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East Anglia ONE Offshore Windfarm – HVAC Option Assessment Environmental Report

East Anglia ONE Offshore Windfarm May, 2015

Environmental Report

EA ONE – Environmental Report

Table of contents 1 Introduction 1

2 Alternative Project Description 2

3 Consultation 5

4 Methodology 5

5 Screening 5 5.1 Introduction 5 5.2 Screening of offshore topics 6 5.2.1 Identification of changes and effects relevant to the offshore assessment 6 5.3 Screening of Onshore Topics 7 5.3.1 Identification of changes and effects relevant to the onshore assessment 7

6 Updated Assessments 14 6.1 Introduction 14 6.2 Traffic and Transport 14 6.2.1 Introduction 14 6.2.2 Methodology 14 6.2.3 Updated assessment 17 6.2.4 Conclusions 20 6.3 Landscape and Visual Impact 20 6.3.1 Introduction 20 6.3.2 Methodology 21 6.3.3 Summary of the original assessment 22 6.3.4 Updated assessment 23 6.3.5 Conclusions 26

7 Conclusions 26

8 References 27

Table of tables Table 2.1 Proposed changes to the project description to include the option for an up to 750MW windfarm with HVAC

transmission infrastructure ......................................................................................................................................................... 3 Table 5.1 Offshore impact assessment screening ............................................................................................................... 8 Table 5.2 Onshore impact assessment screening ............................................................................................................. 11 Table 5.3 Scheme wide impact assessment screening ..................................................................................................... 13 Table 6.1 Transport parameters ........................................................................................................................................ 15 Table 6.2 Cable and duct pipe requirements for the consented and alternative projects .................................................. 19 Table 6.3 Key proposed changes to the onshore converter station/substation parameters .............................................. 21 Table 6.4 Analysis of viewpoint photomontages ................................................................................................................ 24




Table of plates Plate 2.1 Illustrative trench swathe diagram ....................................................................................................................... 2 Plate 6.1 Detailed breakdown of HGV demand for each cable route section .................................................................... 18

Appendices

Appendix 1 Landscape and Visual Impact Assessment figures…………………........………………………………………29




Summary

The East Anglia ONE Offshore Windfarm Development Consent Order (DCO) grants the construction and operation of an

offshore windfarm with a gross output capacity of up to 1,200MW, consisting of up to 240 wind turbines and associated high

voltage direct current (HVDC) electrical transmission infrastructure.

Following the award of the DCO to East Anglia ONE, and participation in the first Allocation Round of the Contract for

Difference (CfD) regime, East Anglia ONE was awarded a CfD for 714MW of capacity. A project with this level of capacity

would need to connect to the national transmission network through high voltage alternating current (HVAC) rather than

HVDC technology. As such, this smaller project requires a number of limited changes to the configuration of the transmission

infrastructure offshore and onshore.

East Anglia ONE Limited is therefore seeking to vary the DCO to include an alternative option to construct an up to 750MW

windfarm (an allowance over 714MW to account for transmission losses) with a HVAC transmission system. The option to

construct the consented HVDC project with a capacity of up to 1,200MW will be retained within the DCO.

This Environmental Report demonstrates that, for the purpose of the Infrastructure Planning (Changes to, and Revocation of,

Development Consent Orders) Regulations 2011 (as amended), the potential impacts associated with the proposed changes

are in all cases no greater (and would in many cases be less) than those previously assessed for the consented project, and

therefore the changes can be described as non-material for the purpose of the Regulations. The proposed non-material

amendments do not have any impact on the provisions in the DCO relating to future projects.

All topics and potential impacts were screened against the proposed changes to the project design. This involved a

consideration of the effects of the proposed changes and whether these effects could result in a different level of impact to

that identified in the existing assessment. Where there is a clear case that the level of significance would be unchanged or

reduced (e.g. due to a decrease in the spatial footprint of the project), these topics have been screened out from further

assessment. Where further analysis was required to determine whether the significance of the impact would be unchanged

or reduced, an updated assessment is provided.

With respect to both the offshore and onshore environment, it is concluded that the worst case scenario in all instances is

unchanged and the potential impacts associated with the proposed changes to the project design are of no greater

significance than those identified in the existing assessment (comprising the Environmental Statement, Supplementary

Environmental Information and ornithological technical assessments). Offshore, this is primarily on account of the fact that

no changes are proposed to the boundaries of the windfarm or the offshore export cable corridor, whilst there would be a

reduction in the number of wind turbines, offshore platforms and export cables installed.

Onshore, this is due to the fact that no changes are proposed to the boundaries of the onshore cable corridor (more cables

would be installed in the same number of trenches), or of the onshore substation. The maximum height of the buildings at

the substation site is reduced, none of the footprints of the buildings will be greater in size than those considered in the

existing assessment and there would be only a slight increase in the height of outdoor equipment at the substation. Certain

aspects of the assessments for traffic and transport, and landscape and visual have been updated in order to provide greater

certainty with respect to these conclusions. No change in the significance of impacts is predicted for either topic following the

updated assessments.

It is therefore considered that the proposed changes would constitute non-material amendments for the purposes of the

Regulations.



EA ONE – Environmental Report Page 1

1 Introduction 1. East Anglia ONE Limited (EAOL) submitted an application for a Development Consent Order (DCO) for the East Anglia ONE

Offshore Windfarm in November 2012. Consent was granted by the Secretary of State in June 2013. The DCO granted

consent for the development of an offshore windfarm with a gross output capacity of up to 1,200MW (1.2GW), consisting of

up to 240 wind turbines (off the coast of Suffolk) and associated high voltage direct current (HVDC) electrical transmission

infrastructure offshore and onshore including inter-array cabling, offshore collector/converter stations, offshore export cables,

onshore export cables and an onshore converter station at Bramford in Suffolk (“the consented project”).

2. Following the award of the DCO to East Anglia ONE, and participation in the first Allocation Round of the Contract for

Difference (CfD) regime, East Anglia ONE was awarded a CfD for 714MW of capacity on 26th

February 2015. A project with

this level of capacity would need to connect to the national transmission network through high voltage alternating current

(HVAC) rather than HVDC technology. As such, this smaller project requires a number of limited changes to the

configuration of the transmission infrastructure offshore and onshore.

3. East Anglia ONE Limited is therefore seeking to vary the DCO to include an alternative option to construct an up to 750MW

windfarm (an allowance over 714MW to account for transmission losses1) with a HVAC transmission system (“the alternative

project”). All changes would fall within the existing Order Limits of the consented project. The option to construct the

consented HVDC project with a capacity of up to 1.2GW will be retained within the DCO.

4. This Environmental Report is submitted in support of the application to vary the DCO under the Infrastructure Planning

(Changes to, and Revocation of, Development Consent Orders) Regulations 2011 (the Regulations) as amended by the

Consequential Amendments Regulations 2012. It provides an overview of the potential impacts of the alternative project and

compares these to the conclusions reached in the original Environmental Impact Assessment (EIA) (East Anglia Offshore

Wind Limited, 2012), Supplementary Environmental Information (SEI) (East Anglia Offshore Wind Limited, 2013) and the

ornithological assessments submitted during the East Anglia ONE examination process (collectively referred to as “the

existing assessment”). It demonstrates that the potential impacts associated with the proposed changes are no greater (and

would in many cases be less) than those previously assessed for the consented project, and that the proposed changes can

therefore be described as non-material for the purpose of Part 1 of the Regulations. Additionally, the proposed non-material

amendments do not have any impact on the provisions in the DCO relating to future projects.

