Apr
2
The CO2 Capture Paradox
April 2, 2008 | Leave a Comment
With biomass, algae in front of late, needing CO2 in the air or in the algae growth media the prospect of capturing CO2 gets up front pretty fast. The flue gas CO2 which is available at any coal or gas fired electrical generating plant is already concentrated and only needs cleaned enough not to poison the plants it is destined for.
But the problem is the cost. So far, the basic process is electrodialysis to separate the CO2 from the medium that captured it. The issue is the amount of electricity that is needed to drive the process. Many researchers are thinking that electric drives are not the way to go forward, and suggest that other methods would be more economical and more likely to achieve the goals of the carbon sequestration crowd.
We’re more interested in supporting the plant contained systems such as Vertigro, Greenfuel Technologies and other systems that can benefit from higher than atmosphere concentrations. Will all due respect to the emotions of global warming, 370 parts per million is not a glory road for plant based CO2 recycling. Over large tracts of land with crops designed for feeding fuel processes the current state is enough, but the strict control systems, those with the highest and fastest return for investments and offing fast scale up for fuel production would benefit from some added CO2.
One leading concern in developing CO2 capture devices is Global Research Technologies in Tucson Arizona. This device holds sheets of material that capture the CO2 as air flows by, whether out in the open or in a flue stream. Then when the material is laden it is washed down with a proprietary fluid that then needs the CO2 removed for the fluid to be recycled. The process used to clean the fluid is – electrodialysis. While the process and technology is slick, the electricity used is substantial.
Skeptics assert that the electricity used is barely breaking even with the CO2 cost to generate it in the first place. Global Research is hoping to drive their devices with solar power in future models. Klaus Lackner a geophysicist at Columbia University says, “Prying the carbon dioxide loose once you absorb it is the hard part.” Mr. Lackner also offers that “In the long term, the price will come down to $30 per ton, but this will not happen overnight.”
The basis for much of the discussion is the assertion that trees over an acre will only sequester between 2 to 8 tons of CO2 each year. That is the base line for argument, with no ideas offered about crops like sugarcane, corn, switchgrass, miscanthus, hybrid popular and other crop type plants. The low leader here is corn, which at 150 bushels an acre is taking out more CO2 than trees do. But, the big gains need to come from cellulosic-based crops that can be processed into fuels. With these, the tons per acre can get large fast and with genetic improvements and improved cultivation the total recycled CO2 volume and the newly available barrels of fuel can get quite large.
These still will require large land areas, which make the strict control algae systems quite attractive. One idea that may be transferable to strict control is from Climos who wants to seed pulverized iron over the ocean in hopes of germinating a plankton bloom. Iron has been shown to promote the growth of ocean algae. These species inhale CO2 at rates that a few months of algae growth can equal decades of tree growth. But Dan Whaley, the CEO of Climos, also thinks from a CO2 global warming perspective. Little concern is offered that the idea of seeding the oceans could well overshoot the goal and drive CO2 to levels too low. The consequences of that would be dire for billions of people and thousands of plant and animal species.
Here’s the paradox. With the global warming crowd screaming such drivel, offering that the debate is over and such distractions to avoid intelligent analysis on the one side, and the realization that man has had, is having, and will always have a role in the planet’s carbon cycle, we don’t have a good idea of what a target CO2 proportion is in an atmosphere that needs to support more than 6 billion humans. That’s not even to consider that impacts we may have on the flora and fauna who share the globe with us.
Yesterday we saw that thinking through to the full useful end of atomic fissionable fuel needs thought through for both extracting the full measure of what it offers and reducing the hazards of making full use. Today the point needs offered that hard consideration needs done, not just for a quick fix, but for centuries to come about how humanity will act in the planet’s carbon cycle.
Gee, it seems the hysteria rules for now. We can only hope that “the gold rules” of biofuels can bring some sense back to the discussion. It won’t be pretty.
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