Bacton Storage Company Limited - European Investment · PDF fileBacton Storage Company Limited Baird Gas Storage Project Offshore Environmental Statement – Non Technical Summary

Bacton Storage Company Limited

Baird Gas Storage Project

Offshore Environmental Statement – Non Technical Summary

March 2010

Rev 02

BSCL Document Ref No.: BD-017-EV-RPT-003

DECC Ref No.: D/3979/2008

Bacton Storage Company Limited

Baird Gas Storage Project

Offshore Environmental Statement – Non Technical Summary


DECC Ref No.: D/3979/2008

Prepared by:

Fay Dobson

March 2010

RPS Energy HSE and Risk Management 1st Floor Cottons Centre Cottons Lane London SE1 2QG

Tel +44 (0)207 939 8000

Fax +44 (0)207 939 8095

Email [email protected]

DISCLAIMER

The opinions and interpretations presented in this report represent our best technical interpretation of the data made available to us. However, due to the uncertainty inherent in the estimation of all parameters, we cannot, and do not guarantee the accuracy or correctness of any interpretation and we shall not, except in the case of gross or wilful negligence on our part, be liable or responsible for any loss, cost damages or expenses incurred or sustained by anyone resulting from any interpretation made by any of our officers, agents or employees.

Except for the provision of professional services on a fee basis, RPS does not have a commercial arrangement with any other person or company involved in the interests that are the subject of this report.

RPS cannot accept any liability for the correctness, applicability or validity for the information they have provided, or indeed for any consequential costs or losses in this regard. Our efforts have been made on a "best endeavours" basis and no responsibility or liability is warranted or accepted by RPS.

COPYRIGHT © RPS

The material presented in this report is confidential. This report has been prepared for the exclusive use of the Bacton Storage Company Limited and shall not be distributed or made available to any other company or person without the knowledge and written consent of the Bacton Storage Company Limited or RPS Energy.

DATE VERSION DESCRIPTION PREPARED CHECKED APPROVED

March 2010 01 1st Draft FD - -

March 2010 02 2nd Draft FD GC EJW

RPS File Reference: P:\Centrica\1756 Baird Gas Storage ES\Rev02


Rev: 02 Baird Gas Storage Project – Offshore ES

Document Number: BD-017-EV-RPT-003 i

Table of Contents

Abbreviations ........................................................................................................................................... iii

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

1.1 Project Background .................................................................................................................... 1

1.2 Environmental Impact Assessment ............................................................................................. 2

1.3 Regulatory Framework ............................................................................................................... 2

1.4 Bacton Storage Company Limited ............................................................................................... 2

1.5 Need for UK Gas Storage ............................................................................................................ 3

2 The Project ........................................................................................................................................ 1

2.1 Overview .................................................................................................................................... 1

2.2 Alternative Development Options Considered ............................................................................ 2

2.3 Proposed Project Schedule ......................................................................................................... 3

2.4 Offshore Construction, Installation and Commissioning Activities ............................................... 3

2.4.1 Drilling Operations .............................................................................................................. 3

2.4.2 NUI Construction and Installation Activities ......................................................................... 7

2.4.3 Pipeline Installation Activities.............................................................................................. 8

2.5 Gas Storage Operations .............................................................................................................11

2.5.1 Storage Profile ...................................................................................................................11

2.5.2 Produced Water .................................................................................................................11

2.5.3 Power Generation and Venting ...........................................................................................12

2.6 Maintenance .............................................................................................................................12

2.7 Decommissioning ......................................................................................................................12

3 Summary of the Results of the Baird Offshore EIA Process ................................................................14

3.1 Physical Environment ................................................................................................................14

3.1.1 Water Quality ....................................................................................................................14

3.1.2 Seabed Sediments ..............................................................................................................14

3.1.3 Air Quality ..........................................................................................................................15

3.1.4 Marine Archaeology ...........................................................................................................16

3.1.5 Accidental Loss of Containment (Hydrocarbon Release)......................................................16

3.1.6 Transboundary Impacts ......................................................................................................16

3.2 Biological Environment ..............................................................................................................17

3.2.1 Benthic Communities (Seabed Organisms) ..........................................................................17

3.2.2 Birds ..................................................................................................................................18

3.2.3 Fish and Shellfish ...............................................................................................................18

3.2.4 Marine Mammals ...............................................................................................................19

3.2.5 Protected and Sensitive Offshore Habitats .........................................................................20

3.3 Socio-Economic Environment ....................................................................................................23

3.3.1 Commercial Fishing ............................................................................................................23

Baird Gas Storage Project – Offshore ES Rev: 02

ii Document Number: BD-017-EV-RPT-003

3.3.2 Shipping Activities, Ports and Navigation ............................................................................24

3.3.3 Employment .......................................................................................................................26

3.3.4 Tourism ..............................................................................................................................26

3.4 Cumulative Impacts ...................................................................................................................26

4 Environmental Management .............................................................................................................30

5 Overall Conclusions of the Baird Offshore EIA ...................................................................................30

6 References .......................................................................................................................................31


Document Number: BD-017-EV-RPT-003 iii

Abbreviations

BSCL Bacton Storage Company Limited

CRA Conestoga-Rovers & Associates

CSL Centrica Storage Limited

DECC Department of Energy and Climate Change

DP Dynamically Positioned

DTI Department for Trade and Industry

EIA Environmental Impact Assessment

EMS Environmental Management System

ES Environmental Statement

FEED Front End Engineering Design

FLO Fisheries Liaison Officer

GSDP Gas Storage Development Plan

GSL Gas Storage Licence

HLV Heavy Lift Vessel

HPU Hydraulic Power Unit

HRL Hydrocarbon Resources Limited

HS&E Health Safety and Environmental

HS&E Health Safety and Environmental

IMS Integrated Management System

JNCC Joint Nature Conservation Committee

KCl Potassium Chloride

MEG Mono Ethylene Glycol

MMO Marine Mammal Observers

MLWM Mean Low Watermark

NaCl Sodium Chloride

NTS Non-Technical Summary

NUI Normally Unmanned Installation

OBM Oil Based Mud

OCNS Offshore Chemical Notification Scheme

OPEP Oil Pollution Emergency Plan

PAM Passive Acoustic Monitoring

pSAC Possible Special Area of Conservation

pSPA Possible Special Protected Area

ROV Remotely Operated Vehicles

RYA Royal Yachting Association

SAC Special Areas of Conservation


iv Document Number: BD-017-EV-RPT-003

SPA Special Protection Area

UK United Kingdom

UKCS United Kingdom Continental Shelf

WBM Water Based Mud


Document Number: BD-017-EV-RPT-003 1

1 Introduction

1.1 Project Background

Bacton Storage Company Limited (here after referred to as ‘BSCL’) is proposing to develop the partially depleted Baird gas field into a gas storage facility. The field is currently produced via a single well (49/23-D5), which is connected via the 49/23-D platform into the Indefatigable field production system, through which gas is exported ashore to Bacton.

The Baird field is located in Block 49/23 of the Southern North Sea, approximately 86 kilometres north east of Bacton (Figure 1). The nearest international boundary to the field is the UK/Dutch median line, which lies approximately 34 kilometres to the east.

Figure 1: Area Map Showing the Location of the Baird Reservoir

The Baird reservoir is located about 2,700 metres under the sea bed and is capable of holding a total storage capacity in excess of 1.7 billion cubic metres of gas. Following an extensive review of gas reservoirs in the southern North Sea, the Baird reservoir was selected for natural gas storage as it displays the following favourable characteristics:

• The porosity and permeability of the reservoir rock is excellent meaning that the gas may be easily injected and quickly recovered;

• It is well defined and contained geological structure;

• It is a single reservoir rather than being divided into compartments, thereby making the location of the wells much simpler;

• It is of a medium size which is economically viable (small reservoirs cannot justify the capital cost of development whereas the capital cost of cushion gas to fill large reservoirs is also prohibitive); and

• It is not too distant offshore to make the capital cost of the pipeline exclusive.


2 Document Number: BD-017-EV-RPT-003

As a storage field, Baird will operate in two modes, namely injection and production. Gas will be taken mainly from the National Transmission System (NTS) during periods of low demand, compressed and sent for storage in the offshore reservoir via a subsea pipeline. During periods of high demand, gas is returned from the offshore reservoir via the same subsea pipeline. Once ashore, the gas is conditioned to meet NTS specifications and compressed, as required, to allow export to the NTS for transport and consumption in the UK.

1.2 Environmental Impact Assessment

An Environmental Impact Assessment (EIA) has been undertaken for the Baird gas storage project. This process analyses the proposed project in relation to the existing environmental conditions (using a combination of site surveys, desktop studies and modelling techniques) to ensure that all potential impacts are identified and appropriately assessed. It examines in detail the need for the project and its design, construction, operation and decommissioning. For those impacts that have been assessed as being unacceptable, appropriate mitigation measures have been identified.

An integral part of the EIA process has been an extensive consultation process undertaken with statutory and non-statutory consultees, interested parties and the general public.

This Non-Technical Summary of the Environmental Statement (ES) documents the results of the EIA undertaken for the offshore aspects of the proposed Baird gas storage project.

1.3 Regulatory Framework

The Energy Act 2008 has introduced a new regulatory framework for the offshore storage of natural gas. Under this Act, BSCL are required to apply for a Gas Storage Licence (GSL) from the Department of Energy and Climate Change (DECC) for the proposed project and obtain a grant of the appropriate rights from The Crown Estates. In addition to the GSL, BSCL must also submit a Gas Storage Development Plan (GSDP) to DECC.

The current suite of environmental legislation used by DECC to regulate the offshore oil and gas industry is being modified in scope so it can be used to regulate offshore gas storage projects, where applicable. As such, the ES has been produced to meet the requirements of The Offshore Petroleum Production and Pipelines (Assessment of Environmental Effects) Regulations 1999 (as amended) and has been written to support the GSDP.

1.4 Bacton Storage Company Limited

The current equity Partners forming the Bacton Storage Company Limited (BSCL) are Centrica plc (70%) and Perenco (UK) Ltd (30%).

Centrica plc, as majority shareholder (70%) in the project, is leading the licensing and consenting process on behalf of the partners. Centrica plc is a major supplier of gas to the UK market. Its interests include the Rough Gas storage field which is operated by Centrica Storage Ltd (CSL) a wholly owned subsidiary, the Morecambe Gas Fields which are also operated by its wholly owned subsidiary Hydrocarbon Resources Limited (HRL) and the Grove & Seven Seas assets.

Perenco (UK) Ltd is a wholly owned subsidiary of Perenco SA and is one of the largest operators in the UK Southern North Sea. They currently operate many offshore facilities, including three compression hub platforms and the natural gas terminal at Bacton.

BSCL proposes to adopt the Centrica Group Health Safety and Environmental (HS&E) Policy. This policy will be applied to all areas of activity associated with the Baird gas storage project and universally endorses health, safety and environmental excellence as a key component of the company’s operating philosophy and culture.



