Over the last decade, advances in technology have made it profitable to extract natural gas from shale, leading to a boom in shale gas development. With Obama’s new rules for reducing carbon emissions from power plants, the natural gas industry is likely to get a further boost.
Natural gas, a fossil fuel, was formed over millions of years as layers of decaying organisms were buried and exposed to intense heat and pressure under the earth. The energy of the sun that these plants and animals absorbed is embodied in the gas.
Traditionally, natural gas was extracted by drilling into porous zones from which it could easily be pumped to the surface, but many of these resources have been tapped out.
Newer technologies, such as hydraulic fracturing or “fracking” have enabled energy companies to access “unconventional” resources of gas, once considered too difficult or costly to extract, such as gas found deep underground, in tight impermeable rock formations, in coal beds, or trapped in layers of shale, fine-grained sedimentary rocks. Some form of fracking is now used in 90 percent of all new onshore oil and gas development, and currently accounts for 60 percent of natural gas production in the U.S.
Because of its potential environmental and health impacts, fracking has become a contentious issue. According to a 2013 Pew poll, 44 percent of respondents support fracking while 49 percent are opposed. Beizhan Yan, a geochemist and assistant research professor at Lamont-Doherty Earth Observatory, noted that both sides sometimes cherry pick scientific evidence to support their own views. “It’s important for both sides to consider the data objectively,” he said.
So let’s try to look at the facts with an open mind.
Hydraulic fracking is not new. When the mining technique began in the 1940s, gas companies drilled vertical wells and pumped pressurized water into rocks to release the gas. Natural gas development really took off in the 1990s when horizontal drilling was developed and combined with fracking; this enabled drills to descend down to 10,000 feet, then curve to drill horizontally thousands more feet so drillers could access gas trapped within shale layers. Horizontal drilling is 3 to 5 times more productive than vertical drilling.
Here’s how it’s done. First a hole (or wellbore) is drilled 1,000 to 4,000 feet deep. After steel casings are placed into the well, the space between the casing and the hole is filled with cement to protect groundwater and prevent gas leaks. This process is repeated several times, with smaller and smaller diameter casings being inserted, down to a depth of 6,000 to 10,000 feet (way below aquifers), where the gas can be accessed. A perforated pipe gun is sent into the horizontal part of the wellbore, producing explosions that create fractures in the shale. Fracking fluid, 3 to 5 million gallons of water drawn from groundwater or surface water resources mixed with chemicals and sand, is then pumped at high pressure into fractures, which expand and release the gas.
Ninety-eight to 99.5 percent of the fracking fluid is water and sand used to keep the cracks open; the rest is made up of chemicals that help reduce friction, kill microbes that might clog the well, prevent pipe corrosion, and acids to reduce drilling mud damage. Some are carcinogens and hazardous pollutants, but the exact chemicals used are usually unknown because the industry contends its fracking fluid formulas are trade secrets. The ingredients of a fracking cocktail depend on the particular conditions at the well.
Once pressure in the well is released, gas flows to the surface, as well as “produced” or “flowback” water (between 3 and 80 percent of the water used) containing chemicals, salt and radioactive materials that occur naturally in shale. The flowback is stored on-site in tanks or pits before it is treated and released into surface waters, injected into deep wells for disposal, or recycled with or without treatment to be reused in more fracking.
The U.S. Environmental Protection Agency (EPA) does not regulate fracking fluids even when they enter our water supply because in 2005, fracking was given an exemption from the Safe Drinking Water Act; called the Halliburton Loophole, it was introduced when Vice President Cheney’s former employer, Halliburton, was moving into fracking.
The U.S. natural gas industry is the world’s largest. According to the U.S. Energy Information Administration (EIA), in 2012, the nation had almost 323 trillion cubic feet of “proved” (able to be produced economically given current market prices) natural gas and natural gas liquid reserves. The EIA estimates that there are 2,203 trillion cubic feet of “technically recoverable” (able to be produced with current technology without regard to economics) natural gas. The U.S. consumes natural gas at a rate of about 24 trillion cubic feet per year, so 2,203 Tcf of gas could theoretically last 92 years.
The largest shale deposits in this country are the Marcellus Shale under the Appalachian Basin, Barnett Shale in Texas, Bakken Shale under Montana and North Dakota, Antrim Shale in the Michigan Basin, and Eagle Ford Shale in Texas. The Marcellus Shale, one of the largest sources of natural gas in the U.S., and perhaps the second largest in the world, may contain 500 trillion cubic feet of gas. Today, there are 45,000 shale gas wells operating in the U.S. and natural gas production is expected to increase 56 percent between 2012 and 2040. The abundance of natural gas has made it a relatively cheap energy source.
