Clean Coal: Pros and Cons


Let’s face it, coal is nasty stuff. It contaminates everything it comes in contact with and creates problems at every step of its life cycle: from unhealthy and unsafe underground mines, to the environmental catastrophe of mountaintop removal, to the problems associated with handling the enormous piles of ash that are produced every day. But by far, the biggest problem is the enormous amount of carbon dioxide emitted. According to the EPA, coal contributes 31 percent of all CO2, the largest of any source.

The people who still support coal basically have one argument: that it’s a necessary evil, being the only source of energy within reach that is sufficiently abundant to keep up with our enormous and ever-growing appetite for energy. We have so much coal, they reason, and we need so much energy, how could we not take advantage of this resource? They could be right, as much as those of us who care about the environment hate to admit it. As much as we would like to believe that conservation, efficiency and renewables will meet our growing, but maybe-not-growing-quite-so-quickly demand, there is certainly no guarantee that they will. Considering that coal accounts for 40 percent of all electric generation (down from 45 percent) and 21 percent of all energy in the US, that’s a lot of energy to replace. Of course, with falling natural gas prices, that is clearly picking up a lot of the slack.

Meanwhile, renewables accounted for just over 10 percent of electric power in 2010, and most of that was from existing hydropower.

If that’s not bad enough, coal powers 70 percent of China’s electric grid, which is growing far faster than ours and shows no sign of slowing down. In fact, the only thing keeping them from increasing coal generation even faster is their limited ability to physically move the stuff. Together, the US and China are responsible for 33 percent of global greenhouse gas emissions.

The other thing about coal is, of course, that it’s cheap, usually cheaper by far than other energy sources, largely because so many of its true costs are still being externalized. It is worth noting that wind at 5-6 cents per kWh is closing the gap.

Given the reality of climate change, any talk of coal must be clean coal, an approach which enables the utilization of our most abundant domestic energy resource so that at least the impact on the climate is minimized. (To put this in perspective, note that the total amount of energy we received from coal in 2010 is equal to the amount of sunshine over the same period, hitting just 460 square miles. If we adjust for the low efficiency of solar PV (17 percent at the low end), then that number goes up to 2706 square miles, well below 0.1 percent of the land area of the US, though we are nowhere close to capturing all of that any time soon.)

Clean coal has a number of variations, but all of them involve stripping the CO2 out of the coal, either before or after it is burned and then capturing it. It is then either utilized for industrial purposes or for enhanced oil recovery, or else it is pressurized into a liquid form where it can be injected underground where it supposedly will stay indefinitely in a process called carbon sequestration. The overall process is called carbon capture and storage (CCS).

No sequestration project existing or proposed removes all the CO2 from the exhaust, because of the high energy penalty for doing so (30 percent or more). Most of them bring the CO2 level down to that of natural gas. Canada has already banned the development of any new coal generation project that does not include CCS.

No doubt the least destructive form of clean coal is underground coal gasification (UCG). This is where the coal is left in the ground and converted to gas by chemical means and then sucked up to the surface where it is burned. Most of these projects include capturing the CO2 and then sequestering it as described above. Pilot plants have been run in China, and the Swan Hills plant is supposed to come online this year in Alberta, Canada.  In the US, the Texas Clean Energy Project, outside Odessa, which received $450 million in DOE funding, will apply UCG, capturing 90 percent of the CO2 and then using that CO2 for enhanced oil recovery in nearby Permian Oil Basin. This approach eliminates most problems associated with coal mining, transportation and burning, leaving only the problems associated with sequestration and gas extraction to be grappled with.

With that background, here are the pros and cons of clean coal.


  • Abundant supply, concentrated in industrialized countries (US, Russia, China, India).
  • Relatively inexpensive.
  • Continuous power. Good utilization. High load factor.
  • Substantial existing infrastructure. Mature industry.
  • Can be made low carbon and clean with CCS and various scrubbers.
  • Can be converted to a liquid or a gas, which burn cleaner.
  • Clean coal technology is currently being used in China.
  • Relatively low capital investment (compared to gas or nuclear).