5. The report is supported by the results of an environmental screening exercise (Section 5) and updated assessments for

traffic and transport, and landscape and visual (Section 6). Drawings of the two scenarios that have been considered in the

updated landscape and visual assessment, as well as the viewpoint locations and associated photomontages, are presented

in Appendix 1. These are:

• Figure 1: HVAC Substation Indicative Layout: Scenario 1

• Figure 2: HVAC Substation Indicative Layout:Scenario 2

• Figure 3: Viewpoint locations

• Figure 4: HVAC Substation Photomontage Viewpoint 3 (Summer): Flowton

• Figure 5: HVAC Substation Photomontage Viewpoint 3 (Winter): Flowton

• Figure 6: HVAC Substation Photomontage Viewpoint 5 (Summer): Canes Farm

• Figure 7: HVAC Substation Photomontage Viewpoint 5 (Winter): Canes Farm

• Figure 8: HVAC Substation Photomontage Viewpoint 10 (Summer): Fidgeons Farm

• Figure 9: HVAC Substation Photomontage Viewpoint 10 (Winter): Fidgeons Farm

• Figure 10: HVAC Substation Photomontage Viewpoint 15: Church Hill

1 Referred to as ‘overplanting’, this allows the Project to be optimised for maximum efficiency taking into account factors such as electrical

losses during transmission.




2 Alternative Project Description 1. As described above, an alternative option to construct an up to 750MW windfarm with HVAC transmission would require a

number of limited changes to the configuration of transmission infrastructure, alongside the corresponding reduction in the

number of wind turbines. It is important to note that the proposed non-material amendments will not have any impact on the

provisions in the DCO relating to future projects.

2. Offshore the changes would be as follows:

• The maximum number of wind turbines is reduced from 240 to 150.

• The maximum total number of offshore platforms is reduced from five platforms (three HVAC collector stations and two

HVDC converter stations) to two platforms (HVAC substations).

• The two HVAC substations will be the same size as the originally proposed HVDC converter stations (60m height, 75m

length and 120m width) but could be located anywhere within the windfarm area, rather than constrained to the western

part of the site as is currently the case).

• There would be up to two 400kV HVAC offshore export cables rather than up to four 600kV HVDC offshore export

cables.

3. There are no proposed changes to the ducting arrangements for future projects. Onshore the changes relate only to East

Anglia ONE infrastructure. These changes would be as follows:

• There would be up to six 400kV HVAC onshore export cables rather than up to four 600kV HVDC onshore export cables.

The six cables would be laid in two circuits of three cables, in two separate trenches, within the original working width of

the cable corridor. There would be no change to the total number of onshore trenches. See illustrative trench swathe

diagram below (Plate 2.1).

• An HVAC onshore substation would be required instead of the currently specified HVDC converter station. The

substation would be contained within the specified footprint of the consented HVDC compound. There would be a small

increase in the maximum height of outdoor electrical equipment from 10m to 15m, in order to cater for the different

technical requirements of HVAC equipment.

• Two extra lengths of duct would be required at each horizontal directional drilling (HDD) crossing due to the increase in

the number of onshore export cables. These would be accommodated within the existing Order Limits.

• There would be a reduced number of jointing bays (57 bays per cable were included in the existing assessment for four

cables, for the alternative project there would be 57 bays for each of the two circuits).

Plate 2.1 Illustrative trench swathe diagram

4. Full details of all of the proposed changes to the project description are given in Table 2.1.




Table 2.1 Proposed changes to the project description to include the option for an up to 750MW windfarm with HVAC transmission infrastructure

Parameter Consented up to 1.2GW HVDC project Alternative up to 750MW HVAC

project

Offshore

Number and size of platforms Up to three HVAC collector station platforms

(40 x 30m x 60m)

Up to two HVDC converter station platforms

(120 x 75m x 60m)

Up to two HVAC substation platforms (120 x

75m x 60m)

No HVDC converter station platforms

Number of offshore wind

turbines

1,200MW comprising a maximum of 240

offshore wind turbines

750MW comprising a maximum of 150

offshore wind turbines

Maximum scour protection

(generation assets)

3.5km2 No change

Maximum scour protection

(transmission assets)

0.029km2 No change

Maximum inert material

disposed (generation assets)

5,603,500m3 No change

Maximum inert material

disposed (transmission assets)

245,000m3 No change

Offshore export cables Up to 4 x 100km 600kV HVDC export cables Up to 2 x 100km 400kV HVAC export cables

Cable separation 200m between cables pairs, 50m between

cables in pairs, 250m outer protection area on

either side (800m corridor in total).

Up to four trenches

50m between cables, 250m outer protection

area on either side (550m corridor in total).

Up to two trenches

Cable protection Cables buried where practical, external

protection at cable crossings

40 export cable crossings, five inter-array

cable crossings

No change

20 export cable crossings, five inter-array

cable crossings

Landfall

Cable installation Method: HDD

Working width: 160m

No change

Transition joint bay parameters Maximum number: 12, plus two smaller boxes

for earthing and fibre optics

Maximum dimensions: 5m x 10m x 5m, 1m x

1m x 5m

Maximum number: No change

Maximum dimensions: No change

Onshore export cables

Cable number and dimensions Up to four onshore HVDC export cables and

fibre optics cables, plus eight ducts for future

projects

Cable length: approximately 37km

Cable rating: 600kV

Trenches: Six trenches in total, for EA ONE

two trenches with two power cables will be

Up to six onshore HVAC export cables and

fibre optics cables, plus eight ducts for

future projects

Cable length: approximately 37km

Cable rating: 400kV

Trenches: No change: Six trenches in total,

for EA ONE two trenches with three power




Parameter Consented up to 1.2GW HVDC project Alternative up to 750MW HVAC

project

installed cables making two circuits

Working width 55m swathe for the majority of the cable route.

Between 110m and 160m at HDD locations.

Special case pinch points exist at 15 and 13m

No change

Cable burial depth Typically 1.2m below ground level

Drilling up to 25m may be required for Deben

crossing

No change

HDD compound size 2500m2 at each drill rig and exit site No change

Jointing bay parameters Maximum number: 57 for each of four cables

(assuming one every 500m) (total 228)

Maximum dimensions: 10m x 5m x 5m

Maximum number: 57 for each of two

circuits (total 114)

Maximum dimensions: No change

Onshore converter station/substation

Number and size of onshore

installations

One HVDC converter station

Maximum compound dimensions: 150m x

190m

Maximum building dimensions:

130m x 85m x 25m

One HVAC substation

Maximum compound dimensions: No

change

The maximum building dimensions are

dependent on the balance of indoor and

outdoor equipment but will be less than the

original assessment. The maximum building

height will reduce from 25m to 21m (see

below)

Equipment height dimensions Primarily indoor but substantial amount of

outdoor electrical equipment

Maximum height of building: 25m

Maximum height of outdoor electrical

infrastructure: 10m (excluding compound

perimeter lightning protection and support

gantries: 25m)

Range: 70-90% outdoor, 10-30% indoor

Maximum height of building: 18m if mostly

outdoor equipment, 21m if mostly indoor

equipment




gantries: 18m)

Construction period Up to 44 weeks, potentially spread over two

years

Six days per week, 12 hour days2

No change

2 The assessment of traffic and transport impacts assumed a five day working week to provide a worst-case construction

traffic demand. See also requirement 23 of the DCO.