1.5 Need for UK Gas Storage

The Baird gas storage project is a response to the Government’s call for increased investment in the UK’s gas supply and storage infrastructure in order to ensure that it benefits from secure and diverse energy supplies. The security and diversity of energy supplies has emerged as an important issue with the decline in UK gas production and the increased reliance on gas imports. Indeed, the latest figures published by National Grid (NG Ten Year Statement, December 2009)forecast that imported gas will account for 46% of UK supply in 2010/11, with import dependency expected to increase to 69% by 2018/19.

Much of the UK’s gas imports currently enter the country via inter-connector pipelines from Norway and continental Europe. This fact, combined with the relatively low level of gas storage, limits the amount of resilience in the system to withstand any disruptions to imported gas supplies. This has potentially serious implications for security of gas supplies.

The challenges facing the UK in terms of maintaining secure gas supplies are further exacerbated by the high daily and seasonal variation in gas demand. This is most clearly illustrated by the significant difference in gas consumption between the summer months (typically less than 200 million cubic metres per day) and the winter (on a cold day consumption can be higher than 400 million cubic metres). Historically this variation in consumption or “swing” (as it is more commonly known in the gas industry) between summer and winter has been dealt with by increasing/decreasing production from the United Kingdom Continental Shelf (UKCS). However, as UKCS gas production continues to decline, the ability to respond to swing conditions is reducing. Gas storage facilities will therefore become an increasingly important management tool in helping to ensure that the UK continues to benefit from secure gas supplies and that peak demand can be met.

A recent paper produced by the House of Commons library on the subject of gas storage (Gas Storage, Standard Note: SN/SC/5010, 12 March 2009) highlights the low levels of gas storage currently in the UK. The paper confirms that the UK has only around the equivalent of 15 days of gas supply in storage (4% of average annual consumption) whereas Germany has around 99 days of supply in storage and France 122 days (both in excess of 20% of average annual consumption).

The above factors clearly underline the national need that exists for additional gas storage infrastructure in the UK to deal with periods of peak demand, such as the recent cold spell, and to guard against disruptions to imported gas supplies. Indeed, Government energy policy confirms the need for increased investment in gas storage and that such infrastructure is in the national interest. The Baird gas storage project will make a valuable contribution towards this objective and will increase UK gas storage capacity by around a third.



2 The Project

2.1 Overview

The main elements of the proposed Baird gas storage project are subdivided into the following offshore and onshore components:

Offshore Project Components

• Normally unmanned installation (NUI) with up to 14 planned wells (18 slots have been provided to allow some contingency for drilling problems and future expansion if required);;

• 38 inch subsea wet gas bi-directional pipeline and 4.5 inch Mono Ethylene Glycol (MEG) line (for hydrate inhibition), approximately 100 kilometres long from the NUI to mean low water mark (MLWM) at the Bacton landfall. Of note is that the 4.5 in MEG line will run parallel to the proposed 38 inch pipeline route at a separation distance of approximately 25 metres.

The proposed location of the NUI and route of the offshore pipelines are illustrated in Figure 2.

Figure 2: Baird Gas Storage Project Offshore Location Map



Onshore Project Components

• 38 inch subsea bi-directional wet gas pipeline and 4.5 inch MEG line from MLWM into the existing Perenco Bacton terminal. The pipeline landfall is located to the south of the Terminal and will be connected by shaft and bored tunnel to the Perenco site.

• Compression plant (comprising three gas fired turbines) within the Perenco terminal site, along with new gas dewpointing facilities, reception gas heaters, MEG regeneration facilities and additional gas fiscal metering systems.

• 36 inch bi-directional gas pipeline to connect the new facility with the NTS.

An EIA for the onshore project components has been undertaken independently by Conestoga-Rovers & Associates (CRA) Ltd and is subject to a separate ES (BSCL Document Reference Number: BD-017-EV-RPT-005).

Provided that the necessary consents are obtained, activities associated with offshore installation of the 38 inch pipeline and 4.5 inch MEG line are preliminarily planned for Q4 2011 to Q4 2012, with initial template drilling scheduled from Q2 2011 to Q4 2012. Offshore installation activities associated with the NUI have been programmed for Q3 2012. It is currently anticipated that the storage development wells will be ready to receive cushion gas in Q3 2013.

2.2 Alternative Development Options Considered

During the conceptual design phase of the project, a number of other development options have been evaluated, based on technical, economic, environmental and safety grounds in order to arrive at the current project strategy. These options included:

1. Platform Selection

2. Platform Design

3. Platform Drilling vs. Jack-up Drilling

4. Pipeline Route Selection

5. Pipeline Installation

6. MEG Line

The selected project configuration has been chosen for the following reasons:

• A Normally Unmanned Installation (NUI) with minimum facilities accommodates the required 18 wells on a single platform and, as an unmanned facility, significantly reduces individual risk levels. It provides the added advantage of ease of maintenance compared to a subsea completion. It also enables remote sphering of the 38 inch subsea wet gas bi-directional pipeline for the removal of liquids. From an economic perspective, the cost of installing subsea completions becomes uneconomic compared to a minimum facilities wellhead platform when greater than two wells are required.

• The platform design will be a conventional four legged jacket structure, capable of standalone wireline intervention and coiled tubing interventions with jack-up support. Key design features of the NUI include: 18 well slots suitable for either withdrawal or injection, process control, well testing and metering, utilities including power generation, export and pigging; fluids handling and planned overnight accommodation for maintenance activities.

• In terms of the selection of the drilling unit, it was concluded that a jack-up drilling rig is safer and more flexible than a platform drilling unit and offers the best option to meet the schedule requirements for the project. Although the project schedule could be further accelerated through the use of multiple platforms allowing two rigs to drill simultaneously, this option would increase environmental impact, cost and complexity due to additional in-field subsea pipelines. The Baird wells will, therefore be drilled using a jack-up drilling rig from a single large wellhead and process platform.



• To achieve the desired injection and production flow rates, a 38 inch subsea wet gas bi-directional pipeline will connect the proposed Baird NUI to the onshore gas reception and processing facilities at the BSCL terminal in Bacton. A number of possible pipeline route options were considered taking into account a range of environmental, engineering and economic criteria. The chosen route options is considered favourable as the minimum water depth along the route is greater than 10 metres, it traverses the North Norfolk Sandbanks pSAC for the shortest distance and has the least amount of pipeline crossings. Pipeline crossings can have a significant environmental impact due to mattress/rock dumping requirements.

• It is proposed that majority of the subsea wet gas 38 inch bi-directional pipeline will be laid directly onto the seabed, thereby minimising the area of seabed impacted by the installation activities. In some areas dredging of the pipeline route pre-lay may be required where pipeline installation on an unmodified seabed would result in unacceptable pipe stresses and the possibility of commercial fishing gear getting caught around the pipe affecting both the integrity of the pipeline and safety of the fishing vessel. Trenching post-lay may also be required to remove unallowable pipeline spans, although concrete weight coating will be applied to the pipeline in order to minimise this. As the majority of spans will be corrected by trenching, it is hoped that the use of rock for post-lay span correction can be minimised.

• To mitigate against the possible formation of gas hydrates and the accumulation of liquids in the 38 inch gas pipeline, BSCL propose to install a 4 inch MEG line. Protection of the MEG pipeline is imperative for operation of the Baird gas withdrawal operation, as one Bscf of gas requires in excess of 100 m3 of MEG for hydrate inhibition.

2.3 Proposed Project Schedule

A provisional project schedule for the development of the Baird gas storage project is shown in Table 1. This programme may change subject to detailed scheduling and, in particular, availability of drilling rigs, specialist construction vessels, pipelay barges and the fabrication times of various key elements. It is therefore possible that activities may occur at other times of the year.

Table 1: Proposed Project Schedule

4Q10 1Q11 2Q11 3Q11 4Q11 1Q12 2Q12 3Q12 4Q12 1Q13 2Q13 3Q13

Drilling

Pipeline

Landfall

Platform

Terminal Construction

Cushion Gas Injection

2.4 Offshore Construction, Installation and Commissioning Activities

2.4.1 Drilling Operations

It is currently proposed that all 14 planned wells will be drilled using a template (dimension of which are estimated to be 24 metres x 7.65 metres) installed at seabed. Four wells increasing to seven may be available to inject the cushion gas and the working volume during the summer of 2013. All 14 wells are planned to be available for the first seasonal production cycle.



The proposed characteristics of the development wells are summarised in Table 2.

Table 2: Baird Development Well Characteristics

Aspect Data

Block 49/23

Anticipated Drilling Location 468800.00 mE 5902800.00 mN

(UTM 31N – WGS84)

Anticipated Drill Rig Jack-up Drilling Unit

Support Location Great Yarmouth

Water Depth (m) (LAT) 28 metres (92 feet)

Depth of Wells 2,625 metres TVDSS

Anticipated Spud date February 2011

Estimated time to reach TD for each well 50 days

Clean-up and well testing (per well) 17 days (including completion clean-up)

Hydrocarbons Anticipated Wet gas

Anticipated Weight of Cuttings (total) 2,080 tonnes per well

Drilling Rig

A jack-up rig will be used to drill the Baird wells. Details of the rig are unknown at this stage, but will be included in the PON 15B application for the Offshore Chemicals permit in due course. It has been estimated that the rig will be on location for a total of 930 days for the 14 pre-drilled wells plus time taken to tieback and complete.

Given previous Operator experience in the area, it is considered unlikely that any form of rig stabilization will be required to prevent scour around the rig’s legs. However, as a worst case scenario, BSCL intends to submit a PON15B to DECC to allow rig stabilization material to be deposited in the unlikely event that scour becomes a problem. It is estimated that up to 1,000 tonnes of gravel/rock or 40,000 bags may be required per spud can. Hence a total of up to 3,000 tonnes of gravel/rock or 120,000 bags could be required for a three legged jack-up rig, should stabilization of all three legs be necessary.

Well Construction

The proposed Baird wells will be deviated “J” and “S” shape development wells with a planned total depth of maximum 2,625 metres TVDSS (refer to Table 3).



Table 3: Typical Baird Well Profile (Big Bore Cased Hole Completion)

Hole Size Casing Size Section Length in

metres (MD) Proposed Mud Use

Millimetres Inches Millimetres Inches Metres (feet)

914.4 36 762 30 165 m Visc. Sea Water with

Vis. Pills.

558.8 26 473.0 18.625 670 m Visc. Sea Water with

Vis. Pills.

444.5 17 ½” 339.7 13.375 2,438 m Salt Sat. KCl Polymer

Water based mud

342.9 13 ½” 298.5 11.750 2,626 m Salt Sat. Water

based mud

311.1 12 ¼” 244.5 9.625 3,078 m Oil based mud

Drilling Muds and Chemicals

The optimal drilling fluid will be selected during detailed well design. It is anticipated that water based mud (WBM) will be used down to top reservoir. WBM and oil based mud (OBM) will both be considered for the reservoir section, the selection depending upon detailed analysis of formation damage, sand control completion compatibility and minimum density. In addition to mud chemicals, cementing chemicals will also be used to seal the well casing in place.

All chemicals have been selected to minimise the potential environmental impacts as much as possible. The vast majority (by volume) of planned chemicals have an OCNS category of E and are naturally occurring products (e.g. barite and bentonite) that are either biologically inert or readily dispersible or biodegradable.

The final selection of chemicals will be subject to change and submitted in the PON15B submissions as required under the Offshore Chemicals Regulations 2002, prior to drilling the Baird development wells.

