Hydraulic fracturing versus surface coal mining: Is one safer for the environment than the other?
A new study is attempting to provide some data for the debate.
First, some background on the reason for the question – it goes beyond the fact that Hollywood actor Matt Damon just made a movie about the subject.
Hydraulic fracturing technology may have shed some of its many outspoken foes, but it’s still an uphill struggle to gain acceptance in many areas.
New York, for example, continues to say no to the technology, while neighboring states such as Pennsylvania are on board, helping to boost the domestic energy supply while enriching the state coffers considerably.
Proponents claim that even though hydraulic fracturing entails underground high-pressure injection of great volumes of water mixed with proppants and various chemicals, it’s been used safely by the industry for many years. Critics claim it does indeed contaminate ground water, although they’ve yet to prove their case conclusively.
Disposal of the wastewater generated by the fracturing procedure also has come under attack by various individuals and organizations – and those criticisms are increasingly becoming a focal point in the dynamic.
In light of all of the fuss over the past couple of years, then, comes an ongoing project that seeks specifically to compare the potential harm of hydraulic fracturing to that of surface coal mining, which is yet another major power-generating fuel source.
Brian Lutz, who recently departed Duke University to become assistant professor of biogeochemistry at Kent State University, is busy at work on this issue.
“The work I do is sort of at the interface of energy extraction of the environment and understanding environmental impacts,” Lutz said. “We’ve mostly been working on surface coal mining and hydraulic fracturing.”
Getting the Whole Story
Just don’t expect to get an either-or from this effort.
Lutz noted that rather than attempting to deliver a concrete answer to whether surface coal mining is better or worse than hydraulic fracturing, the work is more focused on how to develop a framework by which the environmental impacts can be put into comparable units in order to compare the tradeoffs.
“It’s not a black and white message,” he emphasized.
“It’s essentially a back-of-the-envelope calculation we’ve performed using the general strengths of our existing knowledge,” he said, “and substantial uncertainties remain in some key areas.
“It allows us to estimate total water pollution load that could potentially come from coal mining as well as from hydraulic fracturing, and then convert these to similar units of energy.”
Natural gas has a much smaller greenhouse gas footprint, and Lutz noted that’s a quantifiable framework that’s pretty clear-cut.
The research team is trying to move environmental impacts of the extractive side to a similar framework where they can begin to put numbers to wastewater pollution loads of each of these resources.
“When thinking about the water quality impacts of each of these different energy extraction practices, they’re very different,” Lutz said.
“With hydraulic fracturing, the wastewater load is generated from the well and it’s a containable wastewater volume,” he noted. “But with surface mining, the wastewater load is generated in-situ from precipitation interacting with the mined spoil.
“In the mining landscape, you have precipitation every year, and in hydraulic fracturing you get a pulse of water back shortly after the well is turned on,” Lutz said.
“There’s a different temporal dynamic to each,” he pointed out. “Hydraulic fracturing is much more of a one time deal, with mining generating this pollution load every year.”
He did note that hydraulic fracturing produces less wastewater per unit energy than conventional natural gas production in the Marcellus region.
Lutz summarized the issue overall.
“Both mountaintop coal mining and hydraulic fracturing can have substantial environmental impacts,” he emphasized. “Nevertheless, we must make decisions about what resources we are going to rely on to meet our energy needs.
“In doing this, we need to recognize that there are real tradeoffs between these different energy extraction practices,” Lutz noted, “and we can’t evaluate their environmental impacts in isolation.
“This is about trying to put their environmental impacts into comparable units so that informed decisions can be made about our energy future.”