Blog 109. Is clean coal clean?

The concept of “clean coal” has been newsworthy for a decade or more.  In 2009, Senators John Kerry (D-MS) and Lindsey Graham (R-SC) co-authored an op-ed in the New York Times, promoting renewable energy, nuclear energy, and “clean coal.”  Presidential candidate Trump touted “clean coal” during a debate.  Can coal, the dirtiest of fossil fuels, ever be made clean?  That’s seems as likely as senators of opposing parties learning to talk to each other again.

Coal is mostly carbon plus impurities, and when you burn carbon you get carbon dioxide (CO2), the dominant greenhouse gas that induces climate change.  The U.S. government has supported several projects to actually build electric power plants that capture most of the carbon dioxide (greenhouse gas) that comes from burning coal.

Well, the “clean coal” plants haven’t developed very well, and Senators won’t talk across party lines, either.  These two disappointing elements of negative progress are actually linked.  Keep reading.

How does the “clean” part work?

The CO2 must be captured at the power plant and compressed* into tanks or a pipeline, then injected deep into the ground.  The CO2 can be sold for injection into oil fields where it increases the oil production in the same way a solvent makes sticky tar flow, or the CO2 can be injected into a deep salt water reservoir where the cap rock will prevent its escape.  (For an overload of methods and info, see the International Journal of Greenhouse Gas Control.)

Enhanced oil production by CO2 injection is a well-developed, profitable technology.  However, after the oil is gone, will the plugged injection wells and the hundreds of thousands of abandoned oil extraction wells remain tight for many centuries?  A few wells only 30-50 years old have been examined, and only a little corrosion was found.  Some leaks might plug themselves.  A group within the International Energy Agency is studying the how old wells decay, because a lot of work is required to estimate future CO2 leakage.

Even if it worked technically, any effective conversion to “clean coal” would require an injection infrastructure of a scale similar to that of the current entire oil industry.  Coal-fired power plants in the U.S. now generate more than a billion tons of CO2 per year, with one estimate indicating that the daily injected volume in the U.S. would exceed the current national daily rate of oil consumption.  Furthermore, the carbon-removal process would require that every power plant consume 25 percent more coal for the same net power generation.  It’s good to investigate, but “clean coal” doesn’t appear to make economic or technical sense.

However,  “clean coal” makes tremendous political sense …

… because the coal miners and the mines are being put out of jobs and business by the new flush of cheap natural gas—and it’s easy to blame the job loss on environmental protection.  In response, the coal industry does its lobbying well and the money flows to politicians if not to miners.  Maybe we have to fix politics before we can fix climate.

Our decision about energy will test the character of the American People and the ability of  the President and the Congress to govern this Nation.”
President Jimmy Carter, April 18, 1977

* at pressures exceeding 100 atmospheres (1500 psi)

One thought on “Blog 109. Is clean coal clean?

  1. Veronica Palmer ·

    Thanks for the information. Some of this I already knew but I wasn’t aware of the injection aspect. I also agree with you that until our government, (our leaders in government), recognize their ultimate duty and responsibility to the People and not the corporations, there isn’t much hope anything will change.

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