The Benefits of Natural Gas
Natural gas generates 25 percent of our electricity, and approximately two-thirds of the natural gas produced in the U.S. goes into making chemicals, pharmaceuticals and fertilizer, and is used for heating and cooling.
The boom in natural gas has helped make the U.S. much less dependent on countries like Russia and the Middle East for energy, and thus enhanced our energy security.
A 2011 study by IHS, a global information provider, found that shale gas production in the U.S. supported over 600,000 jobs in 2010, and is projected to support 870,000 jobs by 2015. It boosts local economies with jobs, royalties for landowners and tax revenues. IHS estimated that, over the next 25 years, shale gas production could generate more than $933 billion in tax revenues for local, state and the federal governments.
Manufacturers of everyday products and the steel industry also benefit from cheap natural gas and gain a competitive edge in global markets, resulting in more exports and jobs. The National Association of Manufacturers estimates that shale gas production and low natural gas prices will help manufacturers employ 1 million workers by 2025.
Natural gas can help slow climate change because it emits less carbon dioxide when burned than any other fossil fuel; and since we are using more natural gas, we are producing fewer emissions from dirty coal.
The Problems with Natural Gas
The climate change benefits of natural gas are conditional, however. If the availability of cheap and plentiful natural gas makes cleaner energy sources such as nuclear, hydroelectric and renewables less competitive, and if energy efficiency becomes less cost effective, climate change benefits could be negated and the surer methods of combatting global warming could lose headway. Indeed, new investments in renewables last year at $56 billion were the lowest since 2010, while gas and oil investments were $168.2 billion, having more than doubled since 2009.
Natural gas is mostly methane, a greenhouse gas that, over 20 years, traps more than 84 times more heat in the atmosphere than carbon dioxide. Approximately one-third of the global warming we are experiencing today is caused by short-term climate pollutants including methane, and in 2012, natural gas production was the second largest manmade source of methane emissions in the U.S. So unless the methane emissions associated with natural gas production can be curbed, the climate benefits of natural gas could be undone. The problem is that no one knows precisely how much or where in the process methane emissions are occurring.
The Environmental Defense Fund (EDF) and almost 100 partners are now researching how much methane is released across the entire natural gas supply chain; the 16-part study will be completed at the end of 2014.
Methane is released into the atmosphere when it escapes via pneumatic valves that control operations at the well site, other equipment at the production site, or when excess gas is vented. These problems can be fixed with low- or no-emission valves and better leak detection and repair. Green completion equipment can recover excess methane, process it and send it to a pipeline so that it can then be sold. In January 2015, the EPA will require green completions for all natural gas producers; until then they can flare the gas. A study by ICF International concluded that emissions-control technologies and practices could save natural gas companies over $164 million a year.
Natural gas development has also resulted in increased emissions of volatile organic compounds (VOCs) like benzene and formaldehyde, and hazardous air pollutants, which can have health consequences for those living nearby or working in the industry. VOCs can cause cancer and respiratory problems, particulate matter can affect the heart and lungs, nitrogen oxides react with VOCs to produce ozone, and hydrogen sulfide can cause illness or death at some concentrations. These air pollutants emanate from diesel- or natural gas-fueled trucks and equipment, gas production, and leaks from storage facilities, pipelines and valves.
In Wise County, Texas, which sits atop the Barnett Shale, Bob and Lisa Parr are surrounded by gas wells. After several years of experiencing nosebleeds, nausea, ringing ears and rashes, which they attribute to toxic emissions from gas production, the Parrs sued Aruba Petroleum and were recently awarded $2.9 million in damages. The case is significant because it is the first successful U.S. lawsuit linking toxic air emissions from oil or gas production to health impacts on nearby residents, but Aruba will challenge the ruling.
The regulation of oil and gas extraction falls mainly to the states, including enforcement of the federal Clean Air Act, but rules vary widely from state to state. The EPA’s first air pollution regulation on fracking is the 2015 requirement for green completions, but many believe it’s not enough. In May 2014, 64 environmental and community groups petitioned the agency to use its authority under the Clean Air Act to develop “robust emission standards” limiting the amounts of benzene, formaldehyde and other harmful chemicals that can be emitted by oil and gas wells and equipment.
There are many environmental risks related to the large amounts of water used in fracking. The huge volumes of water drawn for fracking can jeopardize the availability and quality of drinking water. Fracking fluids can contaminate surface and groundwater supplies if spilled or leaked. If wells are not constructed properly, fracking fluid might find its way to aquifers or groundwater carrying metals or radioactive materials naturally found underground. Flowback waters can seep into surface or groundwater from trucking accidents or on-site storage leaks. And if wastewater is not properly treated before being released, it could contaminate surface water bodies. The EPA is currently studying fracking’s impacts on drinking water resources at every stage of the fracking cycle. A draft report will be out this year. It could be the first step towards tough federal regulations on fracking.
