ARGYLL ARRAY PROJECT UPDATE No 18 October 2011
There have been a number of consultation and information events in Tiree over the last six months. I also write this regular update in An Tirisdeach. However, a number of people have commented that they would like to find out more about the development directly. I have, therefore, been hosting ‘Township Meetings’ over the last month or so. Two such meetings have been held so far. The meetings are by letter invitation to all residents of a number of neighbouring townships and are planned to be smaller and more relaxed events than island-wide meetings.
There’s no formal programme for the evenings; they’re relaxed opportunities for people to ask questions, discuss issues or hear more about the project, as they wish. I’m the only representative of ScottishPower Renewables at the meetings and members of the Tiree Trust are also invited along. Townships to the south and west of a line from Balevullin to Hynish have been involved in the two meetings held so far. Another three such meetings between now and Christmas will see all townships covered and I hope that as many as possible will be able to attend their particular meeting.
As well as these general meetings I also hope to meet with businesses in important sectors of the Tiree economy before Christmas.
Visit to Offshore Wind Farms
As I said in my last update, one of the issues arising from the visit to wind farms off the town of Barrow in the Irish Sea last month was the visual impact of jacket foundations for offshore wind turbines. Some of the turbines seen during the visit had jacket-type foundations.
The most common type of foundation used in onshore or offshore wind farms is the monopile foundation. As the name suggests, a monopile foundation is a single pile driven deeply and firmly into the ground or sea bed and upon which the turbine tower is fixed. This is what we often see in pictures of offshore wind turbines. Another type of foundation sometimes used in offshore windfarms is a gravity foundation. A gravity foundation is simply a large concrete block, sometimes filled with water, which rests on the sea bed and upon which a turbine tower is fixed. The visual effect of both monopiles and gravity foundations is that the turbine tower appears to rise directly out of the sea. A third type of foundation used for offshore windfarms is a jacket foundation. A jacket foundation looks different to monopile or gravity base foundations. A jacket is essentially a three or four legged structure, whose legs are piled into the sea bed to fix them. The legs are further strengthened by a metal lattice and the structure rises above sea level, with a platform on the top. It is upon this platform that the turbine tower is fixed.
No seabed surveys have yet been carried out on the Argyll Array site nor has any analysis yet been made of the environmental impact of the different forms of foundation. It’s therefore not yet possible to say what foundation type is likely to be used in the Argyll Array. SPR is, however, very aware of possible visual impact concerns about jacket foundations and this will be an important factor to be considered when making a decision about foundation types for the planning application.
Another issue that came out of the visit was the visual impact of the wind farms at night. The lights on the turbines were visible from shore and, while the effect was far from industrial, it was more than some on the visit had anticipated. A possible reason for this is the mandatory guidance on safety lighting and the number of individual wind farms in that part of the Irish Sea. An individual wind farm has navigation lighting on some turbines around its perimeter. When there are several separate wind farms, as is the case in that part of the Irish Sea, each individual wind farm has to be lit round its perimeter. This means that when looking at a number of wind farms off Barrow, there are more lights visible than there would be if these turbines were part of a single wind farm. Another possible reason is that the individual identification lights on the turbines seen during the visit appeared to be visible from 10 kilometres, and were much brighter than would be required in the Argyll Array.
For all individual offshore wind farms, including Argyll Array, one turbine roughly every 4 kilometres round the perimeter has a maritime navigation light. A number also have an aviation navigation light, designed to be seen from the air. Finally, each turbine in the wind farm has an identification light, to illuminate the turbine number on the tower, in the event that a vessel in distress inside the wind farm at night needs to identify its location. The identification lights in the Argyll Array would be no brighter than needed for that purpose i.e. visible from only 50 metres away. SPR therefore anticipates that the night time lighting in the Argyll Array would not have as much visual impact as that seen on the visit but is nevertheless aware of the sensitivity of the issue.
Night time lighting will be assessed in the Landscape and Visual Impact Assessment, carried out as part of the Environmental Impact Assessment of the project.
Questions or comments
If anyone has any questions or comments on any of the above, or indeed any aspect of the project, please contact me at – Donnie Campbell, ScottishPower Renewables Community Liaison Officer, Machair, Kilmoluaig in the first instance. My land line telephone number is 220 352, mobile number 07881 983 753 and email email@example.com