From coal to Coke: the improbable path

"If we don't solve the coal problem, we cannot solve the climate problem" said Princeton physicist Robert Williams to Science in a recent interview.

Climate's biggest challenge

As China keeps putting two new coal-fired power plants online each week and the 600 coal facilities of America are responsible alone of roughly 30% of the 7 billions metric tons of CO2 emitted each year (more than the emissions of all the cars and other industries of the country combined), coal looks indeed more and more like one of the biggest challenge of the climate issue.

The trouble with coal is that no one really wants to get rid of an energy source which is four to five times more abundant than oil, cheap and for once ideally distributed among developed countries (1) instead of being found in improbable locations plagued with chronic political instability.

But as the idea of a near-term cap on carbon dioxide emissions gains support in America, the industry of the by-far-dirtiest-of-all-fossil-fuel (2) is submitted to more and more intense scrutiny. This sudden awareness has prompted a rising interest in the currently only known solution to the coal-fired plants emissions problem: the carbon capture.

Carbon capture: a simple concept plagued with technical challenges

In theory, carbon dioxide capture is pretty simple: one grabs the CO2 emitted by the coal combustion before it gets vented into the atmosphere. But the concept is actually tricky. Current off-the-shelf technologies need at best to be submitted to a thorough improvement if the plant is still supposed to be profitable.

The technique that would be the easiest to implement on most existing plants consists in using a molecule called monoethanolamine (MEA) to bind the CO2 right after the coal combustion and thus to separate it from the other gases emitted by the plant. But in order to capture 96% of the plant's CO2 emissions, 40% of the energy previously sold to the public would have to be used... which would raise the electricity bills by 36% or more! With improved efficiency, the technique should still not permit the capture of 90% of the CO2 emissions without cutting the net output of the plant by 30%.

From coal to Coke

And even if the technical problems got solved, a daunting question still remains: what are we going to do with all this CO2? The coal-fired plant of Warrior Run in Maryland found an interesting answer to this question: the 5% of its CO2 emissions that actually get captured are sold to beverages gas distributors and then incorporated in your Coke. Too bad that no one seems to have realized that unless the Coke bottle is never open, the CO2 that has been so painfully trapped is going anyway to take a short cut to the atmosphere...

(1) Coal known reserves are found in the United States (25.4%), the ex-URSS (23.4%), Europe (12.4%), China (11.6%) and India (8.6%).

(2) For the same amount of energy produced, coal emits 25% more CO2 than oil and 40 to 50% more CO2 than natural gas.

Sources:
Making Dirty Coal Plants Cleaner, Science, 13 July 2007, pp. 184-186
Le Plein s'il vous plait! by Jean Marc Jancovici and Alain Grandjean

Photo: itsgettinghotinhere.org/tag/uncategorized/