Disposal of Drill Cuttings

Cuttings from the conductor hole (36”) will be returned directly to seabed. After the conductor is set mud and cuttings (rock chips) from subsequent hole sections will be returned to the rig where they pass through the cleaning and recycling system. This reduces the amount of drilling fluid retained on the cuttings to between 5-10 percent. The cleaned WBM cuttings together with some residual WBM will then be discharged at the sea surface.

If the 12.25 inch section is drilled with OBM, the cuttings and any retained drilling fluid will be collected at surface in secure containers and shipped onshore for processing at an approved facility. No OBM cuttings or whole OBM will be discharged to sea.

Estimated amounts of cuttings predicted to be produced from the Baird development wells are detailed in Table 4.



Table 4: Estimated Cuttings Discharges Per Well (data is indicative of all 14 wells)

Hole Size (m) Hole size

diameter (in) Length

(m) Volume

(m3)Weight

(tonnes)

914.4 36 91.4 90.07 243.18

558.8 26 505.9 225.29 608.29

444.5 17 ½” 1767.8 342.90 925.83

342.9 13 ½” 487.7 56.29 151.99

311.1 12 ¼” 640.0 55.97 151.11

Discharged to seabed 90.07 243.18

Discharged at surface 625 (OBM Option A)

680 (WBM Option B)

1,686 (OBM Option A)

1,837 (WBM Option B)

Returned to shore 56 (OBM Option A) 151 (OBM Option A)

Total Cuttings per Well 771 2,080

Note: Weight of cuttings calculated assuming density of 2.7 tonnes per cubic metre

Well Completion

After the drilling of the wells has been completed, the mud in the well will be displaced by completion fluid which, for the Baird wells, is expected to consist of potassium chloride (KCl)/ sodium chloride (NaCl) brine and contain small quantities of chemicals to protect the well.

During the initial phase of the well clean up, the completion brine (approximately 1,000 tonnes) will be displaced to the sea.

Prior to final selection, all well completion chemicals will be reviewed as part of the process of permitting under the Offshore Chemicals Regulations, 2002 to determine if more environmentally benign alternatives can be used.

Well Clean-Up and Testing

Nitrogen Injection

Following well completion, a clean up flow period may be carried out in order to minimise formation damage. This flow period will typically be less than 24 hours in duration for each well. Nitrogen will be pumped into the well to displace the completion fluids. Typically liquid nitrogen will be transported to the rig, vaporised and then injected via the drill string at the base of each well. The high pressure nitrogen will displace the completion fluid to the surface. Nitrogen is being used for this operation as it is an inert gas which is readily available and transportable.

The rate of nitrogen injection is anticipated to be approximately 250,000 kg/hour per well, with each well likely to require up to 40 tonnes of nitrogen.

Flaring

As soon as sufficient gas is delivered from the well for ignition, flaring will commence. Typically during a well test, flaring will occur for approximately 24 hours with a total quantity of flared gas of up to 2,000 tonnes. However, given that the Baird reservoir is largely depleted, testing of the storage development is likely to result in the flaring of less than 2,000 tonnes of gas.

It is anticipated that some condensate may be flared. The indigenous gas in the reservoir is water saturated with a water gas ratio between 0.52-0.72 bbl/MMscf. However, the volumes of hydrocarbon liquids flared are expected to be minimal based on historic condensate production levels and the low pressure in the depleted Baird reservoir.



Drilling Support Operations

The drilling rig will be supported by a single supply vessel operating out of a supply base, anticipated to be Great Yarmouth which will keep the rig stocked with the items needed to carry out its operations. In addition, a standby vessel will be stationed in the vicinity of the rig for the duration of the drilling programme.

Rig crews will be transferred to and from the rig by helicopter, assumed to be a Super Puma. Typically around five scheduled flights will be made to the rig per week, with additional ad hoc flights as necessary for urgent/unplanned transport of personnel or equipment to or from the rig.

2.4.2 NUI Construction and Installation Activities

The NUI will be constructed and installed as follows:

• Design and procurement (4Q10 – 4Q11);

• Fabrication (May 2011 – August 2012);

• Installation (September 2012).

Design

A 3D schematic of the Baird minimal facilities platform is shown in Figure 3. The platform has been designed to be as simple as possible, with only the minimum amount of equipment to meet its overall goals.

The footprint area of the platform topsides will be approximately 48 by 30 metres.

The Baird NUI will be a traditional four legged skirt pile driven jacket (refer to Figure 4), with 18 well slots situated over a 9 slot pre-drilling template (i.e. half of the wells could be pre-drilled). The piles will be about 84 inches in diameter.

Because the jacket is wider than it is tall, it will, most likely, be transported vertically to site. A heavy lift vessel (HLV) crane will be able to lift the jacket directly off the transportation barge on to the seabed at the intended location.

Figure 3: Current Baird NUI Structure



Figure 4: Conventional Template-Type Jacket

Conductors supported at horizontal bracing levels

Conductors not used structurally

Piles driven through legs and cemented

or welded at top

Piles support Deck directly

Piling

BAT will be used in considering piling techniques during FEED. If possible a vibratory hammer, which is smaller, lighter and quieter than a conventional hammer, will be used. Further geo-technical work is required to be undertaken, however, before the piling technique can be determined. For the purpose of this ES, it has been assumed that a submersible hydraulic hammer will be used as this is considered to be worst case in terms of noise impacts.

Deck Installation

The deck will be lifted from the transportation barge and placed onto the jacket in a carefully planned and executed operation.

For leg piles, the deck will be stabbed into the top of the piles and welded out. For skirt piles, the deck will be located onto the jacket guides and then be welded to the jacket legs. The commissioning of the jacket and topsides may then commence.

An ROV will be required to perform a final survey of the proposed site, to assist in installation operations and to perform an as-built survey.

Installation of the deck is likely to take approximately 7 days.

2.4.3 Pipeline Installation Activities

Pipelay

38 inch Gas Pipeline

The 38 inch subsea wet gas bi-directional pipeline will be installed using the S-lay process. The vessel used for laying the offshore pipeline will either be an anchored vessel, with associated anchor spread, or a dynamically positioned (DP) lay vessel. If anchors are used, the lay barge will ‘crawl along as a spider’, with the anchor spread typically run up to 1,200 metres from the vessel. The support vessels are most likely to use DP.

BSCL would hope to use a DP lay barge with a working draft of 18 metres or under to install the pipeline, thereby avoiding the need to pre-dredge any ridges or sandbanks to create an access path for the vessel. Meeting this commitment, however, will be subject to a suitable vessel being



available at the time pipeline installation activities are due to commence, currently anticipated to be in Q4 2011.

Prior to the pipelay vessel reaching location, a utility vessel will undertake a pre-lay pipeline survey to confirm the seabed topography and features along the proposed route.

The expected pipelay duration of the Baird gas pipeline is expected to be ca. 50-70 days.

4.5 inch MEG Pipeline

The 4.5 inch MEG pipeline will be laid separately from the 38 inch gas pipeline and not ‘piggy backed’ as it will require trenching along its whole length for protection against damage by fishing equipment.

On completion of both pipelay operations, a post lay survey will be undertaken by the utility vessel to identify the status of the pipelines and any debris incidence.

Pipe Trenching / Dredging

38 inch Gas Pipeline

It is likely that the proposed 38 inch gas pipeline will be laid directly onto the seabed, along the majority of its route. In some areas, however, dredging of the pipeline route pre-lay may be required, as discussed in Section 2.2. The total dredged volume of material from this activity is estimated to be 485,000 m3. This will be disposed of at a licensed disposal site outside of the Haisborough, Hammond and Winterton pSAC.

Post-pipelay trenching works may also be required to ensure the stability of the gas pipeline during the operational phase. The trench will be prepared using a remotely operated tracked trenching vehicle operated (Figure 5) from a specialist trenching support/subsea installation vessel. The trenching machine would typically dig a 12 metres wide trench and 1.8 metres in depth to allow coverage of at least 0.6 metres once the pipe has been laid. Excavated material will be displaced along the side of the trench and the total disturbed area is expected to be 25 metres or less. The total area of seabed directly impacted by post-pipelay trenching is estimated to be approximately 0.56km2, with the total volume of material to be disturbed estimated to be around 240,000m3. Natural sediment transport mechanisms will be used to backfill the pipeline trench.

It is hoped that post-pipelay trenching will avoid the need for rock dumping to correct pipeline spans. However, as a contingency, it assumed that up to five free span corrections may need rock dumping along the 38 inch gas pipeline. It is estimated that a maximum of 4,000m3 of rock will be required for this activity.

Figure 5: Digging Donald Mechanical Pipeline Trencher

4.5 inch MEG Pipeline



The 4.5 inch MEG line will be trenched below natural seabed to a depth sufficient to provide protection, which will be a minimum of 1.0 metre, but preferably 2.0 metres.

It is likely that the trench for the MEG pipeline will be ploughed. During normal operations the plough will deposit the excavated trench spoil either side of the trench. The trench will then be mechanically backfilled. An option to use a jetting machine to create the trench by suspending the seabed sediment is also currently being considered.

It is anticipated the maximum width of the working corridor for both installation scenarios will be 10 metres.

Pipeline / Cable Crossings

The proposed Baird 38 inch gas pipeline will cross the following existing pipelines/umbilical/cable:

• Crossing #1 at Kilometre Point (KP) 78.036: PL370 24” gas pipeline;

• Crossing #2 at KP 84.110 (TBC): Norsea Communications cable;

• Crossing #3 at KP 86.697: PL1610 20” gas pipeline;

• Crossing #4 at KP 86.698: PL1611 4.5” methanol pipeline;

• Crossing #5 at KP 92.385: PL1706 umbilical;

• Crossing #6 at KP 92.416: PL 1705 6” gas pipeline.

The 4.5 inch MEG pipeline is assumed to be laid parallel to the gas pipeline and, therefore, six other crossings are also expected in the vicinity of the locations identified above.

The crossings identified above will be designed in accordance with the relevant codes and standards and a permanent separation between each pipeline, umbilical or cable of 300 millimetres will be provided. The Baird gas pipeline will be laid over the existing pipelines, umbilical and cable on concrete mats or plinths.

The crossings will be protected by rock dumping or concrete mattresses around the crossing areas to prevent damage by/ to fishing trawlers and gear. As a worst case scenario it is predicted that around 26,100m3 of rock will be required for all six crossings.

Pipeline Installation at the Landfall

The general scope of work to be undertaken for the landfall and onshore pipeline installation includes the following:

• Construction of tunnel drive and reception structures;

• The driving of a tunnel to the beach;

• Installation of the 38 inch and 4.5 inch pipelines into the tunnel and shaft;

• Hydrotesting of the 38 inch and 4.5 inch pipelines in the tunnel and shaft;

• Grouting of the tunnel annulus;

• Installation of temporary sheet piled arrangements on the beach for the landfall works;

• Inshore trench dredging (Figure 6);

• Pull-ashore of the landfall pipelines;

• Tie-in of the landfall pipelines to the pipelines in the tunnel;

• Removal of all sheet piling and other temporary works;

• Reinstatement.

