Sarah Wild's article ("New US study inflames SA's fracking feud", June 28) contains untrue comments.
The figure of 390-trillion cubic feet of gas is mere speculation. At this stage it is not known how much or how little gas is available, and it should be reported as such. Further, the figures of potential gas volumes as published by the US Geological Survey have been shown to be substantially overinflated and many of the US gas plays contain less than 10% of the original estimates. It is irresponsible journalism to publish numbers that have not been proven.
South Africa does not need the gas. The new power stations now under construction are coal-fired and will remain so. No amount of shale gas will change that. Similarly, the South African coal-mining industry is not going to go away once gas is used domestically. The coal will simply be exported and burned elsewhere and there will be no net improvement in global greenhouse gas emissions.
There are vast quantities of conventional gas available from our neighbouring states of Namibia, Angola and Mozambique. The concept of energy independence (from fossil fuels) is an American one to avoid dealing with troublesome Venezuelans, Iranians and other unreliable suppliers of oil. South Africa will only be self-sufficient when we begin to put more effort into exploiting renewables, of which we potentially have vast quantities.
The mind-set of "business as usual" when exploiting hydrocarbons cannot be perpetuated. The vast financial resources used to explore for Karoo shale could be better spent elsewhere.
As for the 2000 barrels of water quoted by the "Shell experts", since when are volumes of water measured in barrels? Litres, kilolitres, cubic metres and gallons are commonly used. Assuming that a barrel means a volume of 220 litres, it would imply that the "Shell experts" mean that 440 000 litres of water is used. Yet a Shell borehole drilled recently in Pennsylvania used more than 12million litres.
In South Africa the boreholes will be deeper and geologically more complex and therefore will use more water than in the US. Shell's draft environmental management plan of March 2011 says that "the volume of water required to perform that operation could be up to six million litres" – a far cry from 2000 barrels!
I would suggest that if Wild insists on writing scientific articles, she adopt a modicum of scientific standards in her reporting. – Jan Arkert, PrSciNat
Sarah Wild replies: The "390trillion cubic feet" is from the US Energy Information Agency and is taken as the definitive estimate of shale gas resources. It was updated earlier this year because the previous estimates were considered too low. I quoted barrels because that is what the American expert used when I was in Wyoming, speaking to a project manager on one of Shell's Pinedale Anticline sites. He was using an American metric, which I retained. That number is per fracking phase, and there can be multiple phases. The rest is arguable personal ideology. I will continue to "insist" on writing scientific articles.