Viking says its wind farm is an exemplary model for building on peat land
Published on March 8th 2013
Viking Energy said this week its project sets a high standard for building wind farms on peat land. It incorporates the only plan in existence for reducing the damaging greenhouse gases already escaping from eroded peat in the Central Mainland of Shetland.
The community-backed wind farm developer has highlighted its pioneering approach in response to claims that some wind farms on peat land might release more carbon dioxide than they would save over their lifetime.
Viking Energy project officer David Thomson said the opposite was clearly the case for its wind farm.
"As is already well publicised, the estimated time to pay back the carbon released from building the Viking wind farm is less than one year after starting to generate clean green power.
"One of the reasons our payback time is industry-leading is the greater output levels achievable from Viking's turbines due to Shetland's strong winds."
A number of other aspects make the Viking development an exemplary model for building on peat land. During project development Viking took major steps to avoid areas of pristine peat bog, including removing an entire section of proposed turbines in the Voe and Collafirth area.
Mr Thomson said: "The disturbance of peat in the Viking wind farm is targeted at the areas of peat in poor condition and avoids healthy peat wherever possible. That's why we did so many field studies, so we could demonstrate exactly what would be disturbed."
Up to two-thirds of the peat that would be disturbed on the wind farm site is already degraded and exposed. Its poor condition means it is already emitting rather than storing carbon and without the planned positive intervention by Viking's wind farm it will continue to degrade until it disappears.
In 2010 Macaulay Scientific Consulting (MSC) reported extensive areas of bare peat surfaces with no heather or turf covering, particularly in the Nesting area, concluding that none of the blanket bog within the wind farm site could be described as pristine. In fact, it estimated that the greenhouse gases already escaping from the wind farm site could be as much as those from one of the major industrial complexes in Shetland.
One cause of erosion has been long-term overgrazing and other damage by sheep. Their numbers have much reduced in many Shetland hills in recent years.
Dr Richard Birnie of MSC calculated that peat was being lost from the top of Mid Kame to a depth of about four centimetres each year. MSC estimated some areas of peat up to one metre deep could disappear entirely within 25 years if nothing is done.
Mr Thomson said: "We have a site that is already losing its CO2 and we're proposing to do works that will mean the site releases less than it already is.
A pilot project for bog restoration and re-vegetation of bare peat has been proposed for an area of North Nesting. Lessons learned from that experience would shape the rest of the habitat management plan, which may run for 20 years or more.
The peat restoration and other conservation work would be done at Viking Energy's expense and in partnership with an independent environmental advisory group and a range of conservation bodies.
Mr Thomson commented: "Wind farms offer an opportunity to introduce proactive conservation to the Shetland hills that nobody else is currently showing any inclination to do. It will also provide an additional source of income for crofters in the area."
During wind farm construction most of the peat dug up for roads and turbine bases will be reused. Extensive measures will be taken to prevent hill peat drying out, including drainage control and the restoration and creation of small lochans to help keep peat waterlogged. It is hoped that many of the "floating" roads built over peat will not require drains at all.
The wind farm layout has been devised to minimise the risk of peat slides. Mr Thomson said: "Peat slides occur naturally from time to time in many parts of Shetland and there is evidence of slides from various times in history. It is possible to avoid increasing naturally present risks by using good construction practices and specific peat management plans."