Where the wild wind blows... (Steve Carver)
Author: Steve Carver
Wind turbines may be seen as either a blessing or a curse - as a symbol of our commitment to reducing our carbon footprint through green energy or a blot on the landscape, industrialising our most cherished views. Whatever your opinion, it is hard to ignore them as they sprout up across the countryside. Nowhere in the UK is this as obvious as in Scotland where the renewable energy industry and landowners have erected over 4000 turbines, encouraged by the Scottish government's stated aim of producing 100% of the country's electrical energy needs from renewable sources by 2020. Research by the Wildland Research Institute commissioned by the John Muir Trust in 2015 shows the spread of visual impacts from wind energy developments across Scotland over the last 20 years. In that time, the impacts from wind energy installations has gone from 1% of the Scottish landscape with a view of one or more turbines in 1995, to 16% in 2005 and 48% in 2015. An animated map of visual impacts has been produced and is available here.
Scotland has comfortably reached its intermediate 2015 target of generating 50% of its electrical energy from renewable sources, but it remains to be seen how it will succeed in finding sufficient sites with spare generating capacity to cover the remaining half of the 100% target. With several large, high profile wind farm proposals in remote areas of the country being rejected recently on landscape impact grounds this is causing concern in Scottish renewable energy circles. Knowing just where new capacity could be installed without impacting heavily on sensitive landscapes is therefore of great interest to planners and developers alike.
Viewshed analysis using Viewshed Explorer software (a bespoke rapid voxel-based viewshed modelling tool developed at the University of Leeds) has been used to identify remaining landscape capacity in Scotland that minimises the visual impact on areas of the country that are still free from visual impacts from wind energy developments. This shows how sensitive landscapes such as wild land areas, national parks and National Scenic Areas can best be avoided. This is no mean feat as it involves calculating just how much of a standard 125m high turbine would be visible if placed in any one of the roughly 8 million 100x100m grid cells in the country. Using off the shelf GIS-based visibility tools, this would have taken approximately 8 years of processing time, but using the Viewshed Explorer we were able to reduce this to about 20 days. Not only does the Viewshed Explorer tool calculate where a turbine can be seen from but also just how much is visible and what its relative impact is depending on visual distance decay functions. Example output is shown on the right.
One key finding from this research is that Scotland is essentially full! There are only a very limited number of places where new turbines could be built such that the remaining areas without of view of one or more turbines are not further reduced in size. These locations are in the main inside existing large wind arrays such as the 152 turbine Clyde Wind Farm south of Glasgow off the busy M74 motorway or the Fallo Rigg and Crystal Rigg sites in the Lammermuir Hills near Edinburgh. So called "Repowering" of older wind farms with newer, higher efficiency turbines might also be an option for helping close Scotland's renewable energy gap. Beyond these two options, it is likely that Scotland will have to target areas that will not have overly adverse impacts on the sensitive and beautiful landscapes for which Scotland is rightly famed. Sacrificing some landscapes to save others using an "eggs in one basket" model might be better than a more distributed approach when building large, industrial scale wind farms.
Author: Steve Carver
Links:
- https://www.johnmuirtrust.org/latest/news/721-animation-shows-dramatic-change-in-scotlands-landscape
- http://maptube.org/map.aspx?s=DHxXqBNgnLKiV3AsEJDApcHAp1bAoTjd
- http://www.wildland research.org/