Friday 11 May 2012

Gas Fracking

Ever heard the term? When i first heard the word 'fracking', i had to look it up in the dictionary. And all my spell checks do not recognize the word but trust me, such a word exists and along with its existence, it has several energy and environmental consequences.

Natural gas is used as a primary source of electricity generation in most countries and is usually associated with petroleum. Some natural gas reservoirs are found not associated with petroleum in large gas fields. It is a naturally occurring hydrocarbon that is essentially made of methane, carbon dioxide and other hydrocarbon components. Natural gas is used to heat up homes and provide electricity, it is also used to power industries, used as fuel in vehicles and is essential for the manufacture of certain chemicals. It is the major feed stock in the haber process, used in the production of ammonia for fertilizers.

Natural gas may sometimes contain heavier hydrocarbons like ethane, propane, butane and pentane which have to be removed before methane can be used commercially. Natural gas is also sometimes produced artificially (which sounds like an irony) when methane is produced by the decay/decomposition of organic matter or biomass and is referred to as biogas. Biogas is largely produced in waste and waste water treatment processes such as in marshes, anaerobic digesters for sewage sludge, landfills when there is a decomposition of waste components as well as in animal waste such as manure.

As energy demand increases, there is more dependence on natural gas which is found in large reservoirs in deep underground natural rock formations or other hydrocarbon reservoirs such as coal beds. The downside of the use of natural gas to produce electrical energy and heat is the emission of greenhouse gases such as methane and carbon dioxide into the atmosphere. These gases cause the greenhouse effect that leads to global warming and climate change. (See earlier posts for the greenhouse effect, global warming and climate change) 

Since we now have a basic understanding of what natural gas is, Gas Fracking was actually coined from the term 'Hydraulic Fracturing' or 'Hydrofracking' and then 'Fracking'. It is basically a technique used to extract petroleum and natural gas, particularly shale gas from rock formations. Shale gas is natural gas trapped in a type of sedimentary rock (made up of components such as clay, silt and other minerals such as quartz and calcite). As unlike natural gas found in underground reservoirs associated with petroleum or in gas fields, shale gas, trapped in rocks, require a different approach for its extraction.

Hydraulic Fracturing or Fracking is the introduction of fractures in a rock layer by the use of a highly pressurized liquid. The fractures are created by the use of holes drilled into the rocks and then liquid forced through at high pressure to release the oil or gas. The energy from the injection of a highly-pressurized fracking fluid creates new channels in the rock which can increase the extraction rates and ultimate recovery of fossil fuels.

This method has proven to be quite effective for the extraction of gas trapped in rock formations but has also generated a lot of uproar due to the effects. Fracking has been discovered to potentially contaminate groundwater, which is the source of water for drinking and other domestic purposes. Fracking also poses a risk to air quality due to emissions from leaks and natural gas or diesel powered rigs and equipment used during the process. Chemicals from the fracking process can migrate to the surface and cause health effects which can include cancer and death over a prolonged exposure period. Fracking can also lead to explosions as well as spills which can have severe environmental impacts.
In parts of the US where hydraulic fracturing is being carried out, waste water from the process have been observed to be radioactive and with public sewage treatment plants not being equipped to deal with the radioactivity, the untreated radioactive water may be discharged into local rivers raising contamination levels.

A recent report in the UK suggested that Gas Fracking causes low magnitude earthquakes from the forceful injection of wells for waste collection. As is being predicted by energy experts, there will be a higher demand for natural gas in the near future, and those in favor of the Fracking process argue that previously inaccessible hydrocarbon deposits found in rocks can now be accessed and extracted to produce the much needed energy for human need, and those who oppose fracking point out the many negative environmental and human health effects it causes.