3 Consultation 1. EAOL has conducted a programme of informal pre-application consultation in order to brief stakeholders on the nature of the

proposed DCO amendment and the intended approach to the accompanying environmental assessment (this report). This

has included the following:

• Initial briefing meetings for stakeholders (April & May 2015), including Local Planning Authorities, the Environment

Agency, Natural England, the Marine Management Organisation (MMO) and Historic England;

• Draft environmental report submitted to the same stakeholders for review (two week consultation period); and

• Feedback meetings – with above, May 2015.

2. The outcome of the consultation process with each stakeholder is recorded in letters submitted with the variation application

alongside this report.

4 Methodology 1. All topics assessed in relation to the consented project were considered in terms of the alternative project description as set

out in Section 2. The following steps were undertaken:

• All topics and potential impacts as set out in the existing assessment were screened against the parameters of the

alternative project description. This involved a consideration of the environmental effects of the proposed changes and

whether these effects could result in a different level of impact to that identified in the existing assessment.

• Where there was a clear case that the significance of the impact would be unchanged or reduced (e.g. due to a

decrease in the spatial footprint of the project), these topics were screened out from further assessment. The outcome

of the screening assessment is presented in Section 5 (Tables 5.1 to 5.3).

• Where further analysis was required to determine whether the significance of the impact would be unchanged or

reduced, updated assessments have been provided. These assessments are presented in Section 6.

• Where the significance of the impact would be unchanged or reduced from the East Anglia ONE Windfarm alone, it is

considered that the significance of any cumulative impacts would also be unchanged or reduced.

• Where the outcome of the screening or updated assessments confirmed that the significance of the impact would be

unchanged or reduced, the associated changes are considered to constitute non-material amendments for the purposes

of the Regulations.

5 Screening 5.1 Introduction

1. Tables 5.1 to 5.3 summarise the results of the screening exercise on a topic by topic basis. As described in Section 4,

topics have been screened out from further assessment where it is clear that the level of impact would be unchanged or

reduced from that described in the existing assessment. Where this is not the case, updated assessments are presented in

Section 6.




5.2 Screening of offshore topics

5.2.1 Identification of changes and effects relevant to the offshore assessment

2. The proposed changes to the project description (Section 2) that are relevant to the assessment of offshore topics are as

follows:

• The maximum number of wind turbines is reduced;

• The maximum number of offshore platforms is reduced (the maximum size remains the same as the consented HVDC

converter stations);

• The maximum number (and therefore total length) of interconnector cables is reduced;

• The maximum number (and therefore total length) of export cables is reduced;

• The maximum number of cable crossings is reduced; and

• The export cables will be HVAC rather than HVDC.

3. The option to build the two HVAC substations within either the Work No. 1 or the Work No. 2 areas as described in the DCO

is screened out from further consideration on account of the following:

• The DCO currently allows up to three smaller HVAC collector stations of 60m height, 30m length and 40m width within

the Work No. 1 area;

• The two proposed HVAC substations will be no greater than the maximum dimensions of the two consented HVDC

converter stations that are permitted within the Work No. 2 area;

• If the larger HVAC substations are built, any further HVAC substations or HVDC converter stations would be excluded;

and

• None of the existing assessments make assumptions with respect to the exact location of any offshore platforms, which

will only be confirmed as part of the detailed design process nearer the time of construction. Assessments are either

based on a worst case seabed footprint (which is reduced through the reduction in the total number of platforms from five

to two) or, with respect to the risk of a vessel colliding with a structure (termed an allision), on the assumption that all

structures would be located on the perimeter of the windfarm array.

4. Note that there are no changes proposed to the windfarm boundary or the boundary of the offshore export cable corridor.

5. As a consequence of the proposed works described above, the following paragraphs set out the potential changes to the

assessed environmental effects for offshore topics during the construction, operation and decommissioning phases. Whether

these effects could result in a different level of impact to that identified in the existing assessment is considered in Tables 5.1

and 5.3.

Construction

• Reduced footprint of seabed disturbance from installation of cables and foundations (including any associated cable

crossings, scour protection and seabed preparation);

• Reduced volume of suspended sediments from construction work and of the associated effects on marine ecology and

other sensitive receptors;

• Reduced level of disturbance from the generally lower levels of construction activity on site, such as construction

vessels; and

• Reduced level of disturbance from the lower maximum number of piling events required to install foundations (depending

on the selected foundation design).

Operation

• Reduced footprint of cables or foundations above seabed level (including any associated cable crossings and scour

protection) and of the associated effects on the physical environment such as scour processes;

• Reduced potential for electromagnetic field (EMF) effects of buried cables (the export cables will be HVAC rather than

HVDC) due to reduced cable length; and

• Reduced level of disturbance from the lower levels of maintenance activity on site, such as operation and maintenance

vessels.




Decommissioning

• Reduced footprint of seabed disturbance from removal of cables or foundations (including any associated cable

crossings and scour protection);

• Reduced volume of suspended sediments from decommissioning work and of the associated effects on marine ecology

and other sensitive receptors; and

• Reduced level of disturbance from the generally lower levels of decommissioning activity on site, including vessels.

6. Since the type of effects anticipated during decommissioning are similar in nature to those described for construction,

references in the following tables to construction apply equally to the decommissioning phase, where relevant.

7. The outcome of the screening exercise carried out for offshore topics is presented in Table 5.1 below. In keeping with the

structure of the existing assessment, scheme wide topics, including seascape and visual effects, are presented in Table 5.3.

5.3 Screening of Onshore Topics

5.3.1 Identification of changes and effects relevant to the onshore assessment

8. The proposed changes to the project description (Section 2) that are relevant to the assessment of onshore topics are as

follows:

• Maximum number of offshore export cables coming into the landfall has decreased from four to two;

• Maximum number of onshore cables is increased from four to six, but the number of trenches remain as per the original

design (two trenches) and the Order Limits are unchanged;

• The onshore cables will be HVAC rather than HVDC;

• Two extra lengths of duct will be required at each HDD crossing, which will be accommodated within the existing working

width;

• Reduced number of jointing bays (existing assessment assumed 57 bays per cable and 4 cables, the alternative project

assumes 57 jointing bays per circuit and 2 circuits); and

• Maximum height of the substation building has decreased, but the potential maximum height of the outdoor electrical

equipment has increased slightly.

9. There are no changes proposed to the location of the landfall site or the onshore cable corridor, with the length of route and

location of route remaining as per the existing assessment. These also remain within the original Order Limits with the same

working width for the cable route (typically 55m).

