The Energy Grid

Just as using controlled thermonuclear fusion to generate electricity is based on a natural process at the heart of the sun, so carbon sequestration is basically an accelerated version of the natural tendency of the planetary ecosystem to bury organic matter. That process put several trillion tonnes of carbon deep under the surface of the earth over hundreds of millions of years. What we're now talking about is putting it back there many orders of magnitude faster. And that will take energy.

And at the end of the day, the fundamental question that will determine whether or not we can actually afford to capture and sequester the carbon that constitutes a significant portion of the emissions produced by burning coal, oil and gas is how much energy will it take. Or, to put it another way, how much efficiency will we lose by requiring power plants to capture and lock away the carbon?

Unless the efficiency is such that it's still cheaper to burn coal, oil or gas than clean, renewable alternatives, then it doesn't make sense.

Still, if it's just a matter of improving efficiency levels of a technology based on well understood principles, then why should we treat CCS any differently from photovoltaics, which still costs about five times as much as coal-fired electricity? Because photovoltaics are coming down in cost rapidly. CCS, which uses concepts at least as old as solar panels, shows no signs of following a similar path. Consider the example of the Mountaineer coal-fired power plant in New Haven, W.Va., which is being equipped with demonstration CCS technology:

Of the 8.5 million metric tons of carbon dioxide emitted annually by the Mountaineer plant, only 100,000 to 300,000 will be removed with the new technology. And American Electric and the maker of the technology, Alstom, are spending $100 million on the initiative -- a daunting expense for some producers. (New York Times, Feb. 15, 2009)

So, under an unrealistic best-case scenario, capturing 90% of the carbon dioxide (a typical maximum for any CO2-scrubbing mechanism, CCS will add about $2.5 billion to the cost of the power plant, more than tripling the cost. Even if this can be cut in half, we're still talking about making coal far more expensive than it is today. No viable cap-and-trade mechanism or carbon tax will make that kind of investment attractive, not in the next few decades, which brings us to the timing issue.

There's a widespread consensus that we need to starting bringing down global emissions within the next six years, and that by 2025, they should be down by at least 25-40%. By 2050 they should be down by 80 or 90 or even 100 percent (1990 or 2005 levels -- take your pick; it's really not that important). And given the glacial pace at which CCS technology is improving, by the time it's ready we'll either have already stopped burning fossil fuels or it will be too late to do anything about the consequences to the climate of doing so.

Note also that no one's talking about applying CCS to non-point sources of greenhouse gases, like automobile tailpipes. Only large-scale stationary power plants are viable candidates to incorporate the technology. And even then, most power plants won't be attractive thanks to their location, far enough from geologically appropriate places to put the carbon to make expensive pipelines necessary.

Furthermore, capturing carbon doesn't address the serious environmental damage done by decapitating mountains, a common practice in the coal-mining business.

Add it all up and the prospects for CCS just don't look good. Not when existing clean alternatives, such as solar (concentrated thermal and PV), wind, geothermal and hydroelectric, offer so much more for much smaller investments. While it's probably wise to continue spending a few million dollars per annum researching the possibilities of CCS, there are many other things that should be higher on our priority list.

In case you're still interested, here's a web journal devoted to the subject. Lots of positive spin there, but read between the lines and there's no reason to start celebrating.