Carbon Capture and Storage: To Be or Not To Be? Or, To Partially Be?
Posted Mar 30 2009 3:22pm
by Richard T. Stuebi
One of the more contentious questions in the cleantech community is the role of coal in the energy sector of the future. There's a lot of coal in the world -- many decades of supply left -- including here in the U.S. It's pretty darned cheap to mine. So, it would be great to figure out a way to use it in non-harmful ways.
And there's the rub: it's a pretty nasty fuel. Putting aside the issue of how to mine coal in an environmentally-acceptable manner, coal is one of the most highly carbonaceous of hydrocarbons, meaning that it generates a lot of carbon dioxide per unit of energy released when burned -- much more so than oil or natural gas. As a result, the worldwide use of coal -- primarily for power generation -- is the largest component of global carbon dioxide emissions, which in turn is the most important of the greenhouse gas emissions contributing to climate change.
In the arena of climate change, coal is therefore the main culprit. Not the only culprit, to be sure, but the main one.
For coal advocates, the first line of defense is to dismiss the climate change issue outright. That tactic is still used, but is becoming increasingly untenable under the Obama Administration, which appears to be remaining steadfast in pushing for climate change legislation.
That leaves the coal industry in the position of promoting new approaches for coal utilization wherein the carbon dioxide produced from combustion is somehow prevented from being released into the atmosphere. The most well-known of these approaches is termed carbon capture and storage, or CCS.
The idea behind CCS is intellectually appealing, if a bit fantastic: extract the carbon dioxide from the exhaust stream of a powerplant, and inject the carbon dioxide underground in such a way that it stays entrained in the earth. The technological concepts are pretty well-understood.
Alas, as this article in the March 7 issue of The Economist shows, the main challenge associated with CCS is the cost. CCS has never been undertaken at a large-scale at any powerplant, much less attempted for a fleet of powerplants, because the capital and operating costs of a CCS system are seen to be so high as to be daunting.
As with many things in life, a half a loaf is better than none, and so may be the case with CCS. As indicated in this article in the March/April issue of Technology Review, perhaps the economic challenges can be tackled by biting off something less than 100% carbon capture and storage.
Many environmental advocates can't stand the concept of coal utilization in any guise, and decry the use of the phrase "clean coal" as an oxymoron. I don't think we can afford idealistic dogma, but neither do I think we can afford the environmental cost of unlimited conventional coal use. There's got to be a middle-ground somewhere.
In the energy and environmental realm, I have consistently found in my 23 years of experience that there is rarely a perfect solution to any situation, and everything involves tradeoffs. Partial CCS might yield an outcome in which neither the green community nor the coal/power industry get all of what they want, but produces a far better result than the "worst-case" scenario each side fears.