navitus bay wind park - planning inspectorate... · 2.1.4 the project exceeds 100 mw and is...

NAVITUS BAY WIND PARK Response to Deadline VII

Appendix 17 Design and access statement v2

5 March 2015

Application Reference: EN10024

Navitus Bay Development Limited

navitusbaywindpark.co.uk

Navitus Bay Wind Park

Design and Access Statement v2

Appendix 17 (Document 8.2)

March 2015

Pursuant to Regulation 5(2)(q) of the Infrastructure Planning (Applications:

Prescribed Forms and Procedure) Regulations 2009


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Page ii Design and Access Statement

DOCUMENT CONTROL

DOCUMENT PROPERTIES

Author Navitus Bay Development Limited

Title Design and Access Statement v2

Document Reference

8.2

VERSION HISTORY

Date Version Status Description/Changes

4 March 2015 2.0 Final Issued at Deadline VII


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Design and Access Statement Page iii

TABLE OF CONTENTS

1. Introduction ........................................................................... 1

2. Policy Framework .................................................................... 4

3. Site Selection ......................................................................... 6

4. Site Description and Consenting Considerations ........................ 11

5. Project Design ...................................................................... 15

6. Access ................................................................................. 33

7. References ........................................................................... 38

8. Glossary .............................................................................. 39

9. Abbreviations ....................................................................... 44


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Page iv Design and Access Statement

LIST OF TABLES

Table 1.1 – Onshore Design Parameters .............................................. 3

Table 8.1 – Glossary ....................................................................... 39

Table 9.1 - Abbreviations ................................................................. 44

LIST OF FIGURES

Figure 5.1 - Indicative Landfall arrangement ...................................... 18

Figure 5.2 - A typical HDD compound at cable landfall (courtesy of Visser

Smit & Hanab) ............................................................. 19

Figure 5.3 - Typical HV cable configuration for a single circuit in both

trefoil and flat spaced formation ..................................... 21

Figure 5.4 - Indicative Onshore Cable Corridor working width ............... 22

Figure 5.5 - Indicative Onshore Substation Layout .............................. 27

Figure 5.6 - Indicative Onshore Substation Landscaping Scheme .......... 32

Figure 6.1 - Landfall access route ..................................................... 34


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Design and Access Statement Page 1

1. Introduction

1.1 Project Brief

1.1.1 Navitus Bay Development Limited (NBDL) is a joint venture

owned 50:50 by Eneco Wind UK Ltd (Eneco) and EDF Energy

(EDF). In January 2010, The Crown Estate awarded Eneco the

exclusive rights to develop an offshore wind park within Zone 7

(West of Isle of Wight), following Round 3 of its Offshore Wind

Programme. The development zone has a target capacity of up

to 970 MW.

1.1.2 Consent is being sought from the Secretary of State for Energy

and Climate Change. Subject to approval, it is anticipated that

the construction of the offshore wind farm and associated

onshore electrical infrastructure will take up to five years to

complete.

1.2 Purpose of the This Document

1.2.1 The purpose of this Design and Access Statement (DAS) is to

demonstrate the evolution and rationale of the design of the

onshore components of the Project within the Onshore

Development Area, comprising the Landfall, the Onshore Cable

Corridor and the Onshore Substation. It describes how the

design has been influenced by the technical and operational

requirements of the wind park electrical infrastructure. The

design approach incorporates comments received during pre-

application consultation under Section 42, 47 and 48 of the

Planning Act 2008, as well as outputs of environmental

assessments of the environment in which the infrastructure

would be located.

1.2.2 The DAS supports the Application for a Development Consent

Order (DCO) submitted to the Planning Inspectorate (PINS) by

NBDL. The DAS should be read in conjunction with the

Enviromental Statement (Document 6.1). The Application seeks

consent for the Navitus Bay Wind Park (‘the Project’).

1.2.3 Existing policy set out within the Overarching National Policy

Statement for Energy (NPS EN-1) makes clear the requirements


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Page 2 Design and Access Statement

for good design in energy projects. The DAS provides a tool to

communicate how the requirements for good design and access

provision have been considered.

1.2.4 There is no specific guidance provided for the preparation of

design and access statements in relation to Nationally Significant

Infrastructure Projects (NSIPs). NBDL has therefore decided to

prepare this DAS in line with the Commission for Architecture

and the Built Environment guidelines (CABE, 2007). The bullet

points below set out the key parameters set out in the CABE

guidelines:

use – what is the purpose of the development and how it will

fit within the surrounding environment;

amount – size and volume of the development and its

constitute elements;

layout – the relationship between the development, and

surrounding buildings;

scale – the physical size and shape of the proposed

development;

appearance – the physical look of the development specifically

the design and materials;

landscaping – how mitigation proposals will be applied to

screen the development from wider views; and

access – inclusive of construction and operational traffic and

how crossings over roads and watercourses will be achieved.

1.3 Project Description

1.3.1 The DAS focuses on the onshore elements of the Project

comprising the Onshore Development Area (as described above).

In order to bring electricity generated offshore by the wind

turbines offshore export cables will make Landfall at Taddiford

Gap, between Barton-on-Sea and Mildford-on-Sea and the

Onshore Cable Corridor would then head north-west, to the new

Onshore Substation at Three Legged-Cross, north of Ferndown in

East Dorset. The new Onshore Substation would then be


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connected to the National Grid substation at Mannington, by

underground cable.

1.3.2 The proposed onshore electrical infrastructure is required in

order to connect the Navitus Bay Wind Park to the 400 kV

national electricity network. Table 1.1 below sets out the primary

infrastructure associated with the onshore Project components.

Table 1.1 – Onshore Design Parameters

Project component

Design Parameters

Landfall up to six offshore cables;

up to six transition joint bays; and

two temporary construction compounds.

