What's the latest thinking on carbon sequestration?

[muriel_volestrangler]

It sounds great in theory - pump the carbon dioxide underground, where it could remain for thousands (millions?) of years. This gives us much more time to stop using fossil fuels for electricity production.

But I've also seen people saying it's not practical on a large scale - you have to find the right geological formations, it takes a lot of energy to do, and so on.

So does anyone know any up-to-date, relatively unbiased (ie not what a coal mining company's PR department has put out), and accurate websites telling us what the state of the art is - how much can practically be done, and where, and if there are particular problems that need to be solved (and if so, are they being worked on?).

[papau]

1. Saw a dump on the idea saying it caused underground chemical changes that

would release fairly quickly back into the air.

I have no clue what are the "real" facts.

I just hate the whole coal burning idea when there are better ways (I recall KOS having a few things to say on this that - 'cause he agreed with me? - sounded very wise.

[muriel_volestrangler]

15. I agree burning coal isn't an attractive option

but decreasing the energy demands of the world is going to be such a difficult task that it seems worth investigating CO2 storage as an interim solution.

Any idea where you might have seen the story about chemical changes casuing problems with underground story - or when?

[XemaSab]

2. There are a lot of the proper formations out there

the challenge is siting the plants in such a way that they are both near these formations and near high voltage power lines. There are also a number of other factors such as proximity to public lands, rail lines, water sources, and other factors.

The guy in the next cubicle from me is working on this. :P

And it's not just coal that's a big hassle. Siting solar thermal in California is a regulatory hellhole.

[phantom power]

5. what are the regulatory hurdles for a solar thermal plant?

[XemaSab]

14. Basically the same as any other power plant

You have to do an AFC (application for certification), which is like an EIR. You have to comply with the same environmental laws, and the regulatory hurdles are the same. The likelihood of approval is greater because there are no air quality impacts, but the biggest headaches are geology, proximity to power lines, and desert tortoises. :P

[phantom power]

17. so, in fact, siting *any* power plant is a regulatory hell-hole...

regardless of how it works?

[XemaSab]

19. Pretty much, yeah

The advantage to siting a cleaner plant is in the amount of public outrage. They're discussing putting a nuke near Fresno, and that will be DECADES of public review and litigation.

[Kolesar]

18. The power plant has to be near condenser-water and be near the sequestration-well

Somehow, the idea of turning the draft of a smokestack to go underground seems daft.

[XemaSab]

20. You could also use it for industry,

but siting it close enough to a plant needing CO2 would be a challenge. :P

[NNadir]

22. The carbon dioxide market is nowhere near 27 billion tons.

In any case, with the possible exception of carbon dioxide used as a refrigerant, any carbon dioxide industrially used is likely to end up in the atmosphere. What happens to the fizz in Pepsi Cola anyway? Pepsi Coaler.

There are some industrial processes that fix carbon dioxide for chemicals, mostly for making organic acids like salicyclic acid (for aspirin) and methacrylate for polymers, but these don't touch the surface of the problem.

I have proposed the hydrogenation of carbon dioxide to make dimethyl ether for motor fuel, but again, the carbon would be ultimately released though it would be used twice, rather than once and would slow release.

As you know, I don't buy the sequestration scheme for a New York minute.

[Kolesar]

23. A greenhouse, maybe

A coal stack would have exhaust with mercury, particulates and other unpleasant compounds and elements, though. Mercury can be captured with a compound sprayed into the exhaust (calcium?).

Perhaps a "combined heat and power" natural-gas fired plant might be an appropriate bridge technology to use.

[XemaSab]

25. I had the crazy idea

That you could bubble it through algae grown for biodiesel. It would still go into the atmosphere, but you'd be running it through another 'round of energy production first.

[Kolesar]

26. There is a poster on DU who has posted about ponds of algae->biodiesel in the AZ sun

I suppose such ponds could be located near existing fossil fuel plants in populated states in the southeast.

