JOHANNESBURG (miningweekly.com) – An independent study commissioned by the Department of Environmental Affairs (DEA) has confirmed a long-argued position of shale gas and hydraulic fracturing proponents – that the volume of greenhouse gases (GHGs) emitted during the production and use of shale gas is lower than that emitted during the use and generation of coal-fired electricity.
The study, completed by consulting firm Environmental Resources Management (ERM) Southern Africa, found that, in comparing the GHG emissions profile of shale gas with conventional fuels, the “majority of research” suggested that coal-based power generation was between 30% and 55% more emissions intensive.
The life cycle GHG emissions of shale gas was deemed “comparable” to those of conventional gas sources, provided that “good-practice” shale gas extraction was undertaken to reduce “fugitive” emissions.
The report further held that a review of the literature around the life cycle of shale gas suggested that substituting coal with shale gas for electricity generation was “favourable” from a GHG emissions perspective.
“In addition, the use of shale gas as a direct source of energy for heating and cooking may have GHG mitigation benefits if it was substituting coal-based electricity,” it read.
However, the report also found that the GHG emissions-intensity of shale gas was at its highest after being converted to compressed natural gas (CNG), making its GHG intensity, in the form of CNG, similar to that of petrol and diesel on a per-kilometer basis.
ERM further noted that the “fugitive” emissions along the life cycle of shale gas could contribute “significantly” to the gas’s GHG emissions profile, particularly during the pre-production, production and processing phases.
However, these could be mitigated by implementing low-bleed pneumatic control devices, glycol dehydrator emissions controls and dry seal systems, among others, as well as by improving reciprocating compressor maintenance and pipeline maintenance and repair.
Commenting on the report on Wednesday, DEA chief policy adviser Peter Lukey said, while its findings informed the ongoing debate around fracking, shale gas “was still a fossil fuel” and its environmental implications remained largely unclear.
“What the report shows is that shale gas must replace a dirtier fossil fuel for it to reduce GHG emissions. If it just adds to conventional energy sources, it will also simply add to the overall GHG emissions.
Environmental Affairs Minister Edna Molewa added that it was “clear” from the research that, should shale gas replace other fuels, “certain uses” of the gas could have a “significantly positive” impact on the country’s GHG emissions mitigation efforts.
“However, it must be understood that it may only be some uses, not all uses, that have a positive impact. Furthermore, it must also be understood that, if shale gas is used in addition to, as opposed to, or to replace, other fossil fuels, then this simply means more GHG emissions, albeit possibly at a reduced emission growth rate,” she iterated.
Molewa further observed that the “greatest uncertainty” remained whether or not South Africa actually had an economically viable shale gas resource.
“Although we must be prepared for any eventuality to fully exploit the potentially positive climate change mitigation contribution of shale gas if a viable resource is discovered, we must not bank on this possibility,” she noted.
Lukey added that, while the market retained a largely bullish view on the existence of a significant shale gas deposit, the department was “still not sure” of its existence.
“There is either a lot [of shale gas] or nothing, and that's quite a high level of uncertainty,” he said.
Engineering News Online last week reported that there remained a large degree of confusion over legislation governing the potential exploration for and exploitation of shale gas.
While Mineral Resources Minister Susan Shabangu announced in January that government would move ahead “decisively, yet responsibly”, with the exploration of shale gas in the Karoo basin, she had since published two seemingly contradictory notices in the Government Gazette in February.
The first notice stated that no exploratory licences would be granted until an “appropriate law” was in place, while the other granted exploration licences in the country.
South African Oil and Gas Alliance CEO Ebrahim Takolia told Engineering News Online at the time that, while government appeared to be committed to the development of South Africa’s shale gas potential, it was taking “a measured approach” towards the potential environmental impacts.
He added that the restriction on new licences related to new applications, while companies that submitted applications before the original moratorium was put in place, such as energy and petrochemicals company Shell and Australian oil and gas explorer Challenger Energy subsidiary Bundu Gas & Oil Exploration, would be able to continue with their application processes.
“I sense that government wants to avoid a gas rush and speculative applications. I think the future of shale gas exploration is still positive – given the potential size of the prize – but the regulatory uncertainty, with regard to not only fracking but the current development of the Gas Act, the Mineral Resources Petroleum Development Act and the Gas Master Plan being developed, must be removed to encourage ongoing investment and development,” Takolia asserted.