Function
Decommissioning plans typically are required as part of gaining approval to construct. These may define specific requirements for removal of components below the mud line which in turn may drive the choice or design of substation foundations and installation methods.
What it costs*
Around £35 million for a 1 GW offshore wind farm.
Who supplies them
Substation installation contractors such as Boskalis, Saipem and Seaway Heavy Lifting (Subsea 7) can provide substation decommissioning.
Key facts
The process is likely to be a reverse of the installation process, although it may prove cheaper to cut the substation into sections for removal to enable a series of smaller lifts that can be undertaken by a lower cost vessel.
In some cases, there will be a market for reuse of second-hand electrical components, after refurbishment, as spares or for other applications.
If the remaining life of the substation structure and equipment, after refurbishment, is sufficient, the substation could be left in-situ and reused for a repowered wind farm of the same capacity.