The substation installation vessel transports and lifts the offshore substation into position on a pre-installed foundation.
What it costs
This is included in the substation installation contract.
- Day rates for most substation installation vessels are about £230,000.
- Semi-submersible vessels may have day rates greater than £450,000 but if the oil and gas market is quiet then rates may be more competitive.
Who supplies them
Bonn & Mees, Heerema, Huisman, Saipem, Scaldis Salvage & Marine, Seajacks, Seaway 7 and ZPMC.
There are four main types of substation installation vessel:
- Heavy lift vessel
- Semi-submersible vessel, and
- Sheerleg crane vessel.
The choice of vessel is likely to be driven by market factors and, in many cases, if vessels serve other markets. As a result, there has been little investment in vessels for the offshore wind market specifically.
Heavy lift vessels used in offshore wind include Rambiz, Sleipnir, Stanislav Yudin and Samson.
Crane ratings required for substation installation vessels are from 900 t to over 3,000 t.