10. As a consequence of the proposed works described above, there is limited potential for any changes to the assessed

environmental effects for the onshore topics. Exceptions include: the potential for an increase in heavy goods vehicle (HGV)

traffic during construction on account of the increased number of cables and ducts at HDD crossings; and potential for

changes to effects on landscape and visual receptors during operation on account of the increase in the maximum height of

the outdoor infrastructure (although the maximum height of the substation building has decreased).

11. With respect to EMF, the proposed electrical infrastructure for the East Anglia ONE offshore windfarm will comply with

Government policy and with UK exposure guidelines. The resultant electric and magnetic fields generated will be extremely

low, or negligible, and will fall well under the accepted UK guidelines on exposure levels.

12. The outcome of the screening exercise carried out for all onshore topics is presented in Tables 5.2 and 5.3 below.




Table 5.1 Offshore impact assessment screening

EIA topic Change in project parameters

(as applicable to each topic)

Key changes in effect/s Change in impact significance Updated assessment (Y/N)

No = screened out

Marine Geology, Oceanography

and Physical Processes (ES

Chapter 6)

Reduced installation activity due

to reduced number of cables and

foundations

Reduced re-suspension of

sediments during construction

Reduction in the magnitude of

effect, no change in impact

significance

N

Less physical infrastructure –

reduced footprint on seabed and

in the water column

Reduced interaction with physical

infrastructure during operation

Marine Water Quality (ES

Chapter 7)



foundations





significance

N

Benthic and Epibenthic

Environment (including Shellfish)

(ES Chapter 9)



foundations





significance

N


reduced footprint on seabed

Reduced footprint of direct and

indirect disturbance to the benthic

environment

Reduction in the number of

offshore cables

The export cables will be HVAC

rather than HVDC

Reduced potential for effects

related to EMF

As set out in Section 5.2.1, the

maximum number (and therefore

length) of interconnector cables

and export cables is reduced.

The maximum number of cable

crossings is also reduced.

Meanwhile, there is no change to

the proposed cable burial depth,

or to the external cable protection

at cable crossings. Consequently,

no change in impact significance

is anticipated.

N

Fish Ecology (ES Chapter 10) Reduced installation activity due


foundations





significance

N







No = screened out




indirect disturbance to the benthic

environment

Reduction in the number of

offshore cables

The export cables will be HVAC

rather than HVDC

Reduced potential for effects

related to EMF

As set out in Section 5.2.1, the

maximum number (and therefore

length) of interconnector cables

and export cables is reduced.

The maximum number of cable

crossings is also reduced.

Meanwhile, there is no change to

the proposed cable burial depth,

or to the external cable protection

at cable crossings. Consequently,

no change in impact significance

is anticipated.

N

Marine Mammals (ES Chapter

11)


to a reduced number of

foundations

Reduced disturbance from noise

due to a decrease in piling activity



significance

N

Ornithology (Marine and Coastal)

(ES Chapter 12)


to a reduced number of cables

and foundations

Reduced disturbance and

displacement effects during

construction



significance

N

Reduced number of wind turbines

and offshore platforms

Reduced disturbance,

displacement, barrier effects and

collision risk during operation

Commercial Fisheries (ES

Chapter 13)



and foundations

Reduced interaction during

construction



significance

N




operation

Shipping and Navigation (ES

Chapter 14)



and foundations


construction



significance

N







No = screened out




operation

Aviation and MoD (ES Chapter

15)



The existing assessment

concluded that radar would not

be affected – no change

No change in impact significance N

Telecommunications and

Interference (ES Chapter 16)



Reduced effects on radar and

vessel Automatic Identification

Systems (AIS)



significance

N

Archaeology and Cultural

Heritage (ES Chapter 17)



foundations





significance

N




indirect disturbance

Infrastructure and Other Users

(ES Chapter 18)



foundations


sediments and reduced

interaction with other users during

construction



significance

N



Reduced interaction with other

users during operation

Airborne Noise (ES Chapter 19) Reduced number of wind turbines


Reduced levels of noise

disturbance due to a decrease in

construction and operation

activity



significance

N




Table 5.2 Onshore impact assessment screening




No = screened out

Ground Conditions and

Contamination (ES Chapter 20)

Reduced number of jointing bays

along the cable route

Reduced construction activity and

footprint of disturbance



significance

N

Air Quality (ES Chapter 21) Reduced number of jointing bays


Reduced construction activity



significance

N

Increased number of onshore

cables

Potential for an increase in dust

and emissions from HGV traffic

during construction

Updated traffic and transport

assessment (see Section 6)

confirms worst case traffic flows

are unchanged, therefore no

change in impact significance

Y – see Section 6

Water Resources and Flood Risk

(ES Chapter 22)







significance

N

Land Use (ES Chapter 23) Reduced number of jointing bays






significance

N

The onshore cables will be HVAC

rather than HVDC

Potential change in EMF

properties of the buried onshore

cables

No change in impact significance

Ecology (ES Chapter 24) Reduced number of jointing bays






significance

N


cables

Potential increase in duration of

HDD works at crossings, and

associated disturbance

Although there may be a slight

increase in the duration of HDD

works at each crossing, the

overall construction period is

unchanged. Any increase in

duration would be within the

worst case parameters of the







No = screened out

existing assessment and

consequently there will be no

change in impact significance.

Archaeology and Cultural

Heritage (ES Chapter 25)







significance

N

Noise and Vibration (ES Chapter

26)



Reduced construction activity



significance during construction

N


cables

Potential for an increase in noise

from HGV traffic during

construction

Updated traffic and transport

assessment (see Section 6)

confirms worst case traffic flows

are unchanged, therefore no

change in impact significance

Y – see Section 6

HVAC substation rather than

HVDC converter station

No change - noise generated at

the substation will not exceed

35dB LAeq, 5 min as measured at

nearby receptors, in line with

DCO requirements

No change in impact significance

during operation

N

Traffic and Transport (ES

Chapter 27)



Potential for an increase in HGV

traffic during construction on

account of the increased number

of cables

Updated assessment (see

Section 6) confirms no change in

impact significance

Y – see Section 6


cables




Table 5.3 Scheme wide impact assessment screening

EIA topic Change in project

parameters (as applicable

to each topic)

Key changes in effect/s Change in impact

significance

Updated assessment (Y/N)

No = screened out

Socio-economics (ES Chapter

28)

Reduced number of

turbines and offshore

platforms

Potential reduction in the levels of construction

and operation activity required to support the

project

Whilst a smaller project will result in fewer job

opportunities, the original EIA assumptions

were precautionary and more recent

engagement with the supply chain suggests

that the upper range for estimated jobs for a

750MW scheme overlaps with the lower range

for a 1,200MW scheme. In addition, similar to

the 1,200MW scheme, the 750MW scheme

would not lead to significant impacts or

residual effects at an East Anglia Region level,

although both schemes would provide minor

economic benefits.

No change to the commitment to implement a

skills strategy

No change in impact

significance

N

Seascape and Visual Impact (ES

Chapter 29)

Reduced number of wind

turbines and offshore

platforms

Reduction in construction and operation

activity and the associated seascape and

visual effects

Reduction in the

magnitude of effect, no

change in impact

significance

N

Landscape and Visual Impact

(ES Chapter 29)

Reduced maximum height

of buildings within the

substation compound

Potential changes to landscape receptors and

views of the onshore substation

Updated assessment (see

Section 6) confirms no

change in impact

significance

Y – see Section 6

Increase in height of the

outdoor electrical

equipment at the onshore

substation




6 Updated Assessments 6.1 Introduction

1. Following the outcome of the screening process (Section 5), the following section presents the updated assessments that

have been undertaken for traffic and transport (Section 6.2), and landscape and visual (Section 6.3).

