Friday, December 23, 2005

Coal And The Question No One Is Asking About Carbon Sequestration

The new watchword in the coal mining industry is carbon sequestration. Those who mine coal and those who burn it (primarily electric utilities) are less likely than their counterparts in the oil and gas business to discount the dangers of oil and gas depletion. And, they have an entirely predictable solution: Mine more coal. The natural followup question is: What about global warming? From coal advocates we get another entirely predicable answer: carbon sequestration (i.e., storing the carbon dioxide created by the combustion of coal someplace other than the atmosphere).

These advocates are eager to turn coal into liquid fuel, into slurries for pipeline transport, and into cleaner burning synthetic gas for fuel and chemical feedstocks. In fact, they envision a return to a coal economy as the oil and gas economy declines. They do have one very important fact in their favor: The world still has gigantic reserves of coal, one quadrillion short tons according to the U. S. Energy Information Administration.

Of course, there are questions about the energy content of that remaining coal. Will we reach a point (sooner than we expect) at which the net energy from coal begins to decline precipitously and even turns negative making it an energy sink instead of an energy source? Will we find that as we increase our use of coal, a worldwide peak in production will come much earlier than we thought? And, wouldn't we then face the same challenge all over again of having to move quickly to renewable sources of energy?

But, let us set all these concerns aside for the moment and focus on the question of carbon sequestration. Not too long ago I spoke about oil depletion before a Chamber of Commerce-sponsored gathering. I suggested that we as a world society might decide to return to a coal economy. While that might prove practical in the short run, I explained, it would probably be disastrous in the long run because of the damage it would do to the climate.

Afterwards an engineer who works for a large utility approached me. He explained that his company was already successfully sequestering carbon dioxide underground in a pilot program at a generating plant in Virginia. I asked him how long the company was planning to test its program before expanding it. Would it be five years? 10 years? How long will the company wait to be sure that the carbon dioxide doesn't leak out at a later date, possibly by some process as yet unknown? What if any failure of the company's sequestration method doesn't show up until the 11th year?

He responded, "Well, maybe any leakage will be slow."

Are we really willing to bet the future of human civilization on coal based on that response?

7 comments:

odograph said...

This is some thing "the watchers" should watch very carefully.

My understanding, based on Deffeyes' book is that some structures are truly gas impermeable. That's the reason we still have natural gas down there. The CH4 couldn't get out.

Maybe a geologist will show up to correct me, but I'd guess that if we could limit injection to oil/gas fields with a good cap, we'd have pretty long term storage.

On the other hand, 'normal' land might give it all back up over time.

Rod Adams said...

I have several additional questions about coal sequestration:

1. How will removing O2 from our atmosphere affect living creatures?

In case you have not thought about this, consider that advocates are not talking about putting carbon (coal) back underground, they are talking about combining it with O2 and putting CO2 underground. The last time I checked, plants, people and other animals like to breathe O2. The effect might be minimal, but has anyone checked?

2. If nuclear scientists and engineers have trouble convincing people that they can design containers that can hold relatively tiny quantities of solid, corrosion resistant material safely underground, how is it possible for coal sequestration advocates to convince people they know how to store tens of thousands of times more GAS (which leaks far more easily than SOLID materials do) in random structures?

3. Compressing (pumping) gas is an energy intensive operation which will probably require 30 to 40% more fuel for the same quantity of electricity if the CO2 is sequestered deep underground. How long will the coal last if we deplete it at an ever more rapid pace?

4. In many areas of the world, though there are adequate reserves of coal, there are already serious constraints on the RATE at which it can be mined and transported. Who is going to build the additional infrastructure needed for the additional production rate?

IMHO coal sequestration is simply a marketing ploy designed to help sell more coal by telling a story that makes people feel good. It is a fraud, but if it allows coal to retain its market share for a few more years it will be a tremendously valuable lie for coal producers.

Anonymous said...

The only kind of carbon sequestration that makes sense is what Green Fuel Technologies is trying (to bubble the CO2 through algae tubes.)

Anonymous said...

CO2 + H2O => H2CO3 (ie acid)
Will pumping large amounts of CO2 underground in anyway increase the weathering/dissolution rate of the rock intended to store it?

patrick said...

"If nuclear scientists and engineers have trouble convincing people that they can design containers that can hold relatively tiny quantities of solid, corrosion resistant material safely underground, how is it possible for coal sequestration advocates to convince people they know how to store tens of thousands of times more GAS (which leaks far more easily than SOLID materials do) in random structures?"

Just because wilfully ignorant people dont
believe it doesnt make it untrue. Nuclear waste issues are far more manageable
then some scaremongerers tout.

The real question on this is does it really work? Scientific validation is the metric (not a poll).

And is it worth it?

Pumping C02 into the ground, unless it is part of getting better oil recovery seems a real waste of time, money, and, ahem, energy. It's impact on the climate is far below the threshold of cost to do this activity. We are talking Gigatons of CO2 over a century causing some climate impact. .... better to find different sources (eg nuclear) of energy.


"IMHO coal sequestration is simply a marketing ploy designed to help sell more coal by telling a story that makes people feel good. It is a fraud, but if it allows coal to retain its market share for a few more years it will be a tremendously valuable lie for coal producers."

Interesting claim.

Anonymous said...

Anonymous said...

The only kind of carbon sequestration that makes sense is what Green Fuel Technologies is trying (to bubble the CO2 through algae tubes.)

This concept can capture 30-40% of the CO2 + Sun = ethanol + biodiesel
Things which can be sold for a profit, reduce total CO2 emmision, and lessen our dependence on oil.
In addition it uses low tech equipment. Pipes, tanks, wine press, stills, and rakes.

Anonymous said...

The question nobody asks is--- is coal economically viable for the future? If carbon is taxed at $70 per ton, or carbon sequestration costs the same as current pilot project estimates and doesn't increase in cost for the next 30 years a new coal plant the size of Peabody's Southern Illinois plant will have a life cycle cost of about 16 billion dollars.

The life cycle cost for generating the same total energy using current technology utility scale solar thermal will be closer to 8 billion.

No wonder financial institutions have put loans for 50 proposed new coal plants on hold----.