Onshore Cable Corridor

working width of generally 40 m;

up to six cable circuits and fibre optics in six

trenches; and

four temporary construction compounds.

Onshore Substation

electrical footprint of approximately 3 ha (refer to the Works Plan (Document 2.4 of this Application)

which sets out the site boundary);

maximum height of electrical equipment – 11 m;

maximum height of GIS building – 14 m;

maximum height of lightning masts – 19 m;

ground raising above existing ground level – up to

1 m; and

one temporary construction compound.

Working hours generally, construction site working will be during normal working hours (08.00 – 18.00 Monday to

Friday and 08.00 – 13.00 Saturday), with no activity

on Sundays or bank holidays; and

exceptions will be required where seven days

working and/or 24 hours working is necessary for specific construction activities such as Horizontal

Directional Drilling (HDD) works.


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2. Policy Framework

2.1 Framework

2.1.1 This section provides a summary of the main planning policies

relevant to the Project and associated DCO documents. It

includes a summary of the national policy and guidance relevant

to the Project. A detailed appraisal of planning policy has been

carried out within the Planning Statement (Document 8.4).

a) National Policy

2.1.2 The UK Government has produced three National Policy

Statements (NPSs) under the Planning Act 2008 that relate to

renewable energy production, including offshore wind:

Overarching NPS for Energy EN-1, July 2011 (DECC, 2011a);

NPS for Renewable Energy Infrastructure (EN-3, July 2011)

(DECC, 2011b); and

NPS for Electricity Networks Infrastructure (EN-5, July 2011)

(DECC, 2011c).

2.1.3 NPSs establish the national need for a particular type of major

infrastructure, together with a series of criteria relating to the

benefits and impacts of a development. Potential benefits include

a development’s contribution to meeting the need for energy

infrastructure, job creation and any long-term or wider benefits.

Potential adverse impacts include any long-term and cumulative

adverse impacts, as well as any measures to avoid, reduce or

compensate for any adverse impacts.

2.1.4 The Project exceeds 100 MW and is therefore classified as a NISP

and will require development consent under the Planning Act

2008. Under the Planning Act 2008 it is possible to include

development associated with the generating station within the

boundaries of the DCO. NBDL has included all the offshore and

onshore infrastructure and grid connection elements of the

Project within the DCO.


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2.2 Project Need and Justification

2.2.1 There is a clear need for the Project as set out in the

Overarching National Policy Statement for Energy (EN-1). EN-1

Paragraph 2.2.20 states that “it is critical that the UK continues

to have secure and reliable supplies of electricity as we make the

transition to a low carbon economy”.

2.2.2 In addition, EN-1 Paragraph 3.3.4 outlines the importance of

having a diverse mix of power generation and that renewables

offer a low carbon and proven (for example, onshore and

offshore wind) fuel source.

2.2.3 The UK has substantial renewable energy resources and EN-1

states that offshore wind is expected to provide the largest single

contribution towards the 2020 renewable energy generation

targets.

2.2.4 EN-1 sets out electricity demand forecasts for the year 2025,

stating that 59 GW of demand will need to be delivered by new

infrastructure. In order to meet renewable energy commitments,

some 33 GW of this has been identified as having to come from

renewable sources such as offshore wind.

2.2.5 EN-3 paragraph 2.1.2 provides that in the light of the statements

elsewhere in the NPS about the benefits of new renewable

infrastructure, the Secretary of State should act on the basis that

need for infrastructure covered by EN-3 has been demonstrated.

The document states that the decision-maker should give

substantial weight to the contribution that projects will make

towards satisfying the need for new infrastructure when

considering applications made under the Planning Act 2008.


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3. Site Selection

3.1 Description

3.1.1 Environmental, social and technical considerations have been

integral to informing the design development of the Project, and

as such, the design of the Project has been evolving over the last

two years following wide ranging consultation inputs from

statutory and non-statutory stakeholders. The key onshore

infrastructure elements of the Project has been listed in Table

1.1 of this DAS. As highlighted, the design of the infrastructure

cannot be achieved in isolation and must take account of the

environment in which it is placed. The criteria and approach to

the site selection strategy is set out below.

3.1.2 The site selection process included the Landfall, Onshore Cable

Corridor and Onshore Substation.

3.2 Site Selection Strategy

3.2.1 The site selection strategy consisted of the following:

initial investigations into electrical connection options to the

National Grid;

key Project decisions to install cables underground rather than

installing any new overhead lines;

desk-based constraints mapping process (identifying technical

and environmental constraints) in the proposed study area;

detailed surveys, studies and assessments to gather

information on the existing environment within the study

area;

environmental and engineering related site visits to confirm

the feasibility of the preferred Onshore Cable Corridor;

use of technical guidance for substation siting (e.g. National

Grid Holford and Horlock rules on siting of a substation);

consultation with a range of statutory consultees (through

meetings, site visits and correspondence);


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discussions with landowners and tenants;

consultation with local communities (through public

exhibitions, newsletters and Project specific website); and

detailed analysis, assessment and route modifications to

identify the preferred Onshore Cable Corridor option, taking

into account environmental, technical, financial and risk

factors and any mitigation measures which may be required

to reduce or minimise environmental impacts.

3.3 Operational and Technical Requirements

3.3.1 The operational requirements for the Landfall, Onshore Cable

Corridor and Onshore Substation include:

safety by design;

risk identification and management;

dimensions and scale of the plant;

construction requirements;

maintenance requirements of plant; and

security.

3.3.2 The operational requirements provide the baseline to design,

build and operate the infrastructure safety in relation to existing

features of the site. The requirements dictate the minimum

spacing requirements to accommodate the plant for the works

e.g. proximity to the overhead lines.

