Big projects, small details
Gode Wind 3
A first for Jan De Nul to install an offshore substation
Made in France

Chantier de l’Atlantique in Saint-Nazaire, France, fabricated the 1,900 tonnes offshore substation and 350 tonnes modular support frame. Because of the size and weight of both components, the transport overseas needed to be prepared meticulously. The size of the barge, the power of the tugboat, the exact position of both components on board, the sea fastening, the position of the rigging tools... everything was prepared down to the last detail, as no manipulation was possible once the barge had left the yard.

“We were able to deliver this part of the project within the set timeframe. This achievement is a good preparation for our staff and installation teams for all future assignments with our next-gen vessel Les Alizés.”
Paolo De Temmerman, Works Manager for Jan De Nul Group on the Gode Wind 3 offshore wind farm project.

Germany
Eemshaven

The Netherlands
45 km
distance to shore

The larger DolWin Kappa convertor station,
in turn, converts the delivered AC of several German offshore wind farms to 320kV DC. Through a 900MW HVDC DolWin6 export cable link the electricity is brought to shore.

For the installation of the monopile foundations we used the IQ6, the largest hydrohammer in the world, fitted with the PULSE system of IQIP for noise reduction at the source.

The installation of this offshore substation is part of the bigger project Gode Wind 3 offshore wind farm of Ørsted. The construction of this 242 MW offshore wind farm is taking place in parallel with the company’s 900 MW Borkum Riffgrund 3 project. Les Alizés is contracted to install all 107 monopile foundations needed for both wind farms, including this offshore substation and connecting modular support frame.

120 km
1,415 km
1 year

from Eemshaven to installation location

from Chantier de l’Atlantique to Eemshaven

of preparations for smooth transport

to reach the
German North Sea

8 days

Windfarm

Eemshaven

Yard in Saint-Nazaire

A modular support frame connects the monopile foundation to the offshore substation’s topside. Les Alizés lifted the frame onto the monopile after which our team secured it with bolts.

The top of the frame has four connection points onto which the OSS fits, thus anchoring both parts together.

The modular support frame
MSF

Planned wind farms

Offshore substation
Gode Wind 3 offshore substation
Gode Wind 3
250,000
242 MW
11 MW each
30 m
40 m
25 m
37 km
distance to shore

DC transmission is needed to transport large volumes of electricity over long distances. From a certain amount of power (MW) and a certain distance (approx. 100 km) the losses in a HVAC system become too big. In such cases conversion to DC is a more economical solution compared to high-voltage AC.

The Gode Wind 3 offshore substation stands as tall as a 5-storey building and gathers the produced electricity of 23 Gode Wind 3 turbines of 11MW each. The substation converts the 66kV AC to 155kV AC and sends the electricity through a subsea HVAC export cable to the DolWin Kappa convertor station.

1,900
tonnes
The offshore substation
A heavy challenge

Extra challenging: the installation needed to be done in floating conditions. The crane vessel Les Alizés is fitted with a powerful dynamic positioning system (DP2), keeping the vessel in position at all times. The barge which carried the offshore substation and modular support frame, moored alongside Les Alizés. The vessel’s main crane picked up its load in floating conditions, a challenge where coordination, precision and weather conditions were key.

After the project kicked-off in July with the installation of the first 6 monopiles for Gode Wind 3, the crane vessel installed her very first offshore substation. The load was lifted and meticulously placed on top of its foundation.

Our next-gen crane vessel Les Alizés successfully installed the heaviest load of the project: a 1,900-tonnes offshore substation topside with connecting modular support frame.

Big
projects, small details

Whether it’s about constructing wind turbines at sea, installing a bridge across a river, or the remediation of a polluted site: large projects only succeed when you pay attention to the smallest details. Even in supersized structures, the margins are narrow, with less than a centimetre to spare.

Let’s take a closer look at the installation of the offshore substation for the Gode Wind 3 offshore wind farm in Germany. A first for Jan De Nul to install an offshore substation, and a first for our newest crane vessel Les Alizés on her maiden assignment.

