Jan De Nul Group was responsible for the full balance of plant, including design, fabrication and installation of the foundations, and the provision of the offshore vessel for the installation of the wind turbines. Also included was a significant electrical scope, including the supply and installation of the cables both onshore and offshore, as well as upgrading an onshore substation.
Hitachi Ltd. was in charge of manufacturing, assembly, installation and other works related to the 21 Typhoon-certified offshore wind turbines using a downwind rotor, each with a capacity of 5.2MW.
The EPCI works have been delivered in 2021. Since then, the Jan De Nul–Hitachi consortium is responsible for the first five years operation and maintenance (O&M) of the TPC Offshore Wind Farm Phase 1. With this 5-year commitment, Jan De Nul solidifies its presence in Taiwan until at least 2026.
21 turbines at 8 kilometres off the coast
The TPC Offshore Wind Farm near Fangyuan Township, eight kilometres off the West coast of Taiwan, comprises in total 21 units of 5.2 MW wind turbines, each installed on a jacket with transition piece, anchored to the seabed by four steel pin piles.
Jan De Nul started the construction works for the offshore wind farm back in September 2018 with the preparatory onshore cable duct installation works to connect the existing onshore substation to the cable interface near shore.
In 2019, fabrication of the different components were initiated and in April 2020, the first foundation components were readied for transportation from the South Korean fabrication yards to the offshore windfarm area.
In June 2020, Jan De Nul installed the first pin piles and by early August 2020, the very first jacket foundation touched ground. One month later, the very first turbine was installed on its jacket foundation. First electricity was generated in December 2020.
The project, suffered significant delays due to restrictions and new regulations implemented by authorities in Taiwan and around the globe as a result of the COVID-19 pandemic.
Turbines with a downwind rotor
The TPC Offshore Wind Farm is constructed in a region where typhoons are very common. Consortium partner Hitachi pioneered this design by obtaining the Wind Turbine Class T certification, an international standard on wind-resistant design recognising the need in regions subject to frequent typhoons.
Onshore cable works
Jan De Nul executed onshore cable installation works to connect the existing onshore substation to the cable interface near shore. The onshore cables were installed in an underground track of 13 kilometres of duct banks. For these construction works, 2 kilometres of horizontal directional drillings were performed over 14 different locations and 50 prefabricated manholes were installed. Jan De Nul engaged the services of Taiwan based company Star Energy Corp (SEC) for the related civil works.
Upgraded substation in Da Cheng
Together with its Taiwanese subcontractor Chung-Hsin Electric & Machinery Manufacturing Corporation (CHEM), Jan De Nul completed the installation and commissioning of new electrical equipment, including high voltage transformers, high-voltage and medium-voltage switchgear, a new SCADA control room and emergency power supply, inside the onshore substation in Da-Cheng.
This custom designed upgrade was essential for the substation to be able to receive power generated by the new offshore wind farm. CHEM was also responsible to supply and install the onshore electrical cables and optical fibre in the underground ductbank system.
Jackets of up to 62 metres high
The 21 jackets for the TPC Offshore Windfarm were fabricated at the Samkang M&T yard in South Korea. They measure between 55 m and 62 m in overall length. The heaviest unit weighs approximately 1,100 tonnes, and the combined total weight is approximately 22,000 tonnes.
The jackets include a 7.2m high Transition Piece (TP) with a diameter of 5.4m to support towers carrying the 5.2MW turbines. Each jacket also has two davit cranes for cargo hoisting and two boat landings to enable personnel access. The jackets are equipped with specialized offshore accessories such as navigation lights, foghorns, cameras etc.
84 pin piles of which a part Taiwan-made
Each jacket is anchored to the seabed by means of 4 pin piles. In total, 80 pin piles with a diameter of 3.1 m, a maximum length of 82 m and maximum weight of 310 tonnes, were manufactured at the South Korean fabrication yard of Edgen Murray.
Four pin piles have been manufactured in Taiwan by the steel fabricator Ming Rong Yuan. These pin piles were the very first Taiwan-made foundation components for the offshore wind farms in the country.
Wired with each other and to the onshore grid
All inter-array and export cables for the TPC Offshore Wind Farm were fabricated by JDR Cables. Jan De Nul’s Cable-Laying Vessel Connector installed parts of the inter-array cables between the 21 wind turbines. It was the very first assignment of the Connector as a Jan De Nul vessel after her acquisition in 2020. Cable-Laying Vessel Willem de Vlamingh was in charge of installing the remainder of the inter-array cables and also the installation of four subsea export cables from the offshore wind farm site to the shore where they were connected at the landfall area near Fangyuan Township.
For the complex beach pull-in operations including passing over a shallow water sandbank and under an existing oyster farm, Jan De Nul teamed up with its Taiwanese partner Hung Hua Construction who provided essential marine equipment, including a jack-up barge.
Cable pulling through marshlands and beneath a nearshore oyster farm
Due to the presence of a nearshore oyster farm and an important shipping lane for fishermen on the subsea export cables route, the cables had to be pulled through 1 kilometre long underground ducts, which had previously been installed by means of horizontal directional drilling (HDD) up to 21 metres below the seabed.