Tuesday, January 27, 2015

Carbon Sequestration vs. CO2 Antarctic Pumpdown

                                   Nice idea, but you can't ignore the geology

Government research agencies have spent billions of dollars on research on carbon sequestion over the last decade.  The research involves finding technologies that remove CO2 from the smokestacks at a power plant (known as carbon dioxide removal or CDR) and then storing or sequestering the CO2 by pumping it into the earth.  Its been assumed by proponents of CO2 sequestration that all the CO2 pumped into the ground would interact with various rocks and saline brines in the earth in such a way that the CO2 would be converted to rock.  However, a new study done at MIT is casting doubt on this basic assumption that underlies Carbon Sequestration.

The MIT scientists recreated high pressure subsurface environments in the lab and then pumped in CO2.  Much to their surprise most of the CO2 did not react with subsurface brines and turn into rock.   In fact, the CO2 tended to displace the brine and form a zone within the rock saturated in CO2 gas.  Where reactions between subsurface brine and CO2 did occur, it tended to form a barrier between areas of rock with brine in the pore spaces and areas where CO2 was displacing the brine.  

These results are very disappointing for advocates of carbon dioxide removal and sub-surface sequestration.  The discovery that CO2 injected into the earth remains in the gaseous form means that mass storage and sequestration of CO2 in the earth becomes much more problematical.  Numerous studies show that naturally occuring gases like methane and CO2 commonly leak up from the earth and into the atmosphere now.   Injecting huge amounts of CO2 removed from power plant exhausts into the earth accomplishes nothing if the CO2 then leaks back up the atmosphere.   

Thats exactly why my CO2 Antarctic Pumpdown proposal is designed around modern industrial processes that use Buckyballs and industrial chemicals to remove CO2, and then store it in the solid state in an ideal geologic reservoir, the Antarctic Ice Sheet. 
People have known for decades that H2S, CH4, CO2 and other gases are actively diffusing up from hydrocarbon reservoirs and other sources within the earth---in fact "gas sniffers" are sometimes used as to find gas leaks as part of a hydrocarbon exploration program.  In my humble opinion, its just wishful thinking to imagine that the geology of the earth is so simple that CO2 captured by CDR and then injected into the earth won't diffuse back up to the surface just like other gases do.  






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