6.2 Traffic and Transport

6.2.1 Introduction

2. This section reviews the traffic and transport impacts presented in the existing assessment in context with the proposed

changes to the configuration of transmission infrastructure and a reduction in the number of wind turbines. As set out in

Section 1, the assessment of traffic and transport for the consented project included the submission of an ES and a

subsequent SEI.

3. Forecast changes in traffic flows resulting from the alternative project design changes are compared to the data presented in

the existing assessment to establish whether the assessed traffic and transport impacts will change.

4. The traffic terms used in this assessment are traffic flows, deliveries or movements. In the context of this report, traffic flow is

a general term that does not imply a specific volume, a delivery is a laden HGV, and a movement refers to the actual journey

being made. Therefore, a single delivery would result in two HGV movements, one each for arrival (laden) and departure

(empty).

6.2.2 Methodology

5. The assessment revisits the quantities of material and programme assumptions that underpinned the traffic forecasts,

identifies the level of contingency and assesses if the amendments resultant from the alternative project design can be

accommodated within those contingencies. If the changes can be accommodated in the contingencies, then it follows that

there will not be a change to the existing assessment.

6. Forecast traffic flows for the consented project were based on a series of parameters developed to inform the EIA (Table 2.1

refers).

7. To minimise the impact of the traffic generation, a transport strategy (set out in the ES and subsequent SEI) was developed

that would require vehicles associated with construction activities to access the onshore cable route using Primary and

Secondary Construction Consolidation Sites (CCSs). These sites would serve to control the movement of HGVs on the local

network to avoid specific time periods and be of an appropriate size and volume for the route that would be utilised.

8. To establish a realistic ‘worst case traffic scenario’ against which to assess the environmental impacts, the transport strategy

was applied to the parameters and augmented with a number of conservative assumptions (as set out in SEI Report Section

3.4, East Anglia Offshore Wind Limited 2013). The headline assumptions were:

• All Onshore Cable Route sections, HDD sections and Converter Station constructed concurrently.

• Haul road not used. Assessment assumes all movements between CCSs conducted via the existing road network. The

ES identifies the specific routes which would be used for HGV and personnel, and terms these the ‘Construction Access

Routes’.

• Estimates of vehicle movements per Onshore Cable Route section based on all construction activities for that section

happening at the same time e.g. arrival of trenching plant at same time as use of trenching plant, arrival of kit to

construct the haul road at the same time as use of the haul road.

9. These assumptions give an overestimate of the vehicle movements required at any one time. This ensures that the traffic

and transport assessment is based on the impacts of the maximum possible number of construction vehicles which would be

on the road network at any one time.




10. Table 6.1 sets out the transport parameters and assumptions that form the basis of the traffic and transport assessment for

the consented project. It then identifies the proposed changes associated with the alternative project. Where a change is

identified, the table notes that the effects of this change must be further assessed.

Table 6.1 Transport parameters

Parameters Worst case definition (assumptions) Change for alternative

project

Further assessment

required?

Landfall

1. Temporary access track

1 track between public highway and

construction compound of 5.5m width.

No change No

2. Construction period

Up to 21 weeks.

Assumes 7 day week and 12 hour period

for traffic movements.

No change No

3. Construction HGV traffic

Maximum 38 HGV deliveries per day (2 x

PD250 rig site)

Potential for change No

There will be no

change to the HGV

demand assessed for

HDD mobilisation and

operation. There will

however be an

increase in the demand

for cabling and ducts at

HDD sites and this is

considered further

under parameter 11.

4. Construction workforce 9 personnel per day involved in HDD

operations at landfall.

No change No

5. Operation and

maintenance

One visit per year at jointing bays plus

non-scheduled maintenance if required.

No change No

Onshore cable route

6. Construction

Use of open-cut trenching along the

majority of the route assumed.

Assumes working width of 55m for

majority of onshore cable route.

Assumes working width of 160m at HDD

locations.

Assumes spoil removal off-site using

tipper trucks. Estimated 25 trucks per

week for removal of spoil. Assumes

importation of sand for backfill,

generating 20 trucks per week.

No change No

7. Cable number and

dimensions

Up to four onshore HVDC export cables

and fibre optics cables, plus eight ducts

for future projects.

Six trenches in total, for EA ONE two

trenches with two power cables installed

Potential for change Yes

Change to the number

of onshore cables from

four HVDC to six HVAC

has the potential to





project

Further assessment

required?

in each trench.

Cable route length: approximately 37km

change the maximum

HGV deliveries

forecast.

No change in

requirements for:

number of trenches;

cable route length;

sand bedding; and

spoil export.

8. HDD construction

compound

Compound area of 2500m2 at HDD rig

site; area of 2500m2 required at exit side.

No change No

9. Construction

Consolidation Sites

Assumes 7 CCSs (2 primary CCSs and

5 secondary CCSs. Primary site areas,

each of 15,000m2; secondary site areas

each of 10,000m2).

No change No


Up to 44 weeks (46 converter station),

potentially spread over 2 years, 5 days a

week (see paragraph 17, Section 6.2.3

for further explanation); 12 hour days.

No change No

11. Construction HGV traffic

Maximum 29 HGV deliveries per day per

cable route section, of which seven were

associated with the delivery of cables

and ducts.

Potential for change

Yes

For each cable route

section additional

cables will be required

(as outlined under

parameter 7) and

additional ducts for

HDD crossings (as

outlined under

parameter 3)

The increase in cable

and ducting will result

in a requirement for

additional HGV

deliveries, potentially

causing an increase to

the peak daily figure of

29 HGV deliveries per

day to each cable route

section.

12. Construction workforce 79 personnel per 500km cable route

section per day.

No change No





project

Further assessment

required?

13. HGV deliveries Via two Primary Construction

Consolidation Sites (south-west of

Woodbridge and Clayton interchange)

and seven Secondary Construction

Consolidation Sites spread along the

route.

Delivery duration: 10 hours (no peak

hour movements between PCCS and

SCCS).

No change No

14. HGV routing A14 and A12 to PCCS.

From PCCS to SCCS to the

Development Area minimising the use of

the local highway network.

Where this is not possible due to ‘land

locks’ the Suffolk hierarchical HGV route

network will be utilised.

No change No

15. Operation and

maintenance

One visit per year plus non-scheduled

maintenance if required.

No change No

Converter station

16. Number and size of

onshore installations


Maximum compound dimensions: 150m

x 190m


130m x 85m x 25m

No change for the

proposed HVAC

substation

The maximum building

height will reduce from

25m to 21m

No

The maximum

compound and building

dimensions will not

increase and therefore

demand for HGVs to

import construction

materials will not

materially change.

17. Converter Station

Temporary Works Area

As shown in Volume 6, Figure 4.10 (East

Anglia Offshore Wind Limited, 2012)

No change for the

proposed HVAC

substation

No


Up to 46 weeks.

