October 2006 - North Pickenham Wind Farm
After obtaining planning consent and resolving the financing of the project, in December 2005 a turnkey order was placed on Vestas to construct the North Pickenham wind farm, with Carters as subcontractors for the groundworks and Lamva for the cabling. Vestas are the largest manufacturer of wind turbines in the world.
Carters' contract for the foundations was design and build. They chose to pile, which reduced the amount of concrete required from 600m3 to 280m3 . Carters initiated the first stage of the construction process in April 2006 with some on-site road improvement. In a previous life, the wind farm site had been a World War Two airfield, so many of the roads and tracks needed for construction were provided by old runways and taxi-ways. The main access point to the Swaffham Road, however, had to be widened to accommodate the low-loader lorries that would eventually deliver the turbines.
| This shows the status of turbine 5, the piles have been hammered in but some of them met with some resistance, so they were left for a week to allow the surrounding chalk to stabilise before having another go with the piling machine. The piles are intentionally put in at angles to give the turbine more stability. The piles are 6m long. |
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| This is turbine 8. You can see from the pictures that the tops of the piles have been broken off and the reinforcement protrudes through the concrete base. The reinforcement was put in place before the concrete was poured to form the foundation. |
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We started with turbine 3 as we had to have an archaeological watching brief on this one, the idea was if we found anything we could stop work here and get on with another turbine. As it was, nothing was found so as you can see the foundation is almost complete. You can clearly see the foundation in the end was a cross and the reinforcement sticking out of the top was linked to the top hat. The top hat was placed between the two circles of steel which were then threaded through it and then it was filled with concrete. |
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Site manager with the completed top hat. |
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Lamva were also on site to carry out the cable laying. This picture shows the trenching machine. The chainsaw device which is in the trench removed the subsoil and it was kept separate from the topsoil (as can be seen in the photo) so that the soil could be returned correctly. |
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Delivery of the turbines commenced on schedule in early September 2006. The blades and nacelles arrived by sea from Denmark via Great Yarmouth. The towers (manufactured in three sections) were dispatched by road from Scotland.
This is a nacelle, the hub and heart of the turbine, looking uncannily like a huge mechanical insect! |
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One of the rotor blades on its low-loader. |
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A tower in three sections, awaiting installation. |
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The delivery in itself was no mean feat as the turbine sections are 26.5m long, and weigh in at 50 tonnes, and the 24 rotors are each 45 m long. Fortunately, no major modifications to the local access roads were necessary and after the removal of a few traffic signs, the low loaders got through comfortably.
The second construction phase commenced when the Vestas team and the 650 tonne crawler crane arrived from Holland (the latter had also been broken down into sections for ease of handling and dispatch).
By the final week of September, the first turbine was standing proud in the hazy autumn sunshine!
The installed capacity of the wind farm is 14.4 Mw (1.8Mw per turbine)
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