With proper regulation, greenhouse gas (GHG) emissions from shale gas operations should represent only a small part of the total carbon footprint of shale gas and would fall within the nontraded sector of the United Kingdom’s carbon budgets, according to the Department of Energy & Climate Change (DECC).

In a 50-page report issued this week, the DECC said the carbon footprint from shale gas used for power generation was likely to be significantly lower than that of coal, but said the short- and long-term effects of shale development in the UK on global GHG emissions rates were complex to predict and depended heavily on global climate policies.

“The effect of a given level of UK production of shale gas on emissions, whether in the UK or globally, will vary over time,” said authors David MacKay and Timothy Stone. “Most of the effects arise through changes in (relative) prices affecting demand for and supply of gas and other fuels, especially coal, given the substitutability of gas and coal in electricity generation.

“In the longer term, price changes may cause changes in investment in alternate supplies of gas, changes in investment in competing energy sources, and changes in investment in demand-side efforts such as efficiency measures. Therefore, the effects on emissions will vary over time in ways that are challenging to predict.”

Many studies use life-cycle assessment (LCA) to analyze GHG emissions associated with shale development, and most of the current LCA data comes from the United States, noted MacKay and Stone.

“We have been cautious when extrapolating U.S. LCA results to the UK, because many of the circumstances differ, for example, geology and regulations that govern operation,” they said.

LCA studies in the United States “use a diverse range of primary research and data from shale gas studies. All authors consider that flowback could cause the highest proportion of emissions from shale gas exploration and extraction. There are, however, few quantifications of these emissions.”

Those quantifications, the authors noted, include 2011 studies by researchers at Carnegie Mellon University and a controversial, and discounted, report by a Cornell University ecologist Robert Howarth (see Shale Daily, Aug. 19, 2011; April 13, 2011).

“Even discounting the Howarth Haynesville [Shale] estimate as an outlier, there are widely varying estimates of well completion emissions,” MacKay and Stone said. “The variations are most likely due to different circumstances between study sites, for example geology and well productivity. Therefore whilst the data collected are a guide to the range of emissions associated with shale gas extraction in the United States, a more reliable figure for the UK can be established only by appropriate field measurements in the UK.”

“The UK is much smaller than the United States, and European energy markets are different, so we extrapolate from the American studies with caution,” the researchers said. “That said, if shale gas were extracted in the UK, and if the price of shale gas were low enough, one would expect, as in America: an increase in demand for gas; a switch of electricity production from coal to gas; and that UK shale gas production would substitute for a mix of UK production and imports, the latter of which could be by pipeline from Norway or the Continent or as LNG.”

The researchers said the net impact on the UK’s GHG emissions “would depend on the fuel that shale gas displaces and the degree to which price changes increase energy demand.

“Using carbon capture and storage on shale gas power generation (or any other uses of gas) would of course help meet climate targets.”

Earlier this month Cuadrilla Resources Ltd. said it would submit a new drilling application to cover flow testing from a conventional horizontal oil exploration well in southern England (see Shale Daily, Sept. 5). The company acknowledged that protests in August against hydraulic fracturing near a test well in Balcombe, West Sussex County, had impacted its plans (see Shale Daily, Aug. 20).

A report by the University of Nottingham suggested that public opinion in the country was beginning to shift in favor of unconventional natural gas development using fracking (seeShale Daily, Aug. 16). British Prime Minister David Cameron also said he supports shale development.