The section of seabed between the beach and the pipelay barge position (from KP0.00 to KP2.0) will require pre-excavation so that the pipeline can be pulled into the dredged trench to provide



the pipelines with the necessary security. The shore approach/landfall section (from KP0.00 to KP0.5) will require backfilling to include armour layer at the beach and in the surf zone to prevent exposure during storms.

Figure 6: Typical Cofferdam and Dredger

Testing and Commissioning of the Pipelines

The platform pipework and risers will be tested onshore during fabrication with the bi-directional pipeline and MEG line tested offshore by a process of:

• Flooding;

• Cleaning and gauging;

• Hydrotesting (to 1.25 times design pressure);

• Leak testing the whole system (1.1 times design pressure);

• De-watering.

2.5 Gas Storage Operations

2.5.1 Storage Profile

As a storage field, Baird will operate in two modes (Figure 7):

• Injection - Gas from the Baird pipeline flows to the NUI via the riser to the slug catcher and then to the injection manifold and on to the individual flow lines and Xmas trees to the reservoir.

• Production - Well fluids from the Baird reservoir flow from the Xmas Trees to the production manifold. From the production manifold, the gas is routed to the riser for export to Bacton.

2.5.2 Produced Water

It is known that particularly during the early years of storage and delivery, the produced gas will have absorbed connate water (water trapped in the pores of a rock during its formation) and be



wholly or partially saturated with water vapour, however the level and duration to which this occurs is unknown. This project has therefore conservatively assumed that all produced gas will be saturated with water vapour, which has consequential effects upon the hydrate inhibition requirement.

BSCL has decided against dewatering the gas offshore and will transport it to shore for dehydrating at Bacton.

2.5.3 Power Generation and Venting

Power generation will be provided by three 3 x 50% diesel generation skids and 3 months diesel storage. This will be sufficient for normal operations, with provision for back-up in case of maintenance. This 3 generator concept is utilised on a number of southern North Sea platforms and has a proven to be very reliable.

The total fuel consumption for the three generators, based on an electrical load of 196 kW is anticipated to be 1,769 kilograms of diesel per day. There is sufficient diesel storage capacity on the NUI for 3 months. It is therefore likely that the diesel units will be refuelled up to 6 times per year.

An atmospheric vent will be provided to dispose of pressure discharges from the offshore platform. It is currently anticipated that the platform would be depressurised on an annual basis (i.e. an annual test of the depressurisation system).

There will be no provision on the platform for flaring.

2.6 Maintenance

It is anticipated that planned maintenance visits to the platform will be made with a typical frequency of once every 4 weeks. Crew sizes are expected to be between six and ten, with maximum shift duration of 12 hours. Transport of personnel and materials to and from the platform will be by means of helicopter or, less frequently, supply boat.

Planned overnight accommodation will be provided for maintenance activities, although extended duration campaigns, such as coil tubing interventions, will be supported via jack-up barge or rig alongside the NUI.

Pipeline inspection (e.g. by intelligent pigging) and route surveys will be performed as a part of the planned maintenance programme for the asset. These inspections will be conducted by operations and maintenance staff supported by specialist pigging and pipeline inspection contractors.

2.7 Decommissioning

The design life for the Baird gas storage facility is 50 years. At the end of their useful life, the Baird onshore facilities will be decommissioned in line with legislative requirements and Best Available Techniques at the time. The relevant statutory and non-statutory bodies would be consulted and a detailed Decommissioning Plan prepared prior to the start of decommissioning.

It is anticipated that abandonment will include:

• The removal and possible re-use of the platform and its substructure;

• Plugging and abandonment of the wells, with casings cut to below the mudline;

• Full recovery or abandoned in situ of the pipelines.



Figure 7: Diagrammatic Representation of the Injection-Production Cycle

Compressed Production

Free Flow Production

Reservoir Pressure

Compressed Injection

1

2

3 4

5

6

Case 1 Start of Cushion Gas Injection: This case represents the start of cushion gas injection into the reservoir. This case only occurs once - when the reservoir is first converted to use for gas storage.

Case 2 Start of Typical Injection Season: This case represents the start of a typical injection season i.e. when the reservoir is at its minimum normal operating pressure. (It is also the condition at the end of cushion gas injection). This case gives the minimum compressor duty in the injection mode.

Case 3 End of Typical Injection Season: This case represents the end of a typical injection season, i.e. when the reservoir has reached its maximum operating pressure. This case gives the maximum compressor duty in the injection mode.

Case 4 Start of Typical Production Season (Freeflow): This case represents the start of a typical production season, i.e. when the reservoir is at its maximum operating pressure. The difference in pressure between the reservoir and the NTS is sufficient for ‘free-flow’ of gas i.e. no compression is required. This case gives the maximum heater duty for the export gas heater.

Case 5 Typical Production Season - Start of Assisted Export: This case represents the point in the production season when there is insufficient pressure differential between the reservoir and the NTS for free-flow of gas at the design flowrate and compression is required. This case gives the minimum compressor duty in the production mode.

Case 6 End of Typical Production Season: This case represents the end of the ‘constant rate’ production season. This is the minimum reservoir pressure at which a gas flowrate can be achieved. Below this pressure,



3 Summary of the Results of the Baird Offshore EIA Process

The Offshore EIA process has identified and assessed a wide range of potential impacts that the proposed offshore Baird gas storage project could have on the local and surrounding physical, biological and socio-economic (human) environment. A summary of the key findings from this process is given below.

3.1 Physical Environment

3.1.1 Water Quality

Discharges to the marine environment that will occur during the offshore Baird gas storage project activities, will include:

• The discharge of WBM, cement and other completion chemicals

• The discharge of hydrotest chemicals;

• Discharge of drainage water, personnel wastewater, anodes and anti foulant paints.

Chemicals will be selected to minimise the potential environmental impacts as much as possible. The suite of chemicals to be used for the hydrotest waters will be selected to limit any potentially harmful impacts on the environment while ensuring the pipelines are appropriately protected. Chemicals identified to be high risk will be substituted for more environmentally friendly alternatives where practicable.

All identified drainage water discharges will be low volume containing only small residual quantities of contaminants. BSCL will ensure that contracted rigs and vessels, and the Baird NUI are equipped with suitable containment, treatment and monitoring systems as part of the contract specification. BSCL will also ensure good housekeeping standards are maintained to minimise the amount of contaminants entering the drainage systems.

3.1.2 Seabed Sediments

In general, the seabed sediments along the offshore section of the proposed pipeline route corridor comprise sand with components of gravel, shell and silt, and frequent large sand waves (Gardline, 2009b). At the NUI location, seabed sediments are interpreted to comprise of coarse megarippled sand with occasional shell fragments (Gardline, 2009a).

It is estimated, as a worst case scenario, that the drilling of the 14 Baird storage wells will generate a total of approximately 29,120 tonnes of cuttings (this assumes a big bore cased hole completion with each well generating a total of 2,080 tonnes of cuttings) (refer to Table 4). Cuttings discharge modelling predicts that there will be very little significant settling of sediments from each of the Baird storage wells, due to the high currents in the area. The maximum extent of the cuttings pile is predicted to be approximately 22 by 11.5 kilometres (at its longest and widest points, respectively) measured to the 0.001 mm thickness contour. The area of cuttings deposition, where cuttings thickness is predicted to be one millimetre or greater, is restricted to an area immediately surrounding the drilling location of approximately 200 metres in radius.

Template drilling operations for the first seven wells will be undertaken between Q2 2011 and Q3 2012. The remainder of the wells will be drilled after the platform has been installed from Q1 2013 to Q2 2014. As such, given the relatively high tidal and wave generated currents in the area it is likely that the cuttings pile may be partially dispersed in between drilling phases.

Any impacts from the discharge of drilling muds and cuttings on the surrounding water quality, particularly suspended sediment loadings, will be very local and transitory. As the modelling shows, the majority of drilling discharges will settle quickly out of the water column with any remaining fine mud solids becoming dispersed. It is unlikely that any discharge will be noticeable above the existing background turbidity.



Within the area of any cuttings pile the natural sediments will become modified, with the initial impact being one of smothering. Given the relatively high tidal and wave generated currents in the area it is likely that any cuttings will soon become mixed with the natural sediments and eventually dispersed.

The impacts on sediments from the installation of the NUI are not anticipated to be significant. It is estimated that an area of approximately 80 square metres (0.008 hectares) will be impacted by the installation of the jacket, which takes into account the four supporting piles of the substructure and the associated steel mudmats. In addition, all 14 development wells will be drilled using a template (dimension of which are estimated to be 24 metres x 7.65 metres) installed at seabed, impacting a further 184 square metres (0.0184 hectares) of seabed.

The long term presence of the NUI will result in the semi-permanent loss of this area during the lifetime of the Baird gas storage project (estimated to be up to 50 years). The physical nature of the sediments in this area, i.e. sandy, is similar to large areas of the southern North Sea. Any loss of seabed from the presence of the NUI is therefore considered to be negligible.

The greatest disturbance to the seabed will be from the installation of the installation of the 38 inch subsea bi-directional gas pipeline and 4.5 inch MEG line as a result of pipe lay activities, dredging, trenching/jetting and subsequent burial. This will disturb an area of around 2.03 square kilometres (203 hectares). Additional areas of seabed may also be disturbed from the anchor pattern of the construction vessels, if DP vessels are not utilised.

Installation of the Baird pipelines is unlikely to significantly impact local sediment processes, as it is a temporary, constantly moving operation. In addition, suspended sediments in this area are already relatively high compared to many other UK coastal areas with significant fluctuations resulting from tidal or weather (storm) conditions. Of note is that studies have shown that the production of sediment plumes from aggregate dredging are negligible (in context of background suspended sediment concentrations for this area of the southern North Sea) (Hitchcock & Drucker, 1996; Newell et al, 1998; Newell et al, 2002).

In order to minimise the area of seabed disruption during pipe laying, trenching/jetting and burial operations the following control measures will be put in place:

• Working widths will be minimised;

• If possible, BSCL will use a vessel with a working draft of 18 metres or under to install the Baird pipelines, thereby avoiding the need to pre-dredge any ridges or sandbanks to create an access path for the vessel. This will be subject to suitable vessels being available at the time pipeline installation activities are due to commence, currently anticipated to be in Q4 2011;

• Where anchored vessels are used, anchor handling procedures will be implemented to minimise impacts of anchor footprints;

• If jetting operations are undertaken for the 4.5 inch MEG pipeline, the project will review the various techniques/equipment available and base their selection upon the option that results in the least suspension of jetted sediment;

• Post-lay surveys will be undertaken to identify any anchor mounds which could affect fishing activities. If significant mounds are found (although this is considered unlikely) measures will be taken to eradicate them by conducting a trawl sweep i.e. a vessel towing a chain between trawl doors across the area to flatten the mound.

All methods will employ industry best practice controlled by procedural approvals and operations will be controlled under the conditions stipulated in the project consents.

3.1.3 Air Quality

The exhaust emissions from the normal running of the construction, installation, drilling rig, pipelay and maintenance vessels will cause a minor, temporary degradation of the air quality in the immediate vicinity of the Baird gas storage project.



