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Friday, 16 October 2015

Issue 14: Shale Gas and Traffic



Figure 1.  The rate of accidents involving heavy trucks in counties in Pennsylvania with 20 or more wells operating before 2012, the rate for those counties with less than 20 wells, and the number of well pads drilled, using Pennsylvania Crash Reporting System data. (Resources for the Future report, September 2014).

Traffic... 
It takes lorries to develop a shale gas pad – lots of lorries and other vehicles. They are needed to prepare the site, construct the rig, carry the drilling string and casing, import the drilling and fracking fluids, export the flow-back fluid, carry drilling staff, inspectors, managers and scientific monitoring teams, take down the rig and sometimes to export the produced gas. If there are protests, there is also an increase in protestors' traffic, and the consequent traffic associated with policing and security.

Balcombe
How much traffic was a question that was asked by the Parish of Balcombe when test drilling was proposed there in 2013. The Balcombe Parish Council produced a very reasonable and readable report that touches on every aspect of the proposed drilling. Its section on traffic states that they were expecting seven to eleven weeks of activity with the largest vehicles being expected at the start and the end of that period, associated with the construction and taking down of the rig. They expected 10 Heavy Goods Vehicles (HGVs) per day for the majority of the period and 30 HGVs per day for the most active two weeks at each end of the drilling. The light vehicle traffic was also expected to increase by 30 vehicles per day.

How does that compare with the background traffic through Balcombe? Well, of the 10,000 vehicles per day that have been measured to pass through Balcombe in several recent surveys, 4000 use the road that was to be used for the drilling traffic, and of those 200 were HGVs. That implies an increase of 15% in the HGV traffic for the busiest 2 weeks, 5% for the remaining 5 to 9 weeks, and less than 1% for the light vehicles.

In practice, it did not work out quite as it was planned. Local figures indicate that fracking protests delayed and obstructed HGV traffic sufficiently to ensure that many lorries took two or more attempts to access the site, while the estimated 5000 fracking protestors' cars and vans increased the light vehicle traffic by over 50% compared to the background level on some days; an irony given that no fracking was even planned at the site.

The Balcombe experience is just an interesting story; the development of a fully-fracked 40 lateral pad such as that which would be used in full scale shale gas exploitation is a different kettle of fish. What would be the traffic required for that?

Likely UK Scenario
The Institute of Directors have used data from high quality sources, mainly provided by the European Union, to estimate the number of lorry movements associated with shale gas production. They estimate that a single 10-well pad of 40 laterals could see 11,155-31,288 truck movements over 20 years, depending on whether the water comes from a mains connection or is brought in by road. Assuming truck movements are concentrated in the early years of drilling activity, this averages out at 6.1-17.1 per day over five years. This number accords well with the Cuadrilla/Balcombe Parish Council figure of about 20 per day, but over a shorter period (6 weeks) for the Balcombe case because they were envisaging one well with one lateral.
Spilt Milk!
It is worth putting this number of lorry and tanker movements into context. British dairy farmers produce 11 million m3 of milk each year. Milk tankers vary in size, but assuming a tanker capacity of 30 m3, 366,667 milk tanker journeys would be needed each year in rural locations to transport milk from the farms where it is produced. Consequently, if you are not inconvenienced by milk tankers, it is unlikely that you will be inconvenienced by the development of the 400 lateral per year annual development , which is the likely size of a maturing UK shale gas industry.

US Shale Gas Road Fatalities
On balance, therefore, it would seem that the increase in traffic caused by shale gas development would be significant, when considered from the point of view of the number of extra vehicle journeys to be undertaken, but insignificant when put in the context of all the other journeys that happen on our roads every day as a matter of course. However, there is one very important piece of information that we have not yet considered. The largest loss of life associated with shale gas developments worldwide (mostly in the USA) is from road traffic accidents; accidents which often involve large tankers using roads that were not designed for them and local rural traffic that had hitherto had the lanes to themselves (Figure 1). Fault does not always lie with the shale gas traffic either, but the sharing of small, rural roads does lead to loss of life. Although the number is still small, and much smaller than the loss of life from coal-generated air pollution, each loss is significant for those involved.


Resources for the Future (RFF) is a voluntary funded organisation in the USA which was involved in developing environmental economics over 60 years ago. It provides high-quality objective research and analysis on critical issues such as energy, climate, ecological quality, and forest management. Resources for the Future published a report in September 2013 which examined the impact of heavy goods vehicles on the safety of roads in those areas where shale gas exploitation was being carried out in Pennsylvania using that state’s Crash Reporting System (CRS). They compared the rate of accidents involving heavy trucks in counties with 20 or more wells operating before 2012 to the rate for those counties with less than 20 wells, and compared both to the number of well pads drilled. The result is shown in Figure1 above. It is clear that the increase in the accident rate for counties with greater than 20 wells compared to those with less than 20 wells after 2009 when they had been approximately the same at earlier dates correlates strongly with the post-2009 increase in well pad drilling. In fact the increase in traffic accidents involving heavy goods vehicles is 2% for every new well drilled per month.

What might we expect in the UK? - That will  be the subject of a further posting.

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