Description
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Requirements of Service scope of O&M Survey 2025 tender; TenneT TSO B.V. (hereafter: Client) is appointed by the Dutch government as the offshore grid operator for The Netherlands. In order to operate and maintain the assets, Client is by law responsible for assets monitoring. The various connections that are developed and are in operation require survey works for cable routes and platforms. This EU-Tender shall consist of 3 lots, a) Borssele, b) 700MW cables and the c) interconnectors Cobra&NorNed. All lots shall have the minimal requirements as set out in this tender. Requirements are the following, TenneT minimum requirements, HSE, offshore The objectives of the services are to: 1. Perform the O&M survey by means of MBES, SSS and airborne survey or other solution to cover landing/tidal area according to technical specification listed above. 2. Establish the bathymetry and topography of the seabed to understand the level of it and identify the obstructions in the corridor with the specified quality as minimum. 3. Establish the seabed features of the seabed to identify the obstructions in the corridor and identify any possible cable exposures or freespans. Resolution of the SSS is described in SPE.06.380-OG and shall be such that the cable if exposed shall be identified using this method (cable diameter ~ 0.2 m). Below defined locations and quantities are currently indicative. Exact routes and amounts shall be published in the second phase, the ITT (Invitation To Tender). LOT 1 - Borssele: Survey of Cables and Areas Summary 1. Export Cables (BSA1, BSA2, BSB1, BSB2) - Quantity in meters: 255,000 / width 20 meters (amount n.a.) - Coverage: 200% - O&M TVU/THU - Lines in reciprocal directions 2. Export Cables Extended (BSA1, BSA2, BSB1, BSB2) - Quantity in meters: 255,000 / width 40 meters (amount X2 – two times) - Special Order TVU/THU - Overlap as per specification 380 - Coverage: 40m each side of the primary corridor (total of 50m) 3. Platform Area (BSA, BSB) - Quantity: 500m X 500m each (amount X2 – two times) - Special Order TVU/THU - Overlap as per specification 380 4. Crossing Structures - Quantity: 100m X 100m (amount X14 – fourteen times) - Coverage: 200% - O&M TVU/THU - Lines in reciprocal directions 5. P2 Spijkerplaat Extended Area - Quantity: 1,600m X 750m (amount X1 – one time) - Special Order TVU/THU - Overlap as per specification 380 - No SSS 6. Honte Extended Area - Quantity: 1,100m X 750m (amount X1 – one time) - Special Order TVU/THU - Overlap as per specification 380 - No SSS 7. Export Cable Corridor within Spijkerplaat and Honte - Quantity: 800m X 20m (amount n.a.) - Coverage: 200% - O&M TVU/THU - Lines in reciprocal directions 8. Spijkerplaat Extended Area - Quantity: 1,600m X 750m (amount X1 – one time) - Special Order TVU/THU - Overlap as per specification 380 - No SSS 9. Honte Extended Area - Quantity: 1,100m X 750m (amount X1 – one time) - Special Order TVU/THU - Overlap as per specification 380 - No SSS LOT 2 – 700MW Cables: 1. Export Cables: BSL (GNB), HKZ, HKN, HKWa. HKWb, and Export Cables: Interlinks: BSL-BSB, HKZa-HKzb, HKWa-HKWb - Length: 725,000 m X 20 m (amount n.a.) - MBES Requirement: 200% coverage, O&M TVU/THU, lines in reciprocal directions 2. Export Cables Extended (BSL GNB) - Length: 212,000 m X 40 m (amount X2 – two times) - MBES Requirement: Special Order TVU/THU, overlap as per specification 380, no SSS 3. Crossing Structures - Length: 100 m X 100 m (amount X85 – eighty five times) - MBES Requirement: 200% coverage, O&M TVU/THU, lines in reciprocal directions 4. Platforms (HKZa, HKZb, HKN, HKWa, HKWb) - Length: 500 m X 500 m (amount X5 – five times) - MBES Requirement: Special Order TVU/THU, overlap as per specification 380 LOT 3 – Interconnectors Cobra and NorNed: 1. NorNed - NL (Inside the Wadden Sea) - Approx. Length: 30,000 m X 120 m (amount n.a.) - MBES Requirement: Exclusive order TVU/THU, overlap as per specification 380 2. NorNed - NL (Outside the Wadden Sea) - Approx. Length: 18,000 m X 120 m (amount n.a.) - MBES Requirement: Exclusive order TVU/THU, overlap as per specification 380 3. NorNed – DE (Optional) - Approx. Length: 222,000 m X 60 m (amount n.a.) - MBES Requirement: Exclusive order TVU/THU, overlap as per specification 380 4. Cobra (NL) + DE - Optional - Approx. Length: 250,000 m X 60 m (amount n.a.) - MBES Requirement: Exclusive order TVU/THU, overlap as per specification 380 Export Corridor: For the Export Corridor and crossings structures 200% MBES coverage is required. O&M THU/TVU for this survey is based on IHO S-44 with a value from Table B-c13, and b value from table B-d9. Data shall not be trimmed to provided surveys corridor, but all acquired data to be provided in raw and processed files. Calibrations and Verifications: Calibrations and verifications shall be performed in the port closest to survey area, unless differently agreed with Client. These shall cover, but not limited to: position check (in the project coordinates system), absolute Z depth check (should be less than 5cm), F-test (3x3 lines of 30m length,200% overlap), Z-test, USBL spin test. Contractor shall provide mobilization, calibration and demobilization port(s) information in the proposal. Once the data is final it shall be provided on 2 copies of HDD and uploaded by Contractor to Azure cloud on the location specified by TenneT.