou County in the North Coast) are another way to encourage sequestration. Some carbon sequestration proponents claim that these techniques (particularly atmospheric scrubbing) could be nearly sufficient to reverse the potential warming effect of carbon dioxide emissions (http://en.wikipedia.org/wiki/Carbon_sequestration ). The only real downside to carbon sequestration efforts is the amount of time that will be required to realize results, even using existing technologies, and the fact that many techniques remain in the conceptual or research and development phase.
Citations:
De Gryze, S., M.V. Albarracin, R. Catala-Luque, R.E. Howitt and J. Six. 2009. Modeling shows that alternative soil management can decrease greenhouse gases. California Agriculture 63(2): 84-90.
Howitt, R.E., R. Catala-Luque, S. De Gryze, S. Wicks, and J. Six. 2009. Realistic payments could encourage farmers to adopt practices that sequester carbon. California Agriculture 63(2): 91-95.
Lehman, J., J. Gaunt, and M. Rondon. 2006. Bio-char sequestration in terrestrial ecosystems – a review. Mitigation and Adaptation Strategies for Global Change 11: 403-427.
Olah, G.A and G.K.S. Prakash. Recycling of carbon dioxide into methyl alcohol and related oxygenates for hydrocarbons. Patent Number 5928806. http://www.google.com/patents?hl=en&lr=&vid=USPAT5928806&id=CFIEAAAAEBAJ&oi=fnd&dq=Olah+carbon+dioxide+alcohol+fuel