14 HGV deliveries per day.

100 personnel per day.

No change for the

proposed HVAC

substation

No

19. Operation and

maintenance

Permanent staff of 5 plus additional

personnel for major maintenance work.

No change for the

proposed HVAC

substation

No

11. It can be noted from Table 6.1 that the only changes to the transport parameters associated with the alternative project are to

cabling and ducts; parameters 3, 7 and 11 refer. These changes are considered further in the subsequent updated

assessment.

6.2.3 Updated assessment

12. It is identified from Table 6.1 that the transport parameters that have the potential to increase the impacts described in the

existing assessment as a result of the alternative project changes are associated with cabling and duct.




13. Plate 6.1 is taken from the SEI Traffic and Transport Chapter (East Anglia Offshore Wind Limited, 2013). It shows, for the

existing assessment, the construction traffic demand for each individual 5km section of the onshore cable route. This traffic

demand forms the basis of the existing traffic and transport assessment.

Plate 6.1 Detailed breakdown of HGV demand for each cable route section

14. As Plate 6.1 shows, the existing assessment was based on a peak HGV demand for each cable route section of 29 HGV

deliveries per day. As set out under methodology in this section, the only source of potential changes to the magnitude of

effects is the potential additional cable and duct HGV peak deliveries. Plate 6.1 shows that the existing assessment was

based on an assumption of seven HGV deliveries per section per day associated with cables and duct.

15. To assess if this peak cable and duct allowance could be accommodated by the alternative project, it is necessary to

compare the total cable and duct requirements for both options. Table 6.2 sets out the cable and duct requirements for the

consented and alternative projects.




Table 6.2 Cable and duct pipe requirements for the consented and alternative projects

Parameters Consented project (up

to 1.2GW) +

associated

development

Alternative project

(up to 750MW) +

associated

development

Notes / assumptions

Length of cable section 5km 5km Seven cable sections

Number of lengths of duct associated

with HDD (EA ONE)

Four Six Consented project assumed four

lengths of duct pipe per HDD site;

alternative project assumes six

lengths of duct per HDD site.

Total number of cables Four Six Consented project assumed four

cables, alternative project assumes

six cables.

Total length of duct required for HDD

and trenchless crossing only (EA ONE))

18,880m 28,320m Estimated length of HDD and

trenchless crossing sections +

railway and road crossings and pinch

points (4,720m) multiplied by

number of cables

Estimated maximum length of duct for

an Onshore Cable Route Section (EA

ONE) **

8,000m 12,000m*** Estimated length of HDD and

trenchless crossing sections

(2,000m) multiplied by number of

cables

Maximum length of duct for future

projects*

40,000m 40,000m No change to consented project. For

each section there will be four

trenches for future projects each with

two ducts (eight ducts x 5000m)

Length of cable required * 20,000m 30,000m Length of cable section multiplied by

the number of cables

Number of HGVs to deliver ducts (EA

ONE + future projects)*

250 deliveries 271 deliveries A low payload of 192 linear metres

per HGV assumed reflecting the

need to use smaller vehicles to

access the cable route.

Number of HGVs required to deliver

cable *

40 deliveries 60 deliveries 500m of cable per HGV

Total number of HGVs to deliver duct

and cable*

290 deliveries

(580 two-way

movements)

331 deliveries

(640 two-way

movements)

A potential increase of 41 HGV

deliveries per cable route section

* per 5km section

** Onshore Cable Route Section 1, including landfall, Ferry Road and River Deben HDD sites.

*** It is noted that the alternative project proposes a reduction in offshore export cables from four to two. To provide flexibility

for future projects, six HDD sites and associated ducting have been assumed at the landfall.

16. From the data outlined above, the following information has been derived:

• The alternative project would be associated with an increase in cable and duct deliveries;

• The consented project assessed seven HGV deliveries per day for cabling and ducting; and

• The total deliveries that would be required for the alternative project cabling and duct (including future project ducts)

would be 331, a potential increase of 41 HGV deliveries per section to the consented project.

17. Table 6.1 notes that the construction duration for each 5km cable section is 44 weeks. Allowing for section mobilisation and

de-mobilisation, the period for cable laying and installing ducts is conservatively estimated at 32 weeks or 160 potential




delivery days (five days per week). Furthermore, whilst five days per week was used to test a worst case, the consented

project allows for Saturday working, which could potentially increase the number of delivery days further.

18. Taking the seven deliveries per day maximum as a constraint for the rate of deliveries, all cable and ducts required for the

alternative project could theoretically be delivered to site in a minimum time period of 48 days (331 total HGV deliveries ÷

seven per day). This minimum delivery time period is significantly less than the 160 delivery days assessed and reveals up

to 112 days of contingency. It can therefore be concluded that the cable and ducts for the alternative project can comfortably

be delivered within the existing assessment peak of seven deliveries per day.

19. In real terms, the process of laying cable is a linear activity which lends itself to an even profile of deliveries, save for limited

peaks in demand (e.g. during mobilisation when it might be beneficial for some stockpiling in advance). Therefore, the total

331 deliveries of cable and ducts are likely to be spread across the entire 160 day delivery window.

20. Peak cable and duct deliveries for stockpiling would be carefully planned to avoid ‘critical path’ items to ensure that the

overall existing assessment, of a maximum of 29 HGV deliveries per day per cable route section, would not be exceeded.

For example, concrete for joint pits and backfill sand would not be required when mobilising. Concrete and backfill sand is

assessed as a peak of six HGV deliveries per day within the maximum 29 HGV deliveries per day (Plate 6.1 refers), this

allocation and programme window could be utilised for the import of cable and ducts when mobilising a cable route section.

21. It is therefore concluded that the forecasts of the peak construction traffic flows utilised in the existing assessment will not be

changed by the alternative project and therefore the conclusions as set out in the existing assessment for the consented

project are unchanged for the construction phase.

22. Table 6.1 notes that the alternative project does not represent a change to operation and maintenance traffic, and therefore

the existing assessment for the operational phase is also unchanged.

23. With respect to air quality and noise, which were screened in (Section 5) in relation to HGV traffic, since the updated traffic

and transport assessment confirms that the worst case traffic flows are unchanged, there will also be no change in impact

significance for either of these topics.

6.2.4 Conclusions

24. It has been demonstrated that an alternative option to construct and operate an up to 750MW windfarm with HVAC

transmission infrastructure would not change the worst case traffic flows that informed the assessment of the consented

project. It is therefore concluded that the potential impacts associated with the proposed changes are no greater than those

previously presented for the consented project. As such, no changes are proposed to the requirements in the DCO regarding

mitigation for traffic and transport impacts, namely Requirement 25 regarding implementation of a Traffic Management Plan,

a Travel Plan and an Access Management Plan upon commencement of the works.

25. These documents will set out the standards and procedures for managing the impact of the proposed project’s traffic. Prior

to commencement of construction, they will be finalised and agreed with relevant highway stakeholders in order to manage

the number, timing and types of vehicles generated on the highway network having regard to the assessed transport

parameters and the identified sensitive routes/junctions.

