Sunday, November 29, 2015

Olivine, Carbon Nonofibers, C02 Snow--More Third Way Technologies



Editor's Note: This is part of an excerpted series of a Yale Environment 360 interview by Richard Schiffman, with Tim Flannery, an Australian scientist and author.  He discusses how “third way technologies,” that mimic the earth’s natural carbon-removing processes could provide a critical tool for slowing climate change.

Olivine


e360: Olivine is one of the most common rocks in the Earth’s crust with the ability to chemically bind with CO2 in the atmosphere. How could this be used? 

Flannery: There is a roofing company in the Netherlands that makes a paint with an olivine based rock that takes C02 out of the atmosphere directly into your roof. There are also people who are using crushed olivine as a soil amendment, absorbing C02 as the rocks decay. There are proposals to create beach sand from olivine. There are other proposals to use olivine to treat the exhaust from shipping, then put it in the sea to help take C02 out of the waters, in a similar way that seaweed farming does.


 Fuels, Carbon nanofibers, & plastics


 e360: You report in your new book that fuels, carbon nanofibers, and certain types of plastics can be made directly from C02 in the atmosphere. But these are futuristic possibilities. Won’t it take a long time to get these technologies up and running at scale? 

Flannery: It’s still at an early stage, but all indications are that the plastic industry is set to be transformed by these technologies as we move away from fossil fuels. And the carbon fiber possibilities are just astonishing. If you want a very light, very strong material, carbon fiber is what you use. At the moment it is very expensive to manufacture. But just a month ago a major breakthrough was announced by a company that devised a way of manufacturing carbon nanofibers directly out of C02 in the atmosphere at one tenth of the production cost of other methods. As carbon nanofibers become cheaper to manufacture, they will start competing directly with steel and aluminum, both of which are very energy intensive and produce
lots of emissions. 

e360: There are already ways to take C02 directly out of the atmosphere or out of the exhaust stream from power plants. But the problem is where to safely store the captured greenhouse gas. 

Flannery: Previously, carbon capture and storage was conceived of as something that you would apply to the end of a coal powered power plant, capture the C02, and store it in bedrock somewhere near that plant. But if you put C02 under the ground, the C02 remains buoyant, the stuff is always trying to escape, to go upwards because it is a gas. In the oceans, however, things are quite different. Water pressure at two or three kilometers depth is sufficient that C02 remains stable. And if you try to bury it even in shallow marine sediments it becomes a solid on its own. 

When you think about it, the ocean floor is where most of that excess C02 is destined to reside, or most of it anyway over geological time. The C02 is absorbed into the oceans, it is turned into a carbonate on the bottom of the sea as limestone or whatever. So the idea that we should pump C02 into deep ocean sediments at 2 or 3 kilometers is really mimicking what happens over the longer term anyway and it provides a stable environment for carbon to be stored. 


 C02 Snow


e360: One of the most surprising ideas in your book is the proposal to create C02 snow in Antarctica. Could you talk about this? 

Flannery: C02 falls out of the atmosphere as snow at -75 degrees Celsius, and sometimes it reaches -90 degrees Celsius over the Antarctic icecap. So C02 is already falling as snow out of the air at times in Antarctica. The thing is it doesn’t get buried or stored anywhere. As temperatures warm, it sublimates and goes back into the air. So the proposal for the Antarctic is that you would build some big chiller boxes, say 100 yards cubed, you would power them using wind energy, which is already being used by the research stations in Antarctica for their electricity generation. You need about half the installed wind power that Germany presently has to run these chiller boxes to capture a gigaton of C02 in the form of snow. So the idea is that you would put the chiller box out, you’d cool the air a few tens of degrees, the C02 would fall out as snow, you would bury it under ice and it would stay there. That is a very exciting option. 



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