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The Perennial Power of Coal: New Directions from an Old Challenge

by Kathryn G. Arlen

Getting the most for one's money [or as much possible output for your input] is more than a basic economic doctrine: that simple phrase has become a philosophical mantra for much of a democratic Western society. Recent field-tested research by University of Alaska Fairbanks Department of Mining and Geological Engineering's faculty, coordinated and documented by Associate Professor Rajive Ganguli, has successfully substantiated this principle by applying it to the more productive, energy-conservation use of harder, bituminous coal, such as found in both Alaska and Powder River Basin near Gillette, Wyoming.
Ganguli et al.'s research focused on a basic combustion science hypothesis previously postulated and advocated by the U.S. Department of Energy: that coarsely grinding hard coal would generate the same amount of electricity as a finer, more extensive, grind.

“The theory existed, as the DOE had conducted some studies, and we said, 'Hey, there are indicators that this theory is true,'” Ganguli began explaining. “'Let's test it on a real scale, on a large scale,' which we did in the Healy [Alaska] power plant to see if the high volatile coal, and that's the key part, the high volatile content coal...could we burn the coal coarser than the standard size and see if there's a loss of combustion? And there was none.” He added that his team also investigated emissions and discovered this process created no further emission problems: “That's important as well.”

While low in sulfur, Alaska's harder coal is highly volatile. With coarser grinding as a larger particle enters the combustion chamber [see diagram] “...the volatile content causes it to explode [to attain the desired effect]...you are ‘getting more for your money.' You're basically fine-grinding it, but not spending money on it. Normally you would keep grinding until [the particle] came to this size, [diagram] but you stop before that and the rest of the work is done by the volatile content of the coal,” Ganguli explained.

Of critical importance to this large scale field test conducted at Healy (the only pulverized coal plant in Alaska, about 100 miles SW of Fairbanks) was significant cost savings. “When more [unnecessary] grinding is going on, you are simply wasting money,” the professor/engineer pointed out, “And just in Healy, a very small power plant at about 25 megawatts, we found that by grinding less we are saving about $56,000/year...Some of the larger plants at 200 megawatts--they'd probably save more.” Ganguli also stressed how this successful research can directly apply to the Powder River Basin (Wyoming) coal based on its similar composition to Alaskan coal.

“That coal is similar to this coal here, but this study was never done there before on this scale. This study is unique because nobody anywhere, as far as we know, had ever tested the theoretical concepts in a power plant in the field, actually putting it to work,” Ganguli continued. As coal from that region presently comprises about 30-40% of our nation's coal supply, our main source of electricity, savings there could also become significantly actual and not just theoretical.

Agreeing that coal has virtually become “invisible” to the average American, Ganguli emphasized the relevance, viability, and practicality of our continued responsible research and development of this valuable natural resource. Even though the ongoing search for alternative energy resources is vital, “It would be stupid to rule out coal in the energy mix,” he reasoned. Statistics reflect that 50% of electricity generated in the U.S. comes from coal, and total electricity demand is expected to grow at a rate of 39% by the year 2030. In time, hopefully sooner than later, the estimated 160 billion tons of Alaskan coal deposits, more than half the nation's supply, will play a significant role in meeting more efficient energy demands.
Considering all these critical factors, “This research is about grinding less, energy savings, and energy efficiency,” Ganguli summarized.”Second, it's about jobs. We probably will end up selling more coal because of this, which means more jobs in today's economy, and that's great.” He has already published two papers on this collective faculty research: the first appeared in the Journal of Fuel Processing Technology and explained primary theoretical concepts before field research began and prior to funding received from the Arctic Energy Technology Developmental Lab. The Minerals and Metallurgical Processing Journal published his second paper, developed as ongoing field studies substantiated the initial combustion theories. Now that the project is complete, he is wrapping up research and preparing his final paper.

One of the most beneficial aspects of this project is the “way it keeps giving,” as Ganguli described.
In addition to selling more coal and creating more jobs, maintenance costs will also decrease: “We did not quantify savings from maintenance because it's tough to quantify, but we know that if you grind less, then you absolutely are going to be saving more money on maintenance...electricity is easier to quantify.”
But the bottom line and “...actually the main reason we did this study to begin with is to remove the 'handicap,' to identify this 'grinding handicap,' to alleviate and remove that, if you will....I want to let others know, especially the Pacific Rim countries, that Alaska coal can be burned, and to help export our coal,” Dr. Ganguli concluded. He and his faculty's work have already made a serious, positive impression at the recent Taiwan Trade talks, particularly with the CEO of Taiwan Power.

Please visit Dr. Ganguli's website at www.faculty.uaf.edu/ffrg