A quest for new gas reserves made headlines when the drilling operation triggered small earthquakes close to Blackpool in 2011
A quest for new gas reserves made headlines when the drilling operation triggered small earthquakes close to Blackpool in 2011. The findings of an inquiry uncovered "strong evidence" that two minor quakes and 48 weaker seismic events resulted from the injection of drilling fluid into shale rocks.
This case study also examines a wider set of physical impacts caused by shale gas exploration. In particular, controversy surrounds the techniques used to recover gas from shale-rock formations using a technique called hydraulic fracturing - or "fracking".
Campaigns have been mounted against the environmental costs of fracking- and now earthquakes can be added to the list of concerns!
We also examine how energy security concerns are leading to increased global use of unconventional fossil fuels such as shale gas.
What caused the Blackpool earthquake?
What are the causes and consequences of the global quest for shale gas?
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Cuadrilla, a UK energy company, recently identified Lancashire as one of four British regions where favourable geological conditions have given rise to large volumes of shale gas, an unconventional fossil fuel. Exploratory drilling began in 2010, despite some local opposition. In April and May 2011, a series of small earthquakes occurred. What is the connection between the drilling and earthquakes? Could it happen again? What arguments support further gas prospecting in Lancashire?
Only four regions of the UK are known to have the optimum geological conditions for recovery of shale gas, including Lancashire and South Wales. Known as "plays", the sites have shale rock formations just 3 km below the surface. US-based Cuadrilla Resources has a license to explore the area between Blackpool and Preston, where the Bowland shale rock formation lies.
Cuadrilla erected their first exploration rig at Preese Hall, 10 km east of Blackpool, in August 2010. A series of exploration wells were drilled there and at several other local sites. Then, in April and May 2011, two earthquakes and a series of minor seismic events hit the Blackpool area.
The strongest quake, centred on Poulton-le-Fylde, registered strength 2.3 on the Richter scale; another reached 1.5. These were accompanied by another 50 smaller seismic events.
None of this physical activity had harmful impacts at surface level, although "people were shaken in their beds," according to the Blackpool Green Party.
A police spokesman said the force's own control room on Bonny Street, Blackpool, began to shake (BBC News, 01 April 2011).
In November 2011, an official internal report by Cuadrilla concluded that the seismic events were "most likely" caused by direct injection of fluid into the wells. An unusual combination of local geological factors and the pressure of fluid injections was cited as the "highly probable" trigger for the earthquakes.
Could it happen again?
The operations conducted by Cuadrilla were fairly routine. The inquiry report’s authors believe there is only a 0.01% chance of such strong reactions happening again: in other words, it was a very rare occurrence. Worldwide, there have been around one million drilling operations comparable to those carried out in Blackpool; and it was only the third time that minor earthquakes of this size have ever been recorded (Financial Times, 02 November 2011). The company is confident that further drilling and, ultimately, commercial gas extraction can be carried out without risk of further ground movement.
The conclusion that the risk of fresh earthquakes remains low isTable unlikely to quell local opposition in Blackpool, however. "Fracking" is frowned upon by many environmentalists and has even been banned in France. There is widespread unease about Cuadrilla’s activities and local pressure groups have formed.
The earthquakes panicked local communities, later leading to demonstrations. Police had to arrest protestors who broke through fences and scaled Cuadrilla’s drilling rig. In another episode, protestors draped banners on Blackpool tower.
The earthquakes could be evidence that the risks of drilling are worse than has previously been believed; some MPs have proposed there should be a moratorium on gas exploration until greater research has been completed.
Full-scale fracking operations, once underway, have sometimes led to the contamination of groundwater aquifers (and could lead to crop contamination for Lancashire farmers).
The high-pressure injection of water and chemicals gives the operation a large water footprint and is environmentally damaging.
Cuadrilla say they discovered 5,660 billion cubic metres of gas at the site: enough to meet the UK’s energy needs for 56 years (although just 10% of this may be exploitable). Until recently, the UK was thought to only possess 150 billion cubic metres.
A discovery of this scale, if commercially exploited, could bring much-needed employment at a time when the north of England is struggling to generate new economic growth. Cuadrilla estimates 1,700 jobs would be created.