3.4 Physical and Environmental Considerations

3.4.1 Physical and environmental considerations are those constraints

that inform the location and site selection process of the onshore

infrastructure. The physical and environmental considerations for

the Landfall, Onshore Cable Corridor and Onshore Substation

include:

the location of sensitive (human) receptors (i.e. residential

housing, schools, hospitals);

impacts to the terrestrial and river ecology and ornithology,

and impacts to designated sites for nature conservation;


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transport infrastructure;

visual appearance of the construction works and plant;

vhange to the existing landscape character;

impacts to the geology and hydrology, and surface water

management;

impacts to soils and agriculture;

the generation of noise and vibration;

impacts to the local air quality; and

impacts to archaeological and heritage assets.

3.4.2 For further detail on these constraints please refer to Section 4

of the DAS or the relevant chapter of the Environmental

Statement (ES Document 6.1).

3.5 Landfall, Onshore Cable Corridor and Onshore Substation

Site Selection

3.5.1 This section provides the key considerations NBDL usd to identify

the preferred locations of the Landfall, Onshore Cable Corridor

and Onshore Substation.

a) Landfall

3.5.2 The Landfall site selection process involved a detailed search of

the adjacent coastline to the offshore development. The key

considerations were:

cliff height;

cliff stability;

cliff geology;

the site’s accessibility from the main highway network for

construction traffic;

the site’s remoteness from environmentally designated areas;

sufficient area for a construction and drilling compound;

sufficient laydown area; and

minimising overall environmental and social impact.


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b) Onshore Cable Corridor

3.5.3 The selection of the Onshore Cable Corridor involved

identification of a wider corridor combined with further detailed

desk top and site specific studies. The key criteria that were

considered were:

use of agricultural land where feasible;

avoidance of sensitive receptors such as housing, schools,

churches etc;

avoidance of environmentally sensitive sites where feasible;

and

avoidance of areas of cultural heritage significance.

3.5.4 Section 4 of the DAS provides detail of the key environmental

considerations within the Onshore Cable Corridor search area.

c) Onshore Substation

3.5.5 The Onshore Substation site selection process involved initially

identifying a suitable search area from the proposed connection

point in which a feasible site could be identified. A long list of

potential sites was identified based on broad site feasibility

requirements. The number of potential sites was gradually

reduced as development constraints were identified. All potential

sites were assessed based on the following key criteria:

the engineering / technical suitability of the site;

the site’s accessibility from the main highway network for

construction traffic;

the site’s impact on environmentally designated areas;

minimise the potential to overall environmental and social

impact;

access for the Onshore Cable Corridor to the site;

the site’s proximity to sensitive receptors (i.e. housing); and

the availability of additional land, allowing for substantial

enhancement of the existing natural screening in the area.


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3.5.6 A detailed description of both the Onshore Cable Corridor

identification and Onshore Substation site can be found in

Volume C, Chapter 4 Alternatives of the ES (Document 6.1).


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4. Site Description and Consenting

Considerations

4.1 Description

4.1.1 This section of the DAS describes the selected Onshore

Development Area (comprising the Landfall, Onshore Cable

Corridor and Onshore Substation) in the context of its

environment within which it is proposed to be located.

4.2 Landscape Character

4.2.1 Landscape character is recorded at both the national and local

levels. The character types / areas are also evaluated in terms of

their sensitivity.

4.2.2 The Landfall site currently comprises a gently rolling pastoral

landscape set on top of the elevated and heavily eroded coastal

fringe where there are panoramic views across Christchurch Bay

and the mouth of the Solent.

4.2.3 The Onshore Cable Corridor extends for an approximately 35 km

between the Landfall site, located at Taddiford Gap, between

Barton-on- Sea and Milford-on-Sea, and the grid connection

point at the Mannington substation. The route passes through a

predominantly rural and frequently rolling landscape comprising

mostly agricultural land and plantation forestry. The Onshore

Cable Corridor passes through the local administrative

boundaries of New Forest District, Christchurch District and East

Dorset District.

4.2.4 The Onshore Substation is situated within the East Dorset Green

Belt, which encompasses much of the surrounding rural

landscape within the East Dorset District. Small areas to the

north-east and south-east lie within the New Forest District and

Christchurch Boroughs respectively.

4.2.5 A number of small and medium sized settlements are located

within 3 km of the Onshore Substation and include Verwood to

the north, St. Leonards, St Ives and Ashley Heath to the east,

and West Moors and Ferndown to the south. Moreover, the


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proposed Onshore Substation currently forms part of an estate,

which comprises open fields used as grazing pasture.

4.2.6 A full Landscape and Visual Impact Assessment (LVIA) has been

undertaken as part of the Environmental Impact Assessment and

is described in more detail in Volume C, Chapter 12 Landscape

and Visual of the ES.

4.3 Nature Conservation and Ecology

4.3.1 The description below provides an overview of the key habitats

considered during the assessment.

4.3.2 There are nine designated sites of international importance

within 1.5 km of the Onshore Development Area; six of these

overlap with the DCO application boundary. These six

designations overlap considerably, with three of the designations

relating to the River Avon and associated habitats and three

relating to the Dorset Heaths. Fourteen Special Sites of Scientific

Interest were identified during the desk study, six of which

overlap with the Onshore Development Area. Of these six sites,

three are constituent components of the international

designations.

4.3.3 There were 81 non-statutory designated sites of county

importance that were identified as part of the desk-study; 15 of

these overlap with the Onshore Development Area. Several of

the habitats recorded within the DCO application boundary are

habitats of principal importance under Section 41 of the Natural

Environment and Rural Communities Act 2006. These include the

following:

broadleaved woodland;

dry heath/acid grassland and shrub heath;

ponds;

rivers and streams; and

hedgerows.


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4.3.4 The environmental and ecological designations as well as results

of the Phase 1 habitats are available in more detail in Volume C,

Chapter 10 Terrestrial and Freshwater Ecology of the ES.

