Might be that I'm missing the point, but this sounds very much like they are trying to reinvent photosynthesis.

It is a little like re-inventing photosynthesis, but at a much greater energy density and much greater production rate than we can get with agriculture and thus without using millions of hectares of land. (While not the focus of this particular research effort one can also make artificial hydrocarbons using energy sources other than Sunlight.) "Only recycling CO2" from the atmosphere would be infinitely better than releasing billions of tonnes of fossil-derived CO2 as we do now. When we finally stop adding more CO2, natural processes which sequester carbon will eventually remove the excess.

This is what biodiesel and biobutanol/ethanol are about. Turning CO2 into fuel. That's a form of CO2 recycling. If you want to more permanently sequester the CO2 you've got to turn the CO2 into something distant than fuel.

Growing wood, then making permanent value products out of wood, is an excellent way of sequestering CO2. All that cellulose tied up in a quasi-permanent structure. Recent work by materials scientists in making car panels and other structural products from wood is intriguing.

We're not going to stop adding more CO2 for decades, especially with India and China. No, we've got to learn to sequester CO2.

This is what you call enviromentally benign fuels and chemicals that basically incorporate man into the carbon cycle. Rather than have man pump more carbon into the atmosphere, it is theoretically and technically feasible to use carbon dioxide directly to produce methanol or other lower chemicals then convert these into higher products. If you heat municipal solid waste at 1000 degrees in a carbon dioxide environment you get a gas that is predominantly carbon monoxide; carbon monoxide can then be reoxidized to operate turbines, engines, make fuels through FT synthesis and the enflluent can undergo the process infinately.

I think the problem that is being addresses is the storage and transportation of energy. The sun doesn't shine and wind doesn't blow when and where you need energy. You produce some energy product when and where it is best. Then you take it to where it will be used.

I have question. Would it not be cheaper and a far quicker process to suck the billions of tonnes of CO2 hovering in the atmoshere, liquify it, and then bury it in the dried up oil wells from where it came. Seal the oil wells and be done with it?

Hydrogen Fan,
Where would the energy come from to do all those wonderful things? Oil? Coal? Natural gas? (Get it?) Do you have any idea how much energy is required to "suck" the CO2 out of the atmosphere (concentration <<0.1%), liquify it (won't it form dry ice first?) and then pump it underground? But then again, as a hydrogen fan, thermodynamics can't be high on your list of specialties...

GRL Cowan,
Why oxygen too? At least you came to your senses about hydrogen...

Once I read about DOE envelope of R&D of so called advanced photovoltaic. The idea was to incorporate in single solar panel PV electricity generation, overnight energy storage, and ultimately elements for synthesis of hydrocarbon fuel. As I remember numbers right, they stated that energy conversion of natural photosynthesis is about 2% at some record plant (by the way sugar cane is pretty close to this limit), so artificial hydrocarbons synthesis should be way more effective that natural photosynthesis in order to compete with regular PV with about 20% of conversion efficiency. BTW, this 2% max efficiency – to total carbon mass, not only for small part we use to extract sugars for ethanol production or oil for biodiesel – made me big skeptic of feasibility of energy crops. Waste derived fuel, like corn stove ethanol – different matter.

>> I like the CO2 Bioreactor MUCH BETTER...

There's also http://www.greenfuelonline.com/ or growing the algea at city sewage plants. These offer factories and cities, respectively, monetary incentive as well. Very space efficient.

Having lots of options is good.

Finally, it is dawning on people that we cannot replace all fossil-derived vehicle fuels with biofuels: there simply isn't enough land available for it, even if we were to plow under every rainforest, prairie, and park in the world and replace them with oil palm and sawgrass farms. Making vehicle fuels from coal releases more greenhouse gas and further worsens global warming, unless CO2 sequestration can be shown to work on a usefully large scale. Lacking that, and without some enormous improvement in energy storage, part of the solution will have to be making vehicle fuels from atmospheric CO2 and .

Where would the energy come from to do all those wonderful things? Oil? Coal? Natural gas? (Get it?) Do you have any idea how much energy is required to "suck" the CO2 out of the atmosphere (concentration <<0.1%), liquify it (won't it form dry ice first?) and then pump it underground? But then again, as a hydrogen fan, thermodynamics can't be high on your list of specialties...

As a supposed expert in thermodynamics, you should realize that the theoretical minimum energy needed to concentrate a dilute gas increases only slowly (logarithmically) with dilution. The energy needed to further compress and pump the CO2 after it has been separated is also a small fraction of the chemical energy liberated when the CO2 was formed. So it's not obviously absurd to think about schemes for extracting CO2 from the air, although clearly practice and theory are not the same.

Klaus Lackner at Columbia has been looking into atmospheric CO2 extraction; he points out that the combustion energy density represented by the CO2 in the wind at a typical location is orders of magnitude higher than the wind energy itself. He points out that while sequestration of concentrated CO2 from central sources will always be easier, there will also be leakage and distributed sources, so atmospheric capture would still be a good thing to have.

Oh, and refamiliarize yourself with the phase diagram of CO2, mister. Compressed CO2 is often handled in liquid form. It doesn't form a liquid at 1 bar, but then we wouldn't be injecting it into the ground at 1 bar.

You guys know nuclear power is the real deal, right?

Anne -

"Imagine, say 1.000.000 sq km of photovoltaic cells. Who's gonna pay for that?"

Considering sunshine is free of charge, the investment decision would have to be based on the alternative: 20+ years of buying fossil fuels, funding military protection to ensure a ready supply and, funding global warming mitigation projects. On that basis, solar would already be competitive today. Consider the hundreds of billions of dollars spent/wasted to "bring democracy to Iraq". After all, decades of Western support for repressive regimes flush with petrodollars have arguably contributed to the rise of al Qaeda and WMD programs (real or imagined).

The big problem with solar-derived electricity is that it's very hard to buffer the energy collected during the daytime to meet nighttime demand. Sure, some can be buffered in existing, fully amortized hydro dams. Some PHEV advocates call for charging up the high-capacity batteries during the workday.

However, using solar energy to produce a chemical energy carrier, e.g. hydrogen or preferably, a liquid hydrocarbon fuel, would more completely eliminate the circadian and logisitics drawbracks of solar power.

For now, biotechnology - including intensive biofuel farming based on algal oil - seems a promising route to achieve this technologically. But I've learnt not to underestimate the capacity of materials scientists and chemical engineers to pull a rabbit out of hats. Relying on biology comes with significant drawbacks. Note that either way, your inputs are CO2, H20 and solar energy.

As for carbon sequestration, the CO2 concentration in the oceans is two orders of magnitude greater than that in the atmosphere. If you could reduce ocean concentrations even just a little, e.g. by growing vast quantitites of limestone using solar power an let that sink to the ocean floor, plain old diffusion would eventually reduce that in the atmosphere as well. Currently, the biorock production process still requires a metal scaffolding, though.

http://www.globalcoral.org/