South West of England Regional Development Agency
Wave Hub Technical Feasibility Study
Final Report
January 2005
Halcrow Group Limited
In association with:
Abbott Risk Consulting
Global Marine Systems Ltd
South West of England Regional Development Agency
Wave Hub Technical Feasibility Study
Final Report
January 2005
Halcrow Group Limited
In association with: Abbott Risk Consulting Global Marine Systems Ltd
Halcrow Group Limited Ambassador House, Ambassador Drive, Exeter, Devon EX1 3QN Tel +44 (0)1392 444252 Fax +44 (0)1392 444301 www.halcrow.com
Halcrow Group Limited has prepared this report in accordance with the instructions of their client, South West Regional Development Agency, for their sole and specific use. Any other persons who use any information contained herein do so at their own risk.
© Halcrow Group Limited 2005
Halcrow Group Limited Ambassador House, Ambassador Drive, Exeter, Devon EX1 3QN Tel +44 (0)1392 444252 Fax +44 (0)1392 444301 www.halcrow.com
South West of England Regional Development Agency Wave Hub Technical Feasibility Study Final Report
Contents Amendment Record This report has been issued and amended as follows:
Issue Revision Description Date Signed
1 0 First Draft for team review 12/04 PS
2 0 Second draft with comments 12/04 PS
3 0 Final 01/05 PS
4 0 Final 01/05 PS
Contents
Executive summary i
1 Introduction 1 1.1 Project background 1 1.2 Project team 3 1.3 W ave energy potential in the South W est of England 5 1.4 W ave Hub concept and its development 7 1.5 Methodology 8
2 Wave energy Developers 11 2.1 Developer requirements 11 2.2 Status of Developer readiness 16 2.3 Conclusions on Developer responses 16
3 Wave Hub design choices 18 3.1 W ave Hub design choices and stage one sifting 18 3.2 Stage two evaluation 18 3.3 Developing the four preferred options and third stage evaluation 20 3.4 Discarding of Options 1 and 3 24 3.5 Concept development 24 3.6 Conclusions 27
4 Site identification 29 4.1 Introduction 29 4.2 Screening of potential sites 29 4.3 Site identification: onshore 30 4.4 Site identification: offshore 32 4.5 Cable route and risk study 36 4.6 Environmental scoping study 40
5 Wave Hub technical specification 45 5.1 Introduction 45 5.2 Offshore equipment - wet hub 45 5.3 Electrical connection from wet hub to shore 47 5.4 W et hub system expansion 47 5.5 Onshore equipment 47 5.6 Specification for Developers 49
6 Operation and maintenance 51 6.1 Organisation and responsibilities 51
6.2 Operating requirements 52 6.3 Maintenance requirements 54 6.4 Training 56 6.5 Quality, health, safety and environmental management 56 6.6 Community liaison 57
7 Power generation potential 58 7.1 Introduction 58 7.2 Methodology 58 7.3 Results 59 7.4 Conclusions 61
8 Technical financial analysis 62 8.1 Introduction 62 8.2 Development and procurement costs 62 8.3 Construction costs 64 8.4 Costs of alternative W ave Hub arrangement 65 8.5 Phasing/modularity 65 8.6 Connection costs 66 8.7 O& M costs 66 8.8 Cost : risk and sensitivity analysis 68
9 Proposed development programme 70 9.1 Development schedule 70 9.2 Construction schedule 71 9.3 Environment impacts on construction schedule 72 9.4 Conclusion 73
10 Conclusions 75 10.1 Aims of the study 75 10.2 Need for the project 75 10.3 Conceptual and outline design 77 10.4 Location and impact 77 10.5 Cost and timing 78
Glossary
Appendices Appendix A - List of associated TFS reports Appendix B - Consultee list Appendix C - Project outline drawings, Nos. 001-004 Appendix D - Capital cost breakdown
Executive summary
The Wave Hub is an exciting opportunity to help ensure the UK continues to lead the development of Wave Energy. In simple terms, it consists of an offshore electrical “socket” connecting Wave Energy Converters (WECs) to the national grid. It will also provide a suitable offshore wave energy site fully monitored for the wave resource and with a simplified route to permitting and consenting.
The mission of Wave Hub is to:
• demonstrate the commercial viability of wave energy by supporting wave energy developers across the funding gap between the R&D stage and supported commercial development, complementing existing UK initiatives such as EMEC, NaREC and the Carbon Trust Marine Energy Challenge. A need for this facility has been established by the emerging wave energy industry to enable WEC developers to bridge the so called 'valley of death' between production prototypes and full commercial wave farms. • be an 'infrastructure plus' project for the South West supporting the emerging marine energy sector and make Cornwall and the South West of England the destination of choice for WEC developers to conduct commercial-scale developments. • build on the work already carried out by NaREC, EMEC, Carbon Trust and the DTI to establish the UK as the world leader in marine energy. Help to develop the emerging UK renewable energy sector, increasing GDP and creating a significant numbers of jobs. • contribute to the South West renewable energy targets in line with the South West Renewable Energy Strategy.
In doing so, there will be a variety of direct and indirect benefits to the region and the industry:
• The production of a significant amount of clean renewable energy in the South West region to help meet regional and national targets • Promotion of the South West region as a leader in the field of wave energy electricity generation • The creation of new jobs and skills in wave energy project development and operation • The creation of new industry and expansion of existing marine and engineering industries capable of manufacturing, deploying, maintaining, inspecting, repairing and decommissioning the potentially wide range of WEC types likely to be deployed • The enhancement of the academic capability and knowledge base in the South West and the provision of a resource in support of local education and training in renewable energy technologies • Provision for WEC developers to install demonstration size projects and plug the gap identified in a number of studies between test machines and large scale commercial projects comprising of arrays of WEC’s
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• Prove the wave energy concept to the satisfaction of potential project lenders to enable future financing of commercial projects
The project fits closely in with both the South West Regional Economic Strategy and the South West Renewable Energy Strategy – it will grow a new industry and develop areas of excellence.
SWRDA appointed Halcrow in June 2004 to assess the technical feasibility of this initiative and to:
• develop the Wave Hub concept in discussion with wave energy converter (WEC) developers & other stakeholders. • prepare a conceptual design and technical specification. • select a location. • prepare an outline assessment of impacts. • gather and analyse evidence to help assess its overall financial feasibility leading to submission to external partners for funding to develop the facility.
The study has included discussions with WEC developers to establish their views and requirements of such a facility. Common themes included:
• The South West is seen as the optimum area for device proving by nearly all developers. • The principal benefits are seen as reducing risk and programme constraints from permitting and consenting, and reducing up front capital costs. • A water depth of 50-60m would serve the majority of promising devices; an additional area at a depth of 25m would allow one further device to be attracted within the next 10 years. • Developers have varied requirements for support services, but telemetry infrastructure for metocean and WEC monitoring was a common theme.
This report focuses on the optimum infrastructure to enable uptake of Wave Hub facilities by WEC developers, however, what can be said from the developer response is that:
• there is a key need to provide additional deployment opportunities with significant grid connectivity. • the present, largely untested, UK offshore consenting regime presents a significant uncertainty and programme risk to developers. • the capital costs and risk of providing grid connection infrastructure is considered to be a significant obstacle to developers in deploying demonstration scale device arrays. While these do not in themselves prove the need for the Wave Hub, they do form an essential precursor for the economic study to complete the business case.
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The analysis of the market and potential “customers”, together with initial assessment of physical and technical constraints led to four principal Wave Hub options being assessed against a combined technical, financial, environmental, health & safety and functionality scoring matrix. The preferred option is to provide a single 33kV armoured sea bed cable to the WEC deployment area, where the following equipment (illustrated in Figure 5.3 on page 50) would be situated on the sea bed:
• Four way termination and distribution unit (TDU) - ie a cable splitter • 11/33kV power connection units (PCU) for each of the four cables to the TDU • Umbilical cables from the PCU for pick up and array connection • Independent remotely operable switchgear and electrical protection on each umbilical
The requirement for land-side infrastructure is modest, with only a 30 x 30m compound proposed, containing switchgear, monitoring equipment and control room together with storage for operation and maintenance hardware.
All the equipment proposed is known technology in current use elsewhere. The sub-sea equipment has been proven in the offshore oil and gas industry.
A coarse screening of the whole of the north coast of Cornwall confirmed Hayle as the optimum location for the landfall of the Wave Hub power cable. This is principally due to the coincidence of a grid connection immediately adjacent to a sandy shore, with a favourable wave climate and the avoidance of direct impact on nationally designated areas. However the location is also reinforced by a number of other factors which make it the preferred choice.
Available connections to the national grid at Hayle will, within certain power quality constraints, allow approximately 30MW input at 33kV and significantly more at 132kV. The scenario of likely initial developer uptake, when set against equipment costs has led to the recommendation that power should initially be exported from the Wave Hub to a 33kV grid connection with offshore equipment capacity up to 20MW. At such time as the 20MW limit looks set to be reached, the additional investment of £2-3m required to up-rate the offshore equipment to 30MW capacity can be assessed. The capacity of the cable is 30MW
The proposed WEC deployment area has been established by a GIS based constraints mapping process. Principal factors affecting the positioning are:
• Depth and bathymetry • The 12 nautical mile perimeter (marking the boundary of the UK territorial sea) • Ministry of Defence practice firing range • Shipping lane locations • Sea bed rock outcrops • Fishing activity
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The assessment of these factors, together with a notional model of possible WEC arrays has led to the recommendation of a 3000m x 1000m deployment area encompassed within a 4000m x 2000m Area To Be Avoided – effectively a shipping exclusion zone. This outer area is as shown on the appended plans 001 and 002. The National Grid References (NGR) of opposing corners are 138069E 059239N and 140513E 055493N (or in WGS 84: N50˙22’29” W05˙41’07” and N50˙20’31” W05˙38’54”)
An initial environmental assessment included an assessment of environmental receptors, designations and a consultation exercise. This has led to a scoping document for an Environmental Impact Assessment (EIA). The conclusion of this part of the study is that the overall environmental impact of the proposed scheme is likely to be beneficial. Clearly, environmental issues are of high importance and, as with all developments, there remains the potential for a number of adverse environmental impacts. The next phase of development is key to establishing the baseline and further detailed survey, consultation and assessment will be required as detailed in the EIA scoping study. Given the novel nature of the proposed development and the timescales involved, it will be necessary to take a precautionary approach, incorporating rigorous monitoring during and particularly after construction.
A cost/risk analysis has been undertaken for the development and construction costs. The outcome is summarised below:
Project Phase 95% probability of Mean probability 5% probability of being being exceeded exceeded
Development £1.25m £1.42m £1.60m
Construction £11.41m £12.42m £13.45m
Operating and maintenance cost has been assessed on an availability /reliability /maintenance plan (ARM) basis and has been estimated as £301k per annum. This has been input to the economic assessment by AD Little, where certain business costs have been added in accordance with the business model to make the total annual O&M costs £423k.
The ongoing implementation programme has been considered in respect of the technical, development, design, procurement, construction, environmental and other constraints and these are detailed within the report. The conclusion is that September 2006 is achievable for commencement of Wave Hub operation but that there are a number of key risks.
Achieving this target is dependent on several key factors which are outside the remit of this study. These are principally:
• The need to commit funds at risk in the development of the project in advance of confirmation of full project funding being available. The first element of this would be the commencement of environmental baseline studies as a matter of urgency early in 2005.
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• Co-operation of the consenting bodies DTI, DEFRA, Crown Estates and other partners in determining favourable SEA Demonstrator Status operating terms and in considering and issuing the necessary permits and licenses • Confirmation of funding availability and timing • The ability of the emerging wave industry to develop WEC’s to a suitable stage whereby they require the services of the Wave Hub in accordance with the proposed timeline
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1 Introduction
1.1 Project background The South West Region is committed to encouraging technologies for renewable energy generation that will contribute to long term regional economic improvements and to the Region's renewable energy target of 11% -to 15% of electricity production by 2010. The region has been identified as having considerable potential for offshore marine energy generation, because it has a good wave and tidal stream resource, is relatively accessible, has a reasonably strong local electrical network, and is subject to less extreme weather conditions than other parts of the UK.
A recent review1 commissioned by the South West Regional Development Agency (SWRDA) found that the north Cornwall coast has particularly high potential for the generation of electricity from offshore wave power. Many companies are currently developing technologies to extract this renewable energy. However, the financial capacity of many companies in this development phase is limited and SWRDA has identified the need for assistance during the demonstration stage to ensure that this industry crosses the so called “valley of death” between the development phase and full commercial deployment and reaches maturity. The South West Region is ideally placed to play a pivotal role in this.
The Wave Hub is an exciting opportunity to help ensure the UK continues to lead the development of Wave Energy. In simple terms, it consists of an offshore electrical “socket” connecting wave energy converters (WECs)2 to the national grid. It will also provide a suitable offshore wave energy site with a fully monitored wave climate and with a simplified route to permitting and consenting.
1 Seapower SW Review; Resources, constraints and development scenarios for wave and tidal stream power in the south west of England. SWRDA, Metoc, January 2004.
2 Wave Energy Converter (WEC) is a term for the offshore machine or device that is the primary converter of wave energy into electrical energy. Often generically referred to as 'device' or 'devices'. An array of WECs or a single large WEC when deployed and grid connected may be referred to as a 'project' or 'development'. Companies or individuals arranging this deployment may be 'WEC developers' or 'project developers', and are referred to generically in this report as 'Developers'.
WGEHUB1214R – Wave Hub Technical Feasibility Study – Final Report (Task 11) – January 2005 1
The mission of Wave Hub is to:
• demonstrate the commercial viability of wave energy by supporting WEC developers (Developers) cross the funding gap between the R&D stage and supported commercial development, complementing existing UK initiatives such as EMEC, NaREC and the Carbon Trust Marine Energy Challenge. A need for this facility has been established by the emerging industry to enable Developers to bridge the so called 'valley of death' between production prototypes and full commercial wave farms. It should be noted that Developers may be either device or project developers. • be an 'infrastructure plus' project for the South West supporting the emerging marine energy sector and make Cornwall and the South West of England the destination of choice for Developers to conduct commercial-scale developments. • build on the work already carried out by NaREC, EMEC, Carbon Trust and the DTI to establish the UK as the world leader in marine energy. Help to develop the emerging UK renewable energy sector, increasing GDP and creating a significant numbers of jobs. • contribute to the South West renewable energy targets in line with the South West Renewable Energy Strategy.
In doing so, there will be a variety of direct and indirect benefits to the region and the industry:
• The production of a significant amount of clean renewable energy in the South West region to help meet regional and national targets • Promotion of the South West region as a leader in the field of wave energy electricity generation • The creation of new jobs and skills in wave energy project development and operation • The creation of new industry and expansion of existing marine and engineering industries capable of manufacturing, deploying, maintaining, inspecting, repairing and decommissioning the potentially wide range of WEC’s likely to be deployed • Enhance academic capability and knowledge base in the South West and provide a resource in support of local education and training in renewable energy technologies • Allow Developers to install demonstration size projects and plug the gap identified in a number of studies between test machines and large scale commercial projects comprising of arrays of WEC’s
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• Prove the wave energy concept to the satisfaction of potential project lenders to enable future financing of commercial projects
The project fits closely in with both the South West Regional Economic Strategy and the South West Renewable Energy Strategy – it will grow a new industry and develop areas of excellence.
To develop this project that covers a wide range of specialisms, SWRDA have chosen to sub-divide the tasks between several specialist organisations. The present report covers the technical feasibility and infrastructure costs of the Wave Hub. Other studies are being conducted in parallel. The structure for the studies is shown in Figure 1.1. Relevant reports from all these studies will be published on the Wave Hub website www.wavehub.co.uk
South West Regional Development Agency
Clients Engineer Scott Wilson Oceans
Technical Feasibility Legal and Project Vehicle Study (TFS) Permitting Study Study (PVS) Halcrow Group (LPS) Arthur D Little Global Marine Systems Bond Pearce Abbot Risk Consulting
Figure 1.1 – Organisation chart for W ave Hub project studies
1.2 Project team Halcrow assembled a team to deliver the project from: Halcrow Group Limited, Global Marine Systems Limited and Abbott Risk Consulting Limited. The team also included wave energy expert Dr Tom Thorpe (Oxford Oceanics).
1.2.1 Halcrow Group Limited Halcrow is a leading, international engineering and environmental consultant operating in the fields of energy, environment, water, commercial development and transport. With over 4000 employees and a turnover in excess of £200 million, Halcrow is able to unite professional resources in the delivery of high level and state of the art advice, while maintaining the capability to deliver more traditional engineering services. Specific relevant capability and experience is
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offered by the coastal management and maritime departments who can provide off-shore engineering expertise, and by the environmental skill group who offer a full set of relevant environmental services.
1.2.2 Abbott Risk Consulting Limited Abbott Risk Consulting Ltd is an independent consultancy providing engineering and management services to the oil and gas, nuclear, defence, marine and transport industries. ARC is a multi-disciplinary consultancy, which combines the skills of safety and reliability specialists with the practical technical skills of hands-on engineers. ARC has extensive experience in the analysis and optimisation of sub- sea, marine and offshore engineering projects by means of structured risk assessment, reliability and availability modelling and maintenance optimisation techniques.
1.2.3 Global Marine Systems Limited Global Marine Systems Limited (Global Marine) is one of the world’s largest and most experienced submarine cable, planning, installation, and maintenance companies. Global Marine operates the world’s most advanced fleet of cable ships and sub-sea vehicles. The company operates in the telecommunications, oil and gas, offshore renewable energy, defence, and security markets.
Experience in grid connection for offshore renewables has recently included making the vital links for Blyth Offshore and Horns Rev wind farms, where more than 160 cable connections for the 80 turbines were made, up to 20km offshore. In addition to sub-sea cable installation and maintenance, a comprehensive range of associated services are provided including: route engineering (including survey), charting services, fishery liaison and shallow water services.
1.2.4 Specialists – Dr T Thorpe – Oxford Oceanics Dr Thorpe is a visiting lecturer at Cranfield University in offshore renewables and has provided technical and commercial advice to Developers and government organisations in relation to wave and tidal energy. He has provided key advice and support to the team during our implementation of the various studies and detailed assessment of WEC technology and energy output.
1.2.5 Parallel studies The whole team has worked together with the consultants for the parallel studies to ensure that information and outputs have been shared. The parallel consultants/studies are:
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Bond Pearce Legal & Permitting Study - reporting on the legal and consenting issues for the Wave Hub and WEC’s AD Little Project Vehicle Study - reporting on the business and economic impact analyses
1.3 W ave energy potential in the South W est of England When considering wave climate for the purpose of locating wave energy converters, the main parameters are considered to be:
• long term mean significant wave height, Hs (average height of the highest one third of waves). • mean annual wave energy. • periods of calm, to allow maintenance operations. • wave directional spectra. • extreme wave height.
Of the seas around Britain the Outer Hebrides and the west coast of Ireland experience the highest wave heights, with long term mean significant wave height, Hs of 3.0m. Considering only the English and Welsh coastline, south-west Wales and western Cornwall experience the highest waves, with long term mean Hs of 2.0 to 2.5m, whilst the English Channel and eastern English coastline are the most sheltered, with long term mean Hs of 1m or less3. The annual mean wave power off the Outer Hebrides, at the 50m depth contour, has been given as 41-45kW/m4, whilst the annual mean wave power at the proposed location of the SW Wave Hub at 50m is 21.8kW/m. This latter value is from the Met Office wave model, and shows a good correlation with the DTI data.
