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with government backing. Newly available forms of gas and 33 on a mass-to-mass basis for 20 and 100 years appear to offer a 50% reduction in carbon emissions — respectively. The authors also stated: "Summing all compared with electricity generation from coal, meaning _ estimated losses, we calculate that during the life cycle of an most countries could easily meet their 2020 emissions average shale-gas well, 3.6 to 7.9% of the total production of targets—agreed at the 2009 Copenhagen climate the well is emitted to the atmosphere as methane... This is conference—at a fraction of the expense of investingin wind, at least 30% more and perhaps more than twice as great as solar and renewables."’ This statistic is based onthe burning the life-cycle methane emissions we estimate for of pure methane, and does not take into account the other conventional gas, 1.7% to 6%." They went on to say: disastrous environmental impacts and all the greenhouse "Considering the 20-year horizon, the GHG footprint for shale gases released during the entire production and _ gasisat least 20% greater than and perhaps more than twice consumption cycle. It seems the "new definition of green" is as great as that for coal when expressed per quantity of just about the ratio of carbon dioxide to energy produced __ energy available during combustion... Over the 100-year when you burn a fuel. frame, the GHG footprint is comparable to that for coal..." Essentially they are saying that carbon dioxide is the only None of these estimates includes accidents, emergency pollutant that we should concern ourselves with. This events or well and ground leakages. contorted perspective can possibly be blamed on the intense In addition, the Cornell study compared oil with shale gas: interest in and the politicisation of "global warming" as the “For the 20-year horizon, the GHG footprint of shale gas is at biggest environmental threat to mankind. What is the point least 50% greater than for oil, and perhaps 2.5-times greater. of stopping the temperature from At the 100-year time scale, the rising if, in the meantime, we have footprint for shale gas is similar to poisoned our waterways and “The large GHG footprint or 35% greater than for oil." This polluted our air with noxious raises an_ interesting chemicals that do not biodegrade of shale gas undercuts the question: when are electric cars and are in our environment to actually greener? stay? logic of its use as a bridging The authors concluded: “The In 2010, the US EPA issued a fuel over coming decades large GHG footprint of shale gas report® stating that natural gas . . v undercuts the logic of its use as a extracted using fracking releases if the goal Is to reduce bridging fuel over coming greater amounts of methane than global warming.” decades, if the goal is to reduce conventional "natural gas" mining. global warming." They finished The authors of a 2011 Cornell their report by stating: University study’ commented: "Finally, we note that carbon- "The new EPA (2010) report notes that the 1996 ‘study was trading markets at present under-value the greenhouse conducted at a time when methane emissions were not a —_ warming consequences of methane, by focusing on a 100- significant concern in the discussion about GHG _ year time horizon and by using out-of-date global warming {greenhouse gas] emissions’ and that emission factors from potentials for methane. This should be corrected, and the the 1996 report ‘are outdated and potentially understated for full GHG footprint of unconventional gas should be used in some emission sources’. Indeed, emission factors presented planning for alternative energy futures that adequately in EPA (2010) are much higher, by orders of magnitude for consider global climate change." some sources.” The Cornell study has seriously challenged the assumption — Underground Coal Gasification that shale gas offers a 50 per cent reduction on burning coal. The method used to extract natural gas from coal seams The authors considered the whole process from extraction to hat are economically unviable to dig out of the ground, is consumption of the gas, i.e., not only the direct emissions of | underground coal gasification (UCG). One method involves CO: from the end-use consumption but "indirect emissions igniting a coal seam underground and pumping out the of CO2 from fossil fuels used to extract, develop, and partially burned gases that result. When the natural transport the gas" as well as the GHG footprint of the — permeability of the coal is low, the coal will have to be hydro- methane that escapes during extraction and transport of the ractured by a similar process as that for shale." gas. They noted: "Methane is a far more potent GHG than is Where the Great Artesian Basin exists “a well has to be CO, but methane also has a tenfold shorter residence time drilled through aquifers to coal beds deep underground. The in the atmosphere, so its effect on global warming attenuates _gas is trapped within the seams and held in place by water more rapidly...". They also wrote: "Recent modeling pressure. To release the gas first the water has to be pumped indicates methane has an even greater global warming ‘o the surface. Then the gas can flow.” potential than previously believed, when the indirect effects In Australia, we have an abundance of coal seams, so these of methane on atmospheric aerosols are considered methods above are used. Where the Great Artesian Basin (Shindell et al. 2009"""')." They calculated the global warming exists, the water table has been seriously depleted making potential of methane compared to CO: at a staggering 105. = more and more farmland unviable. The release of pressure an of shale gas undercuts the logic of its use as a bridging fuel over coming decades, if the goal is to reduce global warming.” Underground Coal Gasification The method used to extract natural gas from coal seams hat are economically unviable to dig out of the ground, is underground coal gasification (UCG). One method involves igniting a coal seam underground and pumping out the partially burned gases that result. When the natural permeability of the coal is low, the coal will have to be hydro- ractured by a similar process as that for shale."! Where the Great Artesian Basin exists “a well has to be drilled through aquifers to coal beds deep underground. The gas is trapped within the seams and held in place by water pressure. To release the gas first the water has to be pumped ‘o the surface. Then the gas can flow.”® In Australia, we have an abundance of coal seams, so these methods above are used. Where the Great Artesian Basin exists, the water table has been seriously depleted making more and more farmland unviable. The release of pressure NEXUS ° 13 “The large GHG footprint AUGUST - SEPTEMBER 2011 www.nexusmagazine.com