Shale gas and GHG emissions: Better than coal, but needs good practice to be comparable with other gas
3 April 2014 at 7:36 pm
On 20 March 2014, the Department of Environmental Affairs launched a new piece of commissioned research on the greenhouse gas emissions associated with shale gas. We reproduce the conclusions from this report below – it makes for interesting reading, particularly for those who have been arguing that shale gas is the answer to the challenges of meeting South Africa’s climate change commitments.
It also supports one of the key recommendations in CER’s Minimum Requirements for the Regulation of the Environmental Impacts of Fracking (December 2013), namely eliminating venting and minimising flaring and other emissions by targeting zero venting and minimal flaring of natural gas, and generally reducing air pollution from fracking and associated activities. The absence or inadequacy of regulatory requirements to this effect was one of the reasons for our criticism of the proposed Fracking Regulations published for comment by the Minister of Mineral Resources in October 2013.
“Typically, natural gas is favoured over other fossil fuels from a GHG emissions perspective owing to its comparatively lower GHG emissions intensity at the point of combustion. However, the relative GHG emissions intensity of shale gas compared with conventional gas as well as other fossil fuels has been questioned given the extraction techniques and technologies (i.e. hydraulic fracturing) employed to access the gas and the estimated rates of fugitive emissions along the life cycle of the gas. The latter is considered by many studies to be potentially significant (although the degree to which varies across studies) but largely controllable using various mitigation technologies and methods.
“At the time of publishing, the research and literature on the GHG emissions intensity of shale gas extraction, production and use is large and growing. However, many studies utilise similar datasets from a small range of sources (primarily from the USA) and only one study based their findings on direct measurements of GHG emissions. Additionally, published studies utilise a variety of assumptions and methodologies which limits their comparability. As such, a clear understanding of the comparative GHG emissions intensities of different shale gas uses, and of the comparative lifecycle GHG emissions intensities of shale gas versus conventional fuels has not yet been reached. However, the majority of studies support the following conclusions:
- Shale gas combustion for electricity generation is less GHG emissions intense than coal-fired electricity generation;
- The lifecycle GHG emissions of shale gas are comparable to those of conventional gas sources, provided that good practice shale gas extraction is undertaken to minimise fugitive emissions;
- Mitigation of the majority of upstream fugitive emissions is possible; and
- Stage II (Production) accounts for the greatest non-use-combustion GHG emissions.
“A review of the literature around the lifecycle of GHG emissions of shale gas and the development of theoretical scenarios for South Africa suggests the following:
- Substituting imported fuel produced from crude oil refineries located outside of South Africa with fuel produced from the GTL process in South Africa with shale gas as a feedstock will likely increase GHG emissions in the country;
- Substituting coal with shale gas for electricity generation is favourable from a GHG emissions perspective;
- The use of shale gas as a direct source of energy for heating and cooking may have GHG mitigation benefits if it is substituting coal based electricity;
- The use of shale gas for the production of LNG may increase South Africa’s GHG emissions assuming that all of the LNG is exported out of the country and is not used to substitute other fossil fuels that would have been combusted in South Africa; and
- Additional research is required to conclude whether the use of shale gas as a source of fuel for transport in the form of CNG is better or worse from a GHG perspective.
“Although this study looks to understand the implications of potential shale gas extraction, production and use in the South African context, it is important to note that the data analysed is not South Africa-specific given that shale gas extraction and production has not taken place in the country at the time of publishing. Therefore caution must be exercised in drawing conclusions on the relative GHG intensity of shale gas against other fossil fuels.
“Overall, more research is required, particularly on direct measurements of GHG emissions, in order to better understand the GHG emissions intensity of shale gas extraction, production and use in South Africa.” (pp. xiii-xiv)
Download the full DEA Research Report.
Read more about the CER’s monitoring and inputs into the regulation of proposed hydraulic fracturing of shale gas in the Karoo.