Although the seas around the west coast of Ireland and the Outer Hebrides provide the most energetic wave climate around the UK they also provide the most severe sea conditions; 50 year return period extreme maximum wave height,
H50max of 30m for the Outer Hebrides, compared to an H50max of 20m for western Cornwall5. The variance in the wave climate is due to the different meteorological conditions and fetch, but also to the different bathymetry, since there is deeper water, 100m plus, much closer to the shore of the Outer Hebrides than that of
3 JERICHO, 2000, UK Wave Climate Analysis web-site
4 DTI, Atlas of UK Marine Renewable Resources, 2004
5 Noble Denton, 1983, Extremes analysis prepared by the Dept of Meteorology and Oceanography, Noble Denton for UK Department of Energy
WGEHUB1214R – Wave Hub Technical Feasibility Study – Final Report (Task 11) – January 2005 5
western Cornwall where the typical offshore depth is 50m, with depths of greater than 100m only beyond the Isles of Scilly.
Figure 1.2 - UK annual mean wave power6.
In addition, the period of calm wave conditions - significant wave height Hs 1m or less - necessary to enable routine maintenance and inspection of some WEC’s, is much shorter for the west coast of Ireland and the Outer Hebrides than for western Cornwall since the Outer Hebrides are exposed to swell energy within an
6 DTI, Atlas of UK Marine Renewable Resources, 2004
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arc of exposure7 of approximately 1600, whilst western Cornwall has an arc of exposure of 550.
Therefore, for the purposes of demonstration of WEC’s, a site off the north coast of western Cornwall would provide an attractive location with a significant annual wave energy climate, and less exposure than sites off the west coast of Scotland, which are subject to more extreme wave conditions and fewer windows of calm weather.
1.4 W ave Hub concept and its development The concept of the Wave Hub project is to support and encourage Developers through the final demonstration stage of development, allowing them to install and operate arrays of WEC’s at full scale, and bring the related economic development benefits to the South West.
The Wave Hub will provide the infrastructure necessary for several different companies to install arrays of wave energy generators in a favourable environment. The Wave Hub would essentially comprise:
• an offshore connection point • a cable running to shore • a connection to the National Grid via a substation.
SWRDA would also set up a management company (project vehicle) to:
• facilitate the permitting process. • provide a management framework. • meter and certify performance where required. • provide ancillary services and support for industry.
The Wave Hub technical feasibility study (TFS) has primarily examined the issues of locating the Wave Hub, its engineering design, environmental assessment, energy analysis and life cycle costs, and its development, operation, maintenance and decommissioning. It has provided data for the preparation, by others, of an economic study and justification.8,9
7 IOS, 1984, Assessment of wave power available at key United Kingdom sites
8 SWRDA Wave Hub Project Vehicle Study. SWRDA, AD Little December 2004
9 SWRDA Wave Hub Wider Economic Impact Study. SWRDA, AD Little December 2004
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To be a success, the Wave Hub facility will need to be reliable, durable and functionally efficient. Above all it must be safe and serve the needs of those customers for whom it is intended, and it must do so in a way that does not damage the environment of the South West for which it is justly renowned.
1.5 M ethodology The study has been organised into eleven separate tasks. As many tasks were interdependent and overlapping in time, the numerical order of the tasks does not necessarily represent the order in which they were undertaken:
Task 1 Kick off meeting – This allowed the team to review, agree and define in detail the scope of the tasks, the deliverables and the schedule.
Task 2 Conceptual design – A review of the potential methods for providing the Wave Hub was carried out and each method was assessed on its strengths and weaknesses. This led to a list of options that were scored using a matrix approach to identify the most promising option to develop further. Four main options were identified for consideration, of which a sub-sea based option – the “wet hub” was the preferred, and a platform option was carried forward as a secondary solution.
Task 3 Definition of Developers’ requirements – This task was to ascertain the likely level of Developer interest and the key requirements for the Wave Hub in terms of functionality and timing. Developers were contacted in a two stage approach. A questionnaire was followed to direct and standardise responses. A final list of seven Developers replied to the second stage detailed questionnaire and although these were not necessarily all the potential primary customers of the Wave Hub, they were considered to give a reasonably good representative sample of the market. A final stage of this task was to carry out an independent informed analysis of the market and the status of the key Developers and their development programmes. Much of the outputs from this task are commercially confidential, but they feed into the subsequent parts of this study and into the Project Vehicle Study.
Task 4 Site identification – This task was subdivided into four parts: • A coarse screening of the whole north coast study area • A more detailed examination of the preferred site • A cable route study • An environmental impact scoping
The process involved collection of relevant constraints including: grid connectivity, wave climate, environmental designations and ecological constraints, coastal form for cable landfall, shipping, fishing activity and military exercise areas. The constraints were collated within a geographical information system and identified an area off St Ives Bay, just within the 12 nautical mile limit, as the optimum
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deployment area, with the landfall at Hayle for connection at Western Power Distribution’s Hayle sub-station.
Task 5 Outline design and technical specification – The objective of this task was to develop the design based on the preferred concept to sufficient detail to generate robust costing and to identify programme constraints for construction, installation and commissioning of the Wave Hub and associated infrastructure. The wet hub option was progressed and discussed with suppliers of the appropriate equipment. The design developed from a single offshore transformer to a series of 5MVA units in order to stay with currently used technology, allow modularity and reduce delivery time.
Task 6 Data collection and survey specification – The requirement of this task was to assess the available data and define and specify further detailed survey requirements to ensure the effective design, construction and operation of the Wave Hub facility. This has resulted in early commencement of a wave and tidal climate real time data collection exercise, and preparation of a detailed Environmental Impact Assessment (EIA) and physical survey proposal.
Task 7 Outline design budget costing –The outline design developed under task 5 was used as a basis to provide a more accurate cost estimate and a minimum time schedule for further development and construction. This output was prepared in conjunction with appropriate manufacturers and contractors and confirmed the wet hub as the preferred option.
Task 8 Operation and maintenance – The objective of this task was to propose how the Wave Hub would be managed post-construction. The report defines the equipment, resources and budget required to operate and maintain the facility over the lifetime of the project. A plan of the operational structure of the Wave Hub facility has been suggested and costed. A conventional availability/reliability/maintenance (ARM) approach has been taken to costing.
Task 9 Energy output – Connection to the distribution grid will enable the facility to receive revenue from the sale of the electricity generated. To enable the preparation of the business plan, an assessment of output has been made for each potential WEC based on the wave climate. A summary of the methodology has been included in chapter 7, however much of the information is commercially sensitive and cannot be published. The figures have been passed into the economic analysis by AD Little.
Task 10 Technical financial analysis – The output from this task was a collated cost plan and risk analysis for the project.
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Task 11 Final report and project programme - The final (this) report summarises the results of the work carried out in the above tasks and identifies the next steps.
A list of the reports associated with these tasks is attached as Appendix A. It should be noted that the reports arising from tasks 3 and 9 contain commercially sensitive information and they are therefore confidential.
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2 Wave energy Developers
2.1 Developer requirements The success of the project will be measured by its ability to attract Developers to use the Wave Hub when it is in operation. The level of demand represents a risk for the project. Therefore, a market assessment canvassing the opinions, needs and status of the developers was carried out at an early stage.
The input from Developers has been obtained in two phases. In Phase 1, initial contact was made with 29 Developers to obtain information on their overall development plans and to ask if they would be willing to provide more detailed information. In Phase 2, a shortlist of Developers was prepared based on the initial responses and a view of on those most likely to utilise the facility. A list of detailed questions was subsequently issued to the short listed Developers. Not all Developers replied due to time constraints and there will be the need to reassess some aspects of this analysis during the development phase in order to have a fully inclusive analysis. The two-stage approach was adopted to focus the effort of extracting detailed information on the most favourable and representative Developers. Due to the wide geographical spread of Developers, the main contact with them was by email with contact by phone to follow up. The outputs from these discussions are presented below in a form that does not compromise the confidentiality agreements made with the Developers.
2.1.1 Initial Developers responses From the 29 initial questionnaires sent out, detailed replies were received from 13 Developers, as shown in Table 2.1.
Company Device AquaEnergy Group Limited AquaBuOY Cleanpower Technology WaveBob Wave Energy Converter Embley Energy Sperboy Energetech OWC Evelop Wave Rotor Ocean Power Delivery (OPD) Pelamis ORECon (UK) MRC1000 OWEC (Ocean Wave Energy Company) OWEC Teamwork Technology Archimedes Wave Swing Wave Dragon Wave Dragon Wavegen Limpet Wave Plane International Wave Plane Wave Star Energy Wave Star Energy Table 2.1 - List of Developers contacted
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A summary of the responses is given below. Percentages are expressed relative to the thirteen responses received.
1) Based on the Project Overview is the location and wave resource attractive to you? Ten Developers (77%) confirmed that the location and wave resource are attractive for deployment of their devices with two (15%) of` Developers not sure. One Developer (7.5%) was not interested in the potential use of the Wave Hub.
2) Based on the Project Overview, would the W ave Hub in principle be of interest to you? Eleven Developers (85%) confirmed that in principle the Wave Hub would be of interest to them. One Developer (7.5%) was unsure and one Developer (7.5%) was not interested.
3) Are there any aspects which would be of particular assistance in the development of your device? No single aspect was identified by all the Developers. Common themes were ease of grid connection with possible financial incentives and ease of permitting would be seen as being of assistance.
4) W hat is the current status of your device? The status of the WECs has been classified as summarised in Table 2.2, based on information provided by the Developers.
Device Status Comments Full scale sea tests of prototype in Two WEC’s, Pelamis and Archimedes Wave progress Swing have full scale sea trials in progress. Ready for full scale prototype sea Four WEC’s are ready for full-scale sea trials tests of a prototype. Model testing in progress or Three WEC’s have been tested or are about to pending be tested at model scale. Concept design Four WEC’s are at the concept stage and are some way from potential sea trials. Table 2.2 - Device status
5) W hen do you anticipate the first commercial demonstration units will be deployed? Eight Developers (62%) anticipate that the first commercial demonstration units will be deployed in 2006. Two Developers (15%) anticipate that the first commercial demonstration units will be deployed in 2007/8. Two Developers (15%) are not able to give a date and one Developer (7.5%) is not interested in the Wave Hub.
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6) Are there any specific features which would be a key driver in making the W ave Hub attractive to you? No single specific feature was identified by all the Developers. Minimising cost of deployment, well-defined site including wave data, all environmental assessments carried out and the easing of permitting procedures are common features.
7) W ould you be willing to provide more information to assist in the development of the W ave Hub? All Developers with the exception of one confirmed that they would be willing to provide more information.
2.1.2 Developers’ detailed responses In drawing-up the Phase 2 questions, a balance was required between obtaining the maximum amount of information and ensuring that the Developers would be willing to devote time to providing answers. The majority of the questions were aimed at obtaining information that would aid in the concept design of the Wave Hub. AD Little also posed a financially based questionnaire at this stage. A total of seven companies replied to the questionnaire, see Table 2.3. The seven companies are not necessarily the most likely to deploy devices at the Wave Hub. They are those willing to respond to the questionnaire sent and they represent a reasonable cross section of the type of devices likely to be deployed. A summary of responses is presented in Table 2.4.
Company Device AquaEnergy Aqua Buoy Energetech OWC Embley Energy Sperboy Ocean Power Delivery (OPD) Pelamis ORECon MRC1000 Wave Dragon Wave Dragon Wave Plane International Wave Plane Table 2.3 - List of Developers responding to detailed questionnaire
A Location 1 Is your device designed for a specific wave resource, and if so, what are the details? A No clear consensus was established. Most of the devices can be designed to suit specific resource parameters. The minimum quoted wave climate is 20 kW/m and the resource in the proposed Wave Hub area is unlikely to be a limitation. 2 W hat is the designed survival wave height for the device? A Most of the devices are designed for 1 in 50 year or 1 in 100 year storm conditions. Two Developers have quoted maximum wave heights of 8.7m and 11m but have also stated that design can be adapted for more extreme sites. The 1 in 100-year wave at proposed Wave Hub site is likely to be greater than 11m but the devices can be designed to suit. 3 W hat is: a) the intended, and b) the minimum acceptable water depth for deployment of your device?
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A Minimum water depth quoted is 30 m, two devices are intended for shallow water. Five of the devices are intended for 50m to 80m water depth. 4 Does your device require any specific seabed conditions for deployment or operation e.g. prepared seabed for set-down, piling? A Most of the devices are anchored; one Developer has stated that a concrete version will require flat seabed. Rocky seabed or lack of sediment has been stated as possibly requiring additional work. 5 Are there any limitations in deployment location such as distance from shore? A The only limitation stated is length of cables due to high costs. Since cables are provided as part of Wave Hub this is not seen as an issue. There is an economic balance to be struck for the Developers between the devices being in a high-energy zone, which would mean far from shore, and the cost of cabling to deliver the electricity to land. 6 W ould a location in the South W est of England offer any advantages or disadvantages in terms of logistics for manufacture, deployment or operation? A Nearly all Developers rate the South West of England as an optimum area for device testing. All referred to the good wave climate in the region when compared to the sporadic conditions of northern Scottish waters. A number of Developers indicated that there was excellent potential for manufacturing facilities in the region and importantly a strong grid connection that has spare capacity. One Developer voiced concerns over manufacturing costs in the region. B Device Parameters 1 W hat is the generating capacity for each device? A Device output ranges from 200 kW to around 4 MW for an individual device in the proposed location. One Developer has stated a maximum size of 11 MW but this would be for a much higher wave energy location. Power output Number of Developers <500 kW 2 >500 kW <1 MW 1 >1 MW 4 2 W hat is the operating range of sea states? A Typical operating range is from 1m to 8m wave heights. 3 How many units might be in an array? A A wide range of answers was given. Typical numbers might be 10 to 20 devices, with smaller devices installed in larger numbers. Larger arrays are seen as more economic. One Developer has quoted 5 as a suitable number for testing but more are required for a commercial project. 4 W hat is the minimum spacing of units in an array bearing in mind the proposed anchoring techniques at the optimal operational water depth? A Minimum spacing for smaller devices is quoted as 30m. More typically for larger devices it is 200m to 600m 5 W hat is the generator type and characteristics? A Generators vary from induction to permanent magnet type. Some devices include power electronics. Details are somewhat limited at this stage. 6 W hat is the export voltage? The majority of devices would operate at 11kV. One Developer stated that a prototype device would be operated at 440V. 7 Do you have any information on power quality, W hat will be the quality of the export power? A Most of the devices use some form of power conditioning either electrical or in some cases hydraulic. There is little hard information on this at present. 8 W hat is the electrical isolation method? A For some devices this has not been defined. Others utilise standard electrical systems with contactors or circuit breakers (automated switchgear).
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9 W hat is the method of mooring or attachment to the seabed? A Some of the devices use a slack mooring system and some use CALM (catenary anchor leg moorings with gravity anchors). C Trials
1 How long a trial period would you anticipate and when would you expect it to take place? A One Developer has indicated only a short-term trial. Others have indicated a minimum of 1 year with a preference for longer periods of up to 10 years. Four Developers indicated a desire to deploy by 2006, the remainder were not specific. 2 During trials would you expect to sell power and do you have a mechanism in mind for such sales? A All Developers expressed a desire to sell power during the trials. Some Developers indicated that they would negotiate a power purchase agreement with a utility company. 3 W hat is the scale of your planned trials (i.e. number of devices and MW output)? A Number of devices varies from a single large unit to five or six smaller units. Power output varies from 1 MW up to 7.5MW. Several Developers indicated a number of phases to the trials. The first phase was defined as one device, followed by the deployment of several devices in a second phase and a full wave farm in the third phase. 4 W hat other sites are you considering for trials, if any? A A wide range of potential sites has been quoted from Europe to the USA. Portugal is quoted by four Developers as a potential rival site. 5 W ould you leave devices on station after the trial period? A All Developers would like to leave the devices on site if an economic case could be made. Other factors cited by one Developer include trial location, results and licensing. Some devices will be designed for a specific location and therefore it would not be sensible to relocate these devices to other wave climates. D Operation and M aintenance 1 W ould monitoring of sea conditions and other meteorological data be required? A All Developers have expressed a desire for monitoring of sea conditions and other meteorological data. 2 If it is intended for maintenance to be conducted on station, what are the sea state limitations for access to the device? A The majority of Developers have said that sea states less than a 2m wave height would be required to allow maintenance. 3 W hat size/type of vessel, special equipment, and operational support is needed for device maintenance (including, where appropriate, mooring inspection and periodic lift/replacement)? A Vessel requirements are variable. Some Developers only require a small work boat others have a requirement for a larger vessel such as an anchor handler. This area will require further discussion. 4 Is it the intention for the device to be towed into harbour for all/some maintenance? If so what are the requirements in terms of draught, quay space etc? A Responses are split between devices to be maintained on station and those that will be towed to harbour. Of those that are towed to harbour there does not seem to be requirements for deep water or other special facilities. 5 W ould a short shut down in periods of calm weather to allow connection/disconnection of other devices be acceptable? A This is acceptable to all Developers. 6 Can you indicate what level of facilities and service from the W ave Hub operator would be preferred or attractive to you? This could range from simple provision of a grid connection through to a comprehensive operation and maintenance facility. Also included could be permitting at other locations and support for future scale-up. A Answers are varied; permitting, wave data, O&M are seen as attractive services. The majority cite a ready-made grid connection of primary importance.
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E Financial 1 W hat is your preferred payment mechanism for using the W ave Hub? A Answers to this question vary with a split over whether payment should be by fixed rates or per kWh produced. Most suggest a payment per kWh produced with maybe a flat rate rental on the seabed. 2 From your initial understanding of the project how much would you be willing to pay for W ave Hub, (indicate ranges to suit service levels, if required)? A All Developers suggest a need to discuss this area further, with more time to calculate and agree terms. One Developer stated a figure of less than £10/MWh generated. 3 W e have further questions on your costs, revenues and sources of funding. These are important to justify the (anonymous and aggregated) figures that will be used for the W ave Hub business plan - an essential component when securing public funding for the project. To get a indicative idea of these figures can we: a) Ask the questions now? b) Sign a confidentiality agreement and have another brief conversation? A All Developers would prefer to sign the confidentiality agreement. Further development of the business plan based on these answers would be valuable.
F Economic 1 If you were involved with W ave Hub how many direct jobs would be created (per device/MW or overall)? A Answers to this question are split into the two stages of (i) development and (ii) operation & maintenance. Where answers vary depending on the size of the device, an approximate rule of thumb is (i) 1 job per 1MW of installed capacity during the development period and (ii) 1 sustainable job per 10MW plant for O&M. 2 W hat proportion of your costs would be spent in the South W est (to the nearest 20%)? A Responses range from 20% to 95%. Most however are in the higher end of the spectrum, around 80-90%.
Table 2.4 - List of questions and responses
2.2 Status of Developer readiness It is understood that there are areas of the responses from Developers which they may wish to present in a particular light for the benefit of their developing business plans. A critical review was undertaken with the assistance of Oxford Oceanics on the design and progress of the various WEC’s. This was reported in Task 9. The discussions and conclusions contained in this report are commercially confidential. The main results however, were that, of the devices surveyed, there is the potential for five Developers to be interested in connecting their devices to the Wave Hub before 2007. There are likely to be many more Developers looking to demonstrate their devices at the site from 2007 onwards.