Modelling of the atmospheric emissions likely to be generated from power generation during drilling, construction, installation and maintenance activities associated with the Baird gas storage development has indicated that elevated levels of exhaust gases would decrease rapidly with distance. At the nearest shore locations calculated levels of all exhaust gases will be consistent with good air quality standards.

3.1.4 Marine Archaeology

During the pipeline route survey, one wreck was identified 120 metres southeast of KP45.405, with dimensions of 65 x 12 x 4 metres (Gardline, 2009b). This will not be impacted by the proposed pipeline installation activities. No wrecks were identified in the vicinity of the proposed NUI location during the site survey for (Gardline, 2009a).

Based on the assumption that the site surveys already undertaken have fully assessed the area for the presence of marine artefacts, it is concluded that there will be no disturbance to marine archaeology as a result of the Baird gas storage project.

3.1.5 Accidental Loss of Containment (Hydrocarbon Release)

For the Baird gas storage facility, the most likely cause of a large fuel spill will be as a result of a collision between a vessel and the drilling rig or proposed NUI. For oil spill planning purposes, trajectory modelling has been undertaken to estimate the time for complete dispersal of a worst case diesel spill (assumed to be a total of 968 tonnes) as a result of a loss of diesel fuel inventory from a jack-up drilling rig.

The model results predict that the diesel spill will disperse within 8 hours, approximately 65 kilometres from the English coastline. Natural dispersion is to be expected as diesel evaporates quickly upon release due to its high levels of low molecular weight components (light ends). It also has a very low asphaltene content, which means that it is unlikely to persist in the environment.

Stochastic modelling (using typical meteorological and oceanographic conditions) of a worst case diesel spill from the NUI location shows that the effect of the predominant wind and currents in this region is to keep the oil largely centred around the spill point and away from shore with a slight drift to the south. As such, the Special Protection Areas (sites classified for rare and vulnerable birds) located along the adjacent coastline, namely The North Norfolk Coast SPA and Wash SPA and the Great Yarmouth North Denes SPA, are very unlikely to be impacted by a spill evident.

Given the above, environmental impacts are anticipated to be minor. Consequences are potentially major for seabirds on the surface of the water at the time of the spill. There may also be a minor effect on shipping in the area in the event of a large spill. Consequences for coastal areas are anticipated to be negligible.

A full Oil Pollution and Emergency Plan (OPEP) will be in place prior to marine operations taking place to provide guidance on actions to be taken in the event of a release or spill. The OPEP will be supported by a range of personnel training in oil spill response and emergency management.

3.1.6 Transboundary Impacts

The issues with the potential for transboundary effects, in the context of this development, are atmospheric emissions and accidental events leading to an oil spill. The nearest international boundary to the proposed Baird NUI is the UK/Dutch median line, which lies approximately 34 kilometres to the east. Atmospheric emissions are undetectable against background levels at 20 kilometres and there will be no transboundary impacts from these emissions.

Oil spill modelling of a 968 tonne diesel spill with a 30 knot offshore wind (westerly) from the proposed Baird NUI location showed that the slick fully dispersed after 8 hours, approximately 18 kilometres from the transboundary line. No significant transboundary impacts are therefore anticipated.



3.2 Biological Environment

3.2.1 Benthic Communities (Seabed Organisms)

NUI Location

The faunal community at the NUI location was found to be fairly homogenous and diverse given the low abundances across the site, and was dominated by the high proportion of the crustacean B. elegans. Statistical analysis of physio-chemical data revealed only Station ENV3 to be statistically distinct from the other five stations sampled. Analysis of the raw data clearly showed this to be due to elevated concentrations of hydrocarbons and most metals along with the high proportion of fines at Station ENV3. The dominant species found within this survey were not indicative of sediment contamination and there was no evidence to suggest a disturbed community at ENV3 or any other station (Gardline, 2009c). No species or habitats of conservation significance protected under the EC Habitats Directive (92/43/EEC) were observed in the NUI platform survey area.

Residual impacts on benthic communities as a result of installation of the NUI and footprint of the drilling rig/heavy lift vessel are anticipated to be minor. Although some of the impacts are long term (ca. 50 years) the overall size of the area that will be lost is insignificant when compared to the overall size of similar sediments present in the southern North Sea.

Along the Pipeline Route

The environmental baseline survey for the proposed pipeline route observed the following visible fauna along the route: Annelida (Pomatoceros sp., Sabellaria spinulosa), Crustacea (barnacles: Balanidae sp., crabs Necora puber, Cancer pagurus and shrimp: Pandalus montagui), mollusca (gastropods, mussels: Mytilus edulis and Calliostoma zizyphinum), pisces (Myococephalus scorpius), cnidaria (anemones), echinoderms (brittle stars: Ophiura albida and starfish: Asterias rubens), bryozoans (hornwrack: Glustra folicea) and porifera (Gardline, 2009b).

The occurrence of the reef building polychaete Sabellaria spinulosa was confirmed at a number of stations in varying abundance and numerous Mytilus edulis mussels were found to be present at the nearshore end of the route. The potential impact to these two species is discussed in Section 3.2.5 below.

Given that the impact to benthic communities from pipeline installation is purely physical, i.e. natural disturbance and smothering, and that the sediments will not have been contaminated, it is anticipated that the sediment communities will begin to recover as soon as operations have ceased. Recolonisation of the impacted area can take place in a number of ways, including mobile species moving in from the edges of the area (immigration), juvenile recruitment from the plankton or from burrowing species digging back to the surface.

Recovery times for soft sediment faunal communities are difficult to predict although some recent studies have attempted to quantify timescales. Collie et al., (2000) examined impacts on benthic communities from bottom towed fishing gear and concluded that in general, sandy sediment communities were able to recover rapidly, although this was dependant upon the spatial scale of the impact. It was estimated that recovery from a small scale impact, such as a fishing trawl (the impact width of which is similar to a pipeline trench) could occur within about 100 days. In this sort of impact, it was assumed that recolonisation was through immigration into the disturbed area rather than from settlement or reproduction within the area. It was also noted that whilst the recovery rate of small bodied taxa, such as the polychaetes which tend to dominate the data set, could be accurately predicted, sandy sediment communities often contain one or two long lived and therefore vulnerable species, e.g. Mya truncata, the recovery of which is far harder to predict.

Further, in a series of large scale field experiments Dernie et al., (2003) investigated the response to physical disturbance of marine benthic communities within a variety of sediment types (clean sand, silty sand, muddy sand and mud). Of the four sediment types investigated, the



communities from clean sands (such as those prevalent along the pipeline route) had the most rapid recovery rate following disturbance.

There may be a local increase in biological diversity in areas of hard substrata along the pipeline route (e.g. exposed pipeline, rock, mattresses etc) but this is generally considered not to affect the large-scale community structure of the southern North Sea.

3.2.2 Birds

The offshore waters of the southern North Sea are visited by several seabird species mainly for feeding purposes. Species using the waters in the vicinity of the development area most notably include fulmar, gannet, kittiwake, guillemot, pomarine skua, common gull, herring gull, and lesser black-backed Gull (UKDMap, 1998). Of these species, fulmar are present in highest numbers in the southern North Sea during the early and late breeding seasons, leading to peak densities in September. Increased numbers of Gannet occur in November and December when dispersion from breeding sites is at a maximum. Kittiwakes, common gull and herring gull are widely distributed throughout the year. Lesser black-backed gull are mainly summer visitors, while in contrast Guillemot numbers are present in greatest numbers during winter months. In addition, substantial numbers of terns migrate northwards through the offshore North Sea in April and May, with return passage from July to September (DTI, 2001).

Special Protection Areas are protected sites classified for rare and vulnerable birds (as listed on Annex I of the EC Birds Directive), and for regularly occurring migratory species. The North Norfolk Coast SPA and The Wash SPA are located around 25 and 64 kilometres east-north-east of the proposed Baird pipeline route at their closest points, and therefore impact to raft-forming species in these areas is anticipated to be negligible. Vessels associated with the project are likely to operate out of Great Yarmouth, to the south of the proposed development, and are therefore unlikely to interact with the SPAs.

Great Yarmouth North Denes SPA is located approximately 10 kilometres south of the proposed Baird pipeline route. The location supports important numbers of breeding Little Tern that feed outside the SPA in nearby waters. Installation activities associated with the Baird pipeline are also considered to be remote from this SPA. Disturbance from project related vessel traffic is unlikely to be noticed above existing traffic movements within the area.

To reduce the potential risk of disturbance to local seabird populations, where possible, all project related vessel traffic will be routed to follow existing traffic movements associated with the oil and gas industry in this area.

As discussed in Section 3.1.5 above, stochastic modelling of worst case oil spill scenario from the proposed NUI location (assumed to be a total of 968 tonnes of diesel) shows that the effect of the predominant wind and currents in this region is to keep the oil largely centred around the spill point and away from shore with a slight drift to the south. As such the SPAs are very unlikely to be impacted by a spill event.

The BSCL will prepare a full Oil Pollution and Emergency Plan (OPEP) which will be in place prior to any marine operations taking place.

Overall, however, the impact to the local bird populations from all aspects of the Baird gas storage project is considered to be negligible.

3.2.3 Fish and Shellfish

Generally, there is little interaction between fish and offshore developments, although some species congregate around platforms and along pipelines. Spawning areas and juveniles, however, can be sensitive to installation activities, discharges to sea and, in some cases, accidental spills.

Fish species spawning over the area of the proposed Baird development area include mackerel, lemon sole, plaice, sprat, sole, sandeels and the Norway lobster (Nephrops norvegicus). In addition to spawning grounds, the waters of the proposed Baird development area also act as a nursery area for mackerel, lemon sole, plaice, Nephrops whiting, cod, sole and sandeels.



The benthic fauna of the UK waters is rich and diverse. An important component of this benthic fauna is a collection of molluscs and crustaceans loosely referred to as shellfish, a number of which are of commercial importance. Most benthic crustaceans are scavengers to some extent, feeding on detritus, although many species are also active predators of a variety of benthic organisms. Molluscs such as scallops, cockles and mussels are filter feeders of material suspended in the water column (DECC, 2009). Crustaceans such as Norway lobster, European lobster and brown (or edible) crab are also commonly found in the region.

Elasmobranchs are a class of fish that is comprised of sharks, skates and rays. Skates and rays (Chondrichtyan fishes) are an important part of the North Sea ecosystem and typically have a slow growth rate and low fecundity, leaving them vulnerable to over-fishing pressures and pollution events. In a survey conducted by CEFAS, twenty six species were identified and recorded from waters surrounding the British Isles. Of these 26 species, 12 may be present within the southern North Sea (Ellis et al., 2005).

The construction and operation of Baird gas storage project is likely to result in only minor impacts to fish and shellfish populations. Possible impact could occur from:

• Piling activity: A ‘soft start’ approach will be implemented to reduce the impact on fish from piling activities associated with the installation of the platform. BSCL will ensure that the JNCC’s protocol for minimising the risk of disturbance and injury to marine mammals from piling noise is adhered to (JNCC, 2009).