6.3 Landscape and Visual Impact

6.3.1 Introduction

26. Table 2.1 sets out the parameters of the consented 1.2GW HVDC project and the changes that would be required under the

proposals for the alternative project of up to 750MW. The following parameters are of particular relevance to landscape and

visual impact assessment (LVIA):

Onshore Cable Route

• Number and size of onshore installations;

• Construction period and traffic; and

• Working width.




Converter Station Compound

• Number and size of onshore installations;

• Equipment height dimensions;

• Construction period and traffic; and

• Operational lighting.

6.3.2 Methodology

27. In order to assess if the magnitude of effect would be reduced, the LVIA chapter of the ES was reviewed. The basis of the

judgements and conclusions and the previously listed parameters were reviewed. This was carried out for the onshore cable

route and the onshore HVDC converter station compound (the latter being termed an onshore HVAC substation under the

alternative project).

28. In order to assist the review of the changes at the converter station compound, the original photomontages were reproduced

in order to explore the visual effects of the alternative option on a number of selected viewpoints. The key proposed changes

to project description parameters in relation to the onshore converter station/substation are summarised in Table 6.3 below.

Table 6.3 Key proposed changes to the onshore converter station/substation parameters

Parameter Consented up to 1.2GW HVDC

project

Alternative up to 750MW HVAC project

Number and size of onshore

installations


Maximum compound dimensions:

150m x 190m


130m x 85m x 25m

One HVAC substation

Maximum compound dimensions: No change

The maximum building dimensions are

dependent on the balance of indoor and outdoor

equipment but will be no greater than the

dimensions used in the original assessment

Equipment height dimensions Primarily indoor but substantial

amount of outdoor electrical

equipment

Maximum height of building: 25m


infrastructure: 10m (excluding

compound perimeter lightning

protection and support gantries: 25m)

Range: 70-90% outdoor, 10-30% indoor

Maximum height of building: 18m if mostly

outdoor equipment, 21m if mostly indoor

equipment




gantries:18m)

29. The new photomontages illustrate two scenarios which represent the potential variation in outdoor and indoor equipment

associated with the proposed substation.

30. Two scenarios have been produced and analysed in order to investigate a range of electrical equipment and buildings which

might be included within the substation compound. The scenarios include a number of worst case options such as electrical

equipment enclosed in buildings which result in taller structures than the same situation with just the electrical equipment. In

addition the two scenarios include a range of building heights with a variation in their locations within the compound and also

include the taller outdoor electrical infrastructure. Please refer to Figures 1 and 2 (Appendix 1) which illustrate the two

scenarios graphically and identify the locations of the various components within the substation compound.




31. The final design of the onshore HVAC substation will be delivered through discharge of Requirement 10 of the DCO

(‘Detailed Design Approval Onshore’) and accord with the Outline Converter Station Design Principles, which will still be

relevant to the substation.

32. The new photomontages illustrate the proposed substation from the same viewpoints as those in the ES which were:

• Viewpoint 3 – Public Right of Way (PRoW) near Flowton;

• Viewpoint 5 – Orchard Lands near Canes Farm (Residential and PRoW);

• Viewpoint 10 – PRoW near Fidgeon’s Farm; and

• Viewpoint 15 – Church Hill, Burstall (Lane and local high point).

33. All of the viewpoint locations as assessed in the ES are shown on Figure 3, Appendix 1.

34. For each viewpoint, the new photomontage includes an existing view, a year 1 view and a year 15 view for each scenario.

This includes both winter and summer views except for viewpoint 15 which is summer only as per the original ES, which was

agreed with the Local Planning Authorities. These new photomontages include the mitigation planting as did the original

photomontages. Please refer to Figures 4 to 10 (Appendix 1).

35. Notwithstanding the focus on these particular viewpoints, the other viewpoints included in the ES were also reviewed and a

judgement made on any changes to the assessment.

6.3.3 Summary of the original assessment

Construction

36. With regard to construction impacts arising from the cable route, the LVIA concluded that there would be the following levels

of significant effect on landscape receptors:

• Landscape Designations – Major;

• Field Boundaries – Not significant;

• Grassland – Moderate; and

• Trees and Woodland – Major.

37. In terms of visual effects arising from the construction of the cable route, the LVIA concluded that these would be mainly

major. A much smaller number of moderate effects were also reported. The majority of these significant visual effects would

arise from the removal of existing trees and hedgerows and the changes this would have on existing views.

38. In the case of the converter station compound, it was reported that moderate significant landscape effects would arise during

the construction period. The temporary visual effects during the construction period would be major significant.

Operation

39. The LVIA concluded that there would be no operational effects arising from the onshore cable route, as the cables and

jointing bays would be buried. It was noted that above ground kiosks would be necessary for the jointing bays. In addition,

permanent marker posts would be visible along the route. However, the presence of these new elements was not considered

significant in terms of landscape and visual impact.

40. In terms of the converter station compound, the assessment concluded that with reference to landscape, there would be a

moderate significant operational effect. This took into account the proximity of the existing substation, the partial loss of key

elements and the introduction of noticeable elements including outdoor equipment, albeit not substantially uncharacteristic

when set within the landscape.

41. With reference to operational visual impacts arising from the converter station compound, the assessment concluded that

there would be major significant effects on sensitive receptors at the following viewpoints:

• Viewpoint 2 – Flowton Village;

• Viewpoint 5 - Orchard Lands near Canes Farm (Residential and PRoW);




• Viewpoint 6 – Near Hill Farm;

• Viewpoint 7 – Burstall;

• Viewpoint 10 – Near Fidgeon’s Farm;

• Viewpoint 11 – Near Bullenhall Farm; and

• Viewpoint 12 – Near Tye House.

42. Moderate significant effects would be experienced at the following viewpoints:

• Viewpoint 3 – Flowton Village;

• Viewpoint 9 – Thornbush Hall; and

• Viewpoint 15 – Church Hill, Burstall.

43. The other five viewpoints were considered to experience not significant effects during operation.

6.3.4 Updated assessment

Construction impacts

44. It is clear from a review of Table 2.1, that the construction and installation of the onshore cable route would be similar with

regard to relevant operations, equipment and timeframes. Examples include the construction period, the working width

generally and its reduction at HDD locations and pinch points. In addition, the cable depth is the same. It is considered

therefore that the landscape and visual impacts would not be worse than those originally reported.

45. With regard to the new substation, the period of construction, the overall location and the size of compound are all the same

as that originally assessed for the converter station compound. It is considered therefore that the landscape and visual

impacts would not be worse than those originally reported.

Operation impacts

46. In terms of the onshore cable, there is no change to the worst case associated with the alternative project in respect that the

cables and jointing bays would be buried and the same marker posts and kiosks would appear above ground. It is

considered therefore that the impacts would not be worse than those originally reported.

47. The new photomontages illustrating the proposed substation have been used to assist the assessment of the proposals on

landscape and visual resources. These have been compared against the photomontages illustrating the converter station

compound.

48. Reference to the figures illustrating the layout of the two scenarios, Figures 1 and 2 (Appendix 1) illustrate that the buildings

and equipment for the proposed substation have a less cohesive layout than that included for the converter station

compound. For the latter, the two large converter station buildings were located side by side towards one side of the overall

compound, with the outdoor electrical equipment filling the remaining space. In both scenarios for the substation, the

electrical equipment and the various buildings are placed according to their function and electrical requirements. As a result,

the larger buildings are located in several places within the overall compound.