2.3 Conclusions on Developer responses From the above it is possible to collate the various responses and extract a guide to design requirements for the Wave Hub. Whilst it is important to note at this point that not all Developers responded to the questionnaire, those that did have provided some consistent messages and some differing opinions, which are summarised below.
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2.3.1 Location It is apparent that most Developers have designed flexibility into their models. In terms of location, a survival wave height of a 1 in 100-year storm in the proposed Wave Hub region is acceptable. A depth of 50m is adequate for most WEC’s currently under development, although one Developer has recently increased their minimum depth to 60 m. Two devices are suited to shallower waters. A cable that is laid from the shore out to the wet hub at 50m depth will encounter all depths in between 0m and 50m. The possibility of a subsidiary wet hub at one of these depths can therefore be considered.
2.3.2 Device Parameters The number of WEC’s in an array can vary from 5 up to 20. Most Developers will require from 5MW to 10 MW capacity for grid connection. Array connection voltage is proposed to be 11kV, which many Developers have indeed cited. One Developer has proposed 440V as their export voltage, meaning that transformers will have to be incorporated. Most of the devices will use anchored moorings, suggesting that this should be a primary consideration. In those that cited a concrete base for installation, a flat seabed was seen as essential and is therefore a less flexible option.
2.3.3 Trials Most Developers have expressed a desire to deploy their devices by 2006/2007. As competition from other European locations is strong, it would seem essential to have it up and running by this date. Most Developers have also expressed a desire for their devices to remain on site post-trial.
2.3.4 Operation and Maintenance Monitoring of sea conditions and other meteorological conditions is seen as essential at this development phase of WEC’s. The availability of special equipment and/or operational support requires further discussion. Most devices would require some form of maintenance vessel. Whether it is a small workboat or an anchor handler is determined by the individual Developer’s needs. Specialist harbour facilities in the region are not considered an issue based on the Developers’ responses.
2.3.5 Financial The pricing strategy is an issue for the PVS report. However, while most Developers favour a rate per kWh generated, there will ideally need to be an element of flexibility to cater to the different stages and sizes of devices.
2.3.6 Conclusion The majority of developers see the South West and the Wave Hub as a potentially attractive prospect. Common themes of interest include good wave climate, provision of grid infrastructure, consents and permitting.
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3 Wave Hub design choices
3.1 W ave Hub design choices and stage one sifting The concept brainstorming session at the kick off meeting identified 14 concepts as potential Wave Hub design alternatives. These were split into four categories: sub-sea, shore based, platform and floating. A list of the design options under each category is shown in Table 3.1. Several options were discarded at the initial design stage for the reasons given in Table 3.1.
W ave Hub Type Concept Rejection reason/acceptance • Single cable / single cable route Accept Shore-based • Multiple cables / multiple routes Accept • Dry well to sea bed Technical complexity/cost Sub-sea Accept • Bathysphere (Fixed or lifted) • Wet hub (Fixed or lifted) Accept • Vessel conversion Accept • Piggy back on WEC Accept Floating • Purpose built structure Accept • Semi-submersible platform Greater hazard to shipping • Tension, fixed, monopile, gravity or Accept jacket structure • Converted oil platform Accept Fixed platform • Converted jack up barge Accept • Artificial island Water depth/cost/practicability • Wind turbine Water depth/cost/practicability Table 3.1 - List of options and reasons for stage one rejection
3.2 Stage two evaluation The comparative analysis of the remaining ten options as part of the second stage of the design selection methodology was completed in the first concept review meeting. A first draft of a basic functional specification was examined and updated. A review of progress to date on parallel studies was made as a part of the input to this first comparative evaluation matrix on the basis of fitness for purpose, safety and anticipated technical performance. A preliminary relative cost evaluation of options was also completed. The results of this evaluation are shown in Table 3.2 below.
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Wave Hub Technical Feasibility Study Task 2 Conceptual Design - First Concept evaluation Matrix - Fit for Purpose and Cost Evaluation Matrix V2 - Post first Concept Design meeting Scoring System Approved by TFS team - 27/07/2004 Each option is assumed to have the same functionality unless noted. Score each option by considering each parameter; 1 = low, 4 = high Each score to be multiplied by 3, 2, or 1 depending high/low weighting. Preliminary weightings agreed by the TFS team after assessment of key project requirements and risks.
Option 1A Option 1B Option 2A Option 2B Option 3A Option 3B Option 3C Option 4A Option 4B Option 4C Sub-options: On-shore Base On-shore Base Sea Bed Sea Bed Floating Device Floating Device Floating Device Fixed Device Fixed Device Fixed Device A Single Cable B Multi - Route (several cables) A Wet Hub (junction box), or B Bathysphere A Vessel Conversion B Purpose Built Structure C Piggy-back on Energy Device A Purpose-Built (incl. Tension / B Converted Oil Platform C Converted Jack-Up Platform Hubs Fixed / Monopile / Gravity) Parameter Weigh t Score & Notes Weighted Score & Notes Weighted Score & Notes Weighted Score & Notes Weighted Score & Notes Weighted Score & Notes Weighted Score & Notes Weighted Score & Notes Weighted Score & Notes Weighted Score & Notes Weighted Score Score Score Score Score Score Score Score Score Score Technical 11kV, No transformers, 11kV, No transformers Special design. Incl. Special design. Incl Refit vessel, but not so Similar to large buoy E.g. on a Wave Standard offshore complexity/novelty capacity limited at sea transformers in hub but transformers & well suited as 3B Dragon or other large technology no switchgear switchgear device 3 4 12 4 12 3 9 1 3 3 9 2 6 2 6 3 9 3 9 3 9 Safety Very little need for No planned Lift to maintain access maintenance 3 4 12 4 12 3 9 2 6 3 9 3 9 3 9 3 9 3 9 3 9 SWRDA Programme fit Most construction Assumes suitable vessel May be available May be available (early start) onshore available second-hand second-hand 1 4 4 4 4 4 4 2 2 3 3 2 2 2 2 2 2 3 3 3 3 Operability 2 1 2 3 6 3 6 4 8 4 8 4 8 3 6 4 8 4 8 4 8 Accessibility All equip on shore Weather windows/swell 1 3 3 3 3 2 2 1 1 3 3 3 3 3 3 3 3 3 3 3 3 Reliability Ring circuit possible 3 3 9 3 9 3 9 2 6 3 9 3 9 3 9 4 12 3 9 3 9 Maintainability Heavy lift needed 2 3 6 3 6 3 6 1 2 2 4 3 6 2 4 4 8 4 8 4 8 Local Assembly / local Specialist construction Possible local May be possible to No suitable base for employment in operation and servicing fabrication fabricate/part fabricate refurb? as a benefit locally 1 1 1 1 1 1 1 1 1 3 3 3 3 2 2 3 3 1 1 1 1 Water depth restriction None 2 4 8 4 8 4 8 4 8 4 8 4 8 3 6 4 8 4 8 4 8 Lifetime 25 years plus Depends on device 3 4 12 4 12 4 12 3 9 3 9 4 12 2 6 4 12 3 9 3 9 Restriction to navigation No restriction 2 4 8 4 8 4 8 4 8 3 6 3 6 3 6 3 6 3 6 3 6 Survivability – extreme Design to deflect/resist Anchor movement conditions/ ship impact/ nets fishing
2 3 6 3 6 3 6 2 4 2 4 2 4 2 4 2 4 2 4 2 4 Land take / sea take for More land take, less sea hub take 1 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 Support requirements (special skills & equipment) 3 4 12 4 12 3 9 1 3 2 6 2 6 2 6 3 9 3 9 3 9 Environmental impact 3 4 12 3 9 4 12 4 12 3 9 3 9 3 9 3 9 3 9 3 9 Ease of construction.
2 4 8 4 8 3 6 2 4 2 4 3 6 2 4 2 4 3 6 3 6 Flexibility in use and for Only good for 1or 2 Phased installation Build in space/capacity future changes to need developers or an interim possible for extra facilities solution 3 1 3 3 9 3 9 4 12 4 12 4 12 2 6 4 12 4 12 4 12 Decommissioning Remove cable only offshore 3 4 12 4 12 4 12 4 12 4 12 4 12 3 9 2 6 2 6 2 6 Aesthetics Not important on shore, not seen offshore
1 4 4 4 4 4 4 4 4 3 3 3 3 3 3 3 3 2 2 2 2 Relocation potential 1 1 1 1 1 1 1 2 2 4 4 4 4 2 2 2 2 3 3 3 3 Difficulty in getting all consents 3 3 9 3 9 3 9 3 9 3 9 2 6 3 9 1 3 1 3 1 3 Expandable/Modularity Assumes lots of space Assumes lots of space on board on board 2 1 2 3 6 3 6 3 6 4 8 4 8 2 4 4 8 4 8 4 8 Total Weighted Score 149 160 151 125 145 145 118 143 138 138
Cost Evaluation 3 2 3 2 4 3 4 1 2 2
Notes: Table 3.2 - Conceptual design scoring matrix 22 parameters above Cost Evaluation not included in analysis - first stage cost ranking based on the experience of the design team
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Analysis of the results from this exercise, using both the weighted score totals and consideration of the likely installed costs of the Wave Hub, identified four options for further study. These were:
• Option 1B: On-shore facility with multiple cables (which might be built in phases, thus including Option 1A as a first phase) - score 160, cost grade 2 (grade 1 - low fit/high cost to grade 4 - high fit/low cost) • Option 2A: Wet hub with underwater connection or secondary cables to be picked up by Developers, and transformer but no switchgear – score 151, cost grade 3 • Option 3B: Purpose-built floating platform - score 145, cost grade 3; a converted vessel to hold transformers and switchgear – score 145 also might be a tender option, cost grade 4 • Option 4A: Purpose-built fixed platform – score 143, cost grade 1; converted platforms may also be a tender option, cost grade 2
These design alternatives are clearly shown as frontrunners in the ‘Decision Frontier Diagram’ shown in Figure 3.1.
Decision Frontier Diagram
170 1b 160 2a 150 1a 3a 4a 3b 140 4b 4c e
r 130
o 2b c
S 120 3c 110 100 90 80 0 1 2 3 4 5
Cost
Figure 3.1 - Visual representation of scoring matrix for initial evaluation.
3.3 Developing the four preferred options and third stage evaluation A more detailed option appraisal was carried out on each of the four most promising concepts output from the stage 2 evaluations. This appraisal included assessment of functionality, safety, risk, cost, environmental impact, flexibility, and modularity. The options as they were envisaged at the time are outlined below and the final scores of the option appraisal are presented thereafter.
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3.3.1 Option 1 - Shore Based Facilities + Multiple Cables (Initially single cable) This option would consist of a shore based sub-station, containing switchgear and protection systems, linked to offshore hubs by a number of individual cables. Each cable would have shore based switchgear and protection. Power would be transmitted to the shore at 11 kV and a shore transformer would be required to link to the local grid. Power would be collected from the individual wave energy converters in groups at 11 kV using a system of cables and sub-sea plug and socket connections.
Figure 3.2 - Shore based Wave Hub facility with multiple cables
3.3.2 Option 2 - W et Hub + Underwater transformer and secondary cables This option would consist of a shore based sub-station, containing switchgear and protection systems, linked to the wet hub by a single cable. Power would be transmitted to the shore at 33 kV. The offshore end of the system would comprise a sub-sea 11 kV to 33 kV transformer, rated at 30 MVA. Power would be transmitted from the individual wave energy converters in groups at 11 kV.
Figure 3.3 - W ave Hub with underwater transformer
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3.3.3 Option 3 - Purpose built floating platform, buoy, or ship (includes vessel conversion if available, for example a converted lightship) This option would consist of a floating platform supporting a sub-station, containing switchgear and protection systems together with step-up transformers. Power would be transmitted to the shore at 33 kV using a single cable. A small grid connection sub-station would be required at the shore end of the cable. Power would be collected from the individual wave energy converters in groups at 11kV.
Figure 3.4 - Purpose built floating W ave Hub
3.3.4 Option 4 - Purpose built platform structure (second hand platform conversion if available and appropriate) This option would consist of a platform supported by a fixed structure. The initial concept design comprised a concrete gravity structure, a 15 metre square steel deck, and a housed sub-station (10 m x 12 m x 6 m) containing switchgear and protection systems together with step-up transformers. Power would be transmitted to the shore at 33 kV using a single cable. A small grid connection sub- station would be required at the shore end of the cable. Power would be transmitted from the individual wave energy converters in groups at 11kV using a system of cables and plug and socket connections.
Figure 3.5 - Purpose built concrete gravity structure
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3.3.5 Further option scoring Based on these descriptions, engineering capital cost estimates were developed, and a further evaluation scoring of the four options took place. The final assessment spreadsheet for this shortlist of four concept alternatives is shown in Table 3.3.
Wave Hub - Concept Sel ection Option 1 Option 2 Option 3 Option 4
Purpose built concrete gravity Shore Based Facilities + Wet Hub - Underwater Purpose built floating device, structure (possibly second Multiple Cables (Initially single transformer and secondary buoy, or ship (includes vessel hand platform conversion if cable) cables conversion if available) available)
No transformers or switchgear at Contains transformer but not Holds transformers and Holds transformers and offshore site switchgear switchgear. switchgear.
Comment Score Comment Score Comment Score Comment Score
Technical Fit to Functional Weighted score from Specification r eview 1: 160 151 145 143 Cost ranking from (1 high cost, first stage review 4 low cost) 2 3 3 or 4 1 or 2 Cost estimate from second review (£) 11,961,625 9,421,000 10,077,250 11,571,625 Second Detailed 1 High Cost / Low Score Review: Weighting: 4 Low Cost / High Score Fit to Functional 3 11kV = high 2 Offshore 3 Specially 4 Specially 4 Spec. losses / transformer, designed, designed, capacity onshore standard standard limitations switchgear technology technology Safety 2 Minimal 3 Minimal 2 1 1 offshore offshore operations maintenance Risk to project 2 3 3 Connection 1 3 and mooring difficulties. Cost 3 1 4 3 2 Environmental 1 Multiple cable 1 3 2 2 Impact routes - maximum disturbance Flexibility and 1 Add more 1 Splice in 3 3 Flexible, on- 3 M odularity cables at high second board capacity cost transformer at for services 30 m Total 23 37 30 31
08/09/2004 Approved by: JB/AWB/PS/AET Notes Weightings were agreed by the TFS team after review of the Functional Specification and assessment of key project requirements and risks. The costs shown are engineering and construction capital cost estimates extrapolated from the second stage review. Background data and assumptions are shown in the Task 2 - Conceptual Design report.
Table 3.3 - W ave Hub concept design scoring matrix
Following the assessment it was concluded that Option 2, a wet hub with underwater transformation and plug and socket connections, was the most suitable concept. The preliminary capital cost estimate of this option was also the lowest but costs varied by only £2.5 million between the four options and this was considered to be within the margin of error at this early stage of costing.
Option 2 a ‘wet hub’ was assessed to have the following advantages:
• relatively low capital cost • minimum equipment is installed offshore. The shore based sub-station uses standard equipment and is easily maintained
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• the sub-sea equipment is not exposed to storm damage • the system can easily be relocated • there is minimum visual impact • no additional support structures are required
3.4 Discarding of Options 1 and 3 It was decided on the basis of the third stage analysis above, to formally discard Options 1 and 3. Brief outlines of the key reasons for these decisions are given below:
• It was felt that Option 1, a shore based hub with multiple cables running out to WEC arrays, although familiar and robust technology, was likely to be prohibitively expensive, and lack functionality. In terms of installation costs the option will incur large cable laying vessel mobilisation costs each time a cable is required. Such an approach is also likely to have the largest adverse effect on the environment and fishing.
• Option 3, a purpose built floating platform housing an offshore dry hub, was perceived to carry the highest project risks.
The technology is conventional and the capital costs are relatively low, but the concept is neither sub-sea, nor super surface, and exists within the highest energy environment, on the sea surface. This leads to high project risks and major safety issues.
Poor seabed conditions resulting in reduced anchoring performance and the continual motion that would result from this approach would lead to fatigue and a high risk of damage on both the main and secondary power cables.
Maintaining and securing a free structure on the sea surface was a problem to be overcome by various Developers and the hub should take the form of a more secure base.
3.5 Concept development Clearly, in order to reach a stage where a final decision on concept could be made with sufficient confidence, further data and a greater understanding of the designs was required to accurately assess their relative strengths and weaknesses. Work therefore continued by investigating further both the wet hub and fixed platform concepts.
3.5.1 Development of Option 2 – A wet hub utilising underwater transformer technology Initially, the possibility of developing a single 30 MVA sub-sea transformer was considered and, while there do not appear to be any over-riding technical problems with this approach, there is considerable risk and development time associated
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with it. Submersible transformers up to 5 MVA capacity operating at 33 kV, have been used for several years in the offshore oil and gas industry. These have been designed to supply seabed mounted well head oil pumps that are remote from the host oil platform. Sealed for life submersible transformers can be considered as maintenance free for long periods of time - 10 years plus - and have been designed for a much greater immersion depths than that being envisaged here. The oil and gas industry has also prompted the development of sub-sea 33 kV plug and socket connectors and remotely operable sub-sea switchgear.
The developed concept includes a termination and distribution unit (TDU) on the sea bed. This provides a fixed termination unit for the main 33 kV cable from the shore, to which a number of short, flexible 33 kV cables spread out to transformer units.
Further study of the connection on-shore and the likely demand for connections in the near term has led to two further design decisions. The maximum short-term capacity required is expected to be no more than 20 MW and therefore the TDU will connect to four transformer units each of 5 MVA. This is considered to be sufficient to accommodate the largest single WECs likely to connect within the foreseeable future.
A connection to the 33 kV bus bars at Hayle sub-station is preferred on a cost basis. The exact capacity of this connection is subject to further study and it depends in part on the quality of the power produced. However, it should be possible to export 30 MW. The 33 kV sub-sea cable is a standard sized product that is rated for at least 30 MVA. The on-shore sub-station has been designed to allow space for upgrading the connection to 132 kV in future, potentially allowing significantly increased capacity, should more cabling and offshore plant be installed.
3.5.2 Development of Option 4 – A dry hub based on a purpose built platform As part of the Task 2 work, the various platform design options were considered and many found inappropriate. After preliminary analysis, the options with their key constraints are shown below in Table 3.4. Further information is to be found in the Conceptual Design (Task 2) report.
The platform appears to have the potential to be more functionally flexible than a sub-sea, or “wet” hub. However, it carries significant risk with it, including hazards associated with personnel working offshore. In practice, only very limited support to the WECs could be provided from an offshore platform and access by boat is problematic in all but the calmest of conditions.
The possibility of obtaining a second hand platform cannot be ruled out, and may be worth reviewing later. However, the likelihood of a suitable structure being
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available at the right time is low and cannot be relied upon; particularly within the programme constraints for the project.
