APL/STG - 41 Proposed Beauly to Denny 400 kV Overhead Transmission Line The use of underground cable as an alternative to overhead line: STIRLING Final Report October 2007 PB In association with CCI Cable Consulting International Ltd. PB Power Page i LIST OF CONTENTS Page No. CHAPTER 1: INTRODUCTION ............................................................................................1 1.1 Background.....................................................................................................1 1.2 Objective of Appraisal.....................................................................................1 1.3 Appraisal Brief ................................................................................................2 1.3.1 Appraisal Process....................................................................................2 1.3.2 Terminology .............................................................................................2 1.3.3 Proposals Received.................................................................................3 1.3.4 Interpretation and Identification of Search Areas.....................................3 1.3.5 Data Used................................................................................................6 1.3.6 Working Strategy .....................................................................................7 1.3.7 Working Method.......................................................................................7 1.3.8 Stated Objectives of Objectors ................................................................8 1.4 Technical Brief ..............................................................................................15 1.4.1 Technical – OHL ....................................................................................15 1.4.2 Technical – SEC ....................................................................................15 1.4.3 Technical - UGC System Design Considerations ..................................15 1.4.4 Environmental Commentary ..................................................................16 1.4.5 Costing...................................................................................................16 1.5 Approach ......................................................................................................16 1.5.1 Basis of Appraisal ..................................................................................16 1.5.2 Methodology ..........................................................................................18 1.5.3 Approach to Routeing ............................................................................18 1.5.4 Scope of Appraisals...............................................................................19 1.6 Limitations.....................................................................................................20 CHAPTER 2: DESCRIPTION OF SEARCH AREAS..........................................................21 2.1 UGC4 A1 and A2: Cambushinnie – Greenyards ..........................................21 2.1.1 Characteristics of the area.....................................................................21 2.1.2 Proposed Alternative Search Areas.......................................................24 2.2 UGC4 A3: Braco – Greenyards ....................................................................27 2.2.1 Characteristics of the area.....................................................................27 2.2.2 Proposed Alternative Search Areas.......................................................30 2.3 UGC4 B: Greenyards – Gartur (South of Cambusbarron)............................31 2.3.1 Characteristics of the area.....................................................................31 2.3.2 Proposed alternative search areas ........................................................33 2.4 UGC4 C1 and C2: Gartur – Denny Substation .............................................34 2.4.1 Characteristics of the area.....................................................................34 2.4.2 Proposed alternative search areas ........................................................36 2.5 UGC4 D: Cocksburn Wood – Logie Villa ......................................................37 2.5.1 Characteristics of the area.....................................................................37 2.5.2 Proposed Alternative Search Areas.......................................................39 2.6 UGC4 E: Logie Villa – Manor Powis .............................................................39 2.6.1 Characteristics of the area.....................................................................39 2.6.2 Proposed Alternative Search Areas.......................................................41 2.7 Abnormal Loads............................................................................................43 2.7.1 Delivery of Cable Drums........................................................................43 CHAPTER 3: WEST OF STIRLING APPRAISAL..............................................................45 3.1 Introduction ...................................................................................................45 3.2 Technical Appraisal - SNH Routes ...............................................................45 3.2.1 UGC4 A1: OHL from Point W (Tower TD170) to SEC 1.......................46 Stirling Undergrounding Master 11.doc Page ii PB Power 3.2.2 UGC4 SEC 1: Milour Moor....................................................................46 3.2.3 UGC4 A2: UGC from SEC 1 to Point X (Greenyards) ..........................48 3.2.4 UGC4 B: UGC from Greenyards (Point X) to UGC4-SEC 2 (Gartur) ...50 3.2.5 UGC4 SEC 2: Gartur .............................................................................55 3.2.6 UGC4 C1: OHL from-SEC 2 (Gartur) to SEC 4 (Denny S/Stn)..............56 3.2.7 UGC4 C2: UGC from-SEC 2 (Gartur) to SEC 4 (Denny Substation).....56 3.3 SBP Route ....................................................................................................60 3.3.1 Hydrocarbon Pipe Lines.........................................................................60 3.3.2 Coincident Highway and UGC Routes...................................................61 3.3.3 UGC4 SEC 3: Braco Substation ...........................................................65 3.3.4 UGC4 A3: UGC - New Braco Substation to Greenyards (Point X) ........68 3.3.5 UGC4 B: UGC from Greenyards (Point X) to Gartur ............................74 3.3.6 UGC4 C1: OHL from Gartur to Denny Substation ................................74 3.3.7 UGC4 SEC 4: Denny Substation ..........................................................74 3.4 General Notes on Cabling for these Route alternatives................................75 3.5 Environmental Commentary .........................................................................77 3.5.1 Geology and Soils..................................................................................77 3.5.2 Hydrology...............................................................................................78 3.5.3 Forestry..................................................................................................80 3.5.4 Ecology and Nature Conservation .........................................................84 3.5.5 Landscape Character.............................................................................86 3.5.6 Visual Amenity .......................................................................................90 3.5.7 Cultural Heritage....................................................................................94 3.6 Cost Appraisal ..............................................................................................98 3.6.1 Unit Costs ..............................................................................................99 3.6.2 Cost Appraisal – SNH Option 1: Milour Moor to Denny ........................99 3.6.3 Cost Appraisal – SNH Option 2: Milour Moor to Gartur ........................99 3.6.4 Cost Appraisal – SBP: Braco to Denny.................................................99 3.7 Conclusions on West of Stirling Appraisal ..................................................105 3.7.1 Technical..............................................................................................105 3.7.2 Environmental......................................................................................105 3.7.3 Costs....................................................................................................109 CHAPTER 4: OCHILS ESCARPMENT ROUTE EAST OF STIRLING APPRAISAL ......111 4.1 Technical Appraisal ....................................................................................111 4.1.1 UGC4 SEC 5: Cocksburn Wood (including UGC4 D - OHL connection) .........................................................................................................112 4.1.2 UGC4 D: Tunnelled UGC from Cocksburn Wood to Logie Villa .........113 4.1.3 UGC4 Tunnel Shaft 2: Logie Villa.......................................................120 4.1.4 UGC4 E: UGC from Logie Villa to Manor Powis .................................120 4.1.5 UGC4 SEC 6: Manor Powis (including UGC4 E - OHL connection)...121 4.2 Environmental Commentary .......................................................................122 4.2.1 Geology and Soils................................................................................122 4.2.2 Hydrology.............................................................................................123