Energy is the driver of any advanced economy, and fossil fuels are a key part of US energy needs. For decades this has mostly meant oil, but natural gas now is seen as a plentiful, relatively clean resource.
The USA has vast reserves of natural gas but falling yields meant production had fallen off from a peak in the early 1970s. Gas extraction now is a priority again and since 2005 domestic production has soared to well past the previous high. The main development that’s made that possible is hydraulic fracturing, commonly known as fracking — a technique that’s been around for decades but is being used more widely than ever before.
Fracking has had its opponents for years but recently they’ve become more numerous and more vocal. What’s the controversy about and why does it matter? Let’s look at the facts about fracking.
Oil and gas collect in certain types of rock formation, usually where a layer of impermeable rock forms a reservoir. The fuels don’t collect in an underground lake, though. They’re soaked through pockets of softer rock, which acts like a huge sponge. Deep underground the pressure is enormous, and this riddles the rock with tiny fractures. It’s these fractures that allow oil drilling to work; when a well is drilled, the weight of the ground above forces oil and gas along the fractures into the pipe so it can be extracted.
Unfortunately, conventional drilling can’t extract all the oil and gas that’s in a reservoir, because the pressure closes many fractures as soon as they form. Plenty of fuel is trapped in the rock because it simply can’t get to the well. Production slowly falls as the amount of free fuel decreases, and eventually it’s no longer economical to keep extracting. Since the 1860s drillers have looked for ways to maximize output by creating new fractures in the rock. Water, acid and solid substances have all been used. The fracking techniques that are used now were first developed in the 1940s and quickly proved much more effective than the others.
The basis of fracking is injecting water into the well at very high pressures. The pressurized water spreads out along naturally occurring fractures, forcing them wider. The stress opens new fractures, which also fill with water and widen, spreading a network of cracks through the reservoir. This opens up previously trapped pockets and allows oil and gas to flow to the well.
Fracking fluid is about 95 percent water but most of the rest is what’s known as proppant, typically sand or ceramic granules. Cracks opened by water can be closed again by pressure, but if the water has deposited a proppant they won’t close fully. As well as the proppant the fluid usually contains a variety of chemicals to increase efficiency. While the chemicals are effective, many of them are toxic. Gels and isopropanol make the fluid thicker, which helps fracture the rock. Polyacrylamide reduces friction between the fluid and the pipe, which keeps the pressure high. Some fracking fluids even replace water with propane.
Use and growth
The first successful fracking experiments were carried out in 1947 and by 1949 it was being used commercially. As oil production in existing fields started to fall in the 1980s it became more common but it was strictly regulated because of pollution worries. Then in 2005 the US government exempted fracking from the Clean Water Act and its use exploded. Largely due to fracking, US production has reached its highest levels since 1992 and energy imports are down. More than a million fracking operations have now been carried out in the USA, 40 percent of the global total.
Because the USA has to import a substantial percentage of its energy needs, the need to secure energy imports is a major driver of foreign policy. This creates pressure to support Middle Eastern regimes like Saudi Arabia even when it isn’t otherwise in the USA’s best interests. It also leaves the economy vulnerable to changes in global oil prices which have a knock on effect on every aspect of life. It’s very much in the USA’s interests to produce as much domestic energy as possible, and fracking is playing a valuable role in that. In March 2013 domestic energy production covered 89 percent of total US requirements, the highest since April 1986. Total crude oil output now averages 7.4 million barrels a day and the Energy Information Administration predicts this will rise to 8.1 million by 2014. That’s an increase of just over 9 percent, and if consumption stays constant it will almost close the energy gap between what America needs and what it extracts itself.
Most of the controversy about fracking centers on possible environmental effects. Because the process creates fissures that liquids can flow through it’s possible for chemicals, either from fracking fluid or naturally occurring ones in the oil reservoirs, to seep through into the aquifers that much of the USA relies on for water supplies.
Until 2005 fracking was controlled by the EPA to ensure it didn’t happen near aquifers or faults that could let fluids run underground for a long distance. Now these restrictions have been eased there’s concern that new fracking operations could be contaminating groundwater. EPA tests in seven different states have found water contaminated with fracking chemicals. Some of these chemicals are either highly toxic or can cause cancer; they include benzene, phenols, toluene and even diesel. Water in some areas is also saturated with methane gas, and tests suggest that the gas comes from deep reservoirs rather than shallow deposits that sometimes mingle with groundwater.
Environmentalists have also complained about the possibility of methane (which is a powerful greenhouse gas) being released into the atmosphere. The reality of global warming is hotly debated but there’s no doubt that greenhouse gases do trap heat – the question is what effect that actually has on the climate. At the moment methane pollution is probably not a major concern, as the amount of methane released is dwarfed by the amount released by livestock.
The Earth’s crust contains many radioactive elements. Normally these are nothing to worry about because concentrations and radiation levels are minute. Some of them dissolve in fracking fluid, though, and higher concentrations build up in the waste water when it’s extracted. This becomes a problem when the fluid is disposed of. Normally it’s pumped into deep injection wells for disposal (the safest method) but in some areas it’s either recycled for future fracking – which increases concentrations of radiation even more – or treated as waste water. The problem is that most water treatment plants aren’t set up to remove radioisotopes. The solution to this is specialist treatment plants, but not many of these exist. At present radium, thorium and even uranium have been detected in rivers where reprocessed fracking fluid has been dumped.
Breaking up rock and injecting liquids can have unforeseen effects under the surface. Earthquakes are caused when tension stored up in the rock is suddenly released, and a new fracture or the addition of a lubricating fluid can easily release that tension. Some opponents of fracking claim that it causes earthquakes and could unleash a dangerously powerful one.
In fact, fracking does cause earthquakes, but they’re small ones. Studies by the USGS and the UK Department of Energy have confirmed that fluid injection has caused many quakes – in the USA the rate of earthquakes over magnitude 3 is six times what it was in the 20th century – but most of them weren’t big enough to be felt by humans. Experts in the USA, UK and Canada have all concluded that there is little or no risk.
If the USA is going to reduce its need for imported energy there are only two alternatives – restrict consumption or increase production. The first isn’t a realistic option. Forcing people to reduce how much energy they use is an unjustified intrusion into the personal sphere, and in any case government’s track record in energy efficiency isn’t a good one. That leaves increased production as the way ahead. The USA has enormous reserves of fossil fuels; the trick is making the best possible use of them.
The question is how serious the risks of fracking are. Like any industrial process it does carry some risks, but most of them aren’t serious, fracking supporters say. The main genuine concerns are the risk of polluting ground water – especially important for people who have their own wells supplying natural ground water – and the radiation hazard from waste fluid.
The benefits of fracking are clear. The problem is that the risks are hard to evaluate. Government and commercial pressure has made it difficult to get at the real facts and statistics. For now, the best advice, if fracking is going on in your area, is to keep a careful eye on the quality of your water supply and be ready to take action if any problems emerge.