• Sediment disturbance from pipe laying and trenching operations: Pipelay, trenching and burial activities are all mobile operations and it can, therefore, be expected that any impact will only affect any one area for a period of a few hours, or possibly a day at the most. Concerns have been raised that dredging in the nearshore area will generate chalk plumes in the water column thereby impacting on shellfish species within the local area (e.g. crabs, lobster, whelks etc). In order to minimise the plumes of chalk BSCL propose to dispose of the dredged material within a licence disposal site rather than re-distribute it along the working corridor. In addition, if possible, the 4.5 inch MEG line will be trenched using a plough rather than jetted into place.

• The Baird NUI may result in some form of artificial reef effect, as fish tend to aggregate around objects placed in the sea. In the longer term, this may have a minor beneficial effect leading to an improved habitat biodiversity in the area.

In summary residual impacts on fish communities as a result of installation of the pipelines are anticipated to be minor. The operation is temporary and any effects will be transitory. Fish may move from the immediate vicinity of operations but should rapidly return. Shellfish species may be smothered in the nearshore region as a result of the dredging activities, but this will be within a localised area close to the proposed pipeline route.

3.2.4 Marine Mammals

Harbour porpoise is the only marine mammal which occurs in the southern North Sea in densities similar to those found further north, while white-beaked dolphin sightings drop off sharply south of the Humber estuary. Atlantic white-sided dolphins are the only other species to have been sighted in extremely low numbers in the southern North Sea (Reid et al., 2003). Of these species, the white-beaked dolphin has been sighted in moderate numbers during April and in low numbers during May in the vicinity of the proposed NUI and pipeline whilst the harbour porpoise has been observed in moderate to low numbers across the year.

It is also possible that harbour seals may be present within the vicinity of the proposed NUI location and along the proposed pipeline route.

Development of the proposed Baird gas storage facility will generate noise, both above and below the sea surface. Significant sources of noise will be generated from the following activities:

• Drilling operations;



• Installation of the NUI (piling);

• Installation of offshore pipelines;

• General vessel activity associated with the drilling, construction, installation and maintenance operations.

BSCL will ensure that the JNCC’s protocol for minimising the risk of disturbance and injury to marine mammals from piling noise is adhered to (JNCC, 2009). As such, two dedicated trained and qualified marine mammal observers (MMO) will be onboard the installation vessel, assisted by passive acoustic monitoring (PAM). This will help to ensure that any marine mammals are at a ‘safe’ distance of at least 500 metres from the vessel before the pile driving commences.

Piling will not commence during periods of darkness or poor visibility (such as fog), or during periods when the sea state is not conducive to visual mitigation (above Sea State 4), as there is a greater risk of failing to detect the presence of marine mammals.

The mitigation zone (at least 500 metres from the vessel) will be monitored visually by MMOs and/or acoustically using PAM for at least 30 minutes prior to the commencement of piling. Piling should not commence if marine mammals are detected within the mitigation zone or until 20 minutes after the last visual or acoustic detection.

A ‘soft start’ approach will be adopted to begin the piling operations, whereby piling is initiated with lower energy blows and built up gradually over a period of time. The soft-start duration shall be for a period of not less than 20 minutes. If a marine mammal enters the mitigation zone during the soft-start then, whenever possible, the piling operation will cease, or at the least, the power will not be further increased until the marine mammal exists the mitigation zone, and there is no further detection for 20 minutes.

If there is a pause in the piling operations for a period of greater than 10 minutes, then the pre-piling search and soft-start procedure will be repeated before piling recommences.

Given the above mitigation measures, it is predicted that residual impacts on marine mammals from noise and vibration generated during the proposed Baird gas storage project will be temporary in nature and are anticipated to be minor.

3.2.5 Protected and Sensitive Offshore Habitats

Marine Protected Areas

The proposed Baird pipeline route crosses two marine sites, which are currently undergoing selection assessment for their Annex I habitat type ‘sandbanks which are slightly covered by seawater all the time’: the North Norfolk Sandbanks and Saturn Reef pSAC and the Haisborough, Hammond and Winterton pSAC. The sites are also being recommended for their biogenic Sabellaria spinulosa reef habitat.

North Norfolk Sandbanks and Saturn Reef pSAC

The route of the proposed Baird pipelines crosses the North Norfolk Sandbanks and Saturn Reef pSAC for approximately 24 kilometres, traversing the Well Bank (KP64.220) and the Broken Bank southern extension (KP78.270) sandbanks.

It is estimated that installation of the proposed pipelines will disturb approximately 0.505 km2

(50.5 hectares) inside the pSAC. This equates to less than 0.015% of the pSAC area. Additional areas of seabed may also be disturbed from the anchor pattern of the construction vessels if DP vessels are not utilised.

Four of the proposed pipeline/cable crossings are located within the pSAC (PL370, Norsea Comm. Cable, PL3610 and PL3611) all of which will require protection by rock dumping or concrete mattresses. As a worst case scenario it is estimated that approximately 19,347m3 of rock will be required to protect these four pipeline crossings. In addition, five free spans along the 38 inch gas pipeline may need to be corrected with rock. It is estimated that a total of 4,000m3 of rock will be needed for post-pipelay span correction along the 38 inch gas pipeline. The need for this and the exact location of the spans will be unknown until after the pipeline has been laid,



therefore, as a worst case scenario it is assumed that all are located within the North Norfolk Sandbanks and Saturn Reef pSAC.

Residual impacts on benthic communities as a result of installation of the pipelines are anticipated to be minor. Faunal communities will be severely impacted where dredging/trenching/jetting operations have taken place, however, given that a number of the dominant taxa are tolerant of smothering or favour physical disturbance, combined with the fact that they are largely typical for the region and sediment type, these communities should recover fully, probably in 3-5 years. There may be a local increase in biological diversity in areas of hard substrata along the pipeline route (e.g. at pipeline crossings). This is generally considered not to affect the large-scale community structure of the southern North Sea.

Of note is that where the Well Bank is crossed (KP64.220), an existing pipeline (30 inch PL311 Gas Sean PP – Bacton) runs parallel to the proposed Baird route, approximately 100 metres to the south. No evidence of structural damage to the sandbank could be seen on the bathymetry or sidescan sonar data collected during the 2009 pipeline route survey for the Baird project.

In addition, where the proposed Baird pipeline traverses the Broken Bank southern extension (KP78.270) sandbanks, the Norsea Communications Cable runs approximately 200 metres to the south. The existing PL370 24 inch Bacton to Thames pipeline cuts the bank in north easterly direction, crossing the proposed Baird pipeline at KP78.036. No evidence of structural damage to the sandbank could be seen on the bathymetry or sidescan sonar data collected during the 2009 2009 pipeline route survey for the Baird project.

Given the small percentage of the pSAC that will be impacted by the pipeline installation activities, that any residual impacts are likely to be minor and that there appears to be no evidence of structural damage to the sandbanks from the existing pipelines/cable, it is concluded that the proposed Baird gas storage development will not have an adverse effect on the integrity of the North Norfolk Sandbanks and Saturn Reef pSAC.

Haisborough, Hammond and Winterton pSAC

The route of the proposed Baird pipelines crosses the Haisborough, Hammond and Winterton pSAC for approximately 44 kilometres, traversing the following three large sandbank features crossed: Winterton Ridge sandbank (around KP36.0), Hewett Ridges sandbank (between approximately KP40 to KP42) and Smiths Knoll sandbank (KP50 to KP51).

It is estimated that installation of the proposed pipelines will impact an area of approximately 0.792 km2 (79.2 hectares) inside the pSAC. This equates to less than 0.05% of the pSAC area. Additional areas of seabed may also be disturbed from the anchor pattern of the construction vessels if DP vessels are not utilised. Of note is that all three of the large sandbank features listed above will be dredged pre-pipelay. This is required as installing the pipeline on an unmodified seabed would result in unacceptable pipe stresses and the possibility of commercial fishing gear getting caught around the pipe affecting the safety of the fishing vessel and the integrity of the pipeline.

None of the proposed pipeline/cable crossings are located within the pSAC, however, it is possible that 4,000m3 rock may be required to correct a total of five free spans along the 38 inch gas pipeline. The need for this and the exact location of the spans will be unknown until after the pipeline has been laid, therefore, as a worst case scenario it is assumed that all are located within the Haisborough, Hammond and Winterton pSAC.

A number of gas fields overlap the northern and eastern boundaries of the pSAC, and several existing pipelines cross the site. Primarily these run around the north western boundary and across the centre of the site although pipelines also cross the southern part of the site. A number of submarine cables also pass through the site. It possible that installation of these pipelines/cables may have affected the structure of the sandbanks at the time of commissioning, however no evidence to prove this was found during recent surveys (Entec, 2008a).

Across Winterton Ridge an existing pipeline (PL311: 30 inch Gas Sean PP – Bacton) runs parallel to the proposed Baird route, approximately 150 metres to the south. No evidence of structural



damage to the sandbank could be seen on the bathymetry or sidescan sonar data collected during the 2009 pipeline route survey for the Baird project.

The PL311 pipeline also runs parallel to the proposed Baird route across the Hewett Ridge, approximately 150 metres to the south. Again, no evidence of structural damage to the sandbank could be seen on the bathymetry or sidescan sonar data collected during the 2009 pipeline route survey for the Baird project.

Residual impacts on benthic communities as a result of installation of the pipelines are anticipated to be minor. Faunal communities will be severely impacted where dredging/trenching/jetting operations have taken place, however, given that a number of the dominant taxa are tolerant of smothering or favour physical disturbance, combined with the fact that they are largely typical for the region and sediment type, these communities should recover fully, probably in 3-5 years. There may be a local increase in biological diversity in areas of hard substrata along the pipeline route (e.g. exposed pipeline and rock) but this is generally considered not to affect the overall community structure of the sandbanks.

Given the small percentage of the pSAC that will be impacted by the pipeline installation activities, that any residual impacts are likely to be minor and that there appears to be no evidence of structural damage to the sandbanks from the existing pipelines/cable, it is concluded that the proposed Baird gas storage development will not have an adverse effect on the integrity of the Haisborough, Hammond and Winterton pSAC.

Potential Annex I Habitat

The habitat assessment undertaken along the proposed route of the Baird pipelines identified the following potentially sensitive habitats, protected under the UK’s Offshore Petroleum Activities (Conservation of Habitats) Regulations 2001:

• Sabellaria spinulosa colonies;

• Mussel beds (Mytilus edulis).

Sabellaria spinulosa Colonies

During the pipeline route survey, the occurrence of the reef building polychaete Sabellaria spinulosa was confirmed at a number of stations in varying abundance. The distinction between what is, or is not, a Sabellaria ‘reef’ is imprecise. Hendrick and Foster-Smith (2006) developed a scoring system based on a series of physical, biological and temporal characteristic reef features, to attempt to make the process of ‘reef definition’ reproducible. Where possible, the Hendrick and Foster-Smith (2006) scoring system has been applied to the Baird survey data in an attempt to define the ‘reefiness’ of the areas of Sabellaria identified along the proposed pipeline route. The ‘reefiness’ scale has been based largely on results of a workshop run by JNCC (Gubbay, 2007). As such, areas of low to medium reefiness are considered to be present at KP5, KP15, KP61.45, KP67.56, KP22, KP37.64, KP58.92, KP68-69 (Gardline, 2009d).

