Case study: Gwynt-y-Mor, 576 MW

 

Kinewell Energy have redesigned the currently operating Gwynt-y-Mor offshore wind farm inter-array cable layout. The input data has been taken from publically available sources with reasonable assumptions used where necessary. We are happy to discuss these sources and assumptions with any potential clients.

 

In total the re-design yielded savings of £2.2m, or 3% of the installed cable cost. The installed design and Kinewell Energy improved design are both shown below along with a comparison between the two.

 

 

The overall cable length has reduced by 1.66 km. Despite this, the cable cost has increased by £0.18m due to a higher proportion of the total length using cable with a larger cross sectional area. At the same time, the installation cost has reduced by £0.34m because a greater proportion of the cable has been laid in shallower waters. The real benefit in this case study however comes through the reduction of electrical losses; some 1.2 GWh per year which is enough energy to boil the water of 5 Olympic sized swimming pools from room temperature.

 

During the re-design, the location of the substations was moved to see the impact on cost, as shown below for one of the substations. If the other substation was to be moved, then these diagrams would also change as a result. In the diagram on the left, the substation was moved over a relatively large area with the full inter-array cable layout designed at each substation location. In the diagram on the right, the inter-array cable layout design was kept constant and the location of the substation was microsited based on that design. The values relate to the cost relative to the lowest cost location within each diagram.