Structure Key Concerns or Risks Purpose Built Monopile Only used in water depths up to 40m. Rocky ground unfavourable for piling Purpose Built Gravity Manufacture within suitable towing distance Structure Purpose Built Tension Poor holding conditions due to seabed geology Leg Rock anchoring at this depth is highly complex and raises safety concerns Purpose Built Steel Jacket Requires piled rock anchors at each leg to secure Structure the structure. Again this is a complex operation in difficult seabed conditions Purpose Built Semi- Anchoring issues due to poor seabed conditions submersible Platform Purpose Built Floating Anchoring issues due to poor seabed conditions Platform Jack-Up Barge Only suitable for water depths up to 40m Second Hand Platform Suitable platform is unlikely to be readily available. Likely to be sourced from the North Sea and therefore a very long floated tow over an extended tow period could prove costly Table 3.4 – Fixed Structures: Alternatives and their major risks
The selection of the preferred structural arrangement is based on economic, safety, environmental and construction considerations. The initial assessment revealed either a concrete gravity or a hybrid steel jacket structure as the most feasible alternatives (see Figure 3.6).
Both options have significant technical challenges and risks associated with them. The steel jacket structure is different to conventional offshore oil and gas platforms in that it has a relatively lightweight superstructure. This presents issues of uplift and horizontal sliding which must be overcome by either massive ballasting or piling. Piling in this location would in itself be somewhat difficult due to the combination of a rocky sea bed and the water depth. However it is thought to be possible to place bored piles by drilling from the positioned platform itself. It is possible that a steel platform could be fabricated in the region; however it may still be more cost effective to fabricate it in the North East of England or Scotland and transport it to the site on a barge. The overall weight of a suitable steel jacket structure has been estimated as 1300t, with total installed cost estimated as £7.7m.
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Delivery time would be approximately 18 months from order, depending on the commitments of suitable yards at the time.
A concrete gravity structure would not need to be piled, by merit of its much greater mass. This option is technically feasible, but more costly than the steel option. No suitable construction sites are available in the South West and while it may be possible to construct at Milford Haven, industry intelligence suggests that contractors would be more likely to choose from existing suitable fabrication sites in Scotland or the Netherlands.
The structure would then be towed to site, using its ballast tanks as floatation, and then sunk into position.
The delivery time is likely to be similar to a steel platform; however the cost is estimated to be in the region of £13m. The cost of a concrete platform is more difficult to estimate accurately, as it is more dependent on site factors.
For both platform options the transformer, switchgear and other offshore electrical plant would be less costly than the sub-sea wet hub equipment. However, even when this is taken into account, the lower cost (steel) platform still represents an additional cost of approximately £4.5m over the wet hub option. Potential marginal functional advantages do not justify this significantly greater cost. This, together with the longer delivery, mean that the platform option is significantly less attractive than the wet hub option and can therefore be rejected.
‘J’ tube
Mass concrete
Figure 3.6 – A Concrete Gravity Structure (left) and Steel Jacket Structure Secured with Concrete Gravity Ballast - NB piling would be an alternative to ballast (right)
3.6 Conclusions Fourteen potential concept designs were considered initially. Preliminary development and analysis reduced this to a short list of four, which were taken forward for more detailed consideration. Of these, two have shown considerable
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potential – a wet hub utilising developed sub-sea transformer technology, and a purpose built platform.
Both options are centred on the novel application of developed technologies. However, considering the requirements of Wave Hub, its users, its environmental impact, technical risks to the project, health and safety, functionality, performance and flexibility, the wet hub concept consistently scores well and appears to offer fewer project risks than the platform. Specifically, the study has shown:
• The use of sub-marine transformer technology is practicable and at the same time presents low risk to the project. • A structure would be a high risk development but nevertheless a feasible one. At higher cost it offers greater functionality and provides a good and reliable second design option.
The fixed platform was thought to score best in terms of pure functionality but suffers under most other criteria and is assessed to be significantly more costly. It was progressed as a fallback option in the event of technical development problems with the wet hub concept, completed in parallel with, but separate to, the main study progressing the wet hub concept. The concept of having an offshore operations and maintenance base, close to the WEC arrays, which this option appears to offer, is in fact illusory. Access to and from a platform in this offshore environment by boat is difficult and dangerous. A helipad adds further costs and complexities to the design through the requirement to consider services support, refuge for maintenance workers and escape equipment provision.
A wet hub (now defined as four 5 MVA sub-sea transformers in the first instance, connected to a termination unit on the main 33 kV cable) appears at this stage to offer a sensible mix of functionality and flexibility while utilising an innovative approach that could well be a benchmark for the industry. Manufacture and supply of the sub-sea equipment is expected to take between six and eight months therefore offering least risk of delay to the project programme.
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4 Site identification
4.1 Introduction This section of the report summarises two distinct phases in identifying a location for the Wave Hub:
• Screening for sites and the identification of a preferred site • Environmental scoping of this preferred site
It summarises the results of a range of study tasks. Detailed findings of each study are contained in the following task reports, which are also referenced at appropriate points in the text:
• Site Identification Report (Task 4) • Screening of potential sites (Report 4A) • Electrical Connection Feasibility Study (Report 4B) • Cable Route Study (Report 4C) • Environmental Scoping (Report 4D)
4.2 Screening of potential sites The location of the Wave Hub is a function of physical, technical, environmental and economic factors for different physical elements of the project.
• Onshore: Connection point to electricity network Landfall • Offshore: WEC deployment area Wave Hub offshore connection point • Cable route to shore
Building on the results of the Seapower SW Review10 of the South West Region, a ‘coarse screening’ process was used to select the most suitable site for the Wave Hub development on the North Cornwall coast. The screening process involved:
10 SWRDA, 2004, Seapower SW Review: Resources, Constraints and Development Scenarios for Wave and Tidal Stream Power in the South West of England
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a) Identifying geographically-differentiated factors (technical and environmental) that could constrain the location of the development b) Assigning significance ratings to each factor based on the extent to which the factor could be regarded as a constraint, using a green to red ‘traffic light’ scheme c) Overlaying all of the constraints geographically (using GIS) to identify the locations with the fewest constraints d) Assessment of the constraints operating at each location and identification of a preferred site for the Wave Hub and an indicative cable route
4.3 Site identification: onshore 4.3.1 Screening of potential sites The study area for the screening extended from Land’s End to Hartland Point in Devon, with one of the major constraints being identified as the presence of a suitable connection to the electricity grid.
4.3.2 Electrical connection studies Early discussions with the network operator for Devon and Cornwall, Western Power Distribution (WPD), identified nine potential connection points accessible from the North Cornwall/West Devon Coast that could possibly accept in excess of 15 MW of generation capacity. These are: Bude, Camborne, East Yelland (near Instow), Fraddon, Hayle, Indian Queens, Newquay Trevemper, Rame and Truro.
Of these Hayle and Newquay Trevemper were selected for further study on the basis that they were proximate to a suitable wave climate and accessible from the coast. WPD were commissioned to undertake a detailed technical assessment of these connection points, which is reported in the Electrical Connection Feasibility Study (Report 4B).
The WPD 132/33kV substation at Hayle was assessed by WPD as offering the best location point of connection to the mainland electrical system on technical grounds and ease of access to the shore. A more detailed discussion of electrical connection issues can be found in Chapter 5.
4.3.3 Landfall In a similar way, the coast between Land’s End and Hartland was screened for potential landfall points. Table 4.1 presents the constraints used during this process, and describes the significance assigned to each.
The results of the screening exercise show very few landfall points which are suitable for the development. However, potential landings sites are available in
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reasonable proximity (<5km) to both the Hayle and Newquay Trevemper electrical connection points.
4.3.4 The preferred site Determining the preferred site for the landfall and electrical connection of the Wave Hub is a function of a number of factors. The two most favourable sites of Hayle and Vugga Cove, near Newquay are compared in Table 4.3. It can be seen from this analysis that the Hayle site is the clear leader, although the Newquay site may well be an option for the future.
The key characteristics of Hayle as the most appropriate landfall for the cable, are:
• Proximity to a favourable wave climate and water depth for wave energy development • Proximity to a suitable electricity grid connection point, and • Availability of a route to shore which does not cross any nationally designated sites.
There are four potential landing sites close to the Hayle connection point that were considered in terms of technical, environmental and financial feasibility:
• Option 1: Hayle beach, on the eastern side of the Hayle estuary mouth • Option 2: Gwithian beach, towards the northern end of St Ives Bay • Option 3: Riviere Towans, between Hayle and Gwithian beaches • Option 4: Carbis Bay, on the western side of the estuary
Option 1 (Hayle beach) was selected as the Preferred Option as it is the clear favourite, on technical, financial and environmental grounds. The beach landing site is located on the east side of the estuary, and would be joined to the electricity connection substation by a bored and buried cable. It is proposed that the substation would be located within an existing industrial area on the site of the disused Hayle power station. The preliminary site layout is illustrated in drawing WGEHUB/004.
4.3.5 Access Offshore construction, operation and maintenance tasks will be serviced by a range of vessels, dependent on the task to be undertaken. Routine monitoring, maintenance and inspection is likely to be undertaken from a suitable workboat operating from either Hayle, Padstow or Penzance/Newlyn. The installation of sub-sea transformers and WEC arrays will require anchor handling tugs (AHT) or similar vessels, most likely to be chartered from ports on the east coast of England or the Netherlands. Construction and cable laying will be performed by specialist vessels that may be sourced specially from the UK or Europe for the task. Onshore access to the substation site will be by existing or reconstructed roads, as
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shown on Drawing WGEHUB/003. Following the construction period, vehicular access requirements will generally be limited to light vans or cars.
4.4 Site identification: offshore
The constraints used and the significance assigned to each are detailed in Table 4.2. The study is described in full in the Screening of Potential Sites (Report 4A).
4.4.1 The preferred site Such is the presence of constraints in the offshore area that there are only two potential areas for the Wave Hub: one close to Hayle, and one close to Newquay. These are illustrated in Figure 4.1. With the suitability of the connection point at Hayle, the preferred location is the area offshore of Hayle, see drawing WGEHUB/001. An area located in approximately 50m of water, outside the military exercise area and out of the direct commercial shipping channel was identified. The locations of both array field and cable route will need to be more accurately identified in consultation with fishermen and other marine users and with reference to detailed survey information to be gathered during the detailed design and survey stage.
4.4.2 Offshore deployment area The actual area of sea take for the proposed deployment area is shown in Drawing WGEHUB/002 (between 50˙22’29”N 05˙41’07”W and 50˙20’31”N 05˙38’54”W) and was specified after analysis of devices likely to deploy at this depth (50 to 60 m). It should be noted that devices will be contained within the ‘Safety Zone’ shown but that device anchoring may extend outside this area as long as it remains well within the ‘Area To Be Avoided (ATBA)’.
The deployment area is notionally subdivided into four sections each with a width of 750m facing the predominant wave direction (WSW) and 1 km length in the down wave direction. Each of these areas will be serviced by one of the four sub- sea 5 MVA transformers and this sets the maximum capacity of wave generation that each area can accommodate. The methodology used to develop the predicted deployment area has by necessity had to draw on a variety of sources, as design details of many of the WECs that may potentially be deployed at the site are still to be determined. Additionally, Developers have not generally developed array descriptions or full mooring plans at this stage in their development process. Therefore, the area described could be seen as a compromise between what is currently known about potential Wave Hub users’ requirements, and limiting the area of sea-take. The methodology adopted and assumptions made are described in more detail in the Site Identification (Task 4) Report.
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Constraint Reason for including Significance rating Network constraints Distance to nearest suitable network connection Proxy for cost and technical difficulties in laying the cable 0-1km - green from the shore to the connection point 1-5km - yellow 5-10km - orange >10km - red Environmental constraints International designations: World Heritage sites, Ramsar sites Development must not affect the integrity of these sites Red National designations: Special Areas for Conservation, Special Protection Development should not affect the integrity of these sites Orange Areas, Sites of Special Scientific Interest, National Parks, National Nature Reserves, Local Nature Reserves, Environmentally Sensitive Areas, Areas of Outstanding Natural Beauty, Heritage Coast Ancient Woodland, other reserves Identified as being of national importance Orange Geology: Geological Conservation Review sites, Regionally Important Identified as being of national importance Orange Geological Sites Heritage: Scheduled Ancient Monuments Development should not affect the integrity of these sites Orange Physical constraints Presence of cliffs Cable laying would be very difficult Red Presence of an estuary Dynamic environment not suitable for cable laying Red Presence of sand dunes Constraint to cable laying Orange Note: Red = unsuitable for development, Orange = subject to significant constraints, Yellow = subject to some constraints, Green = suitable for development
Table 4.1 - Constraints included in the onshore screening exercise
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Constraint Reason for including Significance rating
Physical and technical constraints 12 nautical mile limit Development and consents outside this limit would be significantly more complex, Outside 12nm limit – red additional risks from non-UK fishing vessel activity Depth Hub needs to be at approximately 50m depth for current Developer requirements >60 m red Presence of bare rock Cable cannot be buried therefore requires armour and is at risk of damage Orange Presence of sediment Cable can be buried, but type and depth of sediment is unknown and therefore Yellow may present a constraint Environmental constraints Marine Nature Reserves Development should not affect the integrity of these sites Orange Sensitive Marine Areas Identified as being of national importance Orange Wrecks Of heritage importance, areas of heavy fishing activity 0-100m buffer zone - red 100 - 500m - orange Spawning and nursery areas for important Important for maintaining fisheries, but will not necessarily be affected by the Yellow commercial species development Marine users In-service and out-of-service fibre optic cable routes Development not permitted - maintenance works for existing cables would pose a Cable route – red risk to other cables in close proximity 0 - 500m buffer zone – orange Cable faults Reported cable faults from existing sub-sea cables may indicate particularly severe 100m buffer zone – red seabed rock conditions. Shipping lanes Development would be difficult and potentially dangerous, shipping lanes would Orange need to be diverted Designated anchorage sites Development not permitted, anchors cause major damage to cables Red Ministry of Defence military exercise areas Consent unlikely to be granted if there is significant overlap with the area Red 0 - 1km buffer – orange Note: Red = unsuitable for development, Orange = subject to significant constraints, Yellow = subject to some constraints, Green = suitable for development.
Table 4.2 - Constraints included in the offshore screening exercise
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Factor Newquay Hayle Comments Proximity to favourable Range of average mean wave power 11 – 20 Range of average mean wave power 16 - 25 Within 20 km of the shore, the wave energy wave climate kW/m of wave crest kW/m of wave crest climate is significantly greater at Hayle than Newquay Proximity to required water Water depths of over 50m are available Water depths of over 50m are available Whilst similar distance to necessary water depth (>50m) within 20km of connection point. May need within 20km of connection point depth, the Newquay location is within to divert around Military Exercise Area or Military Exercise Area, and may therefore not accept shallower water (~40m) be acceptable Cable route does not cross Seabed conditions are generally coarse sand Coarse sand and broken shell within St.Ives More difficult seabed conditions will be designated sites or rocky and broken shell, with some bare rock bay, but cable route does cross areas of encountered at the Hayle site, but neither seabed towards the shore extensive rock route crosses designated areas Possible landing site Landing limited to southern edge of Crantock Four potential sites within St. Ives Bay, but a Landing on Hayle beach is preferable since it Beach and Vugga Cove. Areas of high clear preference for Hayle Beach, with short has a lower amenity value and is adjacent to amenity value and adjacent to SSSI drilled duct formal industrial area Distance to electrical Requires overhead or buried cable for 3 – 5 350m buried cable Hayle preferred due to shorter onshore connection point km (depending on routing) connection length Location of switchgear Either amongst village/hotel buildings in area In former power station site, adjacent to Preferred location of switchgear building is as building of high amenity value, or in open country existing transformer station close to landing site as possible, as network operator can use statutory powers to acquire wayleaves for onshore cable route. Hayle therefore provides a preferable solution Electrical connection Connection capacity varies with cost: 6.5MW Connection capacity varies with cost: 30MW All connection capacities are quoted at 0.95 capacity (£0.7M); 7.5MW (£1.2M); 21MW (2.2M); (£0.3M); 30+MW (£1.0M) power factor for comparison 30+ MW (£5.6M)
Table 4.3 Comparison of Hayle and Newquay sites
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4.4.3 W EC array sizes Deep water WECs are usually moored floating structures. The actual configuration of device arrays is a matter of conjecture since most Developers are only at the preliminary stage of deploying or testing a single device. Normally, Developers show arrays of WECs containing several rows of units facing into the oncoming waves. However, this type of array makes sense only if the device is not very efficient at capturing wave energy. A power density of 0.02 – 0.04 kW/m2 of sea bed is typical. From this it is assumed that a distance of 200–250m (front to back) for each row in an array will be sufficient.
If a WEC is relatively efficient, such as a wave concentrating device (e.g. an overtopping surface moored device), then the first row extracts so much energy from the incoming waves that there is little left for the next row to absorb. Since such WECs are usually large, relatively few will meet the capacity of the power export system. The area is considered large enough to easily accommodate the small number required of such devices.
Point absorber WECs (e.g. semi submerged structures and oscillating water column devices), generally have lower rated generation capacities and therefore may well require a greater number to be placed within the available area. These smaller WECs will have to populate the entire length of 1km provided using an offset arrangement in the prevailing wave direction. It should be noted that point absorber WECs have an effective width that is much greater than the device’s physical dimensions. In wavelengths up to 150m which this area may be expected to experience, the minimum separation of these units should be 75m. It is expected that up to 12 small point absorber WECs could be accommodated using two or more offset rows and the 1km down wave length available.
Identifying the correct size and shape of the optimal array sizes and therefore the exact requirements of a deployment area would require considerable information on the device characteristics and the local wave climate. However, it is believed that the area shown provides for most eventualities and requirements without excessive sea- take.
4.5 Cable route and risk study 4.5.1 Introduction This study, carried out by Global Marine Systems Ltd (GMSL), is contained in full in the Cable Route Study (Report 4C). The aim of the study was to assess potential constraints and influences on submarine cable routing and to make preliminary recommendations on cable routing, marine survey and installation routing, and techniques to feed into subsequent studies conducted as part of the TFS. The study also included a preliminary consideration of legal and permitting issues, marine survey
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requirements, marine installation considerations and cable composition, all of which fed into other parts of the overall feasibility work reported on elsewhere in this report.
4.5.2 Cable routing The study investigated routing to shore grid connection points at Hayle and Newquay, potential landing sites in St Ives Bay, and offshore factors that would influence the siting of the deployment area. The results provided a detailed assessment of potential cable routes and landfall points, the results of which were fed into the screening exercise.
4.5.3 Potential risks The north coast of Cornwall is a high-energy environment, which complicates submarine cable planning, installation and maintenance. However, it is noted that the telecommunications industry has operated submarine cable systems with success in this environment for a considerable period through careful risk management.
Offshore, fishing activity is historically the primary risk to a submarine cable. Whilst there is a potential for the cable in this area to be snagged during its design life, this is likely to be a very infrequent occurrence. The cable will be marked on navigational charts and would clearly be identified as a hazard to fishing gear and crews. Additionally, the cable will only be surface laid in areas of rocky seabed, which are unsuitable for bottom trawls. Inshore, St Ives Bay is one of the few areas on the north Cornish coast where anchor holding is known to be available, and vessels regularly shelter in the Bay from southerly winds in bad weather. Careful consideration therefore needs to be given to either final cable routing within the bay, or to the possibility of significant cable burial in this area.
The exposed high-energy environment off the north Cornish coast will result in engineering operations being constrained by seasonal operational weather windows and the distance to ports (Falmouth, Milford Haven) suitable for deep draft vessels.
A summary of the cable risk analysis, based on known constraints, is presented in Table 4.4.