Because of the upsurge in fracking, more and more radioactive waste is coming to the surface more quickly from the shale, which naturally contains radioactive metals. Some radioactive metals may dissolve into the fracking fluid, contaminating it; some may remain in the dirt and rock being drilled that are eventually brought to the surface. Regulations about the disposal of fracking waste are different in each state, but often, radioactive waste ends up in landfills ill-equipped to handle it, from where it can contaminate groundwater.
Geochemist Steven Chillrud, a senior research scientist at Lamont-Doherty, said, “We are dealing with an industry that has done fracking for decades without any oversight. It was limited before, but now they are trying to expand rapidly, and the monitoring and oversight is way behind the ball.” Chillrud and Yan are working on groundwater testing and air pollution monitoring in heavily fracked areas of northeastern Pennsylvania. They have just begun to analyze water samples and research air quality. ”Monitoring is key to doing fracking in a rational way,” said Chillrud “We need more data to know how we need to regulate the industry and at what level. Research and monitoring programs also have a lot to offer for public health.”
Lately, there have been reports that “fracking causes earthquakes.” But usually it is not the process of fracking, but the pumping of wastewater deep into injection wells for disposal that can cause tremors. The number of earthquakes in central and eastern U.S. has increased significantly in recent years, coinciding with increased fracking and the injection of wastewater in disposal wells in Colorado, Oklahoma, Texas, Arkansas and Ohio, according to the Seismological Society of America. The society also recently revealed that earthquakes from wastewater disposal may have been triggered tens of miles from the wellbore, much farther than previously thought.
Geoff Abers, a seismologist research professor at Lamont-Doherty, is studying the potential for earthquakes caused by the injection of wastewater, whether from fracking or other methods of extracting oil and gas that involve disposal of large amounts of fluid. Abers explained that wastewater is pumped deep into injection wells (some wells receive 1 million barrels each month), down into porous formations where it is soaked up; as pressure gradually builds, it sometimes triggers dormant faults. Some operations can run for 10 to 15 years without incident, whereas with others, quakes happen quickly. “We don’t understand why some injection wells have earthquakes and others don’t,” said Abers. “We know very little about where the fluid goes at depth, what the pressure is, or if there are any abandoned wells nearby.” Usually scientists only know when the larger earthquakes occur, but if monitoring were better, they would be able to detect signs of stresses building and faults getting close to failure.
Like Chillrud and Yan, Abers believes that more monitoring and more data made public are essential to understanding what the problems are and what the best practices for the natural gas industry should be. Many strategies to protect the environment and public health have already been identified—getting them implemented, though, is often a question of political will.
In February 2014, Colorado became the first state to adopt rules to directly reduce emissions of methane and VOCs from oil and gas. The requirements include: leak detection and repair on all wells to control methane and VOC leaks from equipment; monthly inspections for the largest emitting wells; a statewide retrofit using lower emission valves on all valves on well sites that control routine operations; and requiring existing storage tanks to comply with pollution laws. The new rules will remove 90,000 tons of VOCs and 100,000 tons of methane each year.
Meanwhile, a patchwork of regulations is being developed as states come to grips with the local impacts of fracking. Illinois requires companies to reveal their fracking chemicals and test the water before and after drilling. Other states, like Wyoming, Arkansas, Pennsylvania, Michigan and Texas have enacted regulations requiring some disclosure of fracking chemicals. Towns, cities and counties in states such as New York, California, Colorado, Texas and Ohio, have established moratoria or bans on fracking. In 2012, Vermont became the first state to ban fracking altogether.
Around the country, lines are being drawn in the sand. But our need for energy will continue to grow and hydraulic fracturing is not going away any time soon. In his Huffington Post blog, Steven Cohen, executive director of the Earth Institute, offered perhaps the most reasonable perspective on fracking:
While advocates of hydraulic fracturing minimize the risk of extracting natural gas this way, and opponents of this practice do not want it to proceed under any circumstances, we need to at least explore the possibility of a middle ground. Our modern economy and the conveniences we all enjoy cannot be run without risk…. There is no pristine way to fuel a modern economy. It is delusional to think we can obtain these benefits without cost. However, it is even more delusional to think that we should develop energy without regard to its impact on human and environmental health. We should do everything we can do to understand, minimize and manage these negative impacts. Our goal should be to use these fuels as transition fuels to a renewable energy economy.