Tuesday, November 20, 2007

Geologic CO2 sequestration?

A friend of mine sent me a review of geologic CO2 sequestration in Australia and the United States. Quite interesting, very upbeat. I'm not buying it.

I think costs are a big problem here. Powder river basin coal costs $5/ton at the mine mouth, and by the time it gets to the various powerplants, it's anywhere from $9/ton to $30/ton. The coal burned is about 75% of the cost of electricity generated, if you believe these guys. That means, in summary, the costs of electricity in the U.S. are driven by the costs of transporting coal from mine to powerplant via rail.

Zoom on the loopy thing at the bottom, that's a friggin COAL TRAIN at the mine mouth for what I think may be the Black Thunder mine in Wyoming. These mines are operating at gigantic scale and are very efficient. Coal transport is handled by two competing train operators who are also efficient.

View Larger Map

Now for the problems with sequestration: CO2 weighs about 44/12 = 3.7x as much as the coal that it came from. Right there, big problem. More mass to move costs more.

Worse still, you can't just transport CO2 in an open coal car on a railroad. Instead, you have to cool it (costs energy, capital equipment, access to water or some heat sink, etc), compress it (this costs energy and some capital equipment), then pump it through a high pressure pipeline. That's going to cost more than moving the coal did.

So, if the CO2 is useful for something, like oil or gas extraction with a result worth $0.25/pound or more, then that value can cover a lot of transport costs for the CO2. But if not, the transport cost of the CO2 from powerplant to sequestration site will come to dominate the cost of electricity in the U.S. And I think that any fix for the coal addiction we have now will have to be something that makes electricity for less money, not more.

Anyone want to argue that CO2 pipelines are going to be at least 4x cheaper than coal trains, or that deep CO2 sequestration is going to be more conveniently located than coal mines?

P.S. Southern California's scheme of having a mine-mouth powerplant ship electricity to beautiful people far away from the black stuff is just stupid. Transporting electricity is way more expensive than transporting coal. The scheme only makes sense because beautiful people are willing to pay extra to have their powerplants well downwind and out of sight. It's only a matter of time before Mexico wakes up to this fact and builds a bunch of nuke plants in Tijuana to ship the power across the border.

1 comment:

  1. Geologic Issues

    I agree. I like the idea, but I don't think we will ever be able to get the injection rates high enough to make a dent in what we put into the air. Also, the long term affects of injecting CO2 into the ground are currently unknown. CO2 + Water = carbonic acid which eats through some types of rock. It is likely that sequestration as a means of reversing global warming will be scrapped in the next few years unless the government ignores the recent scientific data. For now lots of people have jobs because of all the research being done to determine if sequestration is even possible on a large scale.