Scottish and Southern Electricity Networks (SSEN) and Balfour Beatty have successfully energised the connection for Dorenell wind farm in Moray.

The wind farm connection, which will add capacity for a further 220 MW of renewable energy to the GB transmission system, has seen the deployment of composite poles, the first time this innovative technology has been used on the GB transmission system.

As the transmission owner for the north of Scotland, SSEN is responsible for providing connections to its transmission network for generators looking to export to the national grid. When planning the connection for Dorenell wind farm SSEN had to overcome various challenges to meet the grid connection date required for its generation customer, EDF Renewables.

These challenges began with local opposition to the use of conventional steel towers due to the cumulative impact in the local area. To further complicate matters, local landowners opposed the alterative conventional infrastructure of twin trident overhead wooden poles, due to the footprint this would have on their land.

To overcome these challenges and maintain the grid connection date for the wind farm, SSEN and Balfour Beatty developed an innovative solution whereby composite poles were deployed to provide the grid connection. This resulted in a far smaller footprint on the land and a less visually intrusive impact than both steel lattice towers and twin trident wooden poles would have had.

In order to install the innovative technology in the tight timescales required to meet the grid connection date, a specialist helicopter was deployed to the fly the composite poles into location. All the poles were pre-constructed in a purpose-built assembly yard which improved efficiencies, safety and quality control and crucially, allowing each pole to be flown into position, greatly speeding up the time taken to construct the overhead grid connection.

All 140 composite poles required for the grid connection were safely and successfully installed in just five days, far quicker than conventional crane installation methods would have taken. The impact on the land was also massively reduced, removing the need for significant access tracks that would normally be required to provide this type of grid connection.

As well as meeting the primary objective of maintaining the grid connection date for SSEN’s generation customer, composite poles also provide a number of benefits compared to more traditional forms of network infrastructure.

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This innovative technology - which is already being used successfully in Canada, the USA, Scandinavia and Ireland - uses a durable composite polymer instead of the traditional timber and has been specially adapted to meet the unique terrain and environment of the north east of Scotland. This therefore eliminates the need to harvest trees, which helps reduce greenhouse gas emissions, carbon consumption, and the degradation of ecosystems. In addition, composite poles demonstrate a longer lifespan and can be repurposed or recycled at the end of their useful life.

SSEN’s lead project manager, Paul Higginbotham, said: “We are delighted that we have delivered the successful energisation of the Dorenell wind farm connection on time, ready for our generation customer to start exporting to the National Grid.

“Despite being faced with a number of significant challenges to overcome, the innovative solution we developed with Balfour Beatty has ensured that we met the needs of our customer as we continue to enable the transition to a low carbon economy through the decarbonisation of the electricity system in the north of Scotland.

“The successful deployment of composite poles on our network is also an exciting development which we will now be considering for future grid connections and network reinforcements.”

Andy Smith, operations director for Balfour Beatty’s power transmission and distribution business in Scotland, added: “Working in collaboration with SSEN, Balfour Beatty identified and developed a truly innovative infrastructure solution that ensured the safe and efficient energisation of the Dorenell wind farm.

“The use of a specialist air crane helicopter and durable composite plastic poles, allowed the Balfour Beatty construction team to overcome the rugged terrain in North East Scotland whilst minimising disturbance to the environment and community.”