Why clean coal is a dirty lie: simple science explained

July 9, 4:40 PMPopular Science ExaminerAsta Gindulyte

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Greenpeace activists hang banners on the tower of a coal-fired power plant in Italy,
calling on the Group of Eight summit to take the lead in fighting climate change.
  (AP Photo/Max Frigione)

The phrase "clean coal" has been repeated by politicians so frequently, that average people should not  be blamed for believing in it. And if politicians didn't convince them, they might have been tricked by clever public relations campaigns run by coal producers. Yet any scientist, who does not happen to be paid by the coal industry, will agree that there is no such thing as clean coal. The scientific explanation behind this is surprisingly straightforward.

Coal is an easily combustible rock composed mainly from carbon and various hydrocarbons. It comes in varying grades, however, and depending on where it's mined, it can also contain  different amounts of noncombustible ash and rock. Sulfur, mercury, and other nasty pollutants are usually present as well.

Environmental pollution is caused by both mining and burning coal. Coal mining causes release of carbon dioxide and methane (both greenhouse gases) as well as toxic dust, acid rain, water pollution, and the list goes on. When coal is burned, the main pollutants released into the atmosphere are carbon oxides, sulfur oxides, and nitrogen oxides. And then there are waste products like arsenic, led, mercury, and so on.

The so called clean coal technologies can roughly be classified into two categories:

1. technologies focused on purifying the coal by removing sulfur and various other non-carbon pollutants before burning it;

2. technologies that try to capture carbon and sulfur oxides produced while burning the coal.

The first type of technologies would reduce the pollution from non-carbon based pollutants, but would do nothing to address global warming. Supposing that coal was composed of nothing else, but carbon and hydrogen, which would make it the cleanest, highest grade coal out there, burning it would still result in massive carbon dioxide emissions, and carbon dioxide is the main culprit of global warming. The reaction of burning carbon is C + O2 → CO2 (carbon dioxide), it's as simple as that. If one wanted to produce carbon dioxide, burning coal would be the way to do it.

The second type of technologies would seem to address the carbon dioxide emissions problem, but the big puzzle is what to do with all the captured carbon dioxide gas. Storing it somewhere is not a practical solution. Sure, it can be liquefied, but it would still need to be stored somewhere. There are all kinds of research projects focused on trying to use up the carbon dioxide by feeding it to bacteria or plants, for instance, which is great. Yet the world burns so much coal, that there is no technology on the horizon which could offer a way to capture and get rid of a good portion of the carbon dioxide that is produced.

While one might think that there is no harm in pursuing the technologies which could reduce the pollution caused by mining and burning coal even by a small amount, that is not quite true. The problem is that none of those technologies have been proven on a large scale and would take many years to implement. In the meantime, while excuses to keep burning coal are being made, the global warming is accelerating. Worse yet, the "clean coal" technologies come with exorbitant price tags. Often at the taxpayer expense.

Common sense would dictate that the taxpayer money could be much better spent in pursuing the clean energy technologies that already exist. Like building solar panels and investing in wind energy. Yet the coal industry is trying to protect it's status quo, and the politicians are going along with it. It's not a big surprise, of course, as politics is full of dirty lies, and clean coal is just one of them.