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.
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 (1952-2021), was an author and inventor who shined a powerful light on numerous environmental and technological topics. His work appeared in TriplePundit, GreenBiz, Justmeans, CSRWire, Sustainable Brands, Grist, Strategy+Business, Mechanical Engineering, Design News, PolicyInnovations, Social Earth, Environmental Science, 3BL Media, ThomasNet, Huffington Post, Eniday, and engineering.com among others . He was the co-author, with Roger Saillant, of Vapor Trails, an adventure novel that shows climate change from a human perspective. RP was a professional engineer - a prolific inventor with 53 patents and President of Rain Mountain LLC a an independent product development group. RP was the winner of the 2015 Abu Dhabi Sustainability Week blogging competition. RP passed away on September 30, 2021. We here at TriplePundit will always be grateful for his insight, wit and hard work.
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