Within the tendering course of for the development of the 235-kilometre-long offshore grid connection system BorWin6, TenneT has awarded the contract for the converter stations at sea and on land to the McDermott and GEIRI/C-EPRI consortium. The “stations” lot has thus been awarded, the second “cable” lot for the cable between the 2 stations will comply with in summer season 2022.
“With regard to the excessive growth targets for offshore wind vitality within the North Sea, we’re happy that a world consortium was capable of prevail in our tendering process. Though this consortium is new to us, it has numerous expertise within the offshore in addition to the high-voltage direct present transmission (HVDC) enterprise,” mentioned Tim Meyerjürgens, COO of TenneT. “As a transmission system operator, we are going to want many dependable companions within the coming years to allow the offshore growth on the desired tempo and with the focused connection capacities. By way of dashing up the method, we’ve taken the lead with this mission: It was initially deliberate with a connection capability of 930 megawatts. Within the technical planning, we had been capable of enhance the capability by 50 megawatts. The mission was lately confirmed within the newest grid improvement plan.”
The direct connection precept can be used for BorWin6, which implies that TenneT connects the wind generators on to TenneT’s offshore platform BorWin kappa by way of 66-kilovolt three-phase cables. This eliminates the necessity of transformer stations that had been beforehand obligatory in every wind farm. As well as, 155-kilovolt three-phase cables aren’t required to attach TenneT’s offshore platform with that of the wind farm. Economically talking, this in-novative expertise results in monumental value financial savings.
Tim Meyerjürgens: “With the award of BorWin6, we’re persevering with the continued value discount within the building of offshore grid connection techniques. We’re additionally making use of the sensible platform idea by putting in notably low-maintenance expertise on the offshore platform. This permits us to cut back the upkeep effort and finally the working prices of the asset.”
On a 235-kilometre-long route, TenneT transmits the electrical energy by way of underground cable through the use of low-loss direct present expertise (DC) from the offshore converter station BorWin kappa to the converter station in Büttel (Schleswig-Holstein) on land. Right here, the direct present is transformed again into three-phase alternating present (AC) and fed into the extra-high voltage grid.
Throughout the consortium, the main target of McDermott will probably be on the converter stations; they draw on a variety of offshore expertise and their very own worldwide fabrication yards. International Power Interconnection Analysis Institute Co. Ltd. (GEIRI) & C-EPRI Electrical Energy Engineering Co. Ltd. (C-EPRI), in flip, will give attention to electrical engineering. Many high-voltage DC tasks have already been realised, primarily in Asia, and GEIRI/C-EPRI is considered an skilled HVDC developer and provider worldwide.
BorWin6 is the final offshore grid connection system to be carried out by TenneT within the German North Sea with 320-kilovolt expertise. The technological leap to 525-kilovolt and a transmission capability of two gigawatts will probably be carried out in future tasks. BorWin6 is scheduled to enter operation in 2027.
The milestones at a look
The contract for the second lot, for the manufacturing and laying of the cables, will probably be awarded earlier than the top of this yr. As well as, the primary preparatory measures for the development of the land station in Büttel are deliberate. The precise building of the land station will start in 2024. Development of the topside, i.e. the precise converter station at sea, which will probably be in-built Qing-dao (China), is anticipated to start out in mid-2023. Development of the jacket in Batam (Indonesia) may even begin on the finish of 2023. The jacket will type the substructure on which the platform will probably be positioned within the roughly 38-metre-deep water, most likely in mid-2026.
In 2023, horizontal drillings are additionally deliberate to underpass the land safety dike (close to Büsum) and the Kiel Canal; the land cable will probably be laid in 2024 and 2025, and the subsea cable in 2025 and 2026.
Info and figures on BorWin6
Subsequent to the tasks BorWin1+2+3 and 5, BorWin6 is the fifth offshore grid connection to be realised by TenneT off the coast of Borkum utilizing extra-high voltage direct present transmis-sion expertise. BorWin6 has a transmission capability of 980 megawatts, and commissioning is deliberate for 2027.
- 235-kilometre HVDC reference to a most transmission capability of 980 megawatts
- 45 kilometres of land cable, 190 kilometres of subsea cable
- Grid connection level: Büttel (west of Itzehoe in Schleswig-Holstein)