Natural gas extracted using hydraulic fracturing could be more damaging for the environment than coal, according to new research from the US.
The study, from Cornell University, reveals that shale gas, as it is known, releases at least 30% more methane into the atmosphere than conventionally-sourced gas and has a larger greenhouse gas (GHG) footprint than coal.
Hydraulic fracturing, or “fracking”, releases gas trapped underground by forcing large volumes of pressurised water into the shale and fracturing the rock. According to the study, during this process, and the subsequent drilling of wells, 1.9% of the methane in the natural gas is released, compared to just 0.01% in conventional gas extraction.
It concludes that the amount of methane released when creating the wells mean that over a 20-year period shale gas has a GHG footprint that is 20% greater than that of coal.
The lead author of the study, Robert Howarth urges caution in viewing natural gas as good fuel choice for the future.
“While it is true that less carbon dioxide is emitted from burning natural gas than from burning coal per unit of energy generated, the combustion emissions are only part of story and the comparison is quite misleading,” he said.
The research has refocused the debate around the safety and sustainability of fracking.
“The UK government should be cautious about allowing further shale gas exploitation until it is convinced that our own legally binding GHG emission targets will not be compromised,” warned John Barwise, chair of the Cumbria Green Business Forum and director of QoL Environmental Management and Communications.
Meanwhile, DECC said it would “closely monitor developments and consider the need for additional research to improve our understanding of the implications for policy.”
However, the gas sector has criticised the research, questioning its use of a 20-year timeframe over the 100-year span that is considered more relevant by climate change by scientists.
“This study lacks credibility and is full of contradictions,” said Russell Jones, senior economic advisor for the American Petroleum Institute. “It is really an exercise in selective data and manipulated methodologies used to reach conclusions that deliberately contradict mainstream science.”