[madokie]

3. here is a link to the DOE, if that would help

Carbon Sequestration Leadership Forum

http://www.fe.doe.gov/programs/sequestration/cslf/index.html

In September 2005, the Intergovernmental Panel on Climate Change published its Special Report on Carbon Dioxide Capture and Storage which found that technology can capture up to 90 percent of carbon dioxide in large-scale applications; and storage can account for up to 55 percent of the emissions reductions needed to achieve atmospheric stabilization.

Formed in 2003, CSLF marshals intellectual, technical and financial resources from all parts of the world to support the long-term goal of the United Nations Framework Convention on Climate Change - the stabilization of atmospheric carbon dioxide concentrations in this century. Members are dedicated to collaboration and information sharing in developing, proving safe, demonstrating and fostering the worldwide deployment of multiple technologies for the capture and long-term geologic storage of carbon dioxide at low costs; and to establishing a companion foundation of legislative, regulatory, administrative, and institutional practices that will ensure safe, verifiable storage for as long as millennia.

Geologic storage at great depth is possible in depleted and declining oil fields, which can enhance near-term supply by boosting recovery and also increase reserves by making more petroleum recoverable in: natural gas fields; unmineable coal seams, which may add to natural gas supply by displacing methane for recovery and use; saline reservoirs which underlie much of the world; and other significant geologic formations such as basalt.

Preliminary findings indicate the world's potential storage capacity is sufficient to hold all emissions for several centuries and that there is a good match between large-scale carbon dioxide sources and storage formations.

[kestrel91316]

4. Pumping it underground or under the sea is not valid sequestration

IMHO. Making charcoal and using it to improve soil productivity a la Terra Preta seems a better approach.

[eppur_se_muova]

7. Converting CO2 back to C (charcoal) would consume a great deal of energy.

Nice thought, but you'd basically be "unburning" coal, which would cost as least as much energy as was originally produced by burning it.

Technically, coal contains some hydrogen as well as carbon, but I doubt very strongly if recovering the H and leaving the C behind would be at all practical, in terms of energy return on energy invested. If nothing else, you'd be handling huge masses of material.

[GliderGuider]

8. I don't understand where the coal comes from in your argument.

To make charcoal you partially burn wood or similar material in an oxygen-poor environment. The hydrogen from the woody hydrocarbons is driven off, some is used for process heat and some can be captured. The lack of O2 in the process means that the carbon from the hydrocarbons doesn't oxidize to CO2, but stays as carbon. The original conversion from CO2 to C is done by the growing plant, at very little energy cost since photosynthesis provides the energy.

[eppur_se_muova]

9. The OP was referring to CO2 from conventional power plants ...

which mostly burn coal. Underground/underwater "sequestration" (really, sweeping it under the rug) would not even be considered except that fossil fuels are being burned.

What you seem to be suggesting is switching to a process in which the fuel comes from wood or other biomass. That wasn't clear from your earlier post. (Mostly because I read too fast.:P )

If you're going to burn only biomass, then that's carbon neutral already, no further work needed there. No need to bring charcoal into the discussion on that basis -- it's an added extra, if you want to go that way, but not essential to carbon neutrality. I think what you're aiming for is converting some CO2 back to carbon in the soil -- justifiably, that could be referred to as biomass, or TRUE sequestration. So your goal is for a carbon-NEGATIVE system, if I read it correctly.

The OP (and, I thought, the response) was referring to what can be done with CO2 from disinterred fossil carbon. The only suggestion the Industrial Establishment can come up with is pumping it underground or underwater. It sounded like you were suggesting converting this fossil-produced CO2 *directly* to carbon, which I was saying is not at all practical.

The idea of charcoaling biomass to make both energy and charcoal might work, but I suspect the EROI would be poor. It would be kind of like firing coal to make coke, and then not using the coke for fuel. I can see a traditional community doing this to keep its agriculture sustainable, but not large-scale industrial interests. (This is not the same as saying it's not a good idea, just saying it's unlikely to happen in our world as it is.)

on edit: Didn't notice posts were from two different DU'ers. Apologies.

