OFFSHOREoverview WIND SUBMARINE CABLING Fisheries Technical Working Group Final Report | Report Number 21-14 | April 2021 NYSERDA’s Promise to New Yorkers: NYSERDA provides resources, expertise, and objective information so New Yorkers can make confident, informed energy decisions. Our Vision: New York is a global climate leader building a healthier future with thriving communities; homes and businesses powered by clean energy; and economic opportunities accessible to all New Yorkers. Our Mission: Advance clean energy innovation and investments to combat climate change, improving the health, resiliency, and prosperity of New Yorkers and delivering benefits equitably to all. Courtesy, Equinor, Dudgeon Offshore Wind Farm Offshore Wind Submarine Cabling Overview Fisheries Technical Working Group Final Report Prepared for: New York State Energy Research and Development Authority Albany, NY Morgan Brunbauer Offshore Wind Marine Fisheries Manager Prepared by: Tetra Tech, Inc. Boston, MA Brian Dresser Director of Fisheries Programs NYSERDA Report 21-14 NYSERDA Contract 111608A April 2021 Notice This report was prepared by Tetra Tech, Inc. in the course of performing work contracted for and sponsored by the New York State Energy Research and Development Authority (hereafter “NYSERDA”). The opinions expressed in this report do not necessarily reflect those of NYSERDA or the State of New York, and reference to any specific product, service, process, or method does not constitute an implied or expressed recommendation or endorsement of it. Further, NYSERDA, the State of New York, and the contractor make no warranties or representations, expressed or implied, as to the fitness for particular purpose or merchantability of any product, apparatus, or service, or the usefulness, completeness, or accuracy of any processes, methods, or other information contained, described, disclosed, or referred to in this report. NYSERDA, the State of New York, and the contractor make no representation that the use of any product, apparatus, process, method, or other information will not infringe privately owned rights and will assume no liability for any loss, injury, or damage resulting from, or occurring in connection with, the use of information contained, described, disclosed, or referred to in this report. NYSERDA makes every effort to provide accurate information about copyright owners and related matters in the reports we publish. Contractors are responsible for determining and satisfying copyright or other use restrictions regarding the content of reports that they write, in compliance with NYSERDA’s policies and federal law. If you are the copyright owner and believe a NYSERDA report has not properly attributed your work to you or has used it without permission, please email [email protected] Information contained in this document, such as web page addresses, are current at the time of publication. Abstract The number of submarine cables in the New York Bight is expected to increase as New York currently has three offshore wind projects with agreements to sell nearly 2,500 MW of power to the State towards the goal of 9,000 MW of offshore wind (OSW) generation by 2035. It is important that the installation and operation of submarine cables avoid, minimize, or mitigate potential impacts; both to the environment as well as to existing ocean users. Understanding the fundamentals of offshore wind submarine power cable types and construction methods are important in determining the potential impacts cables might have on the commercial fishing industry as well as how commercial fishing practices might impact the cables, once installed.The best and most effective manner to mitigate impacts to fishing interests is engagement with fishermen early in the planning process. Planning tools such as the Cable Burial Risk Assessment (CBRA) determine the recommended depth of lowering (DOL) by taking many factors into consideration, including regional fishing gear activity, type, and penetration depths. Mitigation measures to reduce impacts of fishing to cables may include cable armoring and burial for cable installed on the continental shelf. Reducing the impacts submarine cables may have on stakeholders and vice versa can be achieved by proper and diligent project planning and execution. Keywords OSW, submarine cabling activities, fisheries cable interactions, offshore wind cables OFFSHORE WIND SUBMARINE CABLING OVERVIEW ii Table of Contents Fisheries Technical Working Group NOTICE ii ABSTRACT ii KEYWORDS ii LIST OF TABLES v LIST OF FIGURES v ACRONYMS AND ABBREVIATIONS vii EXECUTIVE SUMMARY ES-1 1 INTRODUCTION 1 1.1 Historical and Existing Submarine Cables in the New York Bight 2 2 THE U.S. OFFSHORE WIND INDUSTRY 3 3 SUBMARINE CABLES IN OFFSHORE WIND PROJECTS 5 3.1 State and Federal Regulatory Requirements