4.4 Historic Environment

4.4.1 The heritage baseline survey identified a total of 60 designated

sites within the study area approximately 500 m either side of

the Onshore Cable Corridor, including Scheduled Monuments and

Listed Buildings. No World Heritage Sites, Registered Parks and

Gardens or Registered Battlefields were identified within the

study area. The small numbers of scheduled monuments

identified within the broad study area are Bronze Age barrows,

which form part of a larger concentration of funerary sites

located in proximity to Hurn Forest.

4.4.2 The majority of the designated sites identified within the study

area are Listed Buildings. These are primarily clustered around

the settlements of Hordle, Bashley, Hinton, North Bockhampton

and Avon, and are predominantly Grade II listed cottages and

farmhouses.

4.4.3 Full details of the heritage and archaeological assessment are

provided in Volume C, Chapter 13 Cultural Heritage and

Archaeology of the ES.

4.5 Transport and Infrastructure

4.5.1 The main vehicular access routes identified in relation to the

Onshore Development Area are described below. Further detail

on the assessment of relevant transport infrastructure can be

found in the associated ES chapter (Volume C, Chapter 14 Traffic

and Transportation).

4.5.2 The only strategic road that the Onshore Cable Corridor crosses

is the A31 dual carriageway which is a trunk road maintained by

the Highways Agency. To the east, the A31 connects to the

motorway network at the M27 near Cadnam. The A338 is the

only other section of dual carriageway that the Onshore Cable

Corridor crosses and is a north-south route connecting the A31

near Ringwood with Bournemouth. There are several other


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classified A roads within this area, the A35 which connects

Lyndhurst with Poole via Christchurch and Bournemouth; the

A337 which connects Lymington with Christchurch, via the

coastal settlements at Barton-on-Sea, New Milton and Highcliffe,

and the A348 which provides access from the A31 to

Bournemouth.


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5. Project Design

5.1 Description

5.1.1 A full description of the onshore elements of the Project is

provided in Volume C Chapter 2, Project Description of the ES.

This section describes the, Landfall, Onshore Cable Corridor and

Onshore Substation. The requirements for access are detailed in

section 6 of this DAS. This section is structured in accordance

with the CABE guidelines and considers the use, amount, layout

and scale of each element.

5.2 Landfall

5.2.1 The Landfall is located to the east of Barton on Sea at Taddiford

Gap. The site is an open arable field above a cliff line where a

narrow beach sits below. The Landfall works will be carried out

over a period of approximately 6 months within the primary

construction period of 2 years. Pre-construction works and cable

installation may occur outside this period.

a) Use

5.2.2 The purpose of the landfall is to bring the subsea export cables

to shore and connect to the buried onshore cable system.

Landfall will be achieved through the use of the Horizontal

Directional Drill (HDD) technique. This involves directional

drilling from the onshore side under the cliff line. The purpose of

this is to install ducts through which the cables will be pulled by

a winch.

b) Amount

5.2.3 The Shoreline Management Plan (Royal Haskoning, 2011)

predicts that the rate of erosion along this stretch of coast is up

to 2.7 m per year, with an expected maximum of 135 m over 50

years. To prevent the cables becoming exposed through coastal

erosion the HDD profile will be designed for a minimum of 50

years erosion. The HDD will start at an appropriate distance, no

closer than 135 m from the cliff edge.


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5.2.4 The typical equipment required to carry out the HDD works at

the landfall includes, though is not limited to:

a Drilling Rig;

a Control Cabin;

a Power Pack;

a Hiab Flat Container;

up to two Bentonite Mud Pumps;

a Storage Container;

a mud Recycling Unit; and

ancillary plant and equipment.

5.2.5 Up to six cable circuits would be required and one HDD bore is

required for each circuit. A transition joint bay will be required to

connect the subsea cables to the onshore cables. A typical single

joint bay will be 12 m long, three metres wide and three m deep.

c) Layout

5.2.6 Figure 5.1 below shows the proposed location of the work and

red line boundary. The export cable will make Landfall at

Taddiford Gap, Barton on Sea and the Landfall will be within an

open pasture field, on the landward side of a minor drain and to

the west of the EA flood alleviation channel.


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Figure 5.1 - Indicative Landfall arrangement


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d) Scale

5.2.7 During construction there will be a variety of plant machinery on

site, portacabins and laydown areas (See Figure 5.2). These will

be secured and site security will be used out of construction

hours.

5.2.8 There will be no permanent structures built at the Landfall. Once

construction is complete the only infrastructure visible will be a

manhole cover above the transition joint bay (if required) where

the offshore cables have connected to onshore cables.

Figure 5.2 - A typical HDD compound at cable landfall

(courtesy of Visser Smit & Hanab)

5.3 Onshore Cable Corridor

5.3.1 The Onshore Cable Corridor will be approximately 35 km in

length, travelling from the Landfall site to the new Onshore

Substation, and then from the Onshore Substation to its

connection at the National Grid’s Mannington Substation. The

Onshore Cable Corridor runs predominately within open farmland

in Hampshire and Dorset.


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a) Use

5.3.2 Onshore electricity cables will carry the power from the Landfall

to the proposed new Onshore Substation and will comprise the

following:

alternating Current (AC) operating at a voltage level of up to

275 kV;

the number of circuits required will be up to six, depending on

the final design and detailed cost analysis and will be identical

to the number of offshore cable circuits;

they will be armoured, single core cables with XLPE

insulation; and

the conductor will be either copper or aluminium with cross

sections up to 2000 mm2.

5.3.3 Cabling is also required to connect the new Onshore Substation

to the existing grid connection point at Mannington. It is

expected that these cables will comprise continuous underground

cabling from the Onshore Substation to the connection point, and

will be up to two circuits of 400 kV AC cables.

