Sushanta Mitra, University of Alberta
Coal is cheap and dirty, yet remains a critical part of electricity generation in North America and around the world. While Canada is heavily reliant on hydro-power, with coal making up only 17% of generation, just under half the United States’ energy generation comes from burning coal. For China, the proportion is a staggering 70%. This opens the door for innovative research into how we can more efficiently and cleanly burn this energy-rich and relatively abundant resource.
Dr. Sushanta Mitra, working at the University of Alberta, is researching a process by which microbes could be used to convert coal seams into natural gas which can then be collected from borehole wells. Dr. Mitra explains, “what happens is, we have natural microbes called methanogens which are available in coal seams.” These micro-organisms exist in different environments all over the world, including wetlands, hydrothermal vents, or within our own digestive systems. What Dr. Mitra and his team are working on is, “how can we use these natural microbes to augment the process of converting the coal into methane, and other value-added products?”
Techniques based on the process being researched by Dr. Mitra and his team could not only cut down on the environmental damage caused by mining, but could also enable mining companies to gain access to energy reserves that would otherwise be economically unfeasible for extraction. Coal that is near the surface is often strip-mined, leading to vast swaths of land being permanently altered or destroyed, depending on the efficacy of reclamation efforts. Deep mining is energy-intensive, expensive, and dangerous. This sort of bioconversion process could be a game changer for the coal mining industry.
“The advantage of this kind of technology is if you have an un-minable coal seam where the source is there, but you are unable to use it in a meaningful way.” With this process, mining firms could extract energy from coal seams that would otherwise be technically or economically unfeasible. This also enables extraction of “low-grade coal, lignites, sub-bituminous coal,” explains Dr. Mitra, “we can trap the energy of these carbon molecules and make some value.”
Pumping coal-eating organisms underground, however, isn’t as easy at it may sound. “The idea is to use wells to pump in nutrients and increase the pore space so there is enough room to transport the nutrient and the biochemical.” This is where Dr. Mitra’s expertise comes into play. He explains, “coal is a complex, porous media, all the way from nanometer to micrometer, to even bigger cracks and fractures. The transport of materials through this media, and the interaction of microbes with the solid substrate, is very interesting.” Anyone worried that we may be polluting our bedrock with bioengineered microbes can rest easy, as Dr. Mitra explains, “there are no risks as we are not providing any engineered microbes.” These are microbes that already exist within coal seams; this process simply adds more and gets them excited.
While there are some other teams and companies working on bioconversion or similar technology, it is still very much the cutting edge. As Dr. Mitra explains, “University of Alberta is trying to look at the energy and technology landscape, for example the national institute for nanotechnology is housed within the university. The faculty of engineering is very strong, interdisciplinary research is very strong.” When they began to look at the problem of bioconversion, they “immediately realized there has to be a multidisciplinary team.” Like many efforts working toward the low-carbon economy, Dr. Mitra and his team are made up of researchers and engineers from a range of fields with varied expertise. “It is a multi- and cross-disciplinary process that will lead to answers on the physical process of bioconversion.” Dr. Mitra continues, “if you look at the way the research enterprise is going, looking at core innovation models, this is more the norm rather than exception: a large group working toward big game-changing technology.”
Many will argue that we should not be using coal at all, but Dr. Mitra argues that for the foreseeable future, it is here to stay. “I feel the coal is still there in 50-70 years, all across the world, not only Canada,” he says. The difference will be moving away from burning the coal in a power plant. “This brings a new angle, a new mix into the possibilities – the advantage is you are using a more clean, more benign, less environmentally impactful way to extract the energy combined in this carbon bond. We want to unleash that energy in a more sustainable way.”
The potential for bioconversion and the work being done by Dr. Mitra and his team is vast, as coal remains the main source of energy production around the world. “This tech is very pertinent in the global perspective, if we are successful in a big way it brings Canada to the forefront of ‘leapfrog’ or game changing tech. I think we can be a global leader in trying to understand this kind of complex process.”