Where possible, the pipeline route has been re-aligned in order avoid these areas. Where this is not possible it is estimated that only a small percent (2.5% or less) of each of the identified reef features will be impacted by the installation of the Baird pipelines.

Sabellaria has been shown to recover from physical impacts, providing that the conditions necessary for its growth, i.e. a suitable substrate and a good supply of suspended sediment for feeding and tube formation, are still present and a plentiful supply of larva are present in the plankton. In a study looking at the recovery of Sabellaria spinulosa following aggregate extraction at the Hastings Shingle Bank site, Pearce, et al., (2007) reported that recolonisation on cessation of extraction operations commenced within a matter of months and that a similar pattern could be expected in other areas assuming a supply of larvae in the plankton. They observed the initial colonisation and development of a significant Sabellaria spinulosa aggregation within an 18 months period and further development to a stage equivalent to the oldest aggregations observed in the area was assessed as likely to be complete within 3 years, a period that could maybe have been faster were it not for disturbance from fish trawling activities.



BSCL has paid particular attention to the sensitivities associated with the presence of S. spinulosa patches. Careful identification of their distribution and abundance in the area of proposed pipeline has been used to plan the installation and to mitigate potential effects, where possible. Should the pipeline installation activities result in any physical impact to the identified reef features it is anticipated that the S. spinulosa would recover rapidly. Consequently, it is considered that the installation of the proposed pipelines will have a minor and transient impact to S. spinulosa colonies.

Mussel beds (Mytilus edulis)

Mytilus edulis mussel beds were identified along the pipeline route at Stations ENV42 (32m SE of KP1) and ENV43 (34m SE of KP0.9), with far higher densities present at ENV42. Although the mussel beds identified at ENV42 are mostly continuous representing approximately 95% coverage, the mussel bed is not raised, being only one mussel deep and would therefore be considered to be a moderately dense mussel bed (Gardline, 2009e).

As a worst case, assuming that the mussel bed extends for approximately 100 metres within the entire width of the working corridor for the 38 inch gas pipeline and the 4.5 inch MEG line then a total area of 4,000m2 (0.4 hectares) may be disturbed from pipeline installation activities.

The area of the seabed where the mussel habitat was found will be dredged pre-pipelay. This is likely to result in the mortality of a large proportion of the individual mussels within the impacted area of the bed. It should be, noted, however that mussel beds are naturally subject to mortality and dissipation through smothering due to the biodeposition of sediment by the mussel bed (“mussel mud”), wave or tidal scouring and predation (Saurel et al., 2004).

The main period of mussel larval settlement (spatfall) in the UK is spring. Summer growth is rapid, but mortality rates are also high and increase as the year goes on. Seed mussel beds are frequently dispersed and lost in autumn or winter. Pre-pipelay dredging along the route of the 38 inch gas pipeline is likely to take place during Q4 2011 and Q1 2012 and, as such, will coincide with the period where seed mussel beds are frequently dispersed and lost.

Based on evidence from previous studies it is suggested that the habitat will recover within 1 to 2 years (ICES, 2009). The presence of shell and stone is seen as important to future settlement success of mussels.

Given the above, it is considered that the installation of the proposed pipelines will have a minor and transient impact to the mussel beds (Mytilus edulis).

3.3 Socio-Economic Environment

3.3.1 Commercial Fishing

The proposed Baird NUI is located in ICES Rectangle 35F2 Subsquare 2. The predominant fishing method in Rectangle 35F2 is beam trawling, with Dutch-registered vessels the largest fleet fishing in the area (81%).

Consultation with CEFAS has indicated that fishing effort in this area is low and consists mainly of Nephrops, beam trawling and long lines for edible crab, Nephrops, plaice and cod. MFA data from 2004 to 2008 shows that fishing effort (in terms of days fished) in Rectangle 35F2 has decreased over recent years from 130 days per year in 2004 to 9 days per year in 2008. The data shows no discernable pattern with regard to seasonality, although effort in spring is generally lower than during the rest of the year.

There will be a loss of access to the area and potential safety risks to fishing vessels while the NUI is being installed (activities associated with this are currently scheduled to occur in September and October 2012). A 500 metre safety zone will be set up around the NUI during this time. From a safety perspective, it is therefore anticipated that fishermen will not experience problems in avoiding the installation.

Once the NUI has been installed, a permanent 500 metre safety zone will be established for the life time of the project in order to protect the installation. This will cover an area of 0.8 square



kilometres (80 hectares) and fishing will be excluded from this area for the lifetime of the project (anticipated to be up to 50 years).

In addition to the above, there will also be some temporary disruption to fishing activity during installation of the 38 inch subsea bi-directional gas pipeline and 4.5 inch MEG line. Within the vicinity of the nearshore zone, beach launched vessels use pots, drift, set nets and also long lines to target local fisheries including a fairly prolific crab and lobster fishery, with catch effort peaking between July and September. Static gear is mainly located within The Would area to the west of Haisborough Sands (within 1 to 7nm off the coast). To the east of Haisborough Sands fishermen are more likely to use net and lines.

Pipeline installation activities are currently scheduled to take place from Q4 2011 to Q4 2012. During this time, fishermen will have to temporarily avoid areas where pipe laying and trenching operations are being undertaken and any static gear which is located within the working width or within area impacted by the anchor pattern of the pipelay vessel and associated safety exclusion zone of the pipelay vessel will need to be removed. Of note, however, is that the Baird pipelines run parallel and between the existing PL24 30 inch Leman pipeline and the PL311 30 inch Sean pipeline for the majority of their route. The PL24 and PL311 pipelines are also laid on the seabed and therefore this area is already restricted in terms of trawling.

In addition, pipeline installation is a mobile operation and loss of access over any one area will be short term (i.e. only certain sections of the pipeline will be restricted to fishing activity at any one time). BSCL has appointed a Fisheries Liaison Officer (FLO) for the project who will communicate with the fishermen, prior to and throughout the installation programme in order to ensure that they are kept up-to-date with the various planned activities. Appropriate charts and information on safety zones will accompany notification of these works and activities.

Residual impacts on commercial fishing activities as a result of the Baird gas storage project are anticipated to be minor.

3.3.2 Shipping Activities, Ports and Navigation

A detailed assessment of the navigational impacts and risks associated with the Baird NUI has been undertaken by Anatec UK Limited. ShipRoutes is a shipping route database developed by Anatec UK to assist in identifying shipping passing in proximity to proposed offshore developments such as oil and gas sites, wind farms and dredging areas. The shipping routes for the Baird NUI location have been validated using 28 days of Automatic Identification System (AIS) shipping survey collected in the area during June 2009.

A 10 nautical mile (18.5 kilometres) search of Ship Routes around the proposed Baird NUI location identified a total of 12 routes, used by an estimated 6,897 vessels per year (approximately 19 vessels per day) (Figure 8).



Figure 8: Shipping routes within 10 nautical miles of the Baird location (Anatec, 2009)

Once the NUI is installed it is anticipated that the likely effects on navigation will be as follows:

• Route No. 1: Great Yarmouth-Wenlock - an estimated 26 offshore support vessels per year use this route, which passes the proposed Baird NUI location to the west at a mean distance of 0.2 nautical mile. Vessels using this minor route are likely to increase their clearance to around 1 nautical mile whilst maintaining a safe clearance from other platforms in the vicinity, such as the Inde Field platforms. Although the sea room in the area is restricted, this action should still be possible for these relatively small, manoeuvrable vessels. The route is used solely by offshore support vessels, which tend to have good awareness of other offshore developments. Given this, and the low volume of traffic using the route, the effect on navigation is considered to be low.

• Route No. 2: Great Yarmouth-Inde - an estimated 26 offshore support vessels per year use this route, which passes the proposed Baird NUI location to the north west at a mean distance of 0.9 nautical miles. The vessels using this route are likely to marginally increase their passing distance to the order of 1 nautical mile whilst maintaining a safe clearance from other platforms in the vicinity. As with Route 1, the ships using this route are all associated with the offshore industry; the impact on navigation is therefore considered to be low.

• Route No. 3: Inde-Great Yarmouth - an estimated 26 offshore support vessels per year use this route as an alternative to Route 2. The route passes the proposed Baird NUI location to the east at a mean distance of 1.0 nautical mile. The effect on this route is likely to be similar to Route 2, namely minor re-routeing of vessels and overall a low impact on navigation.

All other routes pass at more than 2nm from the proposed Baird NUI location, including the busy routes within the deep water route, and the effect on their navigation is considered to be negligible.

A detailed assessment of the vulnerability of the proposed 38 inch gas pipeline and 4.5 inch MEG pipeline to other users of the marine environment (shipping and fishing) has also been undertaken by Anatec UK Limited. This concluded that the smaller diameter 4.5 inch MEG pipeline is much more likely to suffer damage in an incident involving ship anchors or trawl gear compared to the larger diameter 38 inch gas pipeline. To reduce this risk the MEG pipeline will



be trenched and buried as deep as practically possible in order to avoid the pipeline becoming exposed over its design life due to the mobile seabed (e.g. sand wave migration) in the area.

3.3.3 Employment

During the drilling, construction, installation and commissioning phase of the offshore Baird gas storage project, it is unlikely that many direct job opportunities will be created as most work will be undertaken by specialist contractors.

Due to the technical speciality of the onshore pre-fabrication and construction work, it is considered unlikely that much of this work will be undertaken in the Bacton region.

During offshore drilling, installation and construction activities, the port at Great Yarmouth will be used where possible as a supply base for project associated rigs/vessels. The project will therefore be able to draw on the support services as required, which will potentially assist in sustaining employment levels or increase employment opportunities locally.

For the offshore work, the use of an outside temporary labour force is likely to benefit existing services close to the heliport (i.e. local shops, hotels and restaurants).

Once the facility is operational, the NUI has been designed to be highly automated and will therefore be normally unmanned.

Planned maintenance visits to the NUI will be made with a typical frequency of once every 4 weeks. Crew sizes are expected to be between six and ten, with maximum shift duration of 12 hours. These visits will be carried out by a mixture of BSCL staff and contractor personnel with suitably trained personnel, which again may be able to draw on local support services.

Given this, it is anticipated the Baird gas storage project will have a limited impact on increasing employment. However, the indirect benefit will be significant as this strategic development will help safeguard the future of the existing terminals and the associated operational and maintenance workforce. The secondary benefits to the service industry and local suppliers to the terminals are therefore also significant.

3.3.4 Tourism

Leisure based and tourist activities are fairly widespread along the east coast of England. Along the Lincolnshire Coast, Mablethorpe and Skegness are important areas for the holiday industry, but tourist facilities are also widespread between the Humber and The Wash. The north Norfolk coast is an important area for water-based activities, particularly dinghy sailing and wind-surfing. The near-shore end of the proposed Baird pipeline is within a Royal Yachting Association (RYA) sailing area and is crossed by a RYA cruising route.

Bridlington and Great Yarmouth are both popular embarkation points for sea angling trips. The wildlife in the area is also a significant attraction and during the summer there are regular seal watching trips to Blakeney Point (Smith, 1998).

Due to its distance from shore, however, it is considered that the Baird gas storage project will generate little interest from either the local population or visitors to the area.

