Onshore wind farm
Dunmaglass Estate, Inverness, Scotland
Start of Construction
Developed by SSE Renewables, Dunmaglass is a 94.05MW wind farm situated 25km south of the city of Inverness, Scotland. At 700m above sea level, it is the highest wind farm ever constructed by the Scottish energy company.
The Scottish Government approved the wind farm in December 2010. SSE acquired the 33-turbine project from Renewable Energy Systems Group (RES) in May 2013.
Construction of the wind farm was initiated in 2014, and the turbines were delivered in May 2016. The final turbine was installed at the site in October 2016, and full-scale operations started in December 2017. The total investment for the project was £200m ($267.7m).
SSE Renewables reached an agreement with Greencoat UK Wind, a renewable infrastructure investment fund, for the sale of a 49.9% stake in its Dunmaglass and Stronelairg wind farms in a deal worth £635m ($833.2m) in February 2019. The deal was completed by the end of March the same year.
Dunmaglass wind farm make-up
GE was contracted to supply 33 of its 2.85-100 wind turbines with 70m-high towers for the Dunmaglass project. The company custom-designed and developed the turbines for the project to meet the strict constraints imposed by the local authorities, which required a maximum blade tip height of 120m. Each turbine is up to 120m high to the tip of the blade, whereas the hub height is 80m.
Other components of the project include two 80m-high anemometry masts, 12.5km of upgraded roads, 20km of new access roads, a new substation, on-site borrow pits and a construction camp.
Power transmission system for the Dunmaglass wind farm
A new substation known as Farigaig substation was built outside the farm, near Torness, Inverness. The 275/132kV substation comprises a control building, two super-grid transformers and two steel overhead line towers.
The substation connects the wind farm to the national grid for the distribution of the generated power. Scottish Hydro Electric Transmission established a new electrical connection using both overhead and underground cables to establish the connection.
A section of the overhead trident wood poles from the Farigaig substation was connected to a new terminal pole located 1.5km north of the junction. An underground cable section was also built between the new terminal pole and Farigaig substation to avoid unnecessary overhead lines near the substation.
RJ McLeod, a civil contractor based in Highland, was awarded two civil work contracts including a £5.5m ($8.85m) enabling works contract and £16m ($25.74m) civil engineering works contract.
The scope of the enabling works included the construction of two temporary timber deck bridges, main works site compound, new platform for the on-site substation, upgrading of the existing track and development of the on-site rock borrow pit.
The main civil works contract included the construction of bases for the 33 turbines and crane hardstandings as well as related cabling and drainage works.
Ground engineering and sustainable solutions provider Aarsleff was responsible for the installation of 140 piles for four wind turbines.
Dunmaglass wind project benefits
The wind project was expected to help the Scottish Government’s goal of generating sufficient renewable energy to meet 100% of gross annual consumption by 2020. It produces clean, carbon-free electricity sufficient to cater to the needs of more than 40,000 households a year.
The project is also designed to help reduce green gas emissions by displacing between 80,000t and 180,000t of carbon dioxide emissions a year.
Over its lifespan, the wind farm will contribute £4m ($5.35m) towards a community fund, which will be spent on local community projects.