Cuadrilla also expects to introduce a further 3,900 "high-pay, high-skill" jobs elsewhere in the UK should the go-ahead be given for extraction (a decision will be reached during 2012).
Advocates of shale gas say it gives us an opportunity to generate electricity at half the CO2 emissions of coal.
What is shale gas and fracking?
Shale gas is a fossil fuel trapped in sedimentary rocks thousands of metres underground. It can be released by the hydraulic fracturing, or "fracking", of the rocks it is stored in by injecting a high-pressure mixture of water, sand and chemicals.
The process triggers tiny explosions that shatter and crack the hard shale rocks to release the methane gas inside, causing it to flow out to the head of the well.
The process is carried out vertically or, more commonly, by drilling horizontally to the rock layer. The process can create new pathways to release gas or can be used to extend existing channels. Experts also refer to a "frac job" and a "frac unit" (BBC News, 02 November 2011).
All hydrocarbon fuels, when used, release carbon dioxide, a greenhouse gas. So why has it become necessary to tap into new, unconventional sources of oil and liquid gas, given the high environmental costs? Further, the extraction process for shale gas requires enormous inputs of water and can lead to the chemical contamination of local drinking water. The quest for energy security may therefore threaten water security!
Conventional oil supplies are finite and the peak oil moment may be here already. Peak oil is defined as the point at which oil production worldwide reaches a maximum (thereafter to be followed by a decline). Some experts believe we are still a few years or decades away (given that new conventional discoveries continue to be made, for instance offshore in the Gulf of Mexico). However, even if this should prove to be the case, global energy security concerns will keep growing for several reasons.
Renewable resources, such as solar and wind power, offer some hope but cannot meet current and energy demands and projected increases. Even China, the world’s largest investor in green energy, has so far only managed to produce enough power from renewables to provide 8% of its energy mix (Financial Times, 29 November 2011).
Population growth means that there will be at least a further two billion people alive in 2050 compared with today, many of them born into societies where an energy-intensive lifestyle is the norm, or else is fast becoming so.
Global demand for energy grows as more people are lifted out of poverty and attain middle income status in emerging economies. By various estimates, the number of "powered-up" affluent people who are significant users of electricity will rise by between two and three billion before 2050. This prediction factors in a combination of population growth and changing lifestyles for the billions who currently rely on wood and charcoal for light and heat.
Shale gas comes of age
The potential of unconventional fossil fuels such as shale gas has long been recognised. Until recently, however, shale gas reserves were very hard to exploit. Recent technological breakthroughs have finally allowed progress to be made, as the National Geographic interactive shows. Greater exploitation has contributed to an enhanced worldwide flow of gas "that has halved gas prices in the US domestic market, and led to a glut in world markets. It's estimated to have offered gas security to the US and Canada for about 100 years" (BBC News, 02 November 2011).
Over the past three years, American production has soared, thanks to shale gas exploitation, notably in Pennsylvania. The USA even overtook Russia in 2010 to once again become the world’s biggest gas producer for the first time in a decade. Shale gas now accounts for an estimated 20% of US natural gas production.
It is also a major energy source for Canada, where the industry is expected to grow significantly over the next decade. Some European countries have plentiful reserves too; Europe’s greatest shale gas reserves are located in Poland (an estimated five billion cubic metres). Other major shale gas reserves exist in China, Argentina, Mexico and South Africa. To put all this in perspective, adding the shale gas resources that have so far been identified worldwide to other existing gas resources increases their volume by over 40% to 639,000 billion cubic metres.
The consequences of shale gas exploration
There are issues to explore at both the local and global level. Domestic discoveries may allow individual countries to make major changes to their own energy mix. This can help to reduce energy security concerns by freeing sovereign states of dependency on energy imports (for example, in the future Poland may become far less reliant on Russia for imported gas and oil). But these benefits must be measured against a range of reported problems for people and places:
Shale gas wells use vast quantities of freshwater because of the large volume of liquid needed to fracture the rock. Estimates vary, but a typical US well uses an average of between 5 million and 8 million gallons of water. This is equivalent to a week of water use for the entire city of New York, although it is a one-time only requirement (once fracked, a well may be drained of gas).
