Hydraulic fracturing produces less wastewater per unit of gas – but more overall.
Article courtesy of Aurana Lewis, Lutz and Doyle | January 22, 2013 | oilandgasonline.com | Shared as educational material only
Hydraulically fractured natural gas wells are producing less wastewater per unit of gas recovered than conventional wells would. But the scale of fracking operations in the Marcellus shale region is so vast that the wastewater it produces threatens to overwhelm the region’s wastewater disposal capacity, according to new analysis by researchers at Duke and Kent State universities.
Hydraulically fractured natural gas wells in the Marcellus shale region of Pennsylvania produce only about 35 percent as much wastewater per unit of gas recovered as conventional wells, according to the analysis, which appears in the journal Water Resources Research.
“We found that on average, shale gas wells produced about 10 times the amount of wastewater as conventional wells, but they also produced about 30 times more natural gas,” said Brian Lutz, assistant professor of biogeochemistry at Kent State, who led the analysis while he was a postdoctoral research associate at Duke. “That surprised us, given the popular perception that hydraulic fracturing creates disproportionate amounts of wastewater.”
However, the study shows the total amount of wastewater from natural gas production in the region has increased by about 570 percent since 2004 as a result of increased shale gas production there.
“It’s a double-edged sword,” Lutz said. “On one hand, shale gas production generates less wastewater per unit. On the other hand, because of the massive size of the Marcellus resource, the overall volume of water that now has to be transported and treated is immense. It threatens to overwhelm the region’s wastewater-disposal infrastructure capacity.”
“This is the reality of increasing domestic natural gas production,” said Martin Doyle, professor of river science at Duke’s Nicholas School of the Environment. “There are significant tradeoffs and environmental impacts whether you rely on conventional gas or shale gas.”
The researchers analyzed gas production and wastewater generation for 2,189 gas wells in Pennsylvania, using publicly available data reported by industry to the state’s Department of Environmental Protection, in compliance with state law.
In hydraulic fracturing, large volumes of water, sand and chemicals are injected deep underground into gas wells at high pressure to crack open shale rock and extract its embedded natural gas. As the pace of shale gas production grows, so too have concerns about groundwater contamination and what to do with all the wastewater.
Another surprise that emerged, Doyle said, was that well operators classified only about a third of the wastewater from Marcellus wells as flowback from hydraulic fracturing; most of it was classified as brine.
“A lot of attention, to date, has focused on chemicals in the flowback that comes out of a well following hydraulic fracturing,” he said. “However, the amount of brine produced – which contains high levels of salts and other natural pollutants from shale rock – has received less attention even though it is no less important.”
Brine can be generated by wells over much longer periods of time than flowback, he noted, and studies have shown that some of the pollutants in brine can be as difficult to treat as many of the chemicals used in hydraulic fracturing fluids.
“We need to come up with technological and logistical solutions to address these concerns, including better ways to recycle and treat the waste on site or move it to places where it can be safely disposed,” Doyle said. “Both of these are in fact developing rapidly.”
“Opponents have targeted hydraulic fracturing as posing heightened risks, but many of the same environmental challenges presented by shale gas production would exist if we were expanding conventional gas production,” Lutz added. “We have to accept the reality that any effort to substantially boost domestic energy production will present environmental costs.”
The Marcellus shale formation stretches from New York to Virginia and accounts for about 10 percent of all natural gas produced in the United States today. Much of the current production is in Pennsylvania. Prior to technological advances in horizontal well drilling and hydraulic fracturing that made the shale gas accessible, the region accounted for only about 2 percent of the nation’s output.
Lutz and Doyle conducted their analysis with no external funding.
Aurana Lewis, who graduated in 2012 with a master of environmental management degree from Duke’s Nicholas School, co-authored the paper.
SOURCE: Duke University
Really? – Shale Gas Fracking uses a lot of water? – Really!
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Kai Olson-Sawyer is a Senior Research and Policy Analyst in the GRACE Water and Energy Programs. Prior to joining GRACE, Kai was employed at the World Forestry Center in Portland, Oregon and researched with NYC Apollo Alliance. Kai received a Masters in sociology with an environmental focus from The New School for Social Research, and a B.A. from Earlham College. He holds the Water Footprint Network Certificate of the Global Water Footprint Standard. His body is composed of 60 percent water. Visit Kai Olson Sawyer @ Linkedin
The Word on Fracking in the U.S.
Article courtesy of Kai Olson Sawyer | July 8, 2013 | The Word on Fracking in the U.S. | Shared as educational material only
If hydraulic fracturing, or fracking, wasn’t already the hottest topic on the energy front, then it’s now firing up with the arrival of summer. The month of June witnessed a number of major fracking-related events by different states in the U.S. and even the world, including…Read Post
Fracking uses water, and a lot of it: But what might that water use mean for you and your community? See the infographic below to learn more.
Do you know where North America’s largest shale-gas hydraulic fracturing (fracking) operations are? Texas, Wyoming or Pennsylvania? No. It’s Canada’s Horn River Shale Formation, located in northeastern British Columbia. Performing that frack job is oil and gas production giant Apache Corporation, which lauded its own immense size and scale: “When all was said and done, the completions team performed 274 successful fracs on the 16-well pad, using 50,000 tons of sand and 980,000 cubic meters of water.” (That’s over 250 million gallons of water!)
Apache and its partner, Encana, made sure to “celebrate” this achievement of oil and gas engineering within the company, while touting its prowess throughout the industry and the Canadian government.
