The impact of Beauly-Denny


2 February 2010


On 6 January 2010, controversially, the Scottish Ministers approved the Beauly-Denny electricity transmission line upgrade. The proposal, by Scottish Hydro Electric Transmission Limited and ScottishPower Transmission Limited, received some 18,000 objections and was the subject of the longest and most expensive planning inquiry in Scottish history. The country's renewable energy industry has met the go-ahead to upgrade the electricity transmission system between Beauly and Denny with relief. But what is going to be the impact of the upgrade? This article discusses the impact of the new Beauly-Denny line on the renewables industry in Scotland.

Basic Beauly-Denny Facts

  • The overhead line will be 137 miles / 220 kilometres long and will replace the existing single circuit 132kV overhead transmission line with a 400kV double circuit overhead line providing more reliable capacity from Beauly, near Inverness to Denny, near Falkirk.
  • The upgraded line will comprise approximately 600 towers, 25% fewer than at present. The average height will be 53 metres, compared to the current 815 towers of an average height of 33 metres.
  • Over 86 kilometres of wirescape associated with the proposed line can be removed or improved.

  • Most of the new overhead line will be within one kilometre of the existing line which will be dismantled.

  • The spacing between towers on the upgraded line will average 360 metres, compared to a current average spacing of 250 metres.

  • Regulator Ofgem has estimated the cost of the upgrade between Beauly and Denny at £330 million, most of which will be borne by the electricity transmission arm of Scottish Hydro Electric Limited (SHETL) whose licensed area covers 200 of the 220 kilometre-long overhead line. The balance of the line falls within ScottishPower Transmission's licence area.

The Beauly-Denny line

We have regularly been informed that Scotland has the potential to become the "Saudi Arabia of the renewables industry" due to its natural resources and weather, both of which are conducive to renewable technologies such as wind and wave power. It is clear, however, that without the means to transport the electricity which is generated, this important industry cannot exploit its potential, being less able to attract investment and produce investment opportunities. Moreover, it is at risk of failing to reap the benefits of reducing the overall carbon footprint of Scotland and the UK. A lack of transmission capacity would be detrimental to Scotland's economy, losing out on expertise (which would otherwise go elsewhere) and investment in specialised and skilled manufacturing and construction industries.

The impact of the Beauly-Denny consent

The upgrade will increase the capacity of the electricity transmission network between the Highlands and central Scotland, permitting the harvesting of energy generated by windfarms and other renewable technology, and in turn contributing to the target for renewable electricity in Scotland.

In approving Beauly-Denny, the Government confirmed that developing the onshore and offshore grid connections is crucial to connecting, transporting and exporting Scotland’s renewable energy to the UK and Europe. The Beauly-Denny upgrade is designed to assist in meeting that aim.

The upgraded line will see the capacity increase from being able to transport 1.5 GW(gigawatts) of energy to at least 2.5 GW of renewable generation, and support wider grid capacity reinforcement to transport up to 5.2 GW in the North of Scotland grid.

The total generating capacity currently required by Scotland at peak demand is approximately 6.5 GW. It is clear, therefore, that the Beauly-Denny line will also play a large role in reducing the overall emissions of Scotland and the UK.

There are estimated to be over 50 potential projects totalling around 4.2 GW in the north of Scotland, two thirds of peak Scottish demand.

Initially, onshore wind generators will see the greatest benefit of the upgrade. But the consent also opens up transmission export opportunities to offshore wave and wind providers.

Is it enough?

The £330 million cost of Beauly-Denny represents only a fraction of the overall price for meeting the eight grid reinforcements which are "essential" according to the National Planning Framework 2 (NPF2) approved by the Scottish Parliament last year.

NPF 2 anticipates that further infrastructure will be required in addition to Beauly-Denny, however, if the Scottish 2020 target of a 42% reduction in emissions is to be met. The eight upgrades detailed within NPF 2 are:

  • overhead line and substation works to increase north-south transfer capacity in Central Scotland;
  • a new 275kV South-West Scotland transmission line;
  • strengthening the Scotland - England interconnectors to increase export capacity to 3.2GW;
  • upgrading the East Coast transmission route to 400kV;
  • upgrading the existing Beauly - Dounreay overhead transmission line;
  • reinforcing the Beauly - Keith overhead transmission line;
  • reinforcing the sub-sea cable link between Orkney and the Scottish mainland; and
  • new sub-sea cable links for the Outer Hebrides and the Shetland Islands.

It has been estimated that the total cost of National Grid upgrades that are needed to meet the 2020 emissions and renewables targets would be in the region of £4.7 billion, with Scotland's share of this being approximately £2.7 billion. But this sum excludes subsea links or offshore networks, such links being more expensive to install and maintain. And following the third round of offshore wind generation licenses granted by the Crown Estate, there is now an estimated 33 GW of wind capacity across UK waters requiring subsea links or offshore networks. It can be safely said, therefore, that Beauly-Denny is just the beginning.


It is clear that the Beauly-Denny upgrade has created a great deal of controversy. But the ambitious goals that have been set by the Scottish and UK governments to reduce emissions by 80% by 2050 will require some sacrifice. The delicate balance between retaining some of the most beautiful scenery in the world only partially spoilt, or permitting an upgrade which allows for truly renewable generation of electricity to proliferate, is certainly a difficult one not to be taken lightly. More difficult decisions are certain to be needed in the future if the goal of limiting the effects of climate change is to be achieved.