Scale of erosion on hilltops clear – but expert fails to endorse Viking figure
Sheep have destroyed the peat so completely on some Shetland hilltops that there is already little left for Viking Energy to disturb with turbines. That much was clear to a party of windfarm supporters and opponents who climbed Mid Kame on Wednesday with peat erosion expert Dick Birnie and saw the devastation.
Instead of storing carbon this once-intact peaty hill south of Voe is releasing carbon pollution into the atmosphere. As Dr Birnie said: “It is a source of carbon, not a carbon sink.” Some parts of other sites proposed for turbines, like North Nesting, are even worse, he said, having suffered 100 per cent peat loss.
Thankfully, overall “very little” of the windfarm zone is this bad, although he admitted he had not yet tramped the whole territory earmarked for turbines, roads and quarries, from Scatsta to Weisdale.
If you are not able to go and look yourself then check it out on Bing Maps on the internet with its aerial photos of Shetland’s hills, which are much clearer than on Google Earth.
Despite the gross peat erosion evident at Mid Kame, Dr Birnie could not endorse Viking’s recent controversial claim that 67.7 per cent of the windfarm areas are already deteriorating.
He said the calculation could be “hardened up” by Viking carrying out a full baseline survey, providing a true picture of the state of the peat.
Viking has used the statistic to help explain how it could claim in its windfarm application addendum at the end of September that it would take less than one year of generating green power to cancel out the amount of carbon released in the construction. Dr Birnie’s data on peat erosion had helped Viking revise its previous carbon payback estimate dramatically downwards from 14.8 years, to the astonishment and scepticism of opponents. However, carbon payback calculations, or guesstimates, are not his game and although in Shetland to give a public talk for the Windfarm Supporters Group, he is not in anyone’s camp on the big issue.
His view is that a renewable energy project is justified in terms of carbon pollution if it results in even a neutral impact overall, not necessarily having to show a positive benefit. For him the crucial factor with Viking Energy is how the site would be managed post-construction to minimise further damage and repair the ravages of the past.
Incidentally, he had suggested to Viking during his last visit in May that it should organise a summer public meeting on the top of the hill at Mid Kame, where a test mast stands at present, because there is no substitute for being there to see and talk about the erosion problem.
Viking’s revised windfarm plan would still require 735,100 cubic metres of peat to be excavated but one of its pledges is to “enhance” and restore the peat and arrest the nearby erosion. Part of the solution is seen as removing the sheep, controlling rabbits and hares, fencing off sites to allow vegetation to grow and removing drainage ditches which dry out the peat.
As Dr Birnie said: “We can’t do anything about history. We can about the future. The system can recover. It’s not a basket case but it’s a slow process.”
He works for the Macaulay Land Use Research Institute in Aberdeen and began measuring peat erosion on Mid Kame in 1983 until 1987. The small wooden stakes that he planted can still be seen 27 years later although a lot of the peat has vanished. He preached at the time that the cause was overgrazing by far too many subsidised sheep but the message fell on deaf ears.
Updating his information this year, he wrote Erosion of blanket bog within the site proposed for the Viking Windfarm: Field Visit Report which Viking submitted to the Scottish government as part of its addendum in which it cut the number of turbines from 150 to 127.
Viking reduced the amount of bog it would disturb by 23 hectares and cut out all eight turbines planned for the Collafirth area north of Voe to avoid digging up deep peat which is still in pristine condition.
It also proposes a larger number of controversial floating roads, which leave the peat in place but can sometimes sink. They are intended to go where the peat is over one metre deep. Double-track sections of the road are to be reduced from 12 metres to 10 metres wide and then reinstated to single track after construction.
On Wednesday’s walk, as the party of walkers made its way up from the roadside next to Petta Water, Dr Birnie drew attention to the telltale signs of “institutionalised overgrazing” and erosion where the protective heather, which anchors the peat, had gone. You could also still see the deep mossy grooves where a peat extraction machine had once marauded. All up the hillside sheep’s hooves had poached the ground, starting to break up the peat. Cuts become scars become gullies which can be seen easily from your car on the main road up and down much of the length of the site for the proposed windfarm.
Once at the top of Mid Kame the devastation is stark: a wide gash running along the summit to its north end where peat around six feet deep has vanished from an area wide enough to run a very wide main road through. The centre is worn right down to the hill’s grey stone while at either side the peat rises up again in “hags”, sometimes standing dislocated in unstable car-sized chunks, gradually being worn away by wind, rain and sheep seeking shelter. There are few of the small pools and lochans often found on hilltops where the peat bog helps retain the water. Instead it runs off the hillside, causing more erosion.
During his study period Dr Birnie calculated that the peat was being lost at a rate of over an inch a year (up to four centimetres), which is about one metre disappearing in as little as 25 years.
In spots like this Dr Birnie said it is too late to worry about losing peat because it has all gone, perhaps over the course of 60 years but probably 100. “It’s not a product of today
it’s something that’s been going on a long time,” he said. Of more concern here is how Viking would micro-manage its drainage in the area.
But it was not all bad news for the peat on Wednesday’s tour. A few hundred yards south of the great gash is a fence which runs up and down either side of the hill. On the south side the summit is still has some peat cover and is dotted with pools inside which the sphagnum moss is busy laying down the next layer of peat.
The fence, Dr Birnie said, is proof that the devastating over-grazing was worse on one side. Challenged about this theory, he revises it to “a high degree of probability” that the sheep caused it. The other side is an area of “recovering” peat which was more lightly grazed. So, as Kevin Learmonth of Sustainable Shetland, said, why allow Viking to dig up these areas of good peat, of which there are still many.
He said: “From our point of view putting roads and turbines through these areas which are regenerating is the worst possible thing to do.”
Mr Learmonth was joined by fellow Sustainable member James Mackenzie while the Windfarm Supporters Group was represented by Laughton Johnson. Three members of the media also went up and despite the strong wind and strong, totally polarised views, it was a very genial and positive day out.