4 September 2013
Natural gas extraction is being promoted as the solution to South Africa’s energy crisis. Shell and other energy companies want to harness the untapped reserves of natural gas below the Karoo using fracking. This is meeting stiff opposition, particularly from residents of the Karoo who are concerned about the risks.
Pockets of gases, mainly methane, are trapped deep underground in plate-like layers of rock called shale. These natural gases have huge potential for energy and electricity production. To get to the gas a well has to be dug through the rock past the level of underground water (groundwater) into the shale. The well is then turned sideways and drilled horizontally to get to the pockets of gas. A mixture of water, sand and chemicals is pumped at high pressure through the wells, fracturing the shale and releasing the gas. Hydraulic fracturing has been used for extracting natural gas in vertical wells since the 1940s, but didn’t have the potential to access as many gas reserves until it was combined with directional and horizontal drilling. With directional drilling the well can be guided towards the gas reserves giving a much wider area to extract gas from than a vertical well and allowing mining of more reserves from a single site. This was improved by horizontal drilling that allows the well to bend at 90 degrees. By 2002/2003 fracking and directional drilling had boosted natural gas extraction, making it a profitable enterprise.
You need to look no further than the increasing electricity bills and frequent power outages to know that Eskom is struggling to meet South Africa’s energy demands. At the moment South Africa relies heavily on coal for energy. As a fossil fuel, formed from the decomposing of animals or plants millions of years ago, coal isn’t sustainable and comes at a high environmental cost. Mining, processing and burning coal increase the levels of carbon dioxide in the air, contributing to global change, and also adds pollutants like ash and mercury to the air and water.
The South African government wants to lower SA’s dependence on coal by looking at cleaner and more efficient sources. Natural gas extracted by fracking is being pushed as the best alternative to the dwindling coal reserves. The USA has been fracking for years and is being used as the model for fracking in the Karoo. With the push to pass the bill for exploratory drilling before the next elections, it is clear the South African government wants to start generating revenue from natural gas.
Because fracking is a new technology for South Africa we can only guess at the effects it will have. The most optimistic estimates say that there are large amounts of shale gas in the Karoo that could be used for fracking. Again, optimistically, it’s thought these reserves will give us a good supply of gas for about twenty five years and could have a huge impact on our reliance on coal. The economic impact predicted is massive job creation and revenue from exporting gas to other countries.
One concern about fracking in the Karoo is that the process needs a lot of water for the drilling and fracturing. Since the Karoo is a semi-desert and often experiences drought, current water scarcity raises the question of whether fracking will cause further water shortages in the area. Shell claims that the water used in the drilling and fracking can be recovered and re-used, which is being done at sites in the USA.
Another risk is that the water pumped into the wells and the waste water can contaminate groundwater. Groundwater is the main source of water for towns in the Karoo. This can happen if there are any leaks or breakages in the wells allowing the fracking water to seep up to the groundwater.
There is also a risk that methane can move up to the surface after the shale has been fractured. The Karoo also has a unique type of underground structure with a lot of channels of underground water, which may present new risks that already established sites in the US haven’t encountered.
There has been speculation that fracking can lead to earthquakes in areas that are at risk.
Opposition to fracking in South Africa questions whether the promise of job creation will be realised. Sites in the US employ people who are highly skilled and trained. In the initial stages of fracking in SA, skilled workers would be imported from overseas. It is hoped that local skills can be improved as fracking progresses.
There aren’t any long-term studies or even enough conclusive studies for us to say for sure what the potentials dangers are. Most of the research has been done on fracking activities in the United States, but because of lack of funding, there are not a lot of independent studies being done.
It is not clear from the research whether fracking causes more earthquakes, but the US Geological Services who monitor earthquakes say that fracking can cause small earthquakes and that these are mostly too small to be a problem. These small tremors could potentially damage the protective casing around the wells that prevent leakage.
A recent study showed increased methane levels from fracking in the water supply near gas fields in the US, but there are others that haven’t found any difference. It is also unclear whether the methane was released because of fracking.
Another difficulty is that in some areas there is little or no publicly available data on the levels of methane in areas before fracking to compare with current levels.
The highly respected journal Science has recently published a paper looking at the research on fracking and the risks involved in the use of water. It concluded that if the process is tightly monitored and regulated, if wells are maintained to high standards and waste water is properly managed, the risks of groundwater contamination could be reduced. The authors also caution that these risks will increase the longer sites are used for fracking, making research into the risks vital for guiding good management strategies.
What does concern researchers is that as more wells are dug in an area, the risks increase. If fracking happens too close to an old well, which will happen as the natural gas reserves get used up, methane could escape into these old wells, increasing the risks of groundwater contamination.
Does South Africa have the infrastructure and skilled workforce to be able to monitor and plan fracking at the high standard required to minimise the risks?
It is hard to make sense of the fracking debate. The cheerleaders of the pro-fracking groups are often the same people who deny that humans are causing global warming. There is big money in fracking and companies with vested interests are trying to sway public opinion. So far impact studies for fracking in the Karoo are based on estimates, where it seems the best case scenario figures are used by those who support fracking. But anti-fracking groups also make wildly exaggerated claims. Credibility on both sides is close to zero. This debate is a model of how scientific controversies should not be resolved.
The following websites have information on fracking:
Shell - the company that intends to frack in the Karoo.
Treasure the Karoo - the strongest opposition to fracking in the Karoo.