49. The following table (Table 6.4) presents an analysis of the new photomontages for each scenario of the proposed substation

and compares them against the original photomontages for the converter station compound.

50. The analysis illustrates that the potential magnitude of effects associated with the proposed changes are no greater than

those previously assessed for the consented project, with no resulting change in significance.




Table 6.4 Analysis of viewpoint photomontages

Viewpoint Original photomontage


New photomontage

Scenario 1 (equipment external/outdoors)

New photomontage

Scenario 2 (equipment internal/indoors)

Viewpoint 3 - PRoW near Flowton Winter

At the start of operations (year 1), the

higher parts of the building walls,

including the roofs, are visible above

the existing woodland. This

woodland screens the remaining

parts of the building and other

electrical equipment.

At year 15 there is very little change

as the mitigation planting does not

provide any further screening from

this viewpoint.

Summer

Although more dense, the summer

vegetation does not provide

additional screening of the higher

parts of the buildings. This is the

same for both years 1 and 15.

Winter

At the start of operations (year 1), the higher

parts of one of the buildings is barely visible

above the existing woodland. Other electrical

equipment is screened by the existing woodland.

At year 15 there is very little change as the

mitigation planting does not provide any further

screening from this viewpoint.

Summer

Although more dense, the summer vegetation

does not provide additional screening of the

higher parts of the buildings. This is the same for

both years 1 and 15.

Winter


parts of a number of the buildings are visible

above the existing woodland. Other electrical

equipment is screened by the existing woodland.

At year 15 there is very little change as the

mitigation planting does not provide any further

screening from this viewpoint.

Summer

Although more dense, the summer vegetation

does not provide additional screening of the

higher parts of the buildings. This is the same for

both years 1 and 15.

Viewpoint 5 – Orchard Lands near

Canes Farm (Residential and

PRoW);

Winter



including the roofs, are visible above

the existing hedgerows. The

hedgerows screen the remaining

parts of the building and the works

within the compound.

At year 15, the mitigation planting

provides a fair degree of screening

with less of the gables of the

buildings and roofs visible.

Summer

The summer vegetation provides a

Winter


parts of the walls of one of the buildings,

including the roofs is visible above the existing

hedgerows. In addition the Stacom electrical

components and a number of other components

are partially visible above the existing hedgerow.

At year 15, the mitigation planting provides a fair

degree of screening with less of the building

gable visible. The Stacom electrical components

are also more effectively screened.

Summer

The summer vegetation provides a good degree

of screening of the gables to the buildings with

Winter



above the existing hedgerow. Parts of the

electrical equipment are also visible.

At year 15, the mitigation planting provides a fair

degree of screening with less of the building

gables visible. The electrical components are

also more effectively screened.

Summer

The summer vegetation provides a good degree

of screening of the gables to the buildings with

only the uppermost parts of the building visible by

year 15 and the top parts of the electrical




Viewpoint Original photomontage


New photomontage

Scenario 1 (equipment external/outdoors)

New photomontage

Scenario 2 (equipment internal/indoors)

good degree of screening of the

gables to the buildings with only the

roofs visible by year 15.

only the uppermost parts of the building visible by

year 15 and the top parts of the electrical

components.

components.

Viewpoint 10- PRoW near

Fidgeons Farm

Winter



including the roofs, are clearly visible

above the existing hedgerows.

At year 15, the mitigation planting

provides some screening to

approximately 50% of the exposed

gables with the roofs still visible.

Summer

The summer vegetation provides a

further degree of screening to those

areas already screened during

winter. This applies more so in year

15 where the summer mitigation

planting appears more effective.

Winter

At the start of operations (year 1), the electrical

components are barely visible above the existing

hedgerows and between the existing trees with

the buildings barely visible.

At year 15, the mitigation planting provides some

additional screening.

Summer

The summer vegetation provides a further

degree of screening to those areas already

screened during winter.

Winter



above the existing hedgerows and between the

existing trees.

At year 15, the mitigation planting provides some

additional screening but parts of the upper gables

and roofs are still visible.

Summer

The summer vegetation provides a further

degree of screening to those areas already

screened during winter.

Viewpoint 15 – Church Hill,

Burstall (Lane and local high

point)

Summer

The Converter Station Compound

cannot be seen from this viewpoint

and therefore is represented as a red

outline on the photomontage.

Summer

The Converter Station Compound cannot be

seen from this viewpoint and therefore is

represented as a red outline on the

photomontage.

Summer

The Converter Station Compound cannot be

seen from this viewpoint and therefore is

represented as a red outline on the

photomontage.




Decommissioning impacts

51. It is considered that the decommissioning impacts for Landscape and Visual would be no worse than those originally reported

in the existing assessment due to the decrease in the size and mass of the substation buildings compared to those for the

converter station and the fact that both operational compounds would be the same size.

Cumulative impacts

52. It is considered that the cumulative impacts for Landscape and Visual would be no worse than those originally reported in the

existing assessment due mainly to the decrease in the size and mass of the substation buildings compared to those for the

converter station.

Mitigation measures and residual impacts

53. The mitigation measures are the same as those proposed for the existing assessment and the residual impacts would be no

worse than those originally reported.

6.3.5 Conclusions

54. With regard to the alternative project and the changes to the onshore cable route, it is concluded that the potential magnitude

of effects associated with the proposed changes are no greater than those previously assessed for the consented project,

with no resulting change in significance.

55. With regard to the alternative project and the changes to the substation compound, an analysis of the two scenarios

illustrates that the various options and ratios of building to equipment do not make a material difference. The potential

magnitude of effects associated with the proposed changes are no greater than those previously assessed for the consented

project, with no resulting change in significance.

56. As a consequence, no changes are proposed to the requirements in the DCO regarding mitigation for landscape and visual

impacts, namely requirements 10 and 12.

7 Conclusions 1. EAOL is seeking to vary the existing DCO for the East Anglia ONE offshore windfarm to include an alternative option to

construct an up to 750MW windfarm utilising HVAC transmission infrastructure.

2. This report has considered the potential impacts of the alternative (up to 750MW) project and compared them to the

conclusions reached in the existing assessment for the consented (up to 1.2GW) project.

3. Following the outcome of an environmental screening exercise and updated assessment with respect to traffic and transport

and landscape and visual effects, it demonstrates that the potential magnitude of effects associated with the proposed

changes are no greater (and would in many cases be less) than those previously assessed for the consented project, with no

resulting change in significance.

4. It is therefore considered that the proposed changes would constitute non-material amendments for the purposes of the

Infrastructure Planning (Changes to, and Revocation of, Development Consent Orders) Regulations 2011 (as amended).




8 References East Anglia Offshore Wind Limited (2012). East Anglia ONE Offshore Windfarm – Environmental Statement.

East Anglia Offshore Wind Limited (2013) East Anglia ONE Offshore Windfarm – Post-Submission Report 1 and

Supplementary Environmental Information.




Appendices




Appendix 1 Landscape and Visual Impact Assessment figures

Please see Folder 2 of application materials

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