"Clean" Coal for Christmas

Coal is dirty.

Really, really dirty.

Like, filthy dirty.

Coal, when it's mined from the Earth, is chock full of fun - mostly in the form of toxic heavy metals like mercury, lead, arsenic, and (my nemesis) cadmium. So the first time I heard the phrase "clean coal" I was a bit puzzled. Did the energy folks discover a vein of naturally pure coal? Has combustion technology improved to the point that greenhouse gas emissions are no longer an issue?

No, of course not.

The "clean" in clean coal refers only to soot emission. When a representative from the National Federation of Coal or whatever shady private think-tank is defending it today refers to cleanliness, what they really mean is "a minimum of heavy metals are released into the atmosphere as a consequence of burning."

It's a classic trick of industry. Sell a product as clean by sweeping the waste under the rug, or move it somewhere that people don't care about.

It's a shell game! Guess who the losers are.

So where do all the heavy metals go? Conservation of matter can't be defeated by a clever PR campaign.

(Let's leave off the colossal environmental damage and human cost of mining, for now. It's Christmas, and I don't want my little story to be too depressing.)

First, the coal is washed. Literally. Crush the coal in a solvent like water with a pinch of detergent, and most of the metals are leached out. Next, the coal is burned in a plant that has an active scrubber system. Residual nasties are either precipitated as solids back into the furnace or trapped in a filter. If everything's going as planned, all you have belching forth at the end is perfectly clean, harmless greenhouse gases.

Oh, but you're left over with a heavy metal slurry from the washing, and a toxic, radioactive ash. Fortunately, that can be swept under the rug. Out of sight, out of mind.

At least until fate decides that your town is naughty, and decides to dump more than 23 million gallons of the stuff down your collective stockings. Right now, only 400 acres of land have been contaminated, but this is a larger spill than the Exxon Valdez disaster (about 11 million gallons).

So the next time you see an ad for "safe, reliable clean coal technology," remember what it looks like.