5.3.4 Ancillary fibre optic and telecommunications cables will also be

required.

b) Amount

5.3.5 There will be up to six trenches used, containing one circuit of

three cables in each trench. The total length of each trench is

approximately 35 km. Table 5.1 shows the indicative dimensions

at different voltages.

Table 5.1 – Typical dimensions of AC onshore cables

Voltage Conductor

Cross-

Section

132 kV 1200

mm²

132 kV 2000

mm²

220 kV 1200

mm²

220 kV 2000

mm²

400 kV 800 mm²

400 kV 1200

mm²

Conductor type

Aluminium Aluminium Aluminium Aluminium Aluminium Aluminium


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Table 5.1 – Typical dimensions of AC onshore cables

Voltage Conductor

Cross-

Section

132 kV 1200

mm²

132 kV 2000

mm²

220 kV 1200

mm²

220 kV 2000

mm²

400 kV 800 mm²

400 kV 1200

mm²

Outer

diameter (mm)

94 106 112 124.2 116.3 120.4

Cable weight

(kg/m)

8.7 11.8 12 15.4 12.1 13.4

c) Layout

5.3.6 The configuration of the onshore cables will be established during

detailed design but will comprise up to a maximum of six

circuits, each made up of three, single core cables. Within each

circuit, the onshore cables will be installed in either a trefoil or

flat formation, as shown in Figure 5.3.

5.3.7 The final spacing and cable arrangement will be dependent upon

the voltage of the cables, including the available space and the

thermal properties of the soil.

Figure 5.3 - Typical HV cable configuration for a single

circuit in both trefoil and flat spaced formation

5.3.8 The typical burial depth will be 1,200 mm to the top tile, in line

with landowner agreements. However, in some locations the

depth may vary as shown in Table 5.1. The final depth will be


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dependent upon local conditions and include factors such as the

road construction, the presence of other utilities and also the

ground conditions and topography.

d) Scale

5.3.9 All construction activities will take place within the working

width. Figure 5.4 shows a cross section of the working width,

which will generally be up to 40 m wide.

The working width will principally contain the cable trenches, a

temporary access track and storage area for soil and plant.

Figure 5.4 - Indicative Onshore Cable Corridor working width

5.3.10 Where landowner agreements permit or engineering

requirements dictate, the working width may be wider. These

areas are limited to the Landfall, the route through the West

Moors Ministry of Defence base and where there are both

incoming and outgoing cables from the Onshore Substation.

5.3.11 Temporary construction compounds will be required during

construction. A total of seven temporary construction facility

locations have been identified for the onshore construction (two

to be located at the Landfall, four along the Onshore Cable

Corridor and one at the Onshore Substation). The locations have

been selected based on a number of parameters, including their

close proximity to the working width, ensuring sufficient

coverage of the full length of the route, suitable transport access

and sufficient land area.

5.3.12 Trenchless installation working areas will also be required at

certain locations along the Onshore Cable Corridor. These have

been identified specifically to provide sufficient working area to

complete trenchless cable installation operations. Once the

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trenchless installation is complete these compounds will be

reinstated.

5.3.13 The exact installation methods for the cables will only be

confirmed during detailed design, post-consent, and will be

developed to suit the requirements of the respective

stakeholders and landowners, where feasible. The construction

methods will also be subject to several other factors, such as the

ground conditions and any environmental constraints.

5.3.14 Temporary accesses will be taken from the public highway at

regular points along the Onshore Cable Corridor. Design of the

accesses will be suitable for both light and heavy goods vehicles

and will include passing places where required. A total of 73 site

accesses have been identified for the Project. Wherever possible,

the site accesses are based upon using the nearest suitable point

from the public highway.

5.4 Onshore Substation

5.4.1 The Onshore Substation is proposed to be sited to the south of

the substation site, adjacent to the Ministry of Defence fuel

depot and providing sufficient separation from residential

properties to the north. A new access road would come through

the plantation woodland to the west of the site.

a) Use

5.4.2 The use will be for an onshore substation facility accommodated

within a compound containing electrical equipment including

power transformers, switchgear, reactive compensation

equipment, harmonic filters, cables, lightning protection masts,

control buildings, communications masts, back-up generators,

fuel storage, access roads, car parking and hard standing,

fencing and other associated equipment and structures.

b) Amount

5.4.3 The detailed design of the Onshore Substation will be determined

post-consent and would be influenced by factors including the

export voltage, number of cables and the turbine type.


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5.4.4 The substation will require a compound within which will be

located electrical equipment to transform the power generated

by the offshore wind park up to 400 kV. The compound will be

approximately 3 hectares in area, with a maximum height of

infrastructure of up to 14 m for the GIS building, 19 m for the

lightning towers (if required) and up to 11 m high for other

electrical equipment and infrastructure.

5.4.5 The existing ground level could be raised by up to 1000 mm at

the Onshore Substation in order to provide suitable foundations

and facilitate drainage.

5.4.6 These maximum dimensions represent a realistic worst case. As

such, the ES accompanying the DCO has assessed the impact of

the new Onshore Substation on this basis.

c) Layout

5.4.7 The Onshore Substation compound will contain:

transformers;

GIS (gas insulated switchgear) housed in a building;

reactive compensation equipment;

harmonic filters;

control building;

car parking;

access roads;

security fencing;

lightning towers, if required; and

drainage and flood attenuation.

5.4.8 Outside of this compound the Onshore Substation is likely to

have:

hard landscaping;

access tracks;


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planting;

fencing; and

utility connections.