Several hundred different chemicals are used in fracking fluids, a small number of which have been identified as known or potential human carcinogens. Research conducted by the Tyndall Centre has examined 260 chemicals used as part of the fracking process in the USA and "it finds that 58 give rise to concern. Some are known carcinogens, some are suspected carcinogens, some are toxic to people, some are toxic to aquatic life, some are mutagenic (which means they can cause genetic defects) and some have reproductive effects" (Guardian, 31 August 2011). In Bradford County, Pennsylvania, a major shale gas producing area of the USA, local people assert they have been poisoned (BBC News, 28 November 2011).
Once it has been injected into the well, the contaminated water (called "flowback", only half of which of which is ever pumped back to the surface) is either disposed of in underground reservoirs, stored in open pits or treated and released back into the environment.
At the global level, unconventional fossil fuels such as shale gas are changing the energy map, with geopolitical implications. Changing energy pathways mean that new patterns or trade and dependency are emerging. American energy companies have developed strong ties with Canadian gas providers (aided by the framework for investment that NAFTA allows). This may help the USA to reduce its Middle Eastern oil imports (with important implications for US foreign policy i.e. possibly less intervention in Middle Eastern affairs). Europe may become less dependent on Russian gas.
There is also the global issue of climate change to consider. CO2 emissions from burning gas are far lower than from burning coal. This has led supporters of shale gas to suggest that greater use of it, rather than coal, could help ease the transition to a low-carbon economy. Shale gas could function as a "bridge fuel" until renewable energy sources begin to deliver greater amounts of power.
However, opponents of fracking point out that methane, the natural gas produced by the process, is itself a very powerful greenhouse gas (it does not persist in the atmosphere for as long as carbon dioxide, but during the early years following its release, it is 56 times as effective at trapping heat). Plenty of methane is likely to escape from the process of splitting rocks open during the fracking process. For this reason, the overall impact on Earth’s climate is unlikely to be any less damaging than the exploitation and use of conventional fossil fuel sources (Guardian, 23 September 2011).
Keep watching the Blackpool story "in the news" - what will happen next? Will commercial exploitation of the Lancashire shale gas field begin? Cuadrilla expects to have reached a decision by mid-2012.
Compare the environmental impacts of shale gas exploitation with those of tar sands, using the box below as a starting point for your research . Present your findings in a table or diagram.
Write an essay:
Examine the view that all types of fossil fuel, when exploited and used, are equally damaging to the natural environment.
[Tip: the carbon footprint of shale gas, when burned, is lower than that of coal; however, there are a range of other local impacts to compare too, including oil spills and the impacts of fracking.]
Another fine mess: tar sands extraction
Surface mining and in situ at-depth extraction of tar sands (or oil sands) are both highly polluting processes. Surface mining scars the landscape, leaving an "ecological desert". The in situ process involves injecting steam into wells to liquefy deeper deposits of bitumen and allows it to be pumped to the surface. The process generates enormous amounts of fouled water.
Find out more at:
Fracking 'should continue with checks' BBC News, 17 April 2012
"Small earthquake hits Blackpool" BBC News, 01 April 2011
Shale gas fracking blamed for Blackpool quake" Financial Times, 02 November 2011
"What is fracking and why is it controversial?" BBC News, 02 November 2011
"China’s rush into renewables" Financial Times, 29 November 2011
"The UK’s lack of fracking regulation is insane" Guardian, 31 August 2011
"How fracking affects a community in Pennsylvania" BBC News, 28 November 2011
"Is fracking environmentally friendly?" Guardian, 23 September 2011
"Shale gas will change the world" Financial Times, 24 May 2010
One-Quarter of World's Population Lacks Electricity. Scientific American
Mapping a Gas Boom. National geographic
Hydraulic Fracturing FAQs
France becomes first country to ban extraction of natural gas by fracking. Scientific American
World Shale Gas Resources
Written by Dr Simon Oakes, a Geography Chief Examiner who teaches at Bancroft’s School, Essex.
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