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Inshore shipping route
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Risk Description M itigation Estimated Comments M easures Remaining Risk
Rock Abrasion Routing and Medium The lack of seabed sediment off the north Cornish coast is likely to result in the armouring export cable being surface laid over a rocky seabed. Strong currents and wave action are likely to be strong enough to rock a cable, causing progressive damage. Fishing Static potting, Routing, burial and High The lack of seabed sediment off the north Cornish coast is likely to result in the netting & bottom armour export cable being surface laid. It is recommended that cable armour be maximised trawling to act against interaction. Inshore, static pots (anchored) are likely to skid across a rock surface and be caught by the cable. Offshore, beam trawling may cause tangled gear and cable faults. Shipping Anchor Routing, burial and Medium Shipping interaction with the export cable is likely to be limited to anchoring within penetration armour north Cornish coast bays, due to their sediment depths. Vessels particularly shelter from southerly and south westerly winds. In these areas, burial will be imperative. Tele- Submarine cable Routing Low to medium The deployment zone lies inshore of commercial telecommunication routes. communications interaction However, the permitting should ensure that submarine cables are avoided. industry Groundswell Sudden reduction Tidal operational Medium Deep ocean swells arriving from the Atlantic are superimposed on tidally and wind in water depth & windows / induced shallow seas. Such conditions can beach craft in shallow water and can be unexpected heavy operational destructive in storm conditions. seas hazardous to awareness With regard to an installed cable, the effect of groundswell is propagated to the shipping seabed in shallow waters and may cause the cable to rock or strum on a rocky seafloor. Weather Downtime & Operational weather Medium Operational weather windows should be carefully selected because the area is open hazard to shipping windows to Atlantic weather fronts. It should be remembered that there are no major ports on & equipment the north Cornish coast.
Table 4.4 - Preliminary cable risk assessment matrix
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4.6 Environmental scoping study 4.6.1 Introduction The Environmental Scoping study (Report 4D) focussed on the preferred options (wet hub and Hayle site) and was conducted in parallel with the design tasks. The objectives of the study were to provide an overview of existing conditions and constraints; to identify and assess the key potential environmental impacts; to identify the need for additional baseline data collection; to summarise the concerns of statutory consultees and other stakeholders and demonstrate how they should be addressed; and to identify the scope for further studies and an Environmental Impact Assessment (EIA).
The results of the study were fed back into the Feasibility Study to ensure that environmental impacts were designed out or minimised, and will inform the scope of the detailed design and EIA. It is assumed, but not currently confirmed, that the development would proceed prior to the completion of a Strategic Environmental Assessment on the basis of its demonstrator function. Negotiations within Government are on-going at the time of this report.
The study involved the collection of baseline data (including an ecological survey at the onshore site and a desk study on contamination issues at the onshore site); consultation with relevant organisations; assessment of planning issues; and assessment of potential impacts based on the findings of the data collection and consultation. Requirements for mitigation measures and monitoring were also identified. The following environmental receptors were considered: nature conservation, fisheries, tourism and recreation, landscape and visual amenity, heritage and archaeology, land and sea use, traffic and transport, air, noise and climate, water, soil, geology, hydrogeology and geomorphology, coastal processes, waves and currents. Health and safety issues were also assessed as was the presence of potentially contaminated land on shore.
4.6.2 Existing environment (a) Onshore The Hayle substation site itself is of little ecological value, with low visual amenity, as it is located at former power station site within an industrial area. The adjacent Hayle estuary is of significant importance for nature conservation, particularly migrating birds, and is designated as a Site of Special Scientific Interest and an RSPB Nature Reserve.
The beaches of St Ives Bay are very popular for recreation and water sports, particularly surfing, and the dunes host a number of caravan parks and holiday cottages that cater for thousands of tourists. The overall landscape, however, is of high value, including wide sandy beaches, St Ives Bay, the Hayle estuary and the extensive and fragile sand dune systems to the north. The beach in front of the dunes is covered by two county-level designations: Area of Great Scientific Value, and Cornwall Nature Conservation Site. There are no sites of heritage or archaeological importance in or very close to the onshore study area.
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Both the substation site and the adjoining sand dunes have been in long term industrial use, and potentially contain contamination which requires further physical investigation. A procedure for assessing the extent and seriousness of this contamination is contained in the Data Requirements and Survey (Task 6) report.
(b) Offshore Offshore, the study area covered by the Environmental Scoping Report comprises an area radiating out from St Ives Bay to the 12 nautical mile limit. This area is clearly used by a variety of marine life, known to include cetaceans (whales, dolphins and porpoises), basking sharks, fish (the area supports spawning and nursery grounds for several important commercial species) and the communities inhabiting the rocky outcrops amongst the sediments of St Ives Bay. St Ives Bay and the Hayle estuary are designated as a Special Marine Area, in recognition of their national importance for marine and estuarine life.
The study area also supports a range of fisheries of importance to the local economy, including a shellfish industry that is the mainstay of the Hayle fleet, and the lucrative dover sole fishery exploited by trawlers in the outer parts of the study area from December to April. The area is also popular for recreational uses including sailing, diving and angling. In terms of landscape value, the sea is one of the few remaining ‘wild’ vistas in the country, and the coastline on either side of St Ives Bay is designated as both an Area of Outstanding Natural Beauty and Heritage Coast.
There are a large number of wrecks, some of which are designated as Protected Wrecks, within the study area. There are no known sites of archaeological or palaeontological importance in the nearshore, although this is considered to reflect the paucity of data, and it is possible that some sites of importance will exist. Parts of the study area are a designated Ministry of Defence military exercise area, and a major shipping lane crosses its outer edge. There are no known sites of contamination, and no licensed offshore dumping or aggregate extraction areas. The bathing waters of St Ives Bay consistently score excellent for water quality.
The seabed of the study area consists of an intermittent cover of recent ‘soft’ sediments overlying bedrock, such that exposure of rock at the seabed is likely to be frequent and unpredictable without physical survey. The sediment cover within St Ives Bay is more extensive, although currently available data are not sufficient to confidently show the depth or distribution of the material. The major coastal trend within St Ives Bay is one of accretion, with offshore wave activity being the major source of sediment. The beaches of St Ives Bay are considered to be generally stable, although the dunes in front of the power station are known to be eroding rapidly, possibly as a result of sand extraction both on the beach at the foot of the dunes, within the estuary and of the dune system itself.
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4.6.3 Planning issues The area lies within the remit of the Cornwall County Structure Plan and the Penwith District Plan. It is considered that the proposed development does not contradict any of the policies contained within these plans, however, both contain a number of policies of relevance to the scheme. It is considered that the proposal is unlikely to present particular problems in complying with these.
4.6.4 Offshore consents The principal pieces of legislation relating to development of the Wave Hub are as follows:
• Electricity Act 1989 (EA) – Section 36 For offshore generating stations within UK territorial waters adjacent to England and Wales out to the 12 nautical mile limit (and any Renewable Energy Zone designated by the UK Government outside territorial waters under the Energy Act 2004) • Food and Environment Protection Act 1985 (FEPA) – Section 5 For depositing articles or materials in the sea/tidal waters below mean high water springs (MWHS) around England and Wales • Coast Protection Act 1949 (CPA)– Section 34 Construction of works under or over the seashore lying below the level of MHWS
The consents required under these pieces of legislation are administered by the Marine Consents and Environment Unit (MCEU) on behalf of DEFRA and DTI. In addition, agreement will need to be gained from Crown Estates.
The full recommended approach to consenting and other legal requirements is set out in the Bond Pearce’s Legal and Permitting study.
4.6.5 Consultation A consultation leaflet was sent out to statutory and relevant non statutory organisations listed in Appendix B. A large number of replies were received, all of which expressed support, in principle, for renewable energy and for the proposed scheme. The most common issues of concern were: that the development should not affect the integrity of the designated areas or the Hayle estuary; potential impacts on cetaceans, basking sharks and other species of marine importance; potential impacts on fisheries, tourism & recreation, heritage & archaeology, landscape & visual amenity; disruption to shipping; health and safety issues; contamination at the Hayle site; and potential impacts on coastal processes and the wave climate and the knock on effects this could have on nature conservation, recreation, heritage and archaeology interests.
A useful conduit for dissemination of information and gathering feedback has been the Cornwall Sustainable Energy Partnership, which has facilitated regular local meetings of a marine renewables working group of stakeholders with an interest in wave energy.
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Special effort was made to consult with fishermen, with a consultation meeting held in Hayle, and a questionnaire sent out to a range of fishermen with the assistance of the Cornwall Sea Fisheries Committee and the Cornwall Fish Producers Organisation. The fishermen that came to the meeting and that sent responses were generally supportive of the scheme, provided that it would not impinge on their most valuable fishing grounds, and that the cable would not become an Exclusion Zone. However, the majority of respondents were based in Hayle, and further work will be required during detailed design to consult with a greater number (and range) of fishermen.
Preliminary consultations have also been made with the Maritime and Coastguard Agency and the Ministry of Defence.
4.6.6 Environmental impacts The baseline data collected were used to assess the potential impacts of the proposed scheme on all of the environmental receptors, both during construction and during operation. Because the project is only at the feasibility stage, potential impacts could only be identified in outline, and an initial assessment of their magnitude and the feasibility of avoiding or mitigating them made. Furthermore, given the novel nature of the proposed development, there remains a degree of uncertainty over some of the impacts. This is particularly true for the WEC devices themselves, many of which are still under design, development and prototyping. The issues and uncertainties identified at this stage will be investigated and developed further at the design stage, when a formal Environmental Statement will be prepared. Potential environmental impacts, recommended mitigation measures and residual impacts are described in full in the Environmental Scoping [Task 4D] report.
At this early stage, it is envisaged that the major residual impacts (impacts that remain after mitigation measures have been implemented) will be:
• Major benefit arising from the production of potentially 20 - 30 MW of electricity without the emission of greenhouse gases, contributing to the UK’s efforts to reduce the production of gases that contribute to climate change, together with promotion of the industry which could ultimately make far greater contributions • Potential benefit of fish stock recovery arising from reduced fishing pressure in the Area to be Avoided (ATBA) • Adverse impact on fishermen whose grounds are reduced as a result of the ATBA (which may be offset by the benefit described above) • Risk of accidental water pollution from the wet hub and arrays during operation (e.g. the risk of damage from collision or storms), and the impact that this would have on marine ecology in the area
When the unknown impacts can be quantified (with the results of monitoring and ongoing research), other residual impacts may be identified. These may include:
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• Impacts on cetaceans and other important marine species due to noise, vibration and the presence of physical barriers • Impacts on elasmobranchs elasmobranches (eg sharks, skates and rays) and potentially other marine species due to electromagnetic fields generated by the cable and plant • Impacts on seabirds at sea (potentially adverse or beneficial) • Potential benefit to fish populations and fisheries from the protection to spawning fish and juveniles afforded by the Area To Be Avoided, and the arrays themselves as fish aggregating points • Changes to coastal processes and/or the wave climate, which could have a range of ongoing impacts on terrestrial ecology, marine ecology, fisheries, recreational users, sites of heritage, archaeological, geological or palaeontological interest, and coastal defence (note that current indications are that these changes will be immeasurably small)
4.6.7 Recommendations A number of mitigation measures will be required both during construction and operation to avoid and/or minimise environmental impacts. Many of the major potential impacts can be avoided at the design stage through careful location of the WECs (in consultation with relevant stakeholders), and through careful planning and design of construction and equipment. Given the uncertainty over some of the impacts, ongoing monitoring will be particularly important, and is likely to be required as part of the consent. Other organisations, including COWRIE (Collaborative Offshore Wind Research Into Environment) and OWEN (Offshore Wind Energy Network) are undertaking and promoting relevant research, see http://www.owen.eru.rl.ac.uk , the results of which should also be incorporated into further studies. The Data and Survey Specification (Task 6) report contains recommendations for further assessment and on-going monitoring.
4.6.8 Conclusions An initial environmental assessment, including an assessment of environmental receptors, designations, and a consultation exercise have been undertaken. This has led to a scoping for an Environmental Impact Assessment. The conclusion of this part of the study is that the overall environmental impact of the proposed scheme is likely to be beneficial. Clearly, environmental issues are of high importance and, as with all developments, there remains the potential for a number of adverse environmental impacts. The next phase of development is key to establishing the baseline and further detailed survey, consultation and assessment will be required as described in the EIA scoping study. Given the novel nature of the proposed development and the timescales involved, it will be necessary to take a precautionary approach, incorporating a rigorous monitoring for impacts during and particularly after construction.
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5 Wave Hub technical specification
5.1 Introduction This section describes the outline design of the Wave Hub which forms the basis for cost estimates and economic analysis. The Functional Specification and Outline Design Specification form the Task 5 report.
5.2 Offshore equipment - wet hub 5.2.1 Design & development Two designs were investigated for the off-shore part of the Wave Hub, these being (1) an above wave platform and (2) an underwater assembly. Following assessment of costs and development times it was concluded that the off-shore part of the Wave Hub should be designed as a ‘wet hub’ meaning that the equipment to be provided will sit on the seabed and operate under approx 50 m of seawater.
The chosen concept of an underwater or wet hub has many advantages, however the initial concept of using a single, large capacity transformer has the disadvantage that the unit has not yet been commercially developed and would have to be a special design with consequent long development time and heightened risk. Current existing and proven equipment being used in the offshore oil and gas industry includes 11/33 kV – 5 MVA rated transformers and sealed for life switchgear for underwater installation.
A design for the wet hub based on a group of these smaller transformers therefore offers a safer and quicker development route. In conjunction with equipment manufacturers, a scheme has been developed based on these 5 MVA transformers.
The equipment presently being used in the offshore oil and gas industry utilises wet mateable plug and socket connectors for connecting the 33 kV and 11 kV interconnection cables underwater. However since the water depth at the hub’s proposed location is only around 50 m (rather than the >1000 m depth for which they were developed) it has been concluded that it will be possible to avoid the use of these expensive wet mateable connectors in favour of dry-made connections to the equipment, thus making a considerable cost saving.
5.2.2 Sea bed installation The general arrangement of the wet hub equipment is shown on drawing WGEHUB/002 (appended). The complete system is shown pictorially in Figure 5.3.
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5.2.3 Power connection units (PCU) Each WEC unit or interconnected array will be connected to a power connection unit comprising a 33/11 kV transformer built inside a protective clam or shell framework generally as indicated in Figure 5.1 below. Each of these four units will be equipped with two 11 kV cable tails of sufficient length to enable them to be raised to the surface in order to be splice connected to the WEC’s 11 kV umbilical cable.
Power 11kV Circuit Connection Unit Breaker
5MW Transformer Protective Structure
33kV Cable
11kV Cables
Figure 5.1 - Transformer / Power Connection Unit (PCU)
The transformer will be a 5 MVA rated, underwater unit having its primary 33 kV winding protected via a set of 3-phase, 33 kV rated fuse links. The secondary 11 kV winding of this transformer is protected by an 11 kV vacuum circuit breaker. This allows remote resettable protection and isolation of each umbilical.
The power connection unit is designed for ease of installation and retrieval from the surface via a floating crane. The electrical components of the power connection unit sit within a protective structure connected to a demountable base designed to locate the unit securely onto the sea bed in the location specified. The transformer can be removed from the protective structure and base and raised to the surface as a separate unit for repair or maintenance.
5.2.4 Termination and distribution unit (TDU) A group of four 5 MVA transformer power connection units, will be installed to give the required 20 MVA capacity. These units will be spread across the sea bed within the ATBA each connected back to the Termination and Distribution Unit as shown in Figure 5.2. This will make the transition between the 33 kV armoured, sub-sea cable running out from the shore to the underwater, semi- flexible 33 kV cables to the Power Connection Unit.
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Control Pod
Protective 33kV Structure Sub- sea
33 kV Flexible Cables
Figure 5.2 - Termination and Distribution Unit (TDU)
The main 33 kV underwater cable to the TDU will be dry connected at the surface before the unit is lowered to the sea bed. The unit itself will be delivered with the four flexible 33 kV cables already connected and packaged so that they can be dry connected to the PCU’s prior to their deployment.
5.3 Electrical connection from wet hub to shore The main power connection from the underwater wet hub to the shore will be made using standard, commercially available 3-core, lead sheathed, armoured, 33 kV rated sub-sea cable. Approximately 29 km of this cable will be required, laid from the off-shore location of the wet hub to the landfall at Hayle.
5.4 W et hub system expansion Although the offshore connection equipment is designed initially to handle 20 MW total capacity, it is possible that this could be increased to 30 MW if required in the future by the addition of two further power connection transformer units, however this would depend upon either the development of a six-way termination and distribution unit or the ability to connect a second termination and distribution unit in parallel with the original unit.
The capacity of the WPD distribution network is presently limited to approximately 20 MW at 33 kV. However connecting at 132 kV, requiring a new shore based 33/132 kV transformer, would significantly increase this. The sub-sea 33 kV cable and all other on-shore sub-station equipment will have a nominal rating of at least 30 MW and will therefore require no further additional works. The total cost of upgrading from 20 to 30 MW would be in the range of £2-3m. There is little saving to be made by incorporating this additional capacity now.
Future upgrading to develop a power capacity in excess of 30 MW would require the installation of a second 33 kV sub-sea cable.
5.5 Onshore equipment 5.5.1 Choice of Connection Voltage: The Hayle bay area contains points of connection to the UK bulk electrical transmission and distribution system at both 132 kV and 33 kV via the old Hayle power station substation owned and operated by Western Power Distribution.
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There are certain limitations of use for both these voltage systems, regarding the magnitude of power, power factor and harmonic content that could be imported to the grid from the off-shore wave energy converters. However it is possible to note that a practical maximum of approximately 30 MW capacity would be possible at 33 kV. A capacity in excess of 30 MW would only be possible at 132kV.
The variance of power factor against generated power and the harmonic content of the generated energy depends on particular device operational factors which cannot be confidently determined at this stage.
Considering all the factors of demand forecast and probable operational lifetime, against relative costs of the 132 kV rated equipment being significantly greater than the costs of 33 kV rated equipment, it was concluded that an initial 33 kV connection option provides the best compromise between performance characteristics and overall costs for the predicted level of generation. The limit of power export at this stage is therefore limited to 20MW by the wet hub equipment. There may be a need to review this during the development stage, but 20 MW is considered a good working assumption given the information that has been gathered to date.
5.5.2 Onshore substation A new wave hub substation will be constructed on an area of land adjacent to the existing Hayle substation as indicated on drawing WGEHUB/004. The exact location will be determined following discussions with the landowner.
The compound area shown will be sufficient to house a 33 kV rated substation building, the incoming and outgoing 33 kV cable circuits and future possible expansion to a 132 kV substation if required.
The wave hub 33 kV substation will consist of a single storey building comprising three rooms, a workshop or garage, a 33 kV switch-room and a control room. The building will be set in a fenced compound with sufficient maintenance vehicle access and parking and an access route to the public highway.
The workshop/garage will be used for carrying out maintenance of equipment and the storage of an underwater remote operated vehicle.
The switch room will contain the 33 kV metering and synchronising circuit breakers together with the 33 kV underground cables connecting the wave hub to the 33 kV bulk electricity system of Western Power Distribution and the off-shore wave energy converters. The 33 kV circuit breakers provide the point of demarcation between the different systems.
The control room will contain the SCADA and communications equipment for control of the wet hub via local and remote controls. The communications system will connect to the WEC’s via the fibre optic cables integral to the power cables, for monitoring and recording operational parameters.
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The control room will also contain the power metering, electrical protection and fibre optic telemetry and control interface equipment.
