Appendix B.2: Desk Top Survey and Route Engineering Study Route Option Analysis Report NorthConnect KS Phone +47 38 60 70 00 Serviceboks 603, Lundsiden Mail: [email protected] N-4606 Kristiansand Web: www.northconnect.no Norway Desk top survey and route engineering study Route Option Analysis Report NorthConnect KS Assignment Number: A30722-S04 Document Number: A-30722-S04-REPT-002 Xodus Group Ltd The Auction House 63A George St Edinburgh EH2 2JG UK T +44 (0)131 510 1010 E [email protected] www.xodusgroup.com Table of Contents EXECUTIVE SUMMARY 7 1 INTRODUCTION 11 1.1 Project Background 11 1.2 Project Development 12 1.3 Project Description 14 2 OBJECTIVES 16 3 SCOPE OF WORK 17 4 METHODOLOGY 19 5 SUBSEA CABLE ROUTE ENGINEERING 20 5.1 Cable Characteristics 20 5.2 Geotechnical & Geophysical Assessment 20 5.3 Cable Installation 30 5.4 Cable Protection 31 5.5 Scour Protection 31 5.6 Cable & Pipeline Crossing Arrangements 31 5.7 Thermal Properties of Seabed Soils 32 6 CONSTRAINT MAPPING 33 6.1 Introduction 33 6.2 Digital Data Sources 33 6.3 Consultations 34 6.4 Type of Constraints 34 6.5 Weighting of Constraints 37 6.6 Safety & Buffer Distances 38 6.7 Iterative Approach 40 6.8 Challenges & Limitations 41 7 VALUE, DECISION AND RISK MANAGEMENT 43 Desk top survey and route engineering study – Route Option Analysis Report Assignment Number: A30722-S04 Document Number: A-30722-S04-REPT-002 iii 7.1 Objectives 43 7.2 Project Drivers & Success Criteria 43 7.3 Corridor Option Screening & Selection 46 7.4 Route Option Screening & Selection 54 8 COST MODELLING 64 8.1 Cost Basis 64 8.2 Cost Results 68 9 EXECUTION SCHEDULE 69 9.1 Route Cable Length 69 9.2 Installation Strategy 69 9.3 Cable and Pipeline Crossings 69 9.4 Specialised Vessels and Equipment 69 9.5 Sensitive Timings 69 9.6 Assumptions 69 9.7 Installation Durations 70 10 PREFERRED ROUTE DESCRIPTION 71 10.1 Overview Proposed Cable Routes 71 10.2 Installation 71 10.3 Cable Protection 72 10.4 Scour Protection 72 10.5 High-Level Cost Estimate 72 10.6 High-Level Schedule Estimate 73 11 IMPACTS & EFFECTS PREFERRED ROUTES 74 11.1 Cable & Pipeline Crossings 74 11.2 Offshore Oil & Gas Infrastructure 75 11.3 Offshore Renewable Energy Development Sites 76 11.4 Commercial Fisheries 77 11.5 Shipping, Navigation and Anchorages 79 11.6 Dredging, Disposal and Military Practice Areas 80 11.7 Cultural Heritage 81 11.8 Coastal Defences 81 11.9 Environmental Impacts & Effects 82 12 ROUTE POSITION LISTS AND STRAIGHT LINE DIAGRAMS 83 13 DETAILED SURVEY SPECIFICATION 84 Desk top survey and route engineering study – Route Option Analysis Report Assignment Number: A30722-S04 Document Number: A-30722-S04-REPT-002 iv 14 CONCLUSIONS 85 15 RECOMMENDATIONS 86 16 REFERENCES 89 APPENDIX A OPTION SCREENING (QUALITATIVE ASSESSMENT) 90 APPENDIX B OPTION SCREENING (QUANTITATIVE ASSESSMENT) 91 APPENDIX C MEETING MINUTES QUALITATIVE ASSESSMENT 92 APPENDIX D MEETING MINUTES QUANTITATIVE ASSESSMENT 94 APPENDIX E CABLE TECHNICAL DATA SHEET (500KV) 99 APPENDIX F CABLE TECHNICAL DATA SHEET (36KV) 100 APPENDIX G QUATERNARY GEOLOGY 101 APPENDIX H BATHYMETRY 102 APPENDIX I DEPTH PROFILE SAMNANGER ROUTE OPTION 103 APPENDIX J DEPTH PROFILE SIMA ROUTE OPTION 104 Desk top survey and route engineering study – Route Option Analysis Report Assignment Number: A30722-S04 Document Number: A-30722-S04-REPT-002 v APPENDIX K COST ESTIMATES 105 APPENDIX L EXECUTION SCHEDULES 106 APPENDIX M TYPICAL CROSSING ARRANGEMENTS 107 APPENDIX N CABLE AND PIPELINE CROSSINGS 108 APPENDIX O OIL & GAS INFRASTRUCTURE 109 APPENDIX P SHIPPING, NAVIGATION AND ANCHORAGES 110 APPENDIX Q DREDGING, DISPOSAL AND MILITARY PRACTICE AREAS 111 APPENDIX R AERIAL VIEWS 112 APPENDIX S EMAILS 115 Desk top survey and route engineering study – Route Option Analysis Report Assignment Number: A30722-S04 Document Number: A-30722-S04-REPT-002 vi EXECUTIVE SUMMARY NorthConnect awarded Xodus Group the contract for the Desk Top Survey and Route Engineering Study (DTS- RS) on the 2nd of May 2012, in respect of the proposal to install a HVDC subsea cable between the UK and Norway. At the start of this study, the project was at outline design stage. NorthConnect had completed a pre-FEED study which included a cable corridor routing appraisal, environmental screening and constraints mapping for a series of possible locations for the UK landing point, and CAPEX and OPEX estimations. Peterhead was selected as the preferred UK cable landfall point. The Route Option Analysis Report presents the scope of work, the methods and results of the DTS-RS for the proposed NorthConnect subsea cable from the UK to Norway. The overall objective of this report is to ensure that all potential effects on people and the environment have been considered, assessed and documented for all route options identified. It reports on the results of the option screening sessions and the preferred Peterhead to Sima and Peterhead to Samnanger routes selected. This study has analysed route options for both the Peterhead to Sima and Peterhead to Samnanger Norwegian