Industry Guidance 5 3.2 Cable Route Planning 9 3.2.1 Cable Burial Risk Assessment 10 3.2.2 Geologic Constraints and Concerns 11 3.2.3 Environmental, Fisheries, and Fishing Impacts 11 3.3 Cable Types 12 3.3.1 Functions (Export vs. Array) 15 3.3.2 Array Cable Detail 16 3.3.3 HVAC Export Cable Detail 16 3.3.4 HVDC Export Cable Detail 16 3.4 Submarine Cable Installation and Burial 17 3.4.1 Route Clearance and Pre-lay Grapnel Run 17 3.5 Cable Installation—Export 19 3.5.1 Shore-End Installation 21 3.5.2 Main Lay 22 3.5.3 Offshore Substation Platform 24 3.6 Cable Installation—Array Cabling 25 3.6.1 First-End Installation 26 3.6.2 Main Lay 27 3.6.3 Second-End Installation 27 3.7 Cable Burial 28 3.7.1 Simultaneous Lay and Burial 28 3.7.2 Post-lay Burial 34 3.7.3 Pre-lay Burial 37 3.7.4 Cable Burial Tool Summary Table 39 3.7.5 Other Cable Protection Measures 40 3.8 Post-lay Cable Surveys 44 3.9 Cable Crossings and Techniques 45 3.9.1 Legal and Regulatory Viewpoint 45 3.9.2 Common Cable/Pipeline Crossing Methodologies 45 OFFSHORE WIND SUBMARINE CABLING OVERVIEW iii Table of Contents Fisheries Technical Working Group 3.10 Operations and Maintenance 46 3.10.1 Periodic Depth of Burial Surveys 46 3.10.2 Cable Temperature Sensing 46 3.10.3 Cable Vibration Sensing/Distributed Acoustic Sensing 48 3.10.4 Remedial Burial 48 3.10.5 Cable Repair Operations (Array and Export) 48 3.10.6 Decommissioning 49 4 RISK TO CABLES 50 4.1 Seabed Conditions—Geologic and Sedimentary 50 4.2 Navigation Channels and Anchorage Areas 50 4.3 Commercial and Recreational Fishing 51 5 RISK FROM CABLES 52 5.1 Potential Environmental Impacts 52 5.1.1 Seabed/Substrate 53 5.1.2 Sediment Resuspension, Turbidity, and Burial 53 5.1.3 Chemical Pollutants 53 5.1.4 Anthropogenic Noise 54 5.1.5 EMF—Alternating Current versus Direct Current 54 5.1.6 Thermal Gradients 56 5.2 Potential Impacts to Habitat/Potential Impacts to Fishing 56 5.2.1 Fisheries Habitat 57 5.2.2 Reef Effects 57 5.2.3 Fishing Gear 58 6 MITIGATION MEASURES 59 7 CONCLUSION 60 8 REFERENCES 61 OFFSHORE WIND SUBMARINE CABLING OVERVIEW iv Tables Table 1. Summary of Guidance, Regulations, and Industry Recommended Practices 6 Table 2. Basic HVAC to HVDC Technology Comparison 12 Table 3. Cable Type and Size Comparison (all numbers are approximate) 12 Table 4. Cable Burial Tool Comparison 39 Figures Figure 1. Major Components of a Typical Offshore Windfarm 1 Figure 2. Existing Submarine Cable Routes and Offshore Wind Lease/Call Areas in the New York Bight 2 Figure 3. U.S. East Coast OSW Projects and Lease Areas 3 Figure 4. New York State Area OSW Lease/Call Areas 4 Figure 5. GE Haliade-X 12-MW WTG, Size Comparison 4 Figure 6. Industry Standard Cable Burial and Trench Parameters 10 Figure 7. Bundled HVDC Cable Deployment 14 Figure 8. Image of Three Core HVAC Inter-Array Export Cable Showing Relative Dimensional Differences 14 Figure 9. Image of Basslink Submarine HVDC Cable Showing Relative Dimensions of Components 14 Figure 10. Simplified Components of an Offshore Wind Farm, Both for HVAC and HVDC Configurations 15 Figure 11. Gemini Offshore Wind Farm HVAC Offshore Substation Platform 15 Figure 12. Dolwin Alpha HVDC Converter Platform 15 Figure 13. Cable Cross Section, Array Cable 16 Figure 14. Components of Typical HVAC Export Cable 16 Figure 15. Neptune Cable Laying Operations 16 Figure 16. Neptune HVDC Cable Bundle 16 Figure 17. Neptune HVDC Cable Being Bundled during Marine Installation Works 17 Figure 18. Neptune HVDC System Route 17 Figure 19. Boulder Relocation Grab 18 Figure 20. Pre-lay Plow for Route Clearance 18 Figure 21. Typical PLGR Grapnel 18 Figure 22. Grapnels Containing Wire Rope Recovered to Deck 18 Figure 23. NKT Victoria 19 Figure 24. Van Oord Nexus CLV 19 Figure 25. Leonardo da Vinci CLV 20 Figure 26. Triton Knoll Offshore Wind Farm Export Cable Pull in at the Transition Pit 21 Figure 27. Horizontal Directional Drilling (HDD) Operations 21 Figure 28. Image Showing Preparations for Pulling the Export Cable into the HDD Duct 21 Figure 29. Image Showing Preparations for Pulling the Export Cable into a Plow 22 Figure 30. Cable Repair Joint with External Cable Protection 23 Figure 31. Lifting Cable Repair Joint with External Cable Protection 23 Figure 32. Deploying Cable Repair Joint 23 Figure 33. OSP Illustration Showing the Submarine Cables 24 Figure 34. Export Cable Pull-in and Plow Deployment at the OSP 24 Figure 35. Thanet Offshore Wind Farm Layout and Photo 25 Figure 36. First-end Pull-in 26 Figure 37. Cable Protection System Prior to Installation 26 Figure 38. Array-Cable installation Vessel (Foreground) and Service Operation Vessel (SOV), Background 27 Figure 39. Array-Cable installation 27 Figure 40. Cable Deployment Quadrant on Deck 27 Figure 41. Second-End Array Cable Installation, Quadrant Being Deployed, ROV in the Water 27 Figure 42.