5.5.3 Onshore cabling The route between the substation and the wet hub runs directly across the sand dunes. In order to protect the dunes and minimise disturbance of the ground, which may contain contaminated materials, a cable route will be constructed by directional drilling of a duct under the dunes, to emerge on the beach at or near the connection point.
A single circuit of 33 kV three-core cable will run from the synchronising circuit breaker in the substation, through this duct to the beach to meet the 33 kV armoured marine cable where it comes ashore. A high voltage joint shall be made to connect the two cables together and bury them well below beach level for protection.
5.6 Specification for Developers Statutory legislation imposed by regulators of the electricity generation and distribution system in the U.K. will impose certain criteria governing the provision and operation of a connection agreement between the Wave Hub Management Company (WHMC) and the electrical utility company. As a result it will be necessary for the WHMC to impose the same legislation on the Developers in the form of a back-to-back agreement.
Additionally it will be necessary for the WHMC to clearly stipulate certain connection parameters such as connection voltage, magnitude of power generation, power factor and harmonic limitations and electrical protections etc., together with an operational and control procedure.
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Wave Energy Converter Arrays
Utility Company Substatio n 33kV Bus-bar Connection Gen Gen Point Gen Gen
Cable Support Buoys 11kV Wave Energy Device Cables
11kV Cable Splices
Shore Wet Hub based
equipment Wave Hub 11kV Wave Energy Substation Device Connection Cables
33kV Circuit Breakers Communications Workshop and Control
11kV Wave Energy Device Connection Cables 33/11kV Power Connection Unit
33/11kV Power 1 x 3-core 33kV Connection Unit Underground Cable
33kV Sub-Sea Cable Cable Duct Directionally Drilled Through Sand Dunes 33kV Cable Joint 33kV PCU Connection Cables
WAVE HUB EQUIPMENT Termination & Distribution Unit Wave Hub System Diagram Figure 5.3 Figure 5.3 – Pictorial system diagram
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6 Operation and maintenance
6.1 Organisation and responsibilities The staffing requirements for the management of Wave Hub are in part driven by business requirements and these are discussed in the AD Little Project Vehicle Study Report.
This combination of business and technical/operational functions suggests an organisation structure illustrated in Figure 6.1. As stated in the AD Little report, it is considered that the Managing Director will be very much an “outward” facing role, involved in the marketing, etc of Wave Hub. The report suggests that the Technical Director carries the tasks of “day to day” operation of the facility and maintenance of the Wave Hub systems and equipments.
Wave Hub Board
Managing Administration Director Support
Technical Director
Contracted Services Contracted Services
High Voltage O&M Contracted Services Buoy Maintenance On- call support
Contracted Services Contracted Services Marine Services QHSE
Figure 6.1 – W ave Hub M anagement Structure
As the Wave Hub system is similar in general terms to that of the European Marine Energy Centre (EMEC) on Orkney, it is worthwhile examining EMEC’s management structure. EMEC’s original concept was to have just a single Centre Manager with the support provided by service contracts. This included “day to
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day” tasks such as system and environmental data monitoring/logging, response to indications and alarms. However, it was found that the Centre Manager’s focus was on marketing and building a potential client base rather than managing the operational and maintenance tasks involved in the Centre. It was further considered that these tasks would not necessarily reduce when the Centre was fully operational. Hence, an Operations Manager was appointed. It would appear that this post, supported by the contracted services, is now considered sufficient for the roles and tasks required by the EMEC model.
In terms of Wave Hub operation and maintenance requirements, the tasks foreseen for the Technical Director post is set out in Table 6.1. These take into account the Wave Hub system components as postulated in relevant sections of this report, and the operational tasks envisaged.
6.2 Operating requirements Physical plant for the Wave Hub is intended to be relatively autonomous. However, system performance and condition monitoring will still be required including response to system alarms. Data logging (and backing up) of system and Developers’ device information will, to an extent, be automatic but a degree of intervention will inevitably be required. In order to conduct the operational tasks identified, external resource requirements will need to be met by service contracts as stated above.
An aspect of operations which presents a degree of risk is the requirements that may be considered necessary as a result of the navigational risk assessment. Unlike windfarms, there is, as yet, no precedent in the extent and type of controls which may be required other than EMEC, which differs significantly in scale and nature in this respect. Guidance exists in the Maritime and Coastguard Agency (MCA) Marine Notice MGN 275 on the full spectrum of controls which may be deemed as necessary. These include 24hr/7 days radar/AIS/VHF coverage and monitoring which would have to be undertaken as part of Wave Hub’s operational responsibilities. While guidance from regional MCA officers suggest that close monitoring should not be necessary; until these controls can be finally agreed with the MCA, this represents a risk in operational cost terms as well as in capital outlay.
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M ain Task Subsidiary Tasks Contractor Define contractor service level agreements Management Develop tender processes Review tenders for technical compliance Ensure contractor competence (training, qualifications and suitability (including quality, safety and environmental systems)) Review contractor performance during and after contractor activity Maintenance Review Wave Hub equipment maintenance requirements Planning Develop Wave Hub Maintenance Plan Develop maintenance schedules Allocate/contract resource for maintenance Maintenance Conduct minor maintenance e.g. Conduct • Waverider buoy maintenance • ROV Maintenance • ROV Inspections and cleaning operations • Minor repair / replacement of shore-side equipment Developer Review Developers’ requirements and interfaces with Wave Hub Management Review Developers’ procedures such that activities are conducted safely and without risk to others or Wave Hub equipment Provide point of contact with Developers QHSE Tasks Conduct periodic walk-round inspections of Wave Hub offices/infrastructure to ensure workplace safety Plan QHSE audits Review EMS system performance / documentation periodically Operational tasks Monitor Wave Hub equipment using SCADA Monitor Developers’ WEC data output Conduct data logging and archiving Manage Developers’ requirements such that risks arising from conflicts with other Developers/Wave Hub tasks/activities are tolerable. E.g. mooring, switching/connection of WECs. Ensure appropriate resources are provided for Developers tasks which interface with Wave Hub equipments e.g. HV qualified personnel. Emergency tasks Respond to Wave Hub system (and other) alarms and initiate appropriate response in accordance with Emergency Response Procedures e.g. Waverider off-station, navigation marker unlit, collision between vessel and WEC.
Table 6.1 – Operational and maintenance task descriptions
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6.3 M aintenance requirements 6.3.1 Maintenance strategy One of the factors in the choice of the sub-sea option for Wave Hub was the maintainability in the marine environment. The sub-sea option reduces the exposure of the Wave Hub components to the dynamic surface conditions. However, placing the equipments sub-sea means that, in order to meet the system availability requirements, the equipment reliability requirements are, to an extent, higher than for surface equipments.
However, any intervention, whether sub-sea or surface, is limited by the ability to conduct work in the prevailing conditions. For example, the difficulties in conducting transformer repair or replacement sub-sea or on the surface would be equally reliant on suitable specialist vessel availability, weather and sea-state. Additionally, the ability to provide a replacement or repair is dominated by replacement equipment availability times. These have been indicated by the supplier as being in the order of 4 to 6 months for the Power Connection Units (PCU).
The PCUs employ equipment that has been developed for use in the offshore oil and gas industry and incorporate technology designed to withstand extreme depths and pressures where high reliability is a top priority in order to maintain production. Due to their operational environment, these units are designed to be, essentially, maintenance free. The associated equipment (cables, circuit breakers and SCADA) does not employ novel technology and there is an overall low level of complexity. It is considered that routine maintenance will mainly consist of sub- sea inspection and cleaning of the transformer cooling surfaces. However, the modelling undertaken for the Operations and Maintenance (task 8) report indicates that the potential failure rate of the transformers in the PCU, based on current industry figures, is a dominant risk and that such failures may occur once in the 20 year life for each transformer. However it must be stressed that the data used in determining Mean Time Between Failures (MTBF) has not been drawn from such sub-sea transformers (as there is little data) and, therefore, may be overly pessimistic. The costing does, however, reflect this (possibly) pessimistic data. It is strongly recommended that, as this technology matures and data becomes available, consideration should be given to reviewing the maintenance strategy in order that the assumptions made on the repair by replacement approach vice preventive maintenance regimes remain valid. The Operation and Maintenance [Task 8] report expands on risk assessment in detail.
It is expected that the maintenance of the navigation buoys will be conducted under a maintenance contract with, for example, Trinity House or the Ministry of Defence Mooring and Salvage Organisation. It is probable that there will be a requirement for a total of four Class 2, 3 metre, steel buoys as cardinal marks 500 - 1000 yards to the north, east, south and west respectively and 4 “special” marks
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delineating the corners of the actual WEC mooring area. These buoys will require an annual check which will involve the buoy and chain cable, plus mooring arrangement, being hoisted on deck and cleaned and inspected. Components worn beyond specified allowance will be replaced. Every 5 years the buoys will be required to be taken ashore for full refurbishment.
The shore based components of the Wave Hub HV equipment i.e. the substation circuit breakers and power conditioning equipment, will be maintained under contract by Western Power Distribution.
6.3.2 Maintenance facilities and equipment It has been established that Hayle harbour should be able to provide a support base for activities involving workboat type vessel e.g. Remotely Operated Vehicle (ROV) inspections, Waverider buoy changes/maintenance/ environmental monitor maintenance. It has good access by road and adequate quay space with areas where mobile cranes capable of conducting lifts up to approximately 16 tonnes can operate. Vessels with a draught up to the 3 m maximum allowable are limited by tidal conditions to entry/exit 3 hours either side of high water, however it is not considered that this impacts in any significant way on the support requirements.
It is envisaged that storage and maintenance space will be required for the ROV and its ancillary equipment. This will be provided at the Wave Hub substation compound. Power for heating, lighting and tools will therefore need to be provided.
6.3.3 Vessel and ROV requirements Certain tasks, such as the lifting from the seabed of the sub-sea components, will require a vessel capable of re-locating and lifting items up to, approximately, 20 tonnes. Such vessels may range up to Anchor Handling Tugs/Supply (AHTS) vessels which are equipped with Differential Global Positioning Systems (DGPS) and Dynamic Position (DP) systems giving them the required capability. As the requirement for seabed equipment lifts is expected to be low, it is therefore, expected that such vessel requirements would be met from the charter spot market.
It has been determined that a requirement exists for a vessel to undertake operation and maintenance tasks associated with Wave Hub which, whilst not requiring the full capability of an offshore Anchor Handling Tug/Supply vessel e.g. lift capacity, nevertheless requires the ability to operate offshore within the deployment zone. Tasks would include ROV operations (e.g. conducting sub-sea equipment inspection, cable retrieval and transformer cleans). Such a vessel could be either bought or chartered on an as required basis.
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The capital cost of such a vessel could range from £250k (for a vessel with limited capability) to up to £650k Operating costs would be extra (i.e. crew, inspection/ certification, bunkering, maintenance, berth). Despite being able to offset the capital costs by chartering such a vessel to the Developers, it is expected that, for the utilisation envisaged, the charter option provides greater financial benefit, and this has formed the basis for the annual O&M costing in chapter 8.
The major item of work equipment required for the identified Wave Hub tasks is a Remotely Operated Vehicle (ROV) equipped with a camera for inspection tasks and a manipulator capable of conducting cleaning operations and, if required, operating wet mate-able 11kV connectors. A market review has indicated that the capital costs of such an ROV, capable of operating from a small workboat vessel, would be in the order of £78k depending on the requirements for manipulator capability.
6.4 Training Appropriate training will be required for both Wave Hub staff and any external service support personnel. This will include Wave Hub equipment and system training; operational and emergency response procedures training; ROV operations and maintenance. Wave Hub and contracted personnel will require training on the Quality, Health, Safety and Environmental (QHSE) management systems, particularly with regard to the quality standard requirements for measurement of Developers’ device outputs and environmental data and calibration of the equipments used to conduct the measurements.
6.5 Quality, health, safety and environmental management Wave Hub will be expected to conduct its operations to applicable health, safety and environmental regulatory standards and at least as good as industry standards for similar marine activities e.g. wind farms and fish farms. Wave Hub will, therefore, be expected to demonstrate that its management of Health, Safety and the environment, meet those standards. This can be achieved through the establishment of health, safety and environmental management systems which meet specified standards i.e. OHSAS 18001 (Specification for Occupational Health and Safety Management Systems) and BS EN ISO 14001: Environmental Management Systems Specification.
In addition, if the intention of Wave Hub is to provide Developers with industry recognised measurements of output, Wave Hub will have to have a suitable, certificated quality management processes in place to demonstrate that its measurement services (whether internally performed or externally provided) are within known tolerances and comply with, for example, the quality requirements of BS EN ISO 17025:2000 (General Requirements for the Competence of Testing and Calibration Laboratories).
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The management system requirements for all three standards can be established under a single integrated management system which simplifies the system and reduces duplication and costs. This is discussed further in the Task 8 reports.
6.6 Community liaison The operation and maintenance requirements for Wave Hub will place demands on local services. It is envisaged that the following services may be met in the immediate vicinity of Hayle:
• marine support craft capable of ROV/Diving operations • HV Electrical operations and maintenance • QHSE Support • on-call support personnel
In addition, there will be service demands generated by the presence of Developers’ devices. These will mainly be for marine support for maintenance and monitoring activities, but could include fabrication and other services. These wider services that WEC device and project developers may require are being actively considered by SWRDA for special attention. They are, in part, the focus of the Wider Economic Impact Study conducted by AD Little.
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7 Power generation potential
7.1 Introduction The energy output of different WECs was estimated. The estimates were used in the ADL financial model and in considering the connection to the onshore electricity network.
Each WEC will have its own characteristics which will interact with the wave climate to produce different outputs. The estimate of energy output has considered the most likely scenario in terms of mix of devices and likely sizes of arrays.
The predicted gross output has then been modified to take into account aspects such as transmission losses and the effect of availability.
In order to determine the likely levels of generation, an assessment of the potential of each of the devices has been made, based on their particular characteristics and the wave climate at the Wave Hub location. The findings of this assessment are contained within the Energy Output from Wave Power Devices [Task 9] report and have been fed into the economic assessment, as a precursor to determining the revenue generation capacity, but are commercially confidential and cannot be reported here. However the methodology is briefly described below.
7.2 M ethodology The methodology used in this study for the WECs where there was adequate published data is outlined in Figure 7.1. It is based on a methodology derived to assess devices as part of the UK’s wave energy programme (Thorpe 1993) and developed over the past 12 years.
The methodology used in assessing the output from various WECs depended on the amount of information available on the performance of each device.
• Where there is a significant amount of validated data or the device can be modelled theoretically, a detailed prediction of the annual energy output can be made. • Where these criteria are absent, the only available approach is to review the claims made by Developers.
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The principal parameters for this methodology are:
• W ave power resource – this was calculated from the DTI Atlas of Marine Renewable Resources 2004, and from a study of the region proposed for the Wave Hub carried out in the Seapower SW review. • Directionality Factor – this refers to the variation in direction of the incoming waves. No data were available so a factor of unity was assumed. • Capture efficiency – this was based on data from wave tank tests or theoretical modelling of the device. • Power chain efficiency – this refers to the efficiency of the components used to generate electricity (e.g. pumps, generators, transformers). This was calculated from manufacturers’ data. • Availability – this was calculated using an availability model that took into account reliability and limitations of wave height on being able to carry out repairs.
Figure 7.1 – Energy yield methodology
7.3 Results 7.3.1 Energy production per W EC The analyses carried out on the various WECs were summarised in terms of the average annual output per device in the wave climate at the Wave Hub location. The results are shown in Figure 7.2, presenting the devices anonymously.
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3
2.5
2 W M / 1.5 h W G 1 0.5
0 A B C D E F
W EC Figure 7.2 - Average Annual Output for Various W ECs – GW h per M W of W EC rated power
7.3.2 Energy production of a scheme Each of the devices presented in Figure 7.2 occupies different amounts of the sea bed per unit of installed capacity. In the site identification process it has been assumed that in order to allow for environmental assessments and licensing, a fixed area of sea bed will need to be identified. Therefore, it is useful to have an understanding of the sea area required for each unit of installed generation capacity for each type of WEC.
In order to illustrate this effect, a hypothetical scheme has been modelled which consists of a sufficient number of one type of WEC to produce an installed capacity of 4 MW. The average annual generation is subsequently presented in Figure 7.3 as an annual output per square kilometre of sea bed.
) m k
250 q s / h W
G 200 (
d e
B
a 150 e S
t i
n U
100 r e p
t
u p
t 50 u O
l a u
n 0 n
A G H I J K L
Figure 7.3 - Annual Output of 4 M W Schemes per Unit Area of Sea Bed
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7.4 Conclusions The analyses undertaken in this study show a wide variation in yield per WEC and subsequently in the yield per square km of an array. Additionally, it must be remembered that a large proportion of the WECs analysed have yet to be built at commercial scale, and none have been tested as arrays. Therefore a high level of uncertainty must remain in the potential energy throughput of the Wave Hub system. However, those devices that provide a higher level of generation per unit and a high level of generation per unit deployment area, are more likely to prove commercially attractive to investors, whilst also providing the potential for lower operational costs.
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8 Technical financial analysis
8.1 Introduction In the preparation of the cost plan for Wave Hub, a risk based approach has been taken. Rather than introducing an arbitrary contingency sum, each of the cost elements have been assigned a distribution of cost:risk dependant on its particular uncertainties and risk. A quantitative statistical analysis of the probability of likely out-turn cost based on a statistical (Monte Carlo) approach was undertaken, allowing an informed decision on budgeting to be made. The cost table in Appendix D shows the breakdown of costs with upper and lower bounds used as the basis of the risk analysis. The summary of best estimate costs gives a useful guide to out-turn cost, but the mean cost from the risk analysis is a more meaningful figure to use for budgeting. Costs have all been estimated at 2004 values.
8.2 Development and procurement costs Principal costs in the development of the project are summarised in Table 8.1.
Category Best Notes Estimated Cost (£) Physical Surveys and 761,000 To include marine sea bed survey, environmental surveys, wave Studies climate and resource studies, offshore traffic survey and land surveys. Economic and Funding 233,000 Includes economic modelling, applications for funding and Consultancy setting up of the WHMC that will take over development activities in Q4. Also includes PR activities and stakeholder engagement. Legal Consultancy 121,000 To include leases, wayleaves, IPR, confidentiality agreements, funding advice, EA, consents, grid connection, PPAs and WEC
developer agreements. It excludes cost associated with a public enquiry. Engineering Fees 123,000 Includes engineering outline designs for planning, funding and EPC tendering. Management of the EA process. Navigational Safety Assessment. Project Management 86,000 Project management and consultancy on overall project management for a period of ten months during 2005 by when it is assumed the WHMC will take over. Grid Connection system 34,500 Includes system stability studies performed by Utility and studies and WEC technical agreements on grid connection parameters.
commercial connection specifications TOTAL 1,358,500 Table 8.1 – Development cost summary to end of 2005
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Totals of upper and lower bound cost totals for development costs are £1.86m and £1.01m respectively.
The offshore elements of the physical survey requirements are the most costly and are essential for designing the final cable route and for final positioning and foundation details for the offshore electrical plant. This work should be carried out in the summer months when there are more favourable weather conditions and less risk of down-time.
Wave climate studies have been included in the cost plan for completeness, but not all costs are included at this stage as they are currently being funded and undertaken by others. An allowance of £30k has been made, with £100k as an upper bound in case of a shortfall in this area.