3.4 Cumulative Impacts

Cumulative impacts are those that may result from the combined or incremental effects of past, present or future activities. While a single activity may not have a significant impact when treated in isolation, it may, when combined with other impacts occurring at the same time in the same geographical area, result in a cumulative impact that is significant.

The proposed Baird NUI is located in a relatively congested area of offshore development, just over 4 kilometres south of the Indefatigable Field. The general area has therefore been subject to, and continues to be subject to impacts from oil and gas developments including drilling with a range of water and oil based drilling muds, as well as atmospheric and waste emissions from vessels and offshore oil and gas installations. In addition, numerous pipelines and cables already exist within in the southern North Sea.



The nearest licensed dredging area (Area 296 - United Marine Dredging Ltd) is located approximately 55 kilometres to the south of the Baird development. A recent application has been made for a fully licensed dredge area (Area 494) north of Area 296, within 11 kilometres of the coast at Caister and approximately 20 kilometres south of the Baird development) (Crown Estate, 2009).

Currently there is only one offshore wind farm operating in the southern North Sea, the Scroby Sands Offshore Wind Farm (Round one). This is located approximately 80 kilometres to the south of the proposed NUI. The nearest Round two offshore wind farm projected site is the Warwick Energy Ltd Dudgeon East site located approximately 70 kilometres west of the proposed NUI. The proposed pipeline route does not interact with either of these sites. Of note is that the Norfolk Offshore Wind Round Three Zone is located approximately 4 kilometres to the south of the proposed pipeline route. Installation activities associated with any new development within the Round Three Zone are unlikely to be undertaken prior to the Baird gas storage development.

In addition to the above, ENI intend to convert one of the Hewett reservoirs to storage and link this to the UK gas grid via their terminal at Bacton. The development will comprise two new 32 inch pipelines for injection and withdrawal and two new unmanned wellhead platforms at the Deborah reservoir. The proposed beach landing for the ENI pipelines is located some 0.75 to 1 kilometres, to the north west of Baird landfall. The pipeline corridor for the ENI development crosses the Haisborough, Hammond and Winterton pSAC to the north of the proposed Baird pipelines at a separation distance of between 16 and 25 kilometres (refer to Figure 9). The two proposed platforms at the Deborah reservoir will be located at least 50 kilometres to the south west of the proposed Baird NUI. Of note is that information on installation techniques, detailed pipeline routes etc are currently not publicly available.

The current project schedule for the ENI Hewett gas storage development involves installation of the platforms in Q3-Q4 2011 and pipeline installation in Q1-Q2 2012. As such, installation activities associated with the Baird pipelines may interact as this is planned to occur between Q4 2011 and Q4 2012.



Figure 9: Proposed ENI Hewett Gas Storage Project in relation to the Proposed Baird Gas Storage Development and Existing Pipelines/Cables

Potential cumulative impacts that may result from the proposed Baird gas storage project in combination with other past, present or future activities have been identified as follows:

• Some additional impact to commercial fishing activities may arise if the ENI Hewett gas storage pipelines are installed at the same time as the Baird pipelines, particularly in the nearshore section. This may cause static gear to be displaced from the area for an extended period of time; however, the impact will be temporary in nature. BSCL will inform fishermen in the area in advance of all works likely to have an impact on commercial fishing activities. A Fisheries Liaison Officer (FLO) will be responsible for dissemination of all key information.

• There may also be cumulative impact on benthic communities if the ENI Hewett gas storage pipelines are installed at the same time or shortly after the Baird pipelines,



particularly in the nearshore section. Faunal communities will be severely impacted where dredging/trenching/jetting operations have taken place, however, given that a number of the dominant taxa are tolerant of smothering or favour physical disturbance, combined with the fact that they are largely typical for the region and sediment type, these communities should recover fully, probably in 3-5 years. There may be a local increase in biological diversity in areas of hard substrata along the route of the pipelines (e.g. exposed pipeline, rock, mattresses etc) but this is generally considered not to affect the large-scale community structure of the southern North Sea.

• Along the route of the proposed Baird pipelines, from the landfall at the Bacton terminal to KP4.35, chalk is expected to subcrop the seabed veneer of sand. Given that the proposed beach landing for the ENI Hewett pipelines is located some 0.75 to 1 kilometres, to the north west of Baird landfall it is possible that the ENI pipelines will also cross a similar sediment type in the nearshore region. The presence of this chalk layer has created problems during installation of previous pipelines in the area when dredging, resulting in the water column and beach area being temporarily coloured white. During consultation for the proposed Baird gas storage project, the NFFO raised concerns over the generation of plumes of chalk in the water column which have the potential to smother whelks in the area. Chalk particles suspended in the water column may also result in crabs and lobsters not leaving their hiding places for a longer period of time, leading to temporary losses in catch. If the Hewett pipelines are laid at the same time or shortly after the Baird pipelines it is possible that the impact to shell fish species in the area will be prolonged. In order to minimise the plumes of chalk BSCL propose to dispose of the dredged material within a licence disposal site rather than re-distribute it along the working corridor. In addition, if possible, the 4.5 MEG line will be trenched using a plough rather than jetted into place.

• The pipeline corridor for the ENI development crosses the Haisborough, Hammond and Winterton pSAC for a distance of around 12 kilometres to the north of the proposed Baird pipelines. The separation distance between the proposed Hewett and Baird pipelines within the pSAC ranges from 16 to 25 kilometres, thereby significantly reducing the potential for any cumulative impacts. Information on the installation techniques for the Hewett pipelines is currently not publicly available. It is therefore assumed that the working corridor for the two pipelines is around 60 metres (i.e. double the area of the Baird 38 inch pipeline working corridor). This would result in approximately 0.72 km2 (72 hectares) of the pSAC being impacted. When combined with the area impacted by the Baird pipelines approximately 1.51 km2 (151 hectares) of the pSAC will be disturbed, which equates to around 0.08 % of the site. As discussed above, residual impacts on benthic communities as a result of the installation of the pipelines are anticipated to be minor and local sediment processes are unlikely to be impacted. Suspended sediments in this area are already relatively high compared to many other UK coastal areas with significant fluctuations resulting from tidal or weather (storm) conditions. A number of gas fields overlap the northern and eastern boundaries of the pSAC, and several existing pipelines cross the site. Primarily these run around the north western boundary and across the centre of the site although pipelines also cross the southern part of the site. A number of submarine cables also pass through the site. It possible that installation of these pipelines/cables may have affected the structure of the sandbanks at the time of commissioning, however no evidence to prove this was found during recent surveys (Entec, 2008). Given the small percentage of the pSAC that will be impacted by the pipeline installation activities from both developments, that any residual impacts are likely to be minor and that there appears to be no evidence of structural damage to the sandbanks from the existing pipelines/cable, it is concluded that the proposed Baird gas storage development will not have an adverse effect on the integrity of the Haisborough, Hammond and Winterton pSAC either alone or in combination with the Hewett gas storage pipelines.

• It is not currently known if the proposed Hewett gas pipelines cross any Sabellaria spinulosa colonies. It is predicted that installation of the proposed Baird pipelines will



have a minor and transient impact to the S. spinulosa colonies crossed along its route. Sabellaria has been shown to recover from physical impacts, providing that the conditions necessary for its growth, i.e. a suitable substrate and a good supply of suspended sediment for feeding and tube formation, are still present and a plentiful supply of larva are present in the plankton. Given this and the distance separating the proposed Hewett and Baird pipelines it is not anticipated that there will be a significant cumulative impact on any of the identified Sabellaria spinulosa colonies.

4 Environmental Management

The Bacton Storage Company Limited (BSCL) is a joint venture company owned by Centrica Storage Holdings Ltd and Perenco UK Limited. BSCL has been established to convert and ultimately operate the Baird Gas Storage Facility.

The BSCL will have it own Environmental Management System (EMS) for the Baird Gas Storage Facility. The EMS will be based on that of Centrica Storage Limited (CSL), which is ISO 14001 accredited and has been developed and refined over many years of operational experience on the Rough Gas Storage Facility.

BSCL shall ensure formal control of all its operational activities, which may have a significant effect on health, safety and the environment through an Integrated Management System (IMS). This system shall be designed to satisfy the requirements of ISO 14001 and shall be independently verified and regularly audited by a third party.

5 Overall Conclusions of the Baird Offshore EIA

In conclusion, it is considered that, providing the proposed mitigation and monitoring requirements are put in place, the offshore Baird gas storage project will not have a significant adverse impact on the local and far-field physical, biological or social-economic environment, and from a cumulative perspective, is unlikely to comprise a significant component.

In addition, residual impacts on employment are anticipated to be beneficial as although significant numbers of additional jobs are unlikely to be created by the Baird gas storage project, the development will help to underpin the long-term viability of the current gas service industry in the region. There will also be a benefit to existing local service sectors in the area of the onshore terminal and heliport (i.e. local shops, hotels, and restaurants) from the use of an outside temporary labour force, particularly during the construction and installation phases of the project.

BSCL will continue to consult with all interested parties throughout the development and operational phases of the Baird gas storage project, keeping interested stakeholders informed of progress and addressing any comments and concerns.



6 References

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Collie, Hall, Kaiser and Pointer (2000) A quantitative analysis of fishing impacts on shelf-sea benthos. J Animal Ecol. V 69, p 785-798.

Crown Estate, (2009). [Internet], available: <http://www.thecrownestate.co.uk/40_aggregates#licences>

Department of Energy and Climate Change (2009) Offshore Energy SEA, 2009.

Department of Trade and Industry (DTI), (2001). The Energy Report Volume 2. HMSO

Dernie, Kaiser and Warwick, 2003. Recovery rates of benthic communities following physical disturbance. J Animal Ecol. V72, p 1043-1056

Ellis, J. & Parker-Humphreys, M. (2005). Rays in the Irish Sea. CEFAS Lowestoft Contract Report (C2176) prepared for Coastal Fisheries Conservation & Management (on behalf of RWE-Innogy Ltd).

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Gardline (2009a) BSCL Baird Platform Site UKCS 49/23a. October 2009. Report 8208.

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Gardline (2009d) BSCL UKCS Quads 49, 52 and 53. Bacton to Baird Pipeline route and Environmental Survey. October and November 2009. Habitat Assessment Report 8209.1

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Hendrick & Foster-Smith (2006). Sabellaria spinulosa reef: a scoring system for evaluating ‘reefiness’ in the context of the Habitats Directive. J.Mar.Biol.Ass.UK. 86: 665-677.

Hitchcock, D.R., & Drucker, B.R. (1996). Investigation of benthic and surface plumes associated with marine aggregates mining in the United Kingdom. In the Global Ocean - towards operational oceanography. Proceedings of Conference on Oceanology International. Spearhead Publications, Surrey Conference Proceedings 2, 221-84.

ICES (2009) Request from Denmark to review environmental impact assessment of mussel fishery in the Limfjord. ICES Secretariat - 17 December 2009. ICES Advice 2009, Book 11

JNCC, (2009). [Internet], available: <http://www.jncc.gov.uk/>

Newell RC, Seiderer LJ & Hitchcock DR (1998). The impact of dredging works in coastal waters: A review of the sensitivity to disturbance and subsequent recovery of biological resources on the sea bed. Oceanography and Marine Biology: An Annual Review 36: 127-178.

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