There has been little research about the public health impacts of living near unconventional natural gas extraction activities. Rabinowitz et al. a (2015) aimed to assess a possible relationship by generating a health symptom survey of 492 people in households with ground-fed wells in an area of active natural gas drilling. The survey looked at the household’s proximity to gas wells and then the prevalence and frequency of reported dermal, respiratory, gastrointestinal, cardiovascular, and neurological symptoms. The study found that individuals who lived within 1 km of a gas well were twice as likely to experience upper respiratory systems than individuals in households more than 1 km away. No relationship found between well proximity and any of the other possible health conditions that this survey covered. Continue reading →
Our newest book just Released! “Energy, Biology, Climate Change” and available at Amazon.com for $19.95.
The focus of this book is the interactions between energy, ecology, and climate change, as well as a few of the responses of humanity to these interactions. It is not a textbook, but a series of chapters discussing subtopics in which the authors were interested and wished to write about. The basic material is cutting-edge science; technical journal articles published within the last year, selected for their relevance and interest. Each author selected eight or so technical papers representing his or her view of the most interesting current research in the field, and wrote summaries of them in a journalistic style that is free of scientific jargon and understandable by lay readers. This is the sort of science writing that you might encounter in the New York Times, but concentrated in a way intended to give as broad an overview of the chapter topics as possible. None of this research will appear in textbooks for a few years, so there are not many ways that readers without access to a university library can get access to this information.
This book is intended be browsed—choose a chapter topic you like and read the individual sections in any order; each is intended to be largely stand-alone. Reading all of them will give you considerable insight into what climate scientists concerned with energy, ecology, and human effects are up to, and the challenges they face in understanding one of the most disruptive—if not very rapid—event in human history; anthropogenic climate change. The Table of Contents follows: Continue reading →
Hydraulic fracturing is considered controversial for many reasons, including the possible negative environmental impacts, the possible economic benefits of development, and reduction of reliance on foreign oil. Previous national opinion polls have indicated that a sizable minority of the population lack familiarity with this largely unregulated field. Boudet et al. (2014) studied different socio-demographic indicators will predict support of or opposition to hydraulic fracturing. Continue reading →
Directional drilling and hydraulic-fracturing technologies are dramatically increasing natural-gas extraction across the United States. Hydraulic fracturing remains largely unregulated at the Federal level regardless of the growing concerns about contamination of drinking water. However, the potential contamination risks in shallow drinking-water systems are still not fully understood, and a topic of study for many scientists. There are four main reasons why scientists and public health officials are concerned about methane contamination in the ground water: that the chemicals use in fracturing fluid can leak into the ground water, that the water can become explosive if methane levels are high enough, that the methane could be released into the environment, and that the untested and unregulated shallow ground water in rural areas near drilling sites could be ingested during household or agricultural use. Scientists have continued to study whether water wells are being contaminated in any of these ways by hydraulic fracturing and drilling. Continue reading →
The long term environmental concerns having to do with shale gas development are primarily greenhouse gas (GHG) emissions and freshwater consumption, as other forms of environmental degradation can be remediated over time. Ian Laurenzi and Jersey Gilbert (2013) of the ExxonMobile Research and Engineering Company performed a life cycle assessment (LCA) of both GHG emissions and freshwater consumption of Marcellus shale gas. The life cycle begins with well drilling and ends with burning the fuel for power generation. Using their elaborated system boundaries, the researchers found that a Marcellus shale gas well releases 466 kg of carbon equivalent units per megawatt hour of power produced (kg CO2eq/MWh) and consumes 224 gallons of freshwater per megawatt hour of power produced (gal/MWh) over the course of its lifetime. The biggest contributor to both GHG emissions and freshwater consumption is power generation. The result of this study are highly dependent on the variables chosen to represent the shale gas well life cycle, especially the expected ultimate recovery of natural gas. Despite the potential for variability of results, the result of 466 CO2eq/MWh is consistent with other published life cycle assessments for conventional and shale gas, and almost all of the 14 other studies fall within the 10%–90% range of 450–567 CO2eq/MWh. Even considering factors that can increase total results, this study shows that average GHG emissions from shale gas are 53% lower and freshwater consumption is 50% lower than what is required for an average coal life cycle. Continue reading →