Although leases and wayleaves have been excluded from the capital costs on the basis that they will take the form of annual operating costs, the legal costs associated with these have been included in the development costs. Other legal fees (associated with funding, intellectual property rights and confidentiality, consents, grid connection PPA's and plug and pay agreements, and those fees associated with the formation of the Wave Hub Management Company) have also been included. The upper bound figure includes for a public inquiry, although the provisions of the Energy Act are considered to render this unlikely.
A more detailed breakdown of development costs and assumptions can be seen in Appendix D if required.
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8.3 Construction costs The principal elements making up the construction cost are shown in Table 8.2:
Category Best Estimated Notes Cost (£) Engineering fees 552,000 Engineering consultancy fees associated with detailed design, procurement, contract administration, construction supervision and commissioning Construction costs 495,700 To include substation, compound, substation electrical onshore equipment, directional drilling, onshore cabling, communications and metering equipment. Grid Connection 342,000 To include WPD grid connection and capitalised O&M fee. at 33kV Offshore PCU and 3,775,000 Based on manufacture and installation of four sub-sea PCUs and TDU one TDU. Offshore 33 kV 2,800,000 Indicative cable length of 29 km. cabling Offshore cable 3,250,000 Assumes May to September period. Includes insurance and laying project management elements as well as operational risk contingency. Offshore marker 465,000 Includes marker buoys, cardinal buoys, RACON, Waverider buoys and buoy, deployment, cable connections and offshore vessel associated costs support. Capital equipment 170,000 Includes ROV, vehicle, spares and workshop equipment. for O&M Project 247,000 This includes staff costs for project management and an Management costs allowance for PR and stakeholder engagement. It also includes during the for ongoing work on legal agreements. construction phase TOTAL 12,096,700 Table 8.2 – Construction cost summary to end of 2006.
Upper and lower bound cost totals for construction costs are £15.09m and £9.91m respectively.
There are obviously no comparators against which to measure this estimate on an overall basis; however, information from one Developer suggested that they had independently estimated the overall cost of grid connection infrastructure to be in the region of £7.5m. When the costs of multi user capability are extracted from the above total project estimate, the resulting equivalent cost is £8.35m (£12.4m- £4.05m). This strong correlation gives some further confidence in the accuracy of the estimate.
Dominant elements are the cable itself and the sub-sea infrastructure.
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8.3.1 Cable material, laying and installation costs Cable costs are based upon industry prices for standard cable configurations used in the offshore wind industry. These may have spare capacity but will still be cheaper than ordering to a special specification.
The cost of cable laying is dependent upon a number of factors including the time spent mobilising and demobilising (and therefore distance from the base to the site), the market demand at the time and the season of the year. A weather risk element of 35 % is added for summer work and 75 % for winter work. This cost element may be negotiable and the risks borne by the employer or main contractor directly. It is clearly better to work in the summer season if the project schedule allows.
8.3.2 Offshore equipment costs The offshore equipment cost is based mainly on a preliminary design by a recognised manufacturer using proven equipment with some check prices from other sources. Given the high cost of wet mateable connectors, the relatively shallow water depth and the weights of the units it has been concluded that the connectors can be avoided. Potentially some of the connection cost can be passed to the Developer if they are required to make their own connections to the system. The offshore equipment is the area with most potential for value engineering savings (estimated up to 15 %) depending upon the proposals from tenderers and capability of the vessels available. The same seasonal factors as for the cable laying apply to the deployment of the offshore plant.
8.4 Costs of alternative W ave Hub arrangement While the wet hub option covered by this report was considered to be preferred, for reasons described in Section 3, the platform option has been progressed in parallel for completeness. Costs for the platform are estimated to be an additional £4m and a further construction programme time of approximately 12 months would be required. The platform does not offer additional advantages sufficient to justify this additional expenditure and delay.
8.5 Phasing/modularity There is the potential to delay the manufacture and installation of some of the offshore equipment, depending on the level of early Developer uptake. If only one Developer were committed to deployment in the first 2 years, say, of operation, then delay in manufacture of the TDU might be considered. Indeed, if the first WEC were generating at 33kV, then it may be possible to delay manufacture of the PCU, depending on the particular requirements of the WEC in question. This could potentially delay expenditure of up to £4m, and options should be reviewed as the project develops.
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8.6 Connection costs The cost of £342k for connecting to Western Power Distribution is based on a connection at 33kV as included in their report "Feasibility Studies - 30 MW Generation Connection at Hayle and Newquay, Cornwall" - September 2004. Later upgrading to a 132kV connection capacity is estimated to be £2m. This has not been included in the current capital cost estimate.
8.7 O&M costs Annual maintenance and operation costs have been estimated as shown in Table 8.3.
The annual costs are dominated by the estimated staff costs. The contracted service estimates are somewhat tentative because of the lack of data available to allow potential service providers to estimate costs.
The major repair cost is an annualised estimate which is derived from industry reliability figures used in the availability modelling and which assume that a transformer failure will occur once in 20 years. Hence, with 4 transformers, a failure event for each transformer has been assumed in the costings. As explained at Section 2.5, these figures may be pessimistic as there is, at present, no long term data for these specific sub-sea transformers and associated equipments. It is recommended that, as such data emerges, it is used to inform and validate the maintenance strategy.
The operating costs do not include any element for such navigational safety and mitigation controls beyond the area marking (buoyage) currently considered as required. Controls which could impact on the operating costs are the potential requirement for radar/Automated Identification System (AIS) monitoring of the site, continuous VHF Radio watch, provision of guard boats and of the means of notifying and providing evidence of infringement of safety zones or Areas To Be Avoided (ATBA). Consultation with regional MCA officers suggests that these measures will not be necessary, but further negotiations with the MCA to confirm the requirement will certainly be required at the next stage of development. The worst case scenario for costs would be a permanent guard vessel, estimated to cost in the order of £1m per year. It is recommended that this is progressed forthwith in order that the financial impact can be properly assessed.
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Category Best Notes Estimated Cost (£) WHMC Staff 137,500 Includes salaries and overheads for NI, pension, healthcare, life insurance etc. Stakeholder, PR, Marketing 20,000 Includes all marketing costs but excludes travel and accommodation. Includes dues, memberships and conference/exhibition fees. Board Members 20,000 Includes fees and costs for five WHMC board members. Insurance 15,750 Public liability and indemnity. Excludes catastrophic loss or damage to offshore equipment. Technical and legal 15,000 Includes technical, economic and legal due diligence on potential consultants WEC customers. Office overheads and general 49,350 Includes leases, security, rates, utilities, communications, IT support, business costs financial fees, training, travel, accommodation. Contracted Services – On call 30,000 Includes marine and onshore contract services for general boat hire, support quayside crane hire, building and site maintenance, and workshop consumables. Contracted Services – 5,000 Includes for building and site maintenance, waste disposal, vehicle Infrastructure Support maintenance and fuel, office equipment and supplies. Contracted Services – HV 5,000 Specialist High Voltage Maintenance contract. Excludes Utility operations and maintenance equipment capitalised in connection fee. Contracted Services QHSE 10,000 Quality, Health and Safety and Environmental audits, equipment and training. Environmental monitoring 38,500 Estimate until requirements for post construction environmental monitoring are better defined. Annual Scheduled 30,880 Includes routine annual maintenance of navigational buoys, sub-sea Maintenance cable inspections, PCU cleaning and waverider buoy. Annual Unscheduled 9,680 Minor unplanned repairs to buoys, met equipment and substation Maintenance (minor repair) based equipment. Refurbishment (long term) 7,950 Annualised estimate to cover planned refurbishment of buoys in years 5, 10 and 15. Unscheduled Major Repair 28,575 Annualised estimate to cover unscheduled major repairs to PCU, TDU and offshore cables. N.B This does not include cost for complete replacement in case of catastrophic damage or failure. This is covered by a separate contingency fund in the economic model. TOTAL ANNUAL COST 423,185
Table 8.3 - Summary of estimated annual operation and maintenance costs
N.B. for Table 8.3 1. No allowance for 24/7 navigational and safety cover if required as a result of Navigational Safety Assessment. 2. W EC maintenance is assumed to be responsibility of individual array owners. Charges arising from needs to support W EC owners are accounted for separately in the economic model.
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8.8 Cost : risk and sensitivity analysis The cost risk exercise involved an analysis of the factors affecting each of the cost elements in the build up and assigning upper and lower cost bounds and a probability distribution. Clearly it would be extremely unlikely for every element to out-turn at either its upper or lower boundary cost. The current industry standard method of assessing these variables is to use a multiple random sampling approach called a Monte Carlo analysis.
The results of this analysis are included in detail in the Technical Financial Analysis (Task 10) report, and are summarised in the figures 8.4 and 8.5 below.
The two vertical lines on the graphs indicate:
• The cost at which there is a 5 % probability of out-turn cost being lower • The cost at which there is a 95 % probability of out-turn cost being lower.
Probability Distribution for Development Costs £1.25m £1.60m 1 5% 95% Mean = £1.42m 0.8
y t
i 0.6 l i
b a b o r 0.4 P
0.2
0 1 1.3 1.6 1.9 Cost in £millions
Figure 8.4 – Probability distribution for development costs
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Probability Distribution for Construction Cost £11.41m £13.45m 1 5% 95%
Mean = £12.42m 0.8
y t
i 0.6 l i
b a b o r 0.4 P
0.2
0 10 11.25 12.5 13.75 15 Cost in £millions
Figure 8.5 – Probability distribution for works costs
It can be seen that the mean (50 percentile) costs for both development and capital costs are slightly higher than the best estimate totals. This is not unexpected, as the distribution in many of the cost elements is skewed to higher costs. Intuitively this is correct as there is generally the potential for costs to increase by a greater amount than they can decrease.
It is recommended that the total costs taken forward for funding purposes are based on these mean figures of £1.42m for development cost and £12.42m for capital works cost.
While it would be possible for variance in a very few factors to have a disproportionate effect on the total cost of a project, it is considered in this case that there are no over-riding factors of this nature which are not covered by the above analysis.
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9 Proposed development programme
9.1 Development schedule The market forces driving the development of the Wave Hub - discussed in AD Little’s report, but primarily relating to the Developers’ development programme - require that to deliver maximum economic benefit to the region and the UK wave power industry, it must be commissioned in 2006 unless Developers’ own development plans are delayed. The approach to the development programme has been based on this premise.
Success in achieving this challenging programme will depend on a number of factors. The most critical of these are the consenting and funding processes. These are only partially within the control of those driving the project, and measures to mitigate the risk of delay in these areas must include maintaining an ongoing dialogue with the relevant bodies. They must be kept fully appraised of the importance of meeting the programme, the implications of delay, and the critical-path nature of their contribution to the process.
As the Wave Hub is a novel development, there are no clear examples on which to base a consenting period under the revised legislative framework. The schedule presented in Figure 9.1 makes assumptions in these areas based on experience from offshore wind power installations and represents the minimum reasonable time for the preliminary studies, engineering, tender processes, procurement, installation and commissioning. It also assumes that funding is available to maintain maximum progress. These could be considered to be optimistic assumptions, however, it is understood that there is a strong will within DTI, DEFRA, Crown Estates and other relevant organisations to support the industry in general and this initiative in particular.
The equipment selected for the system is all standard, proven, commercially- available equipment which can be sourced from reputable suppliers. Standards and codes for the equipment and its installation have not been specified at this stage but would be specified before procurement.
The schedule requires that environmental surveys must commence early in 2005. A period of 9 months has been adopted for the EIA including all survey work. This is considered to be the absolute minimum time required, based on offshore wind experience. The absence of definitive guidance and the uncertainty regarding the number and type and impact of WECs means that there remains a risk of this period being extended. Unlike offshore wind it is not possible to pre-test WECs onshore. Therefore rigorous environmental monitoring and reporting will be an essential part of the overall Wave Hub program.
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A primary contractor must be selected and terms agreed by the end of 2005 for award no later than January 2006. In order to achieve this, and to minimise the contract periods, a further period of design development will be required during 2005. This has been programmed from July, but there may be merit in bringing this forward if funding is available. This would assist the EIA process, but there is a limit beyond which the engineering cannot progress without the physical surveys, which cannot realistically proceed before the early summer. There remains a risk therefore that the outcomes of the physical surveys on the cable route and deployment area may impact on the EIA process and cause delay.
The establishment of the company managing the Wave Hub has been covered in detail by AD Little. There is no specific problem foreseen in the technical and environmental development work being progressed through SWRDA and title passing to the Wave Hub Management Company (WHMC) at the appropriate time. The WHMC must be in place with sufficient time for the funding process to progress.
Confidence regarding the demand for Wave Hub will need to be improved during the development period. This will entail ongoing discussions and negotiations with WEC and project developers.
9.2 Construction schedule After mobilisation of the primary contractor, a key period of detailed engineering and component procurement begins. The following assessments have been made for the principal items, as shown in Figure 9.1:
• The delivery of the complete wet hub solution is currently quoted at 8 months including final acceptance tests on all components. This may be negotiable to a small extent but is unlikely to take less than six months. • The onshore electrical equipment although standard (typically with an availability of 5 months) will be specified within a very novel connection agreement. This will require negotiations with WPD to develop a Connection Agreement for a multiple connection type system. Further negotiations will then be required with WPD in order to develop clauses for insertion into a connection agreement between the owner /operator of the Wave Hub and the operators of WEC arrays in order to ensure that the generator 'system' meets certain parameters such as harmonic distortion, power generation levels, power factor, G59 protection etc. Finally, preparation of a Technical Connection Specification for the operators of the WEC arrays, detailing connection type, voltage, electrical protection, and operational constraints is required. This process is expected to take several months. • The procurement of the armoured sea bed cable relies on the manufacturing process (a continuous extrusion) and material availability. The 7 months shown is unlikely to be significantly reduced by negotiation.
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The main offshore deployment period is therefore programmed for August and September. This is later than ideal, running a slightly higher risk of stoppages due to poor weather.
9.3 Environment impacts on construction schedule The results from the environmental scoping study indicate constraining factors on operations arising from potential disturbance to marine life and birds in certain seasons. Similarly the marine operations (and the cost) will be influenced by weather windows for operations which are longer and more reliable in the summer months. These constraints, if confirmed, may affect the timing of certain operations but their criticality cannot be evaluated until an initial comprehensive programme has been developed. As a working assumption for the construction schedule it is assumed that marine operations will be confined to the May to September period and any consequent delay arising in the programme which cannot be removed by accelerating into an earlier season is identified as float in the construction programme.
May, June and early July is proposed as being the most suitable time for offshore and inshore operations.
Environmentally, this is generally a good time because it falls outside the main dover sole fishing season, the peak time for birds in the Hayle estuary, and the peak time for recreation and tourism.
The main constraint is that it is the peak of the spawning season for several commercially important fish species. Any eggs on the area of seabed to be covered would be adversely affected, and disturbance may affect the spawning success of adults and the survival of fry. However, it is not envisaged that this will cause any significant problem given the very small proportion of the spawning and nursery areas involved (< 50 m2 to be affected), and given that this timing avoids more marked environmental constraints.
This period also overlaps with the seabird breeding season (when seabirds will be feeding heavily in the area), but again the small area involved should mean there is no significant negative effect.
On land, there is the issue of breeding birds, but this can be avoided by clearing any scrub that needs to be cleared at the site before mid-Feb. With this preparation, the early summer season should be feasible environmentally.
This timing would also avoid impact on the most intense part of the tourism season.
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9.3.1 Timing As construction will take place in the summer months, monitoring will be timed to take place in late summer/autumn. The aim of the pre-construction monitoring is to establish a baseline against which impacts can be compared. Monitoring, likely to include birds, fish, cetaceans and inter-tidal ecology, will be conducted over five seasons as follows:
Pre- Construction Late summer/autumn 2005 Construction Late summer/autumn 2006 Post Construction/Operation Late summer/autumn 2007/2008/2009
Depending on the results, and as some of the impacts may appear only in the longer term, further monitoring may be required in subsequent years. This decision will be taken in consultation with the licensing authorities and other relevant bodies.
9.4 Conclusion The development programme shown to meet the 2006 commissioning date is a challenging one. There remain a number of risks of slippage as described above, but with strong programme management and the necessary support and co- operation from the consenting and funding bodies, it is considered achievable. The consequence of slippage would push the deployment period into a period of more unsettled weather which, while still workable, would increase cost risks due to weather, unless deployment was delayed until the early summer of 2007.
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Figure 9.1 – Outline Construction Schedule
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10 Conclusions
10.1 Aims of the study The aims of the Technical Feasibility Study are summarised in this extract from the commission scope:
The aims of the study are to develop the W ave Hub concept in discussion with Developers & stakeholders, prepare a conceptual design, select a location, and gather and analyse evidence to help assess its overall financial feasibility leading to submission to external partners for funding to develop the facility.
This requires the provision of data and analysis for input into related studies and funding applications and to draw conclusions as to the technical feasibility of the project given market demand and the temporal and legal constraints.
The conclusions of the study are therefore framed around these objectives under the following headings:
• Need for the project, incorporating response from Developers • Conceptual and outline design • Location and impact • Cost and timing
10.2 Need for the project From initial contact with 29 Developers, more detailed discussions were held and responses received from 7 organisations to determine the market need for the Wave Hub. The outputs of this part of the study can be divided into two parts:
• The likelihood of Developers being in a position to use the Wave Hub and when they would be ready • The benefits Developers see and what functionality they would want from the Wave Hub
The first of these has been assessed from the Developer responses and from a critical review of the information supported by industry intelligence. This information, together with independent assessment of the likely energy output from specific devices is commercially sensitive. It has been fed into the Economic Study by AD Little where it has been used to prepare the business model and economic sensitivity analysis. The conclusions to be drawn are most appropriately made in the reporting of that study.
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The outputs in the second category were used to develop the design and location of the Wave Hub. The principal findings are:
• The south west is seen as optimum area for device and array proving by nearly all Developers. • The principal benefits are seen as reducing risk and programme constraints from permitting and consenting, and reducing up front capital costs. • A water depth of 50-60 m would serve the majority of promising WEC’s. An additional 25 m depth area would allow one further device to be attracted within the next 10 years. • The maximum economic advantage to the region from implementing Wave Hub is likely to be realised if it is ready in 2006. • The absence of significant depths of sediment over rock in the deployment area could give rise to some additional anchorage costs on the part of the Developers. • Developers have varied requirements for support services, but telemetry infrastructure for metocean and device monitoring was a common theme. The majority of other physical support services are likely to be difficult for the WHMC to provide directly in a cost efficient way and are assumed to be sourced directly by the Developers from local sources. SWRDA is exploring wider support mechanisms for Developers looking to locate their operations in the south west (see ADL study reports).
The success of the Wave Hub project will ultimately be assessed from its take-up by Developers and the impact that this has on the wave power industry and the economy. The overall need for the Wave Hub must be measured in some part by an assessment of how easily Developers could find alternative means of deploying their devices in the UK. This assessment cannot be made in isolation from the Wave Hub pricing structure to Developers and therefore cannot be fully made within this technical feasibility study.
This report therefore focuses on the optimum infrastructure to enable uptake, however what can be said from the Developer response is that:
• there is a key need to provide additional deployment opportunities with significant grid connectivity. • the present, largely untested, UK offshore consenting regime presents a significant uncertainty and programme risk to Developers. • the capital costs and risk of providing grid connection infrastructure is considered to be a significant obstacle to Developers in deploying demonstration scale WEC arrays.
