Natural gas has many environmental benefits over coal as a fuel for electricity generation. It also has advantages over electricity and traditional heating fuels in the industrial, commercial and residential sectors, and over gasoline as a fuel for the transportation industry. Because natural gas has the lowest carbon content of all fossil fuels and is not a mixture of other carbon containing compounds with inorganic impurities, it is the cleanest "burning" fossil fuel, with lower emissions of sulfur, metal compounds, and carbon dioxide.
Producing natural gas from shale by hydraulic fracturing, or “fracking” has some environmental, safety and health risks, though the degree of these is the subject of much debate. Fracking is a current hot button issue, almost as pervasive as the subject of Climate Change. Both topics give rise to highly polarized groups with strong unwavering sentiments, and both groups are mirrored by disbelievers basing opinions on perception and anecdotal information rather than facts.
One common accusation is that various government officials, the commercial sector, or the scientific community have a vested interest in hiding the truth. To some degree this may be a valid statement. Yet there are some reputable, independent and impartial studies that can be used to understand the issues.
Fracking Is Nothing New
One often-ignored fact is that fracking is not a new technology. It was developed in the earliest days of oil exploration, when nitroglycerin was used to stimulate shallow hard rock wells. Although extremely hazardous and often illegal, nitroglycerin was highly useful for fracturing oil-bearing formations to increase flow and recovery. The same principle was later applied to water and gas extraction.
The modern fracking process, which uses water and sand with chemical additives, can be traced to 1947 when Stanolind Oil conducted the first experimental fracturing in the Hugoton field in Kansas. Since 1949, close to 2.5 million fracking operations have been conducted worldwide.
Advances in fracking technology have made extraction of natural gas from deep (5,000-10,000 feet) shale layers commercial viable. Natural gas is tightly bound in the dense shale layers, and therefore hard to release. Fracking creates fissures in the rock and keeps them open for a sustained outflow of gas. When used in conjunction with horizontal drilling, more of the shale layer is exposed to the fracking fluid. This dramatically increases the yield of natural gas and shifts the economics to a much more favorable position.
Environmental Concerns Not Trivial, Not Apocalyptic
The controversy over fracking centers around the environmental impact and consequent health and safety concerns. These are not trivial issues and should not be dismissed out of hand. Fracking is subsurface, high pressure, water intensive, and employs chemical additives. All of this sets the stage for potential groundwater contamination.
What can be reliably said of fracking comes from the MIT Energy Initiative study, The Future of Natural Gas, which was released last June. This study was a multidisciplinary effort carried out by a team of faculty, staff and graduate students with input from a board of 18 leaders from industry, government and environmental groups.
Some of the key findings:
- Only 42 documented incidents of water contamination were found out of tens of thousands of wells drilled.
- The environmental impacts of shale development, while challenging, are still manageable.
- In the few cases where there has been contamination, the cause was improper cementing of the well casings.Improving the quality of well casing cementing is a key challenge for the industry.
The fracking process uses 3-5 million gallons of water per well. Fracking fluid is a proprietary slurry mixture consisting of no less than 98% water and sand; the remaining 2% or less includes a variety of chemical additives, most of which are in common use with little or no health risks. Though several are classified as toxic or hazardous, only one—ethylene glycol (a component of automotive antifreeze)—can be harmful or fatal if swallowed. The toxic or hazardous substances with their health risks (from their Material Safety Data Sheets) are listed below:
- Glutaraldehyde: Hazardous in case of skin contact (irritant), of eye contact (irritant), of ingestion, of inhalation (lung irritant, lung sensitizer).
- Ammonium persulfate: Harmful if swallowed.
- N,n-dimethyl formamide: Hazardous in case of skin contact (irritant, permeator), of eye contact (irritant), of ingestion, of inhalation.
- Ethylene glycol: Harmful or fatal if swallowed, harmful if inhaled or absorbed through skin, may cause allergic skin reaction, may cause irritation to skin, eyes, and respiratory tract, affects central nervous system.
Greenhouse Gas Concerns Can Be Addressed
Another concern with shale gas is the impact on local air quality and the release of greenhouse gases into the atmosphere. Methane is a potent greenhouse gas with the ability to trap heat almost 21 times more effectively than carbon dioxide. Consequently, although methane emissions account for only 1.1% of total U.S. greenhouse gas emissions, they account for 8.5% based on global warming potential.
Potential emission sources include compressor engine exhausts and oil/condensate tanks, production equipment, well drilling and fracking engines, well completions, gas processing, transmission, and the large number of supporting components such as pumps, flanges, valves, gauges, pipe connectors, compressors, and other pieces.
Still, a 2011 study by researchers at Carnegie Mellon University comparing greenhouse gas emissions from the Marcellus Shale region with emissions from coal used for electricity generation found that wells in the Marcellus region emit 20-50% less greenhouse gases over their lifecycle. Another study at Southern Methodist University detailed various readily available and cost-effective control strategies that can substantially reduce emissions, and in some cases, costs:
- "Green completions" to capture methane and volatile organic compounds (VOC) during well completions.
- Electric motors instead of internal-combustion engines to drive compressors.
- Control of VOC emissions from condensate tanks with vapor recovery units.
- Replacement of high-bleed pneumatic valves and fittings on the pipeline networks with no-bleed alternatives.
Sensible Regulation, Sensible Development
Other public-policy steps can help minimize the environmental, safety, and health risks of shale gas extraction. Some options include:
- Intensifying on-site oversight.
- Closing loopholes that exempt fracking from key federal air and water environmental regulations.
- Toughening up the permitting process.
- Ensuring production companies follow industry best practices.
- Implementing more air and water testing and requiring drillers to disclose chemical additives used in the fracking fluid, which up to now was consider a trade secret.
- Developing new rules over for disposal of waste water.
- Identifying cost-effective emissions control procedures.
Aside from the environmental and health issues, the economic benefits from shale gas production are substantial. The shale gas boom is predicted to have profound economic impacts on the U.S. economy, adding $231 billion in economic output and 1.6 million jobs by 2035. Lower natural gas prices resulting from the increased production are expected to significantly reduce the average family’s energy bill in coming years.
As shown, blanket condemnation of fracking makes little sense; control of fracking makes much sense. Social issues are not black and white—everything has risks. Our job is to manage these risks while exploiting the benefits of shale gas.
Today, the U.S. and other countries find themselves in a precarious energy position. Renewable energy has yet to make a significant impact, while nuclear energy remains a highly charged issue. Conventional hydroelectric is locked up in its own environmental constraints. Traditional fossil fuels are continuing to increase in cost and adversely affect the environment and the health of the public. Other than natural gas, there are few viable choices for the near future.
Rebalancing our energy production and consumption from fossil fuels to clean fuels is a worthwhile goal. For this to happen, our government must enact a true clean energy policy and aggressively fund related programs—but it’s clear that this is not in the current cards. In the meantime, the U.S. has little choice but to leverage its abundant natural gas reserves as a transitional bridge.