I was having an exchange of views with Michael Liebreich on Twitter yesterday. He was getting a bit excited about the number of vehicle movements associated with developing a shale gas pad, saying that the public needed to know that they would be on the receiving end of 60 HGV movements per day. We talked about the duration of these 60 movements per day and I pointed out that the AMEC report on shale had come up with a range of 14-51 movements per day, depending on whether water was tankered in or came straight from the mains.
This seems to have prompted a blog post from David McKay, the former chief scientist at DECC, who set out an analysis of vehicle movements for construction of a shale gas pad, a windfarm and a solar array. He came up with a range of 2900-20,000 movements in total for a 10-well pad, as compared to 7000 for an 8-turbine windfarm. I pointed out to him that his figures had nothing to cover access road construction, and so he redid the figures, coming up with a revised estimate of 7800. One could consider adding more to cover removal of soil for the foundations, but since this might be disposed of onsite, it is arguably valid to leave it out.
So the comparison now looks more reasonable in my opinion. What does need to be emphasised, however, is that the 2900 figure for the shale gas pad is far more plausible than the 20,000 one. Shale gas developments in the UK are going to be close to water mains, almost without exception. It is therefore highly implausible that shale pads are going to need anything like 20,000 HGV movements. Cuadrilla say this:
A high proportion of the vehicle movements associated with onshore natural gas extraction are associated with the transport of water to and from wells. As most of our wells will be supplied by water from the mains, this cuts the number of vehicle movements required. If we started commercial production, much of our water would be recycled, further reducing the numbers of vehicles on the roads.
I conclude that overall windfarms will require a minimum of 2-3 times as many vehicle movements as a typical shale pad.