5.4.9 An indicative Onshore Substation layout is shown in Figure 5.5.

The Onshore Substation design will be in accordance with

applicable Engineering Recommendations and European and

British Standards and will be carried out during the detailed

design phase. It will consider the following design principles:

substation design will pay due regard to the Green Belt

designation and, within the constraints of procurement, will

ensure that the built form associated with the development

represents only what is reasonably necessary to safely

construct, maintain and operate the onshore substation to

ensure that the impact on the openness of the Green Belt is

kept to a minimum

the height of structures will take into account the heights of

existing screening and will seek to limit the impact of the

development on the surrounding area

landscaping will seek to maximise the screening of the site

from surrounding properties, particularly those from the north

and north-west, in addition to the existing mature screening.

buildings required will be of simple, utilitarian design to

minimise the built form in the Green Belt

areas of hardstanding and vehicle car parking will be kept to a

minimum and will relate to the function of the site.

Fire Damage Zones (FDZ) for equipment containing oil will be

considered when producing the layout to ensure there is

adequate spacing between substation components;

equipment containing oil will have a bund type foundation

with sufficient internal clearance at ground level between the

equipment and the bund wall;

the layout will look to optimise the use of space in order to

minimise the overall Onshore Substation footprint; and


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the Onshore Substation will be designed to mitigate noise

pollution and where possible, locate the largest noise sources

away from noise receptors. Noise mitigation/suppression will

be installed where necessary.

d) Scale

5.4.10 The exact size and scale of each of the elements within the

Onshore Substation are not yet known. However the footprint of

the site is fixed (refer to Works Plan, Document 2.4) along with

the maximum height for any element under the DCO (see

Requirement 10 (Detailed design approval onshore)). The details

of details of its layout, design, scale and external appearance will

be agreed with the relevant planning authority pursuant to

Requirement 10.

5.4.11 The design parameters for the Onshore Substation and

associated equipment have been informed by the surrounding

height of onsite vegetation. This will act as natural screening of

the development to surrounding receptors. Figure 5.5 below

shows the zoning of the Onshore Substation site for each activity

relative to the site boundary.


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Figure 5.5 - Indicative Onshore Substation Layout


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5.5 Lighting

a) Landfall and Onshore Cable Corridor

5.5.1 No fixed lighting will be required along the Onshore Cable

Corridor during construction.

5.5.2 At construction compounds and along the Onshore Cable

Corridor, temporary lighting may be required during working

hours in the winter months.

5.5.3 External lighting would be designed and positioned to:

provide the necessary levels for safe working;

minimise risk of accident or injury; and

avoid disturbance to residents and occupiers in the vicinity.

5.5.4 Lighting may be required for 24 hour working at trenchless

installation working areas. As far as is reasonable, appropriate

lighting will be used to direct light towards the working areas.

Lighting would be designed to balance the requirements for safe

access and specific tasks against minimising light pollution and

impact on amenity.

b) Onshore Substation

5.5.5 As a principally unmanned substation there will be two distinct

conditions of lighting for the compound:

unmanned; and

attended site.

5.5.6 The outline lighting requirements for each condition are

discussed below.

i Unmanned

5.5.7 There will be no requirement to provide lighting across the

Onshore Substation compound or plant areas when no personnel

are on site. This is in accordance with the requirements set out

in the National Electrical Safety Code.


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ii Attended Site

5.5.8 Switchable lighting for all external and internal areas of the

Onshore Substation will be provided for periods where work is

carried out on site. This switching could consist of manual and/or

movement sensors.

5.5.9 Site attendance for maintenance will be planned to be completed

during daytime hours where possible. Night time working is

expected to be required for reactive and infrequent maintenance

tasks.

5.5.10 In general, external lighting will be floor, building or pole

mounted and internal lighting will be wall and ceiling mounted.

5.6 Landscaping

a) Landfall and Onshore Cable Corridor

5.6.1 Along the Onshore Cable Corridor the excavated trench will be

backfilled and soil compacted to the equivalent density as the

pre-excavated material. Where the soil type varies over the

depth of the trench, the excavated material will be back-filled

and replaced in the same order and to the same thickness as the

existing ground conditions.

5.6.2 Topsoil replacement and final reinstatement will be undertaken

once construction works have completed. Specific reinstatement

measures may need to be implemented in environmentally

sensitive areas and this will be settled after discussions with

landowners and statutory bodies. The reinstatement works will

include, though are not limited to:

removal of the access and haul roads, temporary fencing and

construction compounds;

removal of any temporary drainage; and

replanting as appropriate.

5.6.3 Where the cable corridor goes through hedgerows, rivers and

woodlands specific reinstatement is described in the Ecological

Mitigation Plan (draft) attached to the Code of Construction

Practice (Document 8.5).


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5.6.4 Where applicable, post-construction drainage may be installed to

ensure water does not drain along cable trench lines and that

land is returned to its previous draining state. These drains are

typically laid parallel to the cable trenches.

b) Onshore Substation

5.6.5 The Onshore Substation site was selected partially for its high

level of natural screening. The design seeks to utilise this

screening and to enhance it by including planting and

landscaping (Figure 5.6) to ensure that any residual visibility of

the site is reduced as far as is practicable. The Onshore

Substation compound has been sited at least 20 metres from the

East, West and South sides of the site boundary to enable

landscaping and planting. This reduces to a potential minimum of

10m for a short length at the South East boundary.

5.6.6 The proposed curved access road limits visibility of the site from

the road by removing a clear line of site through the wooded

area.

5.6.7 Heights of the substation buildings and electrical infrastructure

have been determined so as to be below existing screening.

5.6.8 The final Onshore Substation landscape design and management

plan will be determined through consultation with landowners

and stakeholders, and agreed with the relevant planning

authorities (see Requirement 21 (Landscaping design and

management plan)).


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Page Left Intentionally Blank


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Figure 5.6 - Indicative Onshore Substation Landscaping Scheme


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6. Access

6.1 Access

6.1.1 The following section of the DAS describes the access

requirements and arrangements for the proposed onshore

elements of the Project development during the construction and

operational phases.

6.1.2 Typical vehicles travelling to and from the site during the

construction period will include:

flat bed trucks;

tipper trucks;

low loaders;

excavators;

mobile cranes;

mobile mixers;

delivery vans; and

labour transport (vans and cars).