landfall options. The assessment has not covered in detail the constraints associated with the onshore cable routing, the onshore grid connection and potential requirements for local grid upgrades when comparing the Sima and Samnanger options. NorthConnect will present the results (in conjunction with the Ramboll findings for the onshore part) to the National Regulator in Norway as part of the consultation process. The National Regulator is a key stakeholder and decision-maker during project feasibility, consenting and permitting phases. The study has taken into consideration a wide range of environmental and technical issues as well as feedback from EIA contractors. Technical and environmental constraints have been mapped and visualised into GIS. The study has been conducted based on data sets provided by SeaZone during phase 1 and phase 2 of this project. Additional data sources such as charts and seal haul-out data have also been incorporated into the constraint mapping exercise. One key constraint is the limited amount of information available in terms of future offshore development projects and the location of cable repeaters as this information was not available. The reader must bear in mind that this study has considered a snapshot in time using all available data sources to do so. Xodus has made an assessment of soil conditions and trenchability, with recommendations in terms of installation methods, burial depth, cable protection and crossing arrangements. Cost estimates and execution schedules have been established to allow for a quantitative assessment. Route cost per kilometre primarily considers cable length and number of cable crossings. Minimising cable length and number of crossings has been an objective adopted from the outset of the project. Through careful route assessment and selection, a range of mitigation measures have been incorporated into the design of the project. The identification, assessment and selection of route options has taken into account project objectives and key drivers captured at the start of the project. The qualitative and quantitative option screening process conducted as per Xodus’ Value, Decision and Risk Management (VDRM) methodology has proven very effective in terms of measuring different routeing options against key drivers as well as against each other. The methodology has provided a concise auditable justification for the scoring applied to each option assessed which has included formal minuted inputs from the project team. The methodology has ensured that a number of potentially significant adverse impacts and effects have been avoided, reduced or offset. Some adverse effects may still impose disturbance to people and the environment and will require further assessment during stakeholder consultation and consenting. Desk top survey and route engineering study – Route Option Analysis Report Assignment Number: A30722-S04 Document Number: A-30722-S04-REPT-002 7 9 corridor options were identified which allowed for several permutations for potential cable routes as illustrated in figure below. Figure 0.1: Corridor options Peterhead North was identified as preferred UK landfall option. Peterhead South options were removed due to environmental impact and issues related to consenting & permitting. Consultations with pipeline owner Sandford Bay will be required to discuss potential crossing arrangement. North Sea 1 option was selected as preferred option. North Sea 3 and North Sea 4 options were removed based on economic viability and technical suitability. North Sea 2 options were removed from scope due to cumulative effects and likelihood interference with planned development projects within the Utsira High area. Detailed survey is required to reveal sand waves, pock marks and any other hazards along the North Sea 1 route selected. Sima-to-Samnanger (Bomla Fjord – Langenuen – Selbjorn Fjord – Bjørna Fjord)) route was removed from scope due to significant cost variance caused by cable length (30 – 35km) and 8 extra crossings. Both Peterhead North to Sima and Peterhead North to Samnanger options have been taken forward to meet requirements of the national regulator. Technical feasibility of both Norwegian landfall options needs to be Desk top survey and route engineering study – Route Option Analysis Report Assignment Number: A30722-S04 Document Number: A-30722-S04-REPT-002 8 confirmed. Depth profile, fish farms, cable crossings and unexploded ordnance are key challenges to be addressed during the next phase of the project. Xodus has developed a route proposal which causes least disturbance to people and the environment. Considering the scale of development and the type of constraints identified for the preferred route, it is expected that the environmental appraisal will meet the expectations of all stakeholders involved. Preferred routes selected are: > ‘Peterhead North + North Sea 1 + Samnanger’ (i.e. option1); and > ‘Peterhead North + North Sea 1 + Sima’ (i.e. option 4). Both options are taken forward to the next phase, i.e.