7.4.4.1 Offshore Export Cable Route Selection
Total Page:16
File Type:pdf, Size:1020Kb
Environmental Statement Volume 4 – Introductory Annexes Annex 4.4.1 Offshore Export Cable Route Selection PINS Document Reference: 7.4.4.1 APFP Regulation 5(2)(a) January 2015 sdf Copyright © 2015 All pre-existing rights reserved. SMart Wind Limited Liability Hornsea Offshore Wind Farm Project Two – Environmental Statement This report has been prepared by Intertek METOC Limited, with all reasonable skill, care and diligence within the terms of their contracts with SMart Wind Ltd or their subcontractor to RPS placed under RPS’ contract with SMart Wind Ltd as the Volume 4 – Introductory Annexes case may be. Annex 4.4.1 – Offshore Export Cable Route Selection Document release and authorisation record PINS document reference 7.4.4.1 Report number UK06-050200-REP-0021 Date January 2015 Client name SMart Wind Limited SMart Wind Limited 11th Floor 140 London Wall London EC2Y 5DN Tel 0207 7765500 Email [email protected] i sdf Foreword The proposed offshore cable route for Project Two is immediately adjacent to Hornsea Project One. The synergies were identified at an early stage and the route selection was designed to inform the EIA for both Project One and Project Two. As of such this report while initially produced for Project One is directly applicable to Project Two and sets out the factors that influenced the offshore export cable route selection for both projects. ii sdf Table of Contents Table of Figures Figure 3.1 Landfall options. .....................................................................................................6 Summary .................................................................................................................................... 1 Figure 3.2 Cable route corridor options. ..................................................................................7 1 Introduction .......................................................................................................................... 2 Figure 4.1 Cable route corridor options. ................................................................................ 10 2 Scope of Work ..................................................................................................................... 3 Figure 5.1 Constraints Study Area. ....................................................................................... 13 3 Methodology ........................................................................................................................ 3 Figure 5.2 Key Constraints Map. ........................................................................................... 14 3.1 Design Process ..................................................................................................... 3 Figure 6.1 Potential landfall site locations. ............................................................................ 16 3.2 Selection Criteria .................................................................................................. 3 Figure 7.1 Landfall site and export cable route corridor options. ........................................... 23 3.3 Landfall Site and Export Cable Route Corridor Appraisal ..................................... 5 Figure 7.2 Revised route to Horseshoe Point outside main navigable channels and avoiding 4 Offshore Cable Route Corridor Selection Process ............................................................... 8 deep water anchorages. ....................................................................................... 26 4.1 Summary of the Site Selection Process ................................................................ 8 Figure 8.1 Overview of route options. ................................................................................... 29 4.2 Summary of the Route Development Process ...................................................... 9 Figure 9.1 Hornsea Export cable route corridor overview. .................................................... 31 5 Constraints Study Summary .............................................................................................. 11 5.1 Background ......................................................................................................... 11 5.2 Constraints Study Objectives .............................................................................. 11 Table of Tables 5.3 Approach ............................................................................................................ 11 Table 1.1 Summary of cable route reports. ............................................................................2 6 Landfall Site Visits Report summary .................................................................................. 15 Table 3.1 Landfall site point criteria. ......................................................................................4 6.1 Study Area .......................................................................................................... 15 Table 3.2 Cable routing criteria. .............................................................................................4 6.2 Approach ............................................................................................................ 15 Table 4.1 Chronology of principal Intertek METOC activities (alongside formal consultation phases). .................................................................................................................8 6.3 Conclusions ........................................................................................................ 17 Table 4.2 Results of final appraisal process. .........................................................................9 6.4 Recommendations .............................................................................................. 21 Table 5.1 Landfall sites selected during constraints study. .................................................. 11 7 Cable Route Study summary ............................................................................................. 22 Table 5.2 Key constraints and recommendations. ............................................................... 12 7.1 Introduction ......................................................................................................... 22 Table 6.1 Landfall sites reported on. .................................................................................... 15 7.2 Recommendations .............................................................................................. 25 Table 6.2 Landfall Site Visit Summary. ................................................................................ 18 8 Offshore Cable Route Corridor Risk Assessment – Summary Comparative Risk Assessment ....................................................................................................................... 27 Table 6.3 Rating of proposed landfalls. ................................................................................ 19 8.1 Introduction ......................................................................................................... 27 Table 6.4 Recommended Landfall Sites. ............................................................................. 21 8.2 Objectives ........................................................................................................... 27 Table 7.1 Preferred landfall site options. .............................................................................. 22 8.3 Approach ............................................................................................................ 27 Table 7.2 Risk matrix. .......................................................................................................... 24 8.4 Comparative Risk Analysis ................................................................................. 27 Table 7.3 Ranking of route options. ..................................................................................... 25 8.5 Conclusions ........................................................................................................ 28 Table 8.1 East Newton risk analysis. ................................................................................... 28 9 Export Cable Instatllation Options Report – Summary ....................................................... 30 Table 8.2 Hollym risk analysis.............................................................................................. 28 9.1 Report Summary ................................................................................................. 30 Table 8.3 Horseshoe Point risk analysis. ............................................................................. 28 9.2 Cable Route Overview ........................................................................................ 30 9.3 System Capacity And Configuration ................................................................... 30 9.4 Cable Protection ................................................................................................. 32 iii sdf Glossary Acronyms Term Definition Acronym Full term Demersal Fish Fish that live on or near the Seabed ABP Associated British Ports Material deposited or reworked by the sea since the retreat of the last HDD Horizontal Directional Drilling Holocene Material ice age 10,000 years ago to the present day. These are loose, unconsolidated, material HVDC High Voltage Direct Current Horizontal Steerable trenchless method of installing underground ducts for IMO International Maritime Organisation Directional Drilling routing cables beneath