  • Coal is nonrenewable. There is a finite supply.
  • Coal contains the most CO2 per BTU, the largest contributor to global warming.
  • Severe environmental, social and health and safety impacts of coal mining.
  • Devastation of environment around coal mines.
  • High cost of transporting coal to centralized power plants.
  • Coal ash is a hazard and a disposal problem.
  • Coal mining is the second highest emitter of methane, a potent greenhouse gas.
  • High levels of radiation. Coal plants release more radiation than nuclear plants.
  • Coal burning releases SOx and NOx which both cause acid rain.
  • Burning coal emits mercury and other heavy metals that pose major health risks.
  • Coal emissions linked to increased rates of asthma and lung cancer.
  • Sequestration is new, expensive and its ability to hold CO2 for long periods of time is unproven. Risk of accidental releases of large quantities of CO2.
  • Clean coal is not carbon free.
  • Significant energy penalties are incurred for sequestration.
  • CO2 is toxic at concentrations above 5 percent. The condition is called hypercapnia.

The true costs of coal are not included in what is paid today. Coal would not be competitive if environmental costs were included. When the costs of mitigating these impacts through CCS and UCG are factored in, it will not be competitive against renewables. However we might still need to use it in some localities to meet our ever-growing demand. But with natural gas coming in just as cheap, and with the same level of GHG as Clean Coal, it’s not at all clear that these investments are justified. But there’s no reason I can think of that the same capture and storage technologies that were developed for coal, couldn’t be used in natural gas plants to bring them down to zero carbon.


What about other energy sources?

[Image credit: Marc Wathieu: Flickr Creative Commons]

RP Siegel, PE, is the President of Rain Mountain LLC. He is also the co-author of the eco-thriller Vapor Trails, the first in a series covering the human side of various sustainability issues of energy (including clean coal), food, and water. Now available on Kindle.

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RP Siegel

RP Siegel, author and inventor, shines a powerful light on numerous environmental and technological topics. His work has appeared in Triple Pundit, GreenBiz, Justmeans, CSRWire, Sustainable Brands, PolicyInnovations, Social Earth, 3BL Media, ThomasNet, Huffington Post, Strategy+Business, Mechanical Engineering, and among others . He is the co-author, with Roger Saillant, of Vapor Trails, an adventure novel that shows climate change from a human perspective. RP is a professional engineer - a prolific inventor with 52 patents and President of Rain Mountain LLC a an independent product development group. RP recently returned from Abu Dhabi where he traveled as the winner of the 2015 Sustainability Week blogging competition.Contact:

24 responses

  1. Coals low cost energy is the only thing this country can afford honestly. Not to mention the thousands of jobs coal mining provides. I would suggest you come up with a cleaner energy source that can be produced cleaner and as cost effective. when you figure this out then you would also need to create as many jobs as youve destroyed. Then you could prevent putting all those miners families out on the street because you panicked over rumors. Truth be told coal is cleaner than some of these “experts” will lead you to believe. Before you assume that natural gas burns cleaner, I would suggest you do a liitle better research. China is in fact not the only mines using these new scrubbers. Many if not all US mines use them.

  2. Coal’s health care related costs run up to $.18/kwh, or 500 billion dollars/year (Harvard Medical School study). Its pollution causes premature deaths of at least 24,000/year (American Lung Assoc.)

    O, and then there’s just a chance almost all the world’s climate scientists might be on to something with climate change.

    Coal miners are on the whole hard working, honest and sincere and have helped us for centuries by increasing our national wealth. However, given the serious negatives I described, miners should be retrained and rehired as part of a pivot to modern forms of energy generation.

  3. hello what are u talking abou and our teacher is sdoing good he know what her is talking about say he dont mr bolton knows what hes talking abou because febuary 18 2015 today he is teaching us and what are u talking about it is dead

  4. Coal is still the cheapest , most affordable & reliable energy source for power generation.
    There are still 1.3 billion people living without access to electricity, in particular for third-world or some developing countries.
    Renewables are clean but unreliable due to its intermittency limitation & high infrastructural cost.
    Coal cannot be immediately eliminated as there are no replacement yet.

    We need a disruptive solution that limit coal power plants emission without affecting its efficiency.

  5. Yes, what we need is for those in the Coal industry (e.g. coal mining, power plants, etc.) to find out how to minimize damage, for them to control their use of coal and the effects to the surrounding environment; us, animals, Earth. They need to find out how to keep the damage from spreading. In other words they need to be smart if they don’t want to kill any more of us and the Earth.

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