Carbon Capture: Possible Solutions, Pt. III

No mention of Powerspan or Calera?

Very good series about a subject that isn’t well described in the popular press. I would like to see a new part of the series that looks at the various underground formations that can be used to store CO2, and how much space they represent on each continent. One technology you didn’t describe was subteranean mineralization—basaltic rocks off the California coast and in Oman offer enough of a CO2 sink to take all the carbon—if a good way can be found to insert the carbon into the rocks. Another word on algae—in most studies 90% of the CO2 is lost into the air when bubbled through water. In addition, the algae produce almost as much CO2 when they respire at night as they consume during daytime photosynthesis. Algae is an awful means for sequestering CO2 and the reasons are insurmountable. And on the Calcium carbonate front, the limiting factor is the supply of calcium. Where are we going to get all that calcium from? If it has to be mined, there’s an enormous cost to that, financial and environmental. And it’s my understanding that pure calcium can’t be mined. One more missing technology: deep sea sequestration. It probably will never happen (even if it works, it will be released in 500 years when the water upwells—not enough storage time).

The process flow diagram you show is only about 40 years old. They have been doing it in South Africa and starting in the early 80’s North Dakota as well. The syn gas with the CO2 in it is of limited use. In North Dakota some percentage of the CO2 is piped north to Canadian oil fields for injection into failing wells.

GreatPoint’s process will be a lot more impressive when commercial scale plants are up and running - until then it is a dream. There are hundreds of the processes which have been tried and failed over the years.

One minor item not mentioned is that there are many byproducts of syn gas - all of which require a use. That makes a project much more costly to put into operation.

A very nice overview of challenges and solutions for carbon reduction but an important solution went unmentioned.  Improving the efficiency of coal conversion reduces CO2 as well as other emissions and preserves resources. The Liquid Tin Anode Fuel Cell developed by CellTech Power allows highly efficient production of electricity from coal.  DOE projections are for 61-63% efficiency in a 250 MW plant.  A coal plant operating at t this efficiency will have lower CO2 emissions than a typical natural gas power plant.  In addition, the smaller amount of CO2 that is produced is concentrated in an exhaust stream that will be easier to capture and sequester.

The best way to sequester carbon is to use the immense untapped solar energy potential of the oceans…75% of the earth’s surface…to suck the carbon out of the air and convert it to organic goo at the botton of the oceans.  This is how Gaia has maintained her CO2 balance for billions of years.  If it didn’t work we wouldn’t be here, because the atmophere would have destablized millenia ago.

However the scientific and green community, for various reasons, some political and some emotional, have decided that ocean sequestration is too scary to even consider, much less research.  The sheer volume of distortion on the topic is incredible.  Hopefully someday, reason will again return to that field.

SamJaffe,  I am curious for your thoughts on Skyonic, which turns flue gas into baking soda and Chlorine gas, or other products depending on local markets.  For example, they can make HCl for frac-ing.  As I understand it, they do require large amounts of NaOH, and will have to dispose of very large amounts of baking soda, but I would think that baking soda is safer to store long-term than CO2 gas.  I think underground CO2 gas storage is very risky - failure of a large CO2 reservoir would be catastrophic.  CO2 credits associated with underground storage would likely therefore be de-valued relative to other credits, because of uncertainty related to permanence.  But you sound more informed on this subject than me - are you un-concerned about reservoir failure?