Jan De Nul Group was awarded the EPCI-project (Engineering, Procurement, Construction & Installation) for both the foundations and subsea cables for the Formosa 2 OWF in 2019. This became the third offshore project for Jan De Nul in Taiwanese waters. Formosa 2 was developed by JERA, Macquarie’s Green Investment Group (GIG) and Synera Renewable Energy (formerly Swancor Renewable Energy). GIG was supported by its portfolio company, Corio Generation. The wind farm has a capacity of 376MW, thanks to the 47 Siemens turbines of 8MW each. These turbines stand on jacket foundations in water depths of up to 55 meters. The wind farm is located in an area from 4 to 10 nautical miles off the Miaoli County coast.
We built strong foundations...
For the production of the 188 pin piles, Jan De Nul subcontracted EEW KHPC. Some of these pin piles come with a weight of over 270 tons, a diameter of 2.4 meters, and a length of no less than 79 meters. In 2020, we transported the pin piles from the fabrication yards in South-Korea and Malaysia to the marshalling harbour in Taichung, Taiwan for temporary storage. A Heavy Lift Vessel commenced installing the pin piles on the 47 turbine locations, with the pin piles transported on pontoons. The final pin pile was placed on 22 August 2022. During the installation activities, Jan De Nul also managed to monitor the underwater noise levels and to observe marine mammals according to the environmental restrictions and permits. We did this by installing, among others, an air-bubble curtain around the installation zones, by which we diminished the underwater noise.
Jan De Nul ordered jacket foundations at Sembcorp Marine Ltd and Saipem S.A. in Indonesia, the construction of these commenced in 2020. With a height of up to 91 meters and a weight of over 1,600 tons, they are among the largest and heaviest jackets in the offshore wind industry. They are comparable to a thirty-story building or the Statue of Liberty.
From October 2021 to July 2022, three heavy transport vessels brought all foundations to the marshalling harbour in Taichung for temporary storage and final preparation before installation, which commenced in April 2022 with a Heavy Lift Vessel. In August 2022, Jan De Nul ended the phase of foundation installations.
... and connected them to shore.
In 2020, Jan De Nul subcontracted LS Cable to produce 34.5 km of export-cable and 87 km of inter-array cables. Our Cable Installation Vessels Willem de Vlamingh and Connector picked up, transported, and installed the cables in respectively 2021 and 2022. Both ships also served as support for the Jet Trencher to bury the cables in certain parts of the seabed to protect them. We had already dredged other hard parts, using our dredging vessels Niña and Francis Beaufort.
We pulled the four export cables through the drilled HDD-pipes nearshore in 2021 and joined them onshore with the land cables at the transition joint bays, thanks to our Starfish-machines. The installation of the 47 inter-array cables started in May 2022, with the last cable burial and stabilisation works completed on 30 September 2022.
The Orient Constructor of our local partner DFO facilitated walk-to-work access for the termination and testing teams to connect the cables to the switchgears inside the transition pieces of the respective jacket foundations, through which we put the entire wind farm online.