[kestrel91316]

10. I don't think it has much value on a large scale as CO2 sequestration,

per se, but as soil improvement it has HUGE value. And it could drastically decrease the need for man-made energy-hog fertilizers.

[eppur_se_muova]

12. Point taken.

I hadn't heard of terra preta until very recently. Sounds like something that could be kept alive by tradition, but not by corporatist agribusiness (unless they can bribe their congresscritters into handing out huge subsidies).

[kestrel91316]

16. I also don't think it's a process of converting CO2 back to charcoal directly.

Basically you take wood, that Mother Nature has already made with solar energy, and partially burn it to make the charcoal. As opposed to fully burning it to ash, for heat.

Wood, as you know, manufactures itself in a renewable process. Terra preta makes it a more permanent form of sequestration than wood >>>> decayed wood >>>> loamy forest soil.

[GliderGuider]

6. I remain to be convinced

Underground storage has to be leak-proof in order to work. That basically means using depleted gas fields after the well bores have been thoroughly plugged. This may limit the number of places it can be used. And there is no guarantee that the removal of the original gas didn't disrupt the integrity of the formation, so each site will need to be tested. If you thought finding a place to bury nuclear waste was a political hot potato, this one could dwarf it, especially if there was an accidental high-volume leak.

Oceanic disposal is just insane. The oceans are already acidifying, thereby threatening all organisms with carbonate shells (i.e. plankton and coral). In addition the oceans are losing their ability to keep CO2 in solution - they seem to be nearing saturation already. That way lies madness.

I have a radical thought. We could just produce less CO2...

[Nihil]

11. Far too radical to be supported by any significant people ...

> I have a radical thought. We could just produce less CO2...

Nope ... I can't see that idea taking hold these days ...

Sad isn't it?

[XemaSab]

21. Usually capped oil formations

aren't capped to withstand internal pressure. Otherwise the CO2 would be useful in enhanced oil recovery. But you're have to get a lot of pressure built up to displace oil from the matrix.

[Porcupine]

13. It's a PR scam along with "Clean Coal." Greenwashing the indefensible.

Consider that for every trainload of coal that is burnt three times that volume of CO2 would have to be sequestered to just break even on coal burning. That's just not going to happen. To make the process profitable sequestering the coal plus the coal burning plus the coal mining plus the repair of ravaged mine tailings has to be cheaper than conservation efforts, wind power or solar power is now.

It's just not.

The only carbon sequestration process that has been proven to yield more energy than it consumes is Terra Preta. Atmospheric carbon is converted to geologic carbon and energy with a virtuous cycle in that the next crop cycle captures even more carbon. Machinery required is a hoe and a machete.

[XemaSab]

31. "Clean Coal," according to my boss, is a coal plant

with equal outputs to a conventional natural gas plant.

Under those guidelines, I don't see why we couldn't do that. :shrug:

[leftupnorth]

24. I thought developing a pipeline system for CO2 to distribute it to

greenhouses and algae farms is a novel idea. CO2 gas sequestration is sequestering oxygen as well - that is not good. We could sequester carbon in algae, them pump the algae back into the oil and gas formations. We could use this as a national strategic carbon reserve AND as a means to sink carbon into the earth, and recover the oxygen being locked up by fossil fuels in CO2.

[RestoreGore]

27. I read it hurts groundwater supplies, so I'm not too keen on it n/t

[XemaSab]

32. It's pumped into saline aquifers

so there is a buffer.

[Dogmudgeon]

28. Uh, plant trees?

I'm not aware of any technology that is more efficient or effective than agriculture.

But it's possible, of course, that I'm wrong.

--p!

[efhmc]

29. I laughed so hard when I read this. I am doing a presentation today on

what one can do to help stop global warming and that one thing is the best and most far reaching of all.

[GliderGuider]

30. As has already been said, Terra Preta

It's the only process that makes sense to me. You can simultaneously make fuel, improve the soil's fertility and sequester carbon, all using a process that requires no complex technology and will be possible even in a very low-energy future.