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jshell wrote: ron wrote:
It's business, just like everything else. Opponents to Frac'ing are just sticking their heads in the sand and believing a bunch of scare stories. Frac'ing will happen, we will see the benefits and it'll cost very little in terms of people or environment. It's a low carbon option and reduces our dependence on French Nuclear through the interconnect, not to mention it's a stable source of clean, abundant energy. It's water, sand/glass beads and normal drinking water biocide for the most part.
Bring it on! :-)
The development of unconventional gas deposits is an energy-intensive undertaking. The enormous amounts of heavy equipment needed to pump water and create adequate drilling pressure required to extract gas from shale produce significant emissions. The construction of well pads, the collection of water and disposal of wastes all entail transportation-related emissions. Much of the production on an unconventional well pad, such as horizontal drilling and hydraulic fracturing, is powered by polluting diesel engines.[13]
The Tyndall Centre for Climate Change Research estimates that CO2 emissions from gas drilling amount to 15 kg CO2 per foot drilled from diesel powered engine use alone.[14] Well depths in the Marcellus Shale, which are remarkably deep, can reach up to 8,000 feet vertically and another 11,000 feet horizontally.[15] A total well length measuring 19,000 feet would produce 285,000 kg (285 metric tones) of CO2 from diesel engines alone. When calculating associated CO2 emissions, unconventional wells are set apart from conventional wells for two reasons: extended well distance due to horizontal drilling and, more importantly, hydraulic fracturing.
Hydraulic fracturing, the Tyndall Centre reports, is the main source of CO2 emissions from unconventional gas drilling. Heavy CO2 emissions are linked back to the engine-powered fracking process, including the blending of fracturing chemicals and sand that are pumped from storage, and the high-pressure compression, injection and recovery of materials into and out of the well.[16]
After calculating key CO2 emissions from shale gas extraction, the Tyndall Centre estimates that a single well drilled once for unconventional gas will emit somewhere between 348-438 metric tonnes of CO2. As high as this figure is, it only reflects a portion of CO2 emissions and does not account for the entire spectrum of greenhouse gas (GHG) emissions from unconventional gas drilling.
Beyond the issue of CO2 emissions, there are mounting concerns regarding gas’ main component: methane. Fugitive methane is an enormous additional source of GHG emissions from gas drilling.
According to a recent lifecycle analysis performed by a team of Cornell University scientists led by Professor Robert W. Howarth, unconventional gas—particularly when it is extracted from shale using hydraulic fracturing methods—is likely to present an even greater climate disruption threat than coal and oil, the other dirty fossil fuels. Due to the substantial methane emissions from extraction, processing and transport, unconventional gas may have a greater overall GHG impact than previously understood.
Howarth and his coauthors maintain that when these lifecycles aspects are considered “the large GHG footprint of shale gas undercuts the logic of its use as a bridging fuel over coming decades, if the goal is to reduce global warming.”[17]
The most recent analysis conducted by Howarth’s team at Cornell, recently published in the peer-reviewed scientific journal Climatic Change Letters, states that on a 20-year time horizon “the GHG footprint for shale gas is at least 20% greater than and perhaps more than twice as great as that for coal when expressed per quantity of energy available during combustion.”[18]
Professor Howarth calculates that the extraction, processing and transport of natural gas, when considered in tandem with methane leaks, places natural gas ahead of other fossil fuels in terms of total greenhouse gas emissions. “The take home message of the study” says Professor Howarth, is “if you do an integration [study] of 20 years following the development of the gas, that shale gas is worse than conventional gas and is in fact worse than coal and is worse than oil.”[19]
The Cornell team has cautioned politicians and industry against a large-scale switch to natural gas, warning that the scramble to develop unconventional gas reserves without considering the full impact of the process could bring dire consequences for the global climate. The predicted increase of gas production in the US has some analysts worried that gas will not substitute for other dirty fuel sources like coal, but will instead be used in addition to other sources, further contributing to growing total fossil fuel consumption.[20] Despite rapidly increasing domestic production rates, some industry leaders admit that the US, due to ever increasing energy demands, will continue to be a net importer of gas.[21] The Cornell study does not provide a definitive answer on the methane issue, but it raises enough concerns to warrant both an immediate moratorium on issuing new fracking permits to gas companies and the urgent need for further study.
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