Source: The New York Times, April 9, 2013
In their op-ed “The Facts on Fracking” (Views, March 14), Susan Brantley and Anna Meyendorff use a highly speculative estimate of the gas supply in the Marcellus shale of Eastern America that prevailed for years at the U.S. Energy Department. Using actual results from drilled wells, in 2011 U.S. government geologists slashed the Energy Department figures by about two-thirds.
The writers’ more troubling claim is a well failure rate of “1 to 2 percent.” Last fall, researchers at Cornell University compiled data from Pennsylvania regulators’ reports to confirm failure rates due to faulty cement and/or casing of 6 to 8.9 percent each year since 2010. These were wells just completed, from which methane could migrate into the atmosphere as a green-house gas or contaminate aquifers.
Methane in aquifers has found its way into homes via water wells. Many American families have seen their property values vaporize and their homes rendered unlivable. Drilling companies have settled numerous lawsuits.
Earlier industry studies suggest that over time, cement or casing in half the wells drilled may eventually fail. While calamities from leaky wells are unusual — small comfort if it affects your drinking water, or the water in your favorite stream — let us recognize the magnitude of risk: More than 6,000 wells have been drilled in Pennsylvania, with 100,000 planned. A dozen states have industrial drilling.
Paul Roberts Friendsville, Maryland
Winemaker and citizen representative on a state commission studying shale gas development in Maryland.
The writers respond:
We, like Paul Roberts, are seeking facts and sometimes facts are hard to find with respect to Marcellus issues.
Roberts criticizes several points that we make. First, he calls our statement that the Marcellus formation could contain 500 trillion cubic feet of gas “highly speculative.” However, given current data availability, all estimates are at the level of speculation. In 2009, the U.S. Energy Department estimated that the Marcellus shale may contain as much as 1,500 trillion cubic feet of gas, but usually only about 10 to 30 percent of the gas is recoverable using today’s hydrofracking technologies.
As Roberts points out, 500 trillion cubic feet of gas was estimated by the Penn State geologist Terry Engelder. The estimate is for the technically recoverable reserve, or T.R.R. This represents not just the gas in place but rather that which is likely to be produced from the shale. In other words, it takes into account today’s technology. The T.R.R. was also estimated by the Energy Department in 2011 at 400 trillion cubic feet.
All of these estimates are speculative, since they are assessments of how much gas we can recover from a reservoir at a depth of thousands of feet in a field that underlies more than 100,000 square miles in parts of eight states.
To date, most of the drilling has occurred in only two states — Pennsylvania and West Virginia — and until 2010 Pennsylvania embargoed release of certain kinds of production data. Even today the state controls the data release. Our point in citing 500 trillion cubic feet was to emphasize the fact that the reservoir is large, and we stand by our statement that the Marcellus shale could contain this quantity. The release of additional data will make future estimates less speculative.
Roberts also questions our estimate of a 1 to 2 percent rate of cement or casing construction problems in wells, this based on estimates from engineers in the field. Since we wrote our article, we went back to the Pennsylvania Department of Environmental Protection data online for Notices of Violations in Marcellus wells and calculated a casing/cement problem rate of about 3 percent between 2008 and March 2013. We don’t know of any higher published estimates for casing construction problem rates, but we note that a higher apparent rate can be gleaned from the data if repeats in the data set are not removed.
Cornell researchers have raised considerable concern about loss of methane during natural gas drilling and production, and this is both a valid concern and another area where additional data are welcome. As we stated in our op-ed, we need these facts so we can understand and make decisions about fracking relative to other energy sources such as coal.
We agree with Roberts that methane has sometimes found its way into water wells and that property values have at times been harmed by various incidents. No one should neglect these risks. Like most industrial processes, fracking can have negative environmental consequences, and communities and governments must assess these risks by looking at the facts — which, however, are not always easy to obtain.
Water quality issues, when they happen, often are litigated and the data are removed from public scrutiny. When water wells or surface waters are tested by industry, the data are often not released; likewise, homeowners often do not want to release their well water analyses. Many people in Pennsylvania are cooperating on the shalenetwork.org database. We need these facts and many of us are seeking them.
But in seeking the facts we may also find that shale gas has advantages over other energy sources such as coal. For those of us who live in states in the Marcellus region, development of this resource may occur in many cases right in our backyards. Are we ready for that?
Many would prefer to import energy from someone else’s region and export the environmental problems to someone else’s backyard. Maybe it’s more ethical to use our own energy and be faced with our own environmental consequences. If we don’t like the local consequences, we must demand regulations. But turning away from fracking without seeking the facts is neither the smart nor the ethical choice.
Susan L. Brantley
Distinguished professor of geosciences and director of the Earth and Environmental Systems Institute at Pennsylvania State University.
Faculty associate at the International Policy Center of the Ford School of Public Policy at the University of Michigan.