If one of the big advantages of using supercritical CO2 rather than water for fracturing shale is that it effectively disposes of the CO2 by absorption onto the shale (Middleton et al. 2013—see Jan 13 post), some experimental evidence would be useful. This is provided by Lafortune et al. (2014) who obtained a sample of shale from a Mesozoic marine basin in France, dried and crushed it, put it on an ultrasensitive balance, and flooded it with CO2 at various pressures and temperatures. The highest pressure was 9 MPa (90 bar, or 90 times atmospheric sea level pressure) and the highest temperature 328 K (131ºF), just at the combination of temperature and pressure at which CO2 becomes supercritical (see figure). This is only about a tenth of the pressure sometimes achieved in actual hydraulic fracking, and probably a somewhat lower temperature than normally used, but might be all that is necessary when using supercritical CO2. The higher the temperature the less CO2 adsorbed onto the shale so that the observation by Middleton et al. that temperatures of supercritical CO2 drop suddenly at the shale when the pressure is released augur well for increasing CO2 adsorption. There was a nearly linear increase in the amount of CO2 adsorption onto the shale with pressure, with no sign of leveling off at the pressures these experimenters used, so that too suggests an effective means of both sequestering CO2 and releasing methane, although the adsorption was not as high as it would have been on coal, someplace else it might be profitably sequestered. Continue reading →
The purpose of hydraulic fracturing is to use high pressure to open up pores in deep fuel-bearing shale deposits so that the oil or natural gas can escape through boreholes to the surface. To make this work, very high pressures (hence, much surface equipment) and a great deal of water are required. To keep the pores propped open when the pressure and water recede, something (usually sand) needs to be included. The inclusion of acid can increase pore efficiency, and because water is a good biological medium, antibacterial agents may be required to prevent fouling. Finally, most of the fracking fluid returns to the surface where it presents a treatment and disposal problem. But in theory, any liquid, or supercritical substance, would work, supercritical CO2, for example. According to a study underway at Los Alamos National Laboratory (Middleton et al. 2014) sCO2 has a number of potential advantages over water, and some potential disadvantages as well. Continue reading →
Shale gas development physically and chemically alters the surrounding landscape, and native plants and animals can be particularly susceptible to these changes. In the Marcellus and Utica shale region—a largely forested area that encompasses the states of Pennsylvania, Ohio, and West Virginia—shale gas wells are being drilled with increasing density. A shale gas installation, including the well pad, compressor station, and storage areas, requires 3.56 ha on average. If an edge effect is considered, installations can affect approximately 15 ha of forest per site. Kiviat (2013) reviewed the potential ways that shale gas development can impact biodiversity. The most serious threats are physical alteration of terrestrial landscapes, chemical contamination of water and soil, and alteration of regional hydrology. Terrestrial alterations include construction of well installations, which cause deforestation and habitat loss, and construction of roads and pipelines, which create forest fragmentation. Chemical contaminants come from fracturing fluid and recovered wastewater. Hydrologic alterations are caused by water withdrawals and an increase in impermeable surfaces. Minor impacts on plant and animal health can come from noise, light, and air quality. Certain species are particularly at risk from shale gas development activities and some are able to thrive in the altered conditions. Continue reading →
Stephanie Kurose, a law student at the American University in Washington DC, calls our attention to both the concept of, and two startups trying to push, micro-tracers which could be injected into fracking fluid so that if it escapes, we know whodunit. The idea is simple, if not yet operational; create some long-lived non-toxic chemical compound with enough potential variation that a different version could be mixed in with the fracking fluid for each individual well. The arguments for it, espoused by Kurose, are equally simple; drilling companies would know if they had a problem with leakage and could change their technology, falsely-accused drilling companies could exonerate themselves, and the public should feel much less angst about fracking if evidence of leaked fracking fluid fails to materialize (or vice versa.) It might be that drilling companies would resist in order to avoid any conclusive evidence that their wells have leaked, but so far no one knows because suitable tracers have yet to be deployed. The two startups giving it a shot are BaseTrace and FracEnsure. Continue reading →
How long will shale gas be available until it plays out? The Bureau of Economic Geology (BEG) at the University of Texas at Austin is making a concerted effort to find out for the four largest shale plays currently in development in the US. The first they reported on was the Barnett Shale in Texas. The topic of this post is their second study, conducted on the Fayetteville (Arkansas) Shale by John Browning and eleven colleagues at the BEG. The overall answer is a long time—but well short of a century—with production peaking soon and falling to between half and a third of the current levels by 2030 and continuing to decline thereafter; they ran their model through 2050 and estimate the technically recoverable gas resources if economics were not an issue (38 trillion cubic feet), and the amount likely to be recovered eventually given economic reality, about half that. Continue reading →