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Gas: a destructive energy source
Reserves of gas – another fossil fuel – are, like reserves of oil, distributed unevenly around the globe. Currently most gas burned for fuel is ‘natural gas’, a mixture mostly of methane which flows freely deep in underground rock. However, global gas markets have changed significantly over recent years, with major growth in the extraction of ‘unconventional gas’, especially onshore coal bed methane and shale gas. Extraction of conventional natural gas requires just the drilling of a well, but a controversial technique called hydraulic fracturing or ‘fracking’ is often used to exploit unconventional sources of gas such as shale gas and coal bed methane. Fracking is done by pumping millions of gallons of water mixed with what are often toxic chemicals at extremely high pressure, which helps the gas to flow more freely. About half of the water comes back to the surface and has to be treated. The other half stays underground where its movement cannot be controlled and it risks polluting groundwater serving communities, ecosystems and agriculture.
So far, most of the growth in unconventional gas has been in the US, which is now set to overtake Russia as the world’s primary gas producer within the next 10 years, according to the IEA. Most of the world’s coal bed methane reserves are located in Canada, Russia, China the US and Australia. Other countries looking into potential shale gas extraction include Argentina, South Africa, Tunisia, China and a number of countries in Europe.
The term natural gas is highly misleading, as it implies a clean energy source. In reality, while gas produces significantly less emissions than coal or oil, its combustion as a fuel source still produces carbon dioxide and is therefore a major problem from a climate change perspective. In the US, the average emissions rate from natural gas-fired generation is 1135 lbs/MWh of carbon dioxide – about half the carbon dioxide compared to coal-fired electricity generation but still significant. Natural gas was responsible for 20.4 per cent of fuel’s share of total C02 emissions in 2010.
Energy companies are also misleadingly promoting ‘unconventional gas’ as natural gas and therefore as a lower carbon alternative to conventional fossil fuels. However, unconventional gas extraction is considerably more energy intensive than conventional, with an added risk of the leakage of methane – a highly potent greenhouse gas. Using a very conservative estimate of well-to-burner emissions from unconventional gas, the IEA’s ‘Golden Age of Gas’ scenario puts global emissions on a trajectory for 3.5 degrees of warming, and research from the USA indicates that gas obtained through fracking could have a bigger total greenhouse gas footprint than coal. Like new coal and new nuclear power, investment in unconventional gas is a serious distraction from badly needed investment in renewable energy and reducing energy dependence.
Apart from the climate impacts of increasing reliance on gas as a fuel, gas extraction is the source of serious environmental and social conflicts around the world. Construction projects associated with gas pipelines and infrastructure drive land grabbing and threaten water resources and biodiversity in many places. Furthermore, there are significant risks of water contamination and air pollution from fracking and coal bed methane extraction. Extracting shale gas always involves fracking, while coal bed methane extraction does not – at least not in the early years of operation, although as gas flow starts to decline wells are often fracked to increase productivity. However, there are serious environmental problems associated with coal bed methane extraction, regardless of whether fracking takes place or not. The chemicals used can be just as toxic, and the same risks of spillages, leakages and mobilisation of naturally occurring chemicals and radioactive substances apply. In fact, because coal bed methane is often significantly nearer the surface than shale gas, certain risks such as groundwater contamination are increased.
Researchers in the USA looking at the impacts of gas drilling on human and animal health, have warned that the gas boom is an uncontrolled health experiment on an enormous scale. Many fracking chemicals are known to be toxic and an assessment of 353 chemicals used in fracking in the US found that a quarter could cause cancer and up to half could affect the nervous and immune systems. Another US report lists more than 1,000 fracking-related spills of diesel, oil, chemicals and waste water in Colorado alone in the two years to September 2011. Spillages and leakages of drilling and fracking fluids have led to death and reproductive problems in livestock and the contamination of agricultural land. In one instance, 17 cows died within one hour of the release of fracking fluid from a drilling rig in an adjacent pasture. BTEX chemicals – naturally occurring in coal seams and shale and released by the drilling process – are notorious soil contaminants.
In terms of air pollution, monitoring of air quality near fracking sites in western Colorado found over 50 hazardous pollutants known as non-methane hydrocarbons near shale gas wells. Of these, 35 could affect the brain and nervous system. Some were found at levels which could potentially harm children exposed before birth. Emissions from shale gas wells can also cause photochemical smog associated with asthma. On the basis of this and other evidence, a report for the European Commission assessed fracking as having a high risk of causing problems for the local environment and human health. Scientists are also finding links between increased seismic activity and hydraulic fracturing processes.
Finally, the processing and transportation of gas – both conventional and unconventional –has significant environmental and social impacts. In order to be transported, natural gas has to be turned into liquefied natural gas (LNG) via a super-cooling method which reduces its volume 600 times, turning it into a liquid that can then be transported via insulated tankers. Relying on gas as a fuel therefore requires the construction and maintenance of a vast network of pipelines, liquefaction and regasification plants and the use of energy to fuel the tankers which transport it. All of which bring additional problems in terms of local environmental and social impacts from construction, chemical disposal and so on.