6.2 Construction Access

a) Landfall

6.2.1 Proposed temporary access and egress arrangements will be

arranged from the B3058 (Milford Road), situated immediately to

the north of the Landfall location and using the existing access

into the car park. There will be two temporary construction

compounds at the Landfall area. A temporary access track will be

constructed to the Landfall compound. This will be for the sole

use of construction vehicles and will be removed upon the

completion of construction activities. Figure 6.1 shows the

proposed Landfall access route.


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Figure 6.1 - Landfall access route


6.2.2 Access to the Onshore Cable Corridor will be from temporary

construction compounds. These contain:

construction management offices, car parking and welfare

facilities;

containers for material and equipment storage;

fuel storage and wheel wash facilities;

storage areas for plant and materials; and

waste management facilities.

6.2.3 A total of four temporary construction compounds have been

identified for construction of the onshore cable. The locations

have been selected based on a number of parameters, including

their close proximity to the working width, suitable transport

FF

FF

Def

Def

Pond

Drain

House

Drain

11.6m

Dra

in

Drain

Issues

Cottage

Car Park

Taddiford

Path

(um

)

Legend

Temporary Construction Compound

Proposed Temporary Access Route

This map is the copyright of Navitus Bay Development Ltd. The accuracy, reliability, or completeness of the information is not guaranteed or warranted in any way and Navitus Bay Development Ltd and its

representatives disclaim liability of any kind whatsoever, including, without limitation, liability for quality, performance, merchantability and fitness for a particular purpose arising out of the use, or inability to use the data.

Contains Ordnance Survey data © Crown copyright and database right 2013; © Crown copyright, All rights reserved. 2013 Licence number 0100031673


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access and sufficient land area. The construction compounds

where possible have been sited at equal points along the

Onshore Cable Corridor.

6.2.4 Temporary site access will also be required, to provide entry to

and from the working width from the public highway.

6.2.5 A total of 73 site accesses have been identified for the Project.

Wherever possible, the site accesses are based upon using the

nearest suitable point from the public highway. Locations have

been chosen to minimise the environmental implications (e.g.

hedgerow removal has been kept to a minimum).


6.2.6 Traffic to site will comprise of three types of movements:

daily workforce movements;

deliveries and HGVs; and

abnormal loads.

6.2.7 Construction workforce numbers will vary and suitable temporary

parking will provided within the contractors Construction, Design

and Management (CDM) compound, typically up to 50 spaces.

6.2.8 General deliveries, typically vans and flatbed trucks, will vary

depending on the stage of construction, with peak transport

movements likely during civil construction. HGV movements will

be for the delivery of key components including:

reactors;

steelwork for buildings;

Gas Insulated Switchgear (GIS) electrical equipment;

cable drums;

Static VAR Compensator (SVC) electrical equipment; and

concrete deliveries.

6.2.9 It is anticipated that the only abnormal load deliveries (as

defined by the Road Vehicles (Construction and Use) Regulations

1986) will be for up to three high-voltage transformers. The


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delivery of these items will be coordinated with the local

highways authority and the Highways Agency. The abornmal

loadvehicles used will be multi-axle specialist vehicles with total

lengths over 30 m with a project specific trailer arrangement;

they will be subject to a special abnormal load licence.

6.2.10 All construction access will be obtained from the B3072 (West

Moors Road), through the Mill Nursery plantation and directly

into the site compound. The new access road will allow sufficient

lines of sight along the road for safe access and egress.

Vegetation clearance may be required to create a bell-mouth

entrance during construction. The proposed access road is

designed to minimise direct views into the substation compound.

6.3 Operational access

a) Landfall

6.3.1 Once operational there will be no requirement to have

permanent access to the Landfall. There will be a requirement for

planned maintenance inspections of the Landfall transition joint

bay which will be accessed via a manhole cover. It is not

expected that any plant will be required to carry out the

maintenance.


6.3.2 The Onshore Cable Corridor will be monitored throughout

operation and will include a full check on a yearly basis, including

all the joint bays. Access to the Onshore Cable Corridor will

normally be by foot and apart from routine tests the cable will

remain maintenance free. In the event of a cable failure during

operation, a fault finding system will determine if it is mechanical

or electrical, and the fault will be repaired.

Access for inspections and maintenance would be taken from

existing accesses.


6.3.3 During operation, the Onshore Substation is likely to be

unmanned, requiring only infrequent visits for routine inspection


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and maintenance. Such activities would be undertaken by a

small team of technicians for most works.

6.4 Public access

a) Landfall

6.4.1 Public Rights of Way (PRoW) at the Landfall will be managed

during construction with temporary closures and discussions with

the relevant PRoW officer at the Local Planning Authority. The

affected PRoWs are detailed with the PRoW Strategy (Document

8.3). There will be no disruption to access during the operation

and maintenance phase of the Project.


6.4.2 PRoW and open access land along the Onshore Cable Corridor

will be managed during construction with temporary closures and

discussions with the relevant PRoW officer at the Local Planning

Authority. The affected PRoWs are detailed with the PRoW

Strategy (Document 8.3). There will be no disruption to access

during the operation and maintenance phase of the Project.


6.4.3 There are no PRoW within the development footprint of the

Onshore Substation. The Onshore Substation site will be securely

fenced and there will be no public access during the construction

or operational phases of the Project.


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7. References

CABE (2007) Design and Access Statement: How to Read, Write and Use

Them. London. CABE

DCLG (2004) Circular 01/2006 – Guidance on Changes to the

Development Control System. London. CABE

DECC (2011a) Overarching National Policy Statement for Energy (EN-1).

Department for Energy and Climate Change. London. HMSO.

DECC (2011b) National Policy Statement for Renewable Energy

Infrastructure (EN-3). Department for Energy and Climate Change.