OSS
Big projects, small details
A first for Jan De Nul to install an offshore substation
Gode Wind 3
“We were able to deliver this part of the project within the set timeframe. This achievement is a good preparation for our staff and installation teams for all future assignments with our next-gen vessel Les Alizés.”
Paolo De Temmerman, Works Manager for Jan De Nul Group on the Gode Wind 3 offshore wind farm project.

For the installation of the monopile foundations we used the IQ6, the largest hydrohammer in the world, fitted with the PULSE system of IQIP for noise reduction at the source.

The installation of this offshore substation is part of the bigger project Gode Wind 3 offshore wind farm of Ørsted. The construction of this 242 MW offshore wind farm is taking place in parallel with the company’s 900 MW Borkum Riffgrund 3 project. Les Alizés is contracted to install all 107 monopile foundations needed for both wind farms, including this offshore substation and connecting modular support frame.

to reach the
German North Sea

Yard in Saint-Nazaire

of preparations for smooth transport

1 year

from Chantier de l’Atlantique to Eemshaven

1,415 km

Windfarm

from Eemshaven to installation location

120 km
8 days

Chantier de l’Atlantique in Saint-Nazaire, France, fabricated the 1,900 tonnes offshore substation and 350 tonnes modular support frame. Because of the size and weight of both components, the transport overseas needed to be prepared meticulously. The size of the barge, the power of the tugboat, the exact position of both components on board, the sea fastening, the position of the rigging tools... everything was prepared down to the last detail, as no manipulation was possible once the barge had left the yard.

Made in France

A modular support frame connects the monopile foundation to the offshore substation’s topside. Les Alizés lifted the frame onto the monopile after which our team secured it with bolts.

The top of the frame has four connection points onto which the OSS fits, thus anchoring both parts together.

The modular support frame
MSF

DC transmission is needed to transport large volumes of electricity over long distances. From a certain amount of power (MW) and a certain distance (approx. 100 km) the losses in a HVAC system become too big. In such cases conversion to DC is a more economical solution compared to high-voltage AC.

The larger DolWin Kappa convertor station,
in turn, converts the delivered AC of several German offshore wind farms to 320kV DC. Through a 900MW HVDC DolWin6 export cable link the electricity is brought to shore.


The Netherlands

Germany
Eemshaven
45 km
distance to shore

Planned wind farms

Gode Wind 3
11 MW each
250,000
242 MW
Offshore substations
37 km
distance to shore
1,900
tonnes
40 m
30 m
25 m

The Gode Wind 3 offshore substation stands as tall as a 5-storey building and gathers the produced electricity of 23 Gode Wind 3 turbines of 11MW each. The substation converts the 66kV AC to 155kV AC and sends the electricity through a subsea HVAC export cable to the DolWin Kappa convertor station.

The offshore substation
OSS

Extra challenging: the installation needed to be done in floating conditions. The crane vessel Les Alizés is fitted with a powerful dynamic positioning system (DP2), keeping the vessel in position at all times. The barge which carried the offshore substation and modular support frame, moored alongside Les Alizés. The vessel’s main crane picked up its load in floating conditions, a challenge where coordination, precision and weather conditions were key.

After the project kicked-off in July with the installation of the first 6 monopiles for Gode Wind 3, the crane vessel installed her very first offshore substation. The load was lifted and meticulously placed on top of its foundation.

Our next-gen crane vessel Les Alizés successfully installed the heaviest load of the project: a 1,900-tonnes offshore substation topside with connecting modular support frame.

A heavy challenge

Whether it’s about constructing wind turbines at sea, installing a bridge across a river, or the remediation of a polluted site: large projects only succeed when you pay attention to the smallest details. Even in supersized structures, the margins are narrow, with less than a centimetre to spare.

Let’s take a closer look at the installation of the offshore substation for the Gode Wind 3 offshore wind farm in Germany. A first for Jan De Nul to install an offshore substation, and a first for our newest crane vessel Les Alizés on her maiden assignment.

Big
projects, small details