The Scottish Government has recently approved increases in turbine heights – now set to reach 150 metres (490 feet) to blade tip – at the extension to the Gordonbush wind farm in the far north of Scotland, near Brora in Sutherland. The approval brings many significant public interest questions into the spotlight.
Golden Plover image : Stuart Anthony
The Gordonbush wind farm is notorious for its impact on wildife in the area, particularly Golden Plover. A study by the RSPB found that
"numbers of the plover, which are protected under the European Birds Directive, dropped by 80 per cent within the wind farm during the first two years of operation, with these declines being markedly greater than on areas surrounding the wind farm that were studied over the same period."
The existing Gordonbush wind farm lies behind a grid bottleneck and has consequently been paid over £16.4 million to reduce output since it was commissioned in 2012. The 227.5 GWh of electrical energy discarded over that period is roughly equivalent to the annual consumption of over 50,000 Scottish households. (Wind farm constraint data is available on the Renewable Energy Foundation charity's website.)
Typically, and Gordonbush is no exception, a wind farm makes more per unit of electricity constrained off the network than when selling normally to consumers. In the specific case of Gordonbush, when constrained off, the RO subsidy forgone is about £50 per MWh whereas the site owners charge over £70 per MWh for reducing output when constraints exist.
The volume of energy lost through constraints is in total significant, and in some periods can be very substantial as the following chart shows. In March 2014 a striking 49% of output was constrained off at a cost to the consumer of more than a million pounds. The annual constraints for Gordonbush peaked at 22% of potential output in 2015, and have been at 15–16% for the last two years.
It is important to note that the new £1 billion Western Link interconnector from Scotland to England which was built specifically to improve exports of Scottish wind power has not prevented nearly 20% of Gordonbush’s potential output being constrained off in September and October of 2019. It is not clear that the Western Link interconnector, and its implied standing charge on the consumer, estimated about approximately £50 million a year, is good value for money.
Figure: Generated and constrained off energy by month for Gordonbush wind farm to October 2019
It seems that locating a wind farm at Gordonbush was not clearly in either the public or the environmental interest. The decision to extend and now permit still larger turbines will be very puzzling to many observers.
It is of course advantageous for the wind farm's owners. The addition of extra turbines to sites of this kind is clearly attractive for wind farm shareholders, and there are many such proposals in the offing around Scotland. However, the planning merits of these applications are dubious at best. Nevertheless, Gordonbush extension was consented, as was the application to vary that consent and install larger turbines.
There is clearly a pressing need for a transparent public debate about further expansion of wind power in Scotland. Since 2010, and at a cost of nearly £600 million, some 8.2 TWh of Scottish wind energy has been discarded, a quantity equivalent to the annual consumption of about 2 million households. The total in 2019 so far is 1.6 TWh at a cost of £113 million. A record year seems likely, in spite of the presence of the new Western Link interconnector to England, which was meant to alleviate these costs.
One has to ask whether it is really on balance beneficial to add more wind farms in Scotland when the system cannot accommodate at reasonable cost the output of those already built.