News analysis: Fracking protestors should find their focus
Government support for shale gas must not be at the expense of climate targets
Mark Venables argues that whatever happens about shale gas development, we must still act to tackle climate change.
Arguably, the protests against fracking around the Cuadrilla test site in Balcombe, Sussex, have missed the mark entirely. The protestors are leaving the threat of a serious blow to carbon reduction targets unchallenged.
So what is fracking, or more correctly hydraulic fracturing? Shale gas mainly consists of methane trapped in underground layers of shale with very low permeability. This gas does not readily flow so stimulation by fracking is required.
A borehole is drilled vertically to the gas-bearing rock, then continues horizontally. Once the well has been drilled and cased, electrically-triggered explosive charges perforate holes within the shale formation. A mixture of water, sand and chemicals is then pumped into the well under high pressure. This generates stresses, opening up existing fractures or creating new ones to release the trapped gas.
Fracking is not new. There are 2,152 inland wells in the UK and according to the Department for Energy and Climate Change (DECC) 200 have been fracked.
Under the strict licensing scheme prescribed by DECC, any shale production in the UK will be heavily regulated. Monitoring will control the process through a traffic light system: green for proceed, amber when certain limits are reached that means proceed with caution, and red, a full stop when upper safety limits are reached.
The real apprehensions are about climate change. Despite the recent assertion from Edward Davey, Energy & Climate Change Secretary, that the safe and responsible exploration of shale gas is in line with the UK's climate change targets, there are doubts. Davey was talking at the launch of a government report on greenhouse gas (GHG) emissions associated with shale gas extraction which estimates that the carbon footprint of UK-produced shale gas would be significantly less than coal and also lower than imported liquefied natural gas (LNG).
The report by DECC chief scientific advisor Professor David Mackay and Dr Timothy Stone, senior advisor to the secretary of state, says that with the right safeguards in place the net effect on GHG emissions from shale gas production in the UK will be relatively small.
If global GHG emissions are to be curbed, the production of shale gas needs to be married with carbon capture and storage (CCS) and a global deal on emissions targets at the 2015 UN Conference on Climate Change in Paris. Without such agreement it is likely that the coal and LNG will simply be burnt elsewhere.
Davey insists that shale gas exploration is necessary. "Gas, as the cleanest fossil fuel, is part of the answer to climate change, as a bridge in our transition to a green future, especially in our move away from coal," he said.
UK shale gas will not be the whole answer, though. "Nobody can say, for sure, how much onshore UK shale gas resource exists or how much of it can be commercially extracted, so we can't bank on shale gas to solve all our energy challenges, today or this decade," Davey added.
Prof Mackay agrees. "Shale gas is likely to have a GHG footprint no worse than other fossil fuels," he pointed out. "To ensure that shale gas exploitation doesn't increase cumulative GHG emissions it is crucial that society drives down the costs of low-carbon technologies, including CCS."
Professor Zoe Shipton, from the department of civil engineering at the University of Strathclyde, addressed environmental concerns. "There is no denying that seismic activity is inherent to the fracking process, but you have to consider the magnitude. Take a magnitude 5 earthquake; if you have got a dodgy chimney it may topple it but it won't do any damage to sound buildings. Most of the fracturing at the UK will take place below 5,000ft (1,500m) and its effects will be well below the threshold of what the BGS network can monitor."
Some worry that fracking could penetrate freshwater aquifers. "The concerns about aquifers are unfounded," Prof Shipton insisted. "Fracking will take place far below the drinking aquifers. The closest they will come is when they crack into an existing fault but they will still be the height of Ben Nevis away."
As with every facet of the shale gas process, more information is required both to develop a baseline position and monitor future changes. "The geology of the UK is complex," said Dr Rob Ward, director of groundwater science at the British Geological Survey (BGS). "We need to understand the relationship between aquifers and shale. We need to develop a 3D geological model."
Before there is another dash for gas it is vital to determine exactly how much shale gas lies beneath the British countryside. As BGS director of science and technology Professor Mike Stephenson explained, if there is no resource there is no need for the conflict.
Shale rock is a dull and boring rock, Prof Stephenson said, and has never garnered the interest of geologists. "It is the most common sedimentary rock and in many places in the Peak District you walk on it, although it does go several kilometres beneath the surface," he added.
Over the past year the BGS has used seismic data to plot shale rock formations and has estimated a resource of 1,329 trillion cubic feet of shale gas in the UK. "We were very surprised how high this figure is, but that is because the shale rock is up to 5km thick in some places" Prof Stephenson said.
A resource is the amount of gas that is in the ground, whereas a reserve is what can be extracted, which will be constrained by factors such as the geological formation, the'physical, social and environmental constraints, production capacity, economics and legislation.
"The [greenhouse gas] report should help reassure environmentalists that we can safely pursue UK shale gas production and meet our national emissions reductions targets designed to help tackle climate change," Davey insisted. But, he continued, "we must not and will not allow shale gas production to compromise our focus on boosting renewables, nuclear and other low carbon technologies".
"UK shale gas production must not be at the expense of our wider environmental aims ' indeed, if done properly, it will support them. I am determined to make that happen."
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