THE emergence of so-called green fracking fluids is adding to global debate on the controversial hydraulic fracturing (fracking) method of extracting natural gas.

The worldwide market for hydraulic fracturing is expected to grow 19% this year to a record $37bn, one-third the pace of its expansion last year after tumbling natural-gas prices discouraged exploration for the fuel, oil market analysts Spears & Associates say in a Bloomberg report.

But "green" fracking fluids - in essence partly biodegradable or environmentally friendly - have not yet entered into the equation in SA, where several multinational companies have applied to test the country's large untapped shale gas resources, estimated to be the world's fifth-largest at 485-trillion cubic feet, under the ecologically sensitive Karoo.

Mineral Resources Minister Susan Shabangu's moratorium on fracking in SA is still in place and she has yet to deliver to Cabinet a report from a task team established to investigate its pros and cons. Her office said this was imminent.

However, Energy Minister Dipuo Peters has claimed it would be "sinful" not to determine and exploit SA's resources. She has not been alone; at least two members of the National Planning Commission have also said SA should at least determine its reserve.

Specialist energy lawyer Luke Havermann says, however, that no reference to these fluids was made in any of the environmental management plans submitted by various companies that want exploration rights in SA, and if they wanted to add these fluids to the mix they would first have to make changes to their environmental management plans.

The National Environment Management Act requires environmental management plans - tools for ensuring avoidable adverse effects of the construction, operation and decommissioning of a project are prevented - for various activities, including mining. "The term 'green' is a relative term," says Gideon Steyl, associate professor in the University of Free State's school of chemistry.

The chemicals used to mine for nonconventional gases have been flagged by environmental groups, which say they will permanently damage the environment and infiltrate water reservoirs.

"Firms involved in fracking and even pure chemical companies are trying to sell 'green' fracking fluids.. They are trying to move away from using diesel, or extremely harmful chemicals, to more polymer-based fracturing chemicals.. They want to keep it more water-based or use components that are either biodegradable or environmentally friendly," says Prof Steyl.

FracFocus.org, the US hydraulic fracturing chemical registry, lists chemicals commonly used in shale fracturing: acid to remove near-well damage; biocides to control bacterial growth; corrosion inhibi-tors to prevent corrosion in the pipe; and friction reducers, such as diesel-based lubricants, to decrease the pressure on the surface and the pump engine emissions.

However, there are two stages to natural gas extraction: first, a well is dug, and explosive charges inserted and detonated to perforate the shale; second, the fracking fluid is pumped into the rock to fracture it and liberate the natural gas.

"Fracking fluid is a touchy subject because, to a certain extent, you have fluid staying at the bottom of the well.

"If it is a 'green' fluid, you mitigate your risk," says Prof Steyl.

But antifracking lobbyist Jonathan Deal, chairman of the Treasure the Karoo Action Group, says these "green" fracking fluids are so expensive their introduction into the South African debate would change the dynamics of the debate, from a cost point of view.

"These industry people are very clever. They have focused on fracking itself, and let all the ancillary pollution (issues) fall by the wayside.. Green fluids don't address the land issues, the water-use issues, the knock-on effect in terms of transport. That's one of the biggest costs in the US, transport, the cost of repairing damage to their road networks and our road network is falling down under present conditions," he says.

The most important aspect of natural gas exploration is that the techniques used - from drilling to the composition of the chemicals - vary according to the geography, geology and temperature, among other variables, of the area.

"Each frack job is tailored to a specific environment, so there isn't a standard system they can use," says Prof Steyl.

However, the fact is that while the "green" fracking process may be more environmentally acceptable in situ, it does not address the problem of fugitive emissions, which - according to academics from Cornell University - make the gas "dirtier" than coal.

"Compared to coal, the footprint of shale gas is at least 20% greater and perhaps more than twice as great on the 20-year horizon, and is comparable over 100 years," the authors write in an article, published in Climate Change Letters last year.

"In the short term, about 20-40 years, coal is cleaner than shale gas. But in the long term, about 100 years, then shale is cleaner than coal," Prof Steyl says.

"The question is whether you are prepared to pay that price."