But Apache representatives were sedate during an October 2011 hearing before the United States Senate Committee on Energy and Natural Resources’ Subcommittee on Water and Power. During the hearing, Apache executive Dr. Cal Cooper showed greater interest in the more typical fracking operations that take place in the United States, ones that are much smaller than in the Canadian super-frack job.
What explains Apache’s change in tune before the U.S. Senate panel? In a word: water.[toggle title=” Water – the essential ingredient ” height=”auto”]
Water – the essential ingredient
Water is the main ingredient in fracking fluid, comprising over 99 percent of the total with the remainder a mix of undisclosed, proprietary chemicals. The quantity of water required for a typical frack job is around 4.5 million gallons, of which a substantial amount — approximately 10 to 40 percent — “flows back” to the surface as toxic wastewater. That’s right, 4.5 million gallons are pumped into the ground and up to a million gallons of toxic water flow back up (or the amount of contaminated water equal to the annual water use of up to seven households)!
With so much water involved in fracking, it makes sense that the American public is apprehensive. National polls show that ensuring adequate supplies of clean freshwater is an overwhelming environmental concern. No wonder the oil and gas industry is sensitive about fracking’s water use and have sought to downplay the importance of water by essentially saying, “Don’t worry; it’s not really that much.” But such niceties don’t satisfy critics, so industry has to find ways to justify its heavy water use.
One of the industry’s most common strategies is to emphasize how fracking water use is some fraction of the one percent slice of the “mining, oil and gas” industries’ compared to dominant American water withdrawers like thermoelectric power plants, agriculture and public water supplies [PDF]). Another common justification is what gas giant Chesapeake Energy does by taking the 4.5 million gallon figure and comparing it to other water use examples. For example, drawing comparisons to the amount of water needed to supply New York City for seven minutes or irrigate 7.5 acres of corn in a season.
But such standard comparisons between fracking and other water uses must be drying up because Apache’s Cooper offered a new, more sophisticated line of argument in his testimony:
…[I]t seems especially pertinent for this committee to consider the water budget of energy from shale gas compared with other sources…Natural gas, from both shale gas and conventional reservoirs requires less water per MMBtu of energy generated from combustion than any other common fuel. (PDF)
Hmm. Water requirements per heat energy unit (MMBtu)? Fuel-type comparisons? Cooper’s favorable argument for shale gas is compelling because in such a life cycle analysis — where the entire process is assessed from extraction to power plant combustion — water requirements are lower in comparison to certain fuel types. In addition, the popularity of natural gas relies, in part, on its reputation as a “bridge fuel” — the fossil fuel that will lead to a renewable energy future because it’s cleaner burning, emits less greenhouse gas and uses water less intensively in certain steps of the process. However, substantial debate exists about its presumed life cycle environmental benefits. Cooper conveniently avoids real and legitimate water resource impacts associated with fracking, as summarized in the list below:
- Quality over quantity. In other words, if water is contaminated by the fracking process, then it is either taken out of use or costs money, energy and even more water to remediate the situation. Externalities anyone?
- Glaring omissions [p. 12]. The analysis conveniently leaves off low to no-water renewable electricity technologies, like solar PV and wind.
- Cumulative impacts. The number of gas wells is expected to increase over time. More wells mean more water.
- Recycling is not a panacea. This is mainly because the waste that accumulates in recycled fracking wastewater is never eliminated but concentrated, and ultimately requires disposal. Plus, recycling wastewater requires — guess what? — more water, and more energy.
- Water is consumed. Much of the water used for drilling or fracking is taken out of the water cycle entirely.
- The nature of water. Even as part of the global water cycle, water is experienced locally and is site-specific.
The local dimension of water undermines industry’s water use claims
Cooper openly acknowledges that “[w]ater is a local resource and withdrawal must be managed on a local basis to ensure that the ecological health of riparian systems and the needs of other major users are met.” He notes the historically severe drought in Texas and Oklahoma, where oil and gas companies had to adjust their fracking methods because of decreased water availability and competition with other users, like farmers. This is a constant concern throughout arid western states with active shale gas plays, like Colorado and Wyoming.
If a well site has inadequate water resources, a fairly common problem, water has to be transported via tanker trucks to fill impoundments over the course of hundreds or thousands of visits. Finally, there is the thorny issue of toxic fracking wastewater and its storage, reuse and disposal.
Local differences can explain, in part, the differences between how Apache represented itself regarding the Canadian super-frack operations versus the restrained tone of Dr. Cooper’s testimony before the Senate panel. The Horn River Shale is located in a remote section of British Columbia, far from any population centers. Additionally, the enormous volume of water used for the super-fracking was done with brackish water unsuitable for drinking, and wasn’t a direct draw on freshwater supplies.
On the other hand, fracking in the United States, especially in the Marcellus Shale region, tends to occur in more densely populated areas where it can come into conflict with local water uses like drinking and irrigation. As fracking spurs the proliferation of natural gas wells around the U.S., water-related issues will continue to impact water quantity and quality for both ground and surface water. These local impacts are where the true fault lines lie in the struggle over fracking.
The debate over whether the millions of gallons used for a frack job is outsized might be appropriate within a larger discussion of national water use. But the discussion about water resource impacts of fracking must be a local one. In changing the unit of analysis from the water needed for drilling and fracking at the well site to a more general “water for fuel-type,” Cooper’s argument bypasses localized impacts, where they are felt most intensely and where water use is amplified. Wherever you go, 4.5 million gallons is a lot of water, particularly if in your backyard. That’s a fact that doesn’t change no matter how the industry attempts to minimize it.
4.5 mil. Gal. water usage – One frack job infographic
(h/t Amy Hardberger, Texas EDF and Nicholas Kusnetz, ProPublica)
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