London. HMSO.

DECC (2011c) National Policy Statement for Electricity Networks

Infrastructure (EN-5). Department for Energy and Climate Change.

London. HMSO.

Royal Haskoning (2011) Poole and Christchurch Bays Shoreline

Management Plan 2 Sub-cell 5f: Hurst Spit to Durlston Head


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8. Glossary

Table 8.1 – Glossary

Term Definition

Alternating Current (AC) The flow of electric charge for which

the direction of flow reverses periodically.

Application The application for development consent for the Project submitted to

the Secretary of State for Energy and Climate Change (formerly the

Infrastructure Planning Commission)

for determination.

Boundary Onshore or Offshore geographical

limits to the Project development area.

Onshore cable A single-core cable

Cable circuit Each cable circuit is made up of 3 single-core onshore cables

Cable route The route of the cables from the Landfall to the Onshore Substation

and onto the grid connection at

Manninton, Dorset.

Development Consent Order (DCO) An order made by the Secretary of

State under the Planning Act 2008 (as amended) granting development

consent for a Nationally Significant

Infrastructure Project.

Environment For the purpose of this document,

environment covers physical, biological and human aspects of the

EIA process.

Environmental Impact Assessment

(EIA)

The process defined in the

Infrastructure Planning (Environmental Impact Assessment)

Regulations 2009 (as amended) [the

EIA Regulations] through which

environmental information on the


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Term Definition

likely significant environmental

impacts of a proposed development

is collected and assessed to inform the determination of an application

for development consent. The

Secretary of State is required to

take into account the environmental

information in the determination of an application for development

consent.

Environmental Information The information obtained during the

EIA process and including the ES and representations from statutory

consultees and third parties.

Environmental Statement (ES) The document submitted by the developer that contains the

information referred to in Part 1 of Schedule 4 to the EIA Regulations,

as is reasonably required to assess

the environmental effects of the

Project and of any associate development and which the

applicant can, having regard to

particular current knowledge and

methods of assessment, reasonably

be required to compile; and includes at least the information referred to

in Part 2 of Schedule 4 to the EIA

Regulations.

Export cable The electrical connection from an Offshore Substation to the Landfall

location.

Geographic Information System (GIS)

GIS integrates hardware, software, and data for capturing, managing,

analyzing, and displaying all forms of geographically referenced

information.


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Term Definition

Horizontal Directional Drilling (HDD) HDD is a steerable trenchless method of installing underground

pipes, conduits and cables along a

prescribed bore path by using a

surface-launched drilling rig.

Impact The net change to a sensitive receptor as a result of the proposed

Project activities, which could be

positive, negative or neutral.

Joint Bay Where two onshore cable circuits are

joined together in a buried concrete pit.

Landfall The site where the offshore cable joins the onshore cable at Taddiford

Gap, Barton-on-Sea, Hampshire, comprising a construction compound

and access track.

Mean Low Water (MLW) The mean surface water elevation as determined by averaging the heights

of the water at equal intervals of time and the jurisdiction of the local

planning authorities.

Navitus Bay Wind Park The entire Project including the

proposed Offshore Development Area and the Onshore Development

Area. The terms Navitus Bay Wind

Park or Project can be used

interchangeably.

Onshore Cable Corridor The working width, temporary accesses and temporary construction

compounds from the Landfall to the

Onshore Substation and on to the

grid connection point at Mannington.

Onshore Development Area This includes all onshore infrastructure including the Landfall,

the Onshore Cable Corridor and


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Term Definition

Onshore Substation.

Onshore Substation A new Onshore Substation located near Three Legged Cross containing

switchgear and transformers for collecting electricity from the export

cables and transmitting to the

National Grid 400 kV Substation at

Mannington.

Ramsar Site Area comprising wetlands of international importance, notified

under the Ramsar convention.

Public Rights of Way (PRoW) Paths on which the public have a

legally protected right to pass and re-pass.

Sites of Special Scientific Interest (SSSI)

A wildlife or geological conservation designation denoting a protected

area in the United Kingdom

identified by the Nature Conservancy Council for protection under the

Wildlife and Countryside Act 1981

(as amended).

Source The origin of an impact, such as an activity associated with project

construction, operation, and/or

decommissioning.

Special Areas of Conservation (SAC) Protected sites designated under the

EC Habitats Directive.

Special Protected Areas (SPA) Sites classified in accordance with the EC Directive on the Conservation

of Wild Birds.

Temporary access Accesses taken onto the working

width for construction purposes

Temporary construction compounds Areas outside of the cable working width identified to provide greater

working area (e.g. for trenchless

crossings).


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Term Definition

Wind Turbine Wind Turbine Generator - offshore electricity generating structure

comprising the tower, hub, nacelle

and rotor blades.

Working Width Temporary width required for the

installation of cables during construction, generally 40 m.

Zone Area of seabed demarcated by The Crown Estate for wind farm

development under the Round 3

Offshore Wind Programme.


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9. Abbreviations

Table 9.1 - Abbreviations

Term Definition

AC Alternating current

CDM Construction Design Management

DCO Development Consent Order

EA Environment Agency

EIA Environmental Impact Assessment

EGL Existing ground level

ES Environmental Statement

GIS Gas Insulated Switchgear

Ha Hectare

HDD Horizontal directional drilling

kV Kilovolt (a unit of electromotive force equal to 1000 volts)

m Meter

MHWS Mean High Water Spring

MLW Mean Low Water mark

MOD Ministry of Defence

MW Megawatt

NBDL Navitus Bay Development Limited

OFTO Offshore Transmission Operator

PRoW Public Rights of Ways

SAC Special Area of Conservation

SPA Special Protection Area

navitus bay wind park - planning inspectorate... · 2.1.4 the project exceeds 100 mw and is...

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