Flaring is the process by which natural gas is burned off in a controlled manner when extracting oil. Otherwise, the natural gas can burn in an uncontrolled way and be very dangerous. Usually, natural gas is captured, but when this is impossible it's flared. Flaring reduces the risk of gas ignition to facilities or to eliminate product that has been isn't fit for use. The volume of gas flared off is generally measured in bcm or billion cubic meters.
When oil forms underground, generally some amount of natural gas forms with it and together the two are trapped inside an oil and gas reservoir. Being less dense than oil, natural gas settles above the oil in a pocket of gas. When companies drill for this oil in an attempt to extract it, this natural gas now has a place to escape the reservoir and accompanies the oil to the surface. In some reservoirs enough natural gas exists that it is economic to extract it along with the oil. However in other cases the gas exists in such small quantities that it is essentially of no use, and thus flaring is utilized.. Furthermore, when there is maintenance needed on facilities flaring is used to reduce the levels of natural gas in order to create a safer environment for workers.
The flaring of natural gas results in the release of carbon dioxide into the atmosphere in the same way that burning natural gas as a fuel would. However, one of the main concerns with using flaring is that there is no real use or benefit other than keeping people and equipment safe. Although flaring is widely used, flaring rarely leads to a significant portion of a countries greenhouse gas emissions, with the exception of a few countries (mostly in Africa). Overall in the world, flaring is less than 1% of the CO2 released.
Flaring releases significant greenhouse gas emissions into the atmosphere and doesn't produce any work (useful energy) as a result. However, flaring the gas actually results in a less dramatic global warming effect than if the natural gas was to simply escape into the atmosphere. This is because methane, the primary component of natural gas, has a higher global warming potential than carbon dioxide. Thus by igniting the methane and instead creating carbon dioxide, the carbon released to the atmosphere has less of a negative impact. However, this does not mean that flaring is beneficial, as keeping the carbon underground would have even less of an impact.
Flaring of natural gas does contribute to climate change, because it releases carbon dioxide. Additionally, depending on the purity of the natural gas there are other harmful emissions, such as sulfur oxides and nitrogen oxides, which combine with moisture in the atmosphere to form acid rain. This rain in turn acidifies lakes, streams, and damages vegetation. Other pollutants such as particulate matter, hydrocarbons, and ash can deplete soil nutrients through acidification, harming agriculture.
In addition to harming the environment, there can be health implications of flaring. Exposure to the emissions of flaring can have adverse heath effects including cancer, lung damage and skin problems.
As global warming becomes a more widely recognized issue, many oil companies are developing methods that help reduce the need for flaring. As a result, flaring around the globe has decreased. New technologies are being developed that allow for the natural gas to be utilized in ways that weren't available previously. For example, natural gas can now be pumped back into oil wells in order to increase pressure and allow for oil to be continually pumped. Furthermore, the amount of flaring has been reduced further since natural gas has become a product that companies want to harness and sell. There is still a demand for flaring to be reduced further, especially in less developed countries where the natural gas being flared could be utilized by those in desperate need.
To learn more about projects to reduce gas flaring around the world, please see the World Bank's GGFR project.
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