Offshore power cable extra €50 million due to data?
Transmission System Operator (TSO) TenneT has revealed the Borssele
wind grid connection project cost more than expected before installation
works began. During subsea cable installation contractors found unstable
soil conditions within a specific area cable route (the Northern slope
of the Honte) which lead to increased costs.
Ahead of installation works, TenneT performed a route survey to investigate
the physical conditions of the subsea cable route. This route survey was
executed by an expert contractor who had extensive experience in performing
similar surveys. The data of these surveys did not indicate the physical
conditions of the Northern slope of the Honte. When executing the subsea
cable installation these unstable soil conditions were discovered and made
it necessary to apply a different working method.
The original contract was awarded to NKT Cables and VBMS (now part of Boskalis)
with a value of €160 million. As a result of the discovery of unstable
soil conditions, the work cost TenneT €210 million. Installation of the
subsea cable was completed towards the end of last year.
connection project will connect the Borssele
wind farm to the onshore grid it. The projects included the installation
of a 700 MW offshore substation, subsea cable and a new substation which
has been built next to the existing 380 kV Borssele high voltage substation.
first alternating current (AC) offshore platform on the Dutch part of the
North Sea, was and is now ready for use. Another seven of these 700 MW
standardised platforms will be delivered by 2027 for connecting future
offshore wind farms to the onshore grid. The next offshore connection system,
be completed by 2020. For the IJmuiden Ver wind area TenneT expects to
use two 2 GW converter platforms in combination with 525 kV cable.
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