While these do not in themselves prove the need for the Wave Hub, they do form the essential precursor for the economic study to complete the case.
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10.3 Conceptual and outline design The analysis of the market and potential “customers”, together with initial assessment of physical and technical constraints gave rise to the following principal design parameters:
• Overall capacity requirement of 20-30 MW • Water depth of approximately 50 m • Transmission voltage of 33 kV • WEC units need individual electrical protection and isolation • Not all WECs can currently generate at 33 kV or alternatively house a 33 kV step up transformer within their structure. Offshore transformers are therefore required to allow connect to the Wave Hub at 11 kV if necessary
A number of options were assessed against a combined technical, financial, environmental, health & safety and functionality scoring matrix. The preferred option is to provide a single 33 kV armoured sea bed cable to the deployment area, where the following equipment would be situated on the sea bed:
• Four way termination and distribution unit (TDU) - i.e. a cable splitter • 11/33 kV power connection units (PCU) for each of the four cables to the TDU • Umbilical cables from the PCU for pick up and array connection • Independent remotely operable switchgear and electrical protection on each umbilical
The requirement for land side infrastructure is modest, with only a 30 x 30 m compound containing switchgear, monitoring equipment and control room together with storage for operation and maintenance hardware.
All the equipment proposed is known technology in current use elsewhere. The sub-sea equipment has been proven in the offshore oil and gas industry.
10.4 Location and impact A coarse screening of the whole of the north coast of Cornwall confirmed Hayle as the optimum location for the landfall of the power cable. This is principally due to the coincidence of a grid connection immediately adjacent to a sandy shore, with a favourable wave climate and the avoidance of direct impact on nationally designated areas. However the location is also reinforced by a number of other factors which make Hayle the preferred choice. The other locations may be suitable for commercial developments in future.
Available connections to the national grid at Hayle will, within certain power quality constraints, allow around 30 MW input at 33 kV, but significantly more at 132 kV. The scenario of likely Developer uptake, when set against equipment cost has led to the recommendation that power should initially be exported from
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the Wave Hub at 33 kV. The limit of power generation at this stage has been set at 20MW by the offshore plant. At such time as the 20 MW limit looks set to be reached, the additional investment required to up-rate to 30 MW capacity, can be assessed. Meanwhile the initial proposals have been future-proofed to allow for this option.
The proposed WEC deployment area has been established by a GIS based constraints mapping process. Principal factors affecting the positioning are:
• Depth and bathymetry • The 12 mile perimeter • Ministry of Defence practice firing range • Shipping lanes • Sea bed rock outcrops
The assessment of these factors, together with a notional model of possible WEC arrays has led to the recommendation of a 3000 m x 1000 m deployment area encompassed within a 4000 m x 2000 m Area To Be Avoided – effectively a shipping exclusion zone. This outer area is as shown on the attached plans WGEHUB/001 and 002 in Appendix C. The National Grid References (NGR) of opposing corners are 138069E 059239N and 140513E 055493N (or in WGS 84: N50˙22’29” W05˙41’07” and N50˙20’31” W05˙38’54”)
An initial environmental assessment, including an assessment of environmental receptors, designations, and a consultation exercise have been undertaken. This has led to a scoping for an Environmental Impact Assessment. The conclusion of this part of the study is that the overall environmental impact of the proposed scheme is likely to be beneficial. Clearly, environmental issues are of high importance and, as with all developments, there remains the potential for a number of adverse environmental impacts. The next phase of development is key to establishing the baseline and further detailed survey, consultation and assessment will be required as described in the EIA scoping study. Given the novel nature of the proposed development and the timescales involved, it will be necessary to take a precautionary approach, incorporating a rigorous monitoring for impacts during and particularly after construction.
10.5 Cost and timing The capital cost estimate for the development stage of the project lies in the range £1.01m to £1.86m. The capital cost estimate for the construction stage of the project lies in the range £9.91m - £15.09m.
The 50 percentile estimates obtained from the financial analysis are £1.42m and £12.42m for development and construction respectively. It is these figures which are recommended to be used for budgeting/funding purposes.
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Operating and maintenance cost has been assessed on an Availability / Reliability / Maintenance plan (ARM) basis and has been estimated as £301k per annum. This has been input to the economic assessment by AD Little, where certain additional business costs have been included in accordance with the business model, making the total annual operating cost £423k.
The driver for implementation of Wave Hub is the readiness of Developers to deploy WECs. Scenarios of Developer readiness have been prepared from a critical appraisal of Developer responses and this informs the economic analysis by AD Little. The recommendation is that a target date for commencement of operation should be September 2006. This is subject to confirmation of the industry demand for Wave Hub by this time. Ongoing work in the development phase will be required to test and secure Developer commitment.
The ongoing implementation programme has been considered in respect of the technical, development, design, procurement, construction, environmental and other constraints and these are detailed within the report. The conclusion is that September 2006 is achievable for commencement of Wave Hub operation but that there are a number of key risks.
Achieving this target is dependent on several key factors which are outside the remit of this study and outside the immediate control of those promoting the project. These are principally:
• SWRDA’s ability and willingness to commit funds at risk in the development of the project in advance of confirmation of full project funding being available. The first element of this would be the commencement of environmental baseline studies as a matter of urgency early in 2005. • Co-operation of the consenting bodies DTI, DEFRA, and Crown Estates in determining favourable SEA Demonstrator Status operating terms and in considering and issuing the necessary permits and licenses • Confirmation of funding availability and timing • The ability of the emerging wave industry to develop WEC’s to a suitable stage whereby they require the services of the Wave Hub
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Glossary of Abbreviations
ABTA Area to be avoided AHT Anchor handling tug AIS Automated (ship) Identification System ARM Availability reliability maintenance CSEP Cornwall Sustainable Energy Partnership DEFRA Department of the Environment Food and Rural Affairs Developer Company or organisation developing a WEC DTI Department of Trade and Industry EIA Environmental impact assessment EMEC European Marine Energy Centre EN English Nature GIS Geographical information system GMSL Global Marine Systems Ltd MCA Maritime and Coastguard Agency MTBF Mean time between failures NaREC New and Renewable Energy Centre PCU Power connection unit PPA Power purchase agreement PVS Project Vehicle Study QHSE Quality, health and safety and environment ROC Renewable Obligation Certificate ROV Remote operated vehicle SCADA Supervisory control and data acquisition SEA Strategic Environmental Assessment SWRDA South West Regional Development Agency TDU Termination and distribution unit TFS Technical Feasibility Study WEC Wave Energy Converter WEIS Wider Economic Impact Study WHMC Wave Hub Management Company WPD Western Power Distribution
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Appendices
Appendix A - List of associated TFS reports
Appendix B - Consultee list
Appendix C - Project outline drawings
Appendix D - Capital cost breakdown
Appendix A List of associated TFS reports
• Conceptual Design (Task 2)
• Developer Requirements (Task 3)
• Site Identification (Task 4)
o Screening of Potential Sites (Report 4A)
o Electrical Connection Feasibility Study (Report 4B)
o Cable Route Study (Report 4C)
o Environmental Scoping (Report 4D)
• Technical Specification (Task 5)
• Data Collection and Survey Specification (Task 6)
• Outline Design and Budget Costing (Task 7) (N.B. - Appending to this are the Terms of Reference and 2006 Project Programme)
• Environmental M anagement System (Task 8A)
• Operations and M aintenance (Task 8B)
• Energy Output Estimates (Task 9)
• Technical Financial Analysis (Task 10)
Appendix B Consultee list
W ave Hub Technical Feasibility Study - Consultation list - 16 August 04 STATUTORY BODIES FISHERIES ORGANISATIONS ENVIRONM ENTAL GROUPS South West Regional Development Cornwall Sea Fisheries Committee, Cornwall Wildlife Trust Agency Penzance Environment Agency National Federation of Fishermen’s The National Trust Organisations (NFFO), Grimsby Environment Agency Cornish Inshore Fishermen’s RSPB Federation English Nature Cornish Fish Producers’ Wildfowl and Wetlands Trust Organisation (CFPO) Joint Nature Conservation South Western Fish Producers’ Surfers Against Sewage Committee Organisation (SWFPO) Joint Nature Conservation DEFRA, Sea Fisheries Inspectorate, RECREATIONAL Committee Newlyn ORGANISATIONS/ COM PANIES English Heritage OTHER GOVERNM ENT/ Cornwall Tourist Board AUTHORITIES Cornwall County Council MoD Royal Yachting Association Cornwall County Council MoD British Sub Aqua Club Cornwall County Council USN (SPAWAR) Sports Council Penwith District Council Hayle Town Council Riviere Sands Holiday Park Countryside Agency St Ives Town Council Lands End Diving Crown Estates Commissioners Maritime and Coastguard Agency St Ives Sailing Club Marine Consents and Environmental OTHER COM M ERCIAL / LOCAL ORGANISATIONS/ Unit RESEARCH ORGANISATIONS GROUPS/ CONTACTS Marine Consents and Environmental British Geological Survey St Ives Harbour Master Unit Maritime and Coastguard Agency British Marine Aggregate Producers Hayle Harbour Authority Association Plymouth Marine Laboratories SOS Hayle Western Power Distribution Hayle Towans Foreshore Owner METOC plc Duchy of Cornwall
Appendix C Project outline drawings
W GEHUB/001 - Overall scheme proposal
W GEHUB/002 - Proposed offshore deployment area
W GEHUB/003 - Proposed onshore site location plan
W GEHUB/004 - Proposed onshore site layout
Appendix D Capital cost breakdown
The table below is drawn from the Outline Design and Budget Costing (Task 7) report.
Wave Hub Capital Costs Breakdown Lower Best Upper Cost Cost Cost Comment Phase Item Boundary Estimate Boundary (Cost Origin) (£ k) (£ k) (£ k)
Survey (sediment/geology/bathymetry) prices supplied by Halcrow Geomatics and range between £25k for least cost and £100k for full survey spec. and area coverage); Geotechnical prices supplied by Marine Sea Bed Survey 261.0 403.0 450.0 Halcrow Geotechnics; Geomorphology prices supplied by Halcrow Engineering Geomorphology/Coastal. Major cost element is mobilisation/demobilisation costs for vessels and equipment hire (>50% total costs), hence there is little room for manoeuvre. Costs are included for the following surveys: Intertidal, Benthic Grab, Archaeological Baseline, Bird (vessel based), Fisheries, Fisheries Monitoring, Suspended Solids, Terrestrial Ecology, Contaminated Environmental Surveys 206.0 242.0 278.0 Land, and Unexploded Ordinance. The costs include data analysis and reporting. The costs shown Surveys here assume that a Sidescan and Video survey can be combined with the Geotechnical Marine Sea (Including Bed survey. Further information on the surveys can be found in the Task 6 report. Equipment Provision) Wave climate study including wave measurement, tidal current measurement, cetacean monitoring, and surf impact modelling. Data to be taken from the 'Wave Measurement off North Cornwall Project' Wave Climate 10.0 30.0 100.0 (RegenSW, NPower 2004/5), and the 'Surf Modelling Study' (RegenSW, Heriott Watt University 2005). Best estimate includes for data review, analysis and circulation and also assumes the Wave Hub project is not required to fund the wave measurement studies.
Offshore Traffic Survey 40.0 60.0 70.0 Costs for two 14 day surveys (one in summer, one in winter), data analysis, and reporting. 5 0
0 Site Investigation (SI) contractors costs between old power station site and high water mark, assuming 2
- logging of exposures and trial pitting at each end; seismic refraction along route and one shallow cored Land Geotechnical Survey 21.0 26.0 31.0 t borehole at old power station site. Included are consultant fees for specifying, supervising and n e interpreting the results (40% of SI contractors costs). £5k included for a topographical survey. m s p Commercial development of Wave Hub including formation of the Wave Hub Management Company t o
s Project Vehicle Consultancy During the l 198.0 233.0 288.0 (WHMC) that will take over the project developemnt towards the end of 2005. Figures provided by ADL e o Development Phase - 2005 v C
e (PVS report 9.2.1). Includes PR and Stakeholder engagement. t D n Legal Fees Associated t e c
m with Leases and 18.0 21.0 32.0 Legal Fees associated with Land Lease, Wayleave Arrangement, and Crown Estate Lease. e j p o
o Wayleaves r l Legal Fees e P
Estimate. See ADL PVS report for details. To cover Funding, IPR and Confidentiality Issues, EA and v -
e
s Other Legal Fees 75.0 100.0 300.0 Consents, Grid Connection, PPA and Plug & Play agreements, Formation of the WHMC. Excludes t D s costs associated with a Public Enquiry. o C
Consenting EIA 50.0 60.0 70.0 EIA, consultations, management of surveys, data analysis, and reporting. l a t and i Navigational Safety Conduct of Risk Assessment in accordance with MGN 275, liaison with stakeholders, approval of p Permitting 10.0 13.0 16.0 a Assessment measures with MCA. Best Cost Estimated at 160 hrs@ £70/hr plus travel and subsistence. C Engineering Fees for progressing the design of the entire wave hub system to a level necessary for the Design Development 30.0 50.0 70.0 Fees development of the project, in parallel with permitting activities and application for funding. Project Management Fees During the Project management fees for the overall project management for ten months until take over by the 64.0 86.0 107.0 Development Phase - 2005 WHMC. Based on an external consultant. Range of figures to cover 3, 4, or 5 days a week. Dynamic system stability studies. These studies are performed by the Utility Company prior to the Grid Connection - System Studies 23.0 25.0 30.0 confirmed offer of a point of connection to their system. If these studies identify any system enhancement required in order to provide the point of connection then this will be a further cost. Costs cover three phases: 1) Further negotiations with WPD to develop a Connection Agreement between WPD and the operator/owner of the Wave Hub for a multiple connection type system. 2) Further negotiations with WPD in order to develop clauses for insertion into a connection agreement Wave Generator Commercial Connection 8.6 9.5 18.2 between the owners/operator of the Wave Hub and the commercial operators of the wave generator Negotiations and Specifications arrays in order to ensure that the generator 'system' meets certain parameters such as harmonic distortion, power generation levels, power factor, G59 protection etc. 3) Preparation of a Technical Connection Specification for the commercial operators of the Wave Generator arrays, details connection type, voltage, electrical protection, operational constraints. Sub total 1014.6 1358.5 1860.2
t Wave Hub Management Company (WHMC) commercial set up costs. Includes staff costs for project e l s c Project Management Costs During the t c e
i 185.5 247.0 356.1 management during the construction phase, an allowance for PR and stakeholder engagement, and j s Construction Phase - 2006 h o o
r ongoing legal agreements. Figures provided by ADL (PVS report 9.2.2). e C P V Sub total 185.5 247.0 356.1 Design fees for the entire wave hub system. Calculated as 2% of the overall capital construction cost,
Detailed design 133.0 162.6 206.9 less the amount allowed in development costs above. g n i Procurement and r Engineering 137.2 166.9 207.7 Administration costs. Calculated as 1.5% of the overall capital construction cost. e Contract Administration e Fees n
i Construction Supervision
g Construction supervision. To include all systems commissioning and testing through to final
n and Wave Hub 183.0 222.6 276.9
E completion. Calculated as 2% of the overall capital construction cost. Commissioning Sub total 453.2 552.0 691.5 The Wave Hub substation and workshop building includes a control and monitoring office area, the
onshore switchgear plant room, a storage and workshop area, and welfare facilities. Costs are based 6
0 on SPONS Price book, CESMM3 and current contractors pricing schedules for similar items of work. 0 2
The estimated cost is £77,400. This cost includes building services, security fencing and gates. -
Substation and n 71.6 79.2 87.0 Building facilities include security, lighting, heat, ventilation, small power, water, and sewerage. The
o Workshop i
t building will be sufficient in size for the storage of spares including the ROV and other maintenance a l l and inspection equipment. The substation layout is shown in Drawing WGEHUB/004. The cost of a t providing of a standard 230V AC, metered, domestic supply to the Wave Hub Substation for building s n
I heating, lighting and small power, is also included (best estimate = £1,800).
d It is proposed that the substation compound be 30m by 30m. It will house the control building and n Substation a
Onshore Works workshop, four parking spaces and access roads (4m wide) including a turning area suitable for lorries.
n Compound,
o The rest of the area will be a compacted hardcore working area. Access roads to both the wave hub i
t Parking Area and 40.0 45.0 54.0 E c compound (black-top) and the directional drilling site (compacted granular) are required extending to Site Access Road u R r the main point of access at the southern boundary of the power station site. The cost includes services t O Formation s
H supply, security fencing and gates. n S o A 250mm ID polyethylene sleeve to be inserted beneath the dunes through the underlying bedrock by N C
O ,
directional drilling. Drill length assumed to be no more than 200m. Access for drill rig and pipe stringing t - n
s area assumed to be acceptable. Included are consultant fees for specifying and supervising the work e t Directional Drilling 180.0 217.0 420.0 n m (15% of the contractors costs). The cost also includes for site clearance and preparation. Best e e r estimate assumes minimal requirement to dispose of contamination off site. High price uncertainty is m u e c l due to degree of dependency on ground conditions and contamination. o E r Should WPD agree to purchase this standard equipment on the behalf of Wave Hub, a considerable P n Two 33kV Circuit Breaker Panels 24.0 25.0 26.0 - o
i saving could be made due to their strong buying position. Cost includes installation. t s t c
s Current transformers and voltage transformers to be provided to the circuit breaker manufacturer for u r o t Circuit Breaker Metering Equipment 13.5 15.0 16.5 installation into the circuit breaker at factory. Meters and cable marshalling to be installed in Wave Hub C s l n substation control room. a o t i
C Cost of connecting to Western Power Distribution - 33kV substation busbars. Price includes £50k of p l a a capitalised operations, repairs and maintenance charges. WPD preliminary cost information for a t C i WPD Grid Connection Costs 325.0 342.0 358.0
p connection at 33kV is included in their report "Feasibility Studies - 30 MW Generation Connection at a
C Hayle and Newquay, Cornwall" - September 2004. Costs for furnishing and equiping the workstation and workshop and for the Wave Hub control / monitoring system. Best estimates are as follows: 1) Fibre Optic Cable Termination Equipment - Two Bridge units for dual circuit control - each £500. 2) Ethernet Connection Hubs - Two hub units for dual circuit control - each £500. 3) SCADA System - SCADA PLC plus software configuration and licence - £10k Wave Hub Control System and 4) PLC Control System - PLC plus software and licence - £2k 21.9 26.5 33.1 Substation Equipment 5) Data Logger - Industrial printer unit - £300 6) Alarm Printers - Industrial printer unit - £300 7) Telephone Line and Exchange - Two independent lines and exchange with two handsets - £1,500 8) Internet Connection - Internet card for PLC and Broadband provider - £350 9) Workshop Equipment - Tools, workbench, furniture and storage - £7k 10) Control Room Equipment - Welfare equipment and furnishings etc. - £3k
Installation of Onshore Monitoring, Metering, Control, and Communications 27.2 32.0 36.8 Provision of meters, connections etc, in Wave Hub substation control room. Equipment 33 kV Cable from Jointing Normal 33kV underground 3-core cable, from the jointing chamber through the sand dune conduit Chamber to Wave Hub 21.0 23.0 25.0 terminating at the wave hub 33kV circuit breaker within the substation. Priced as £65/m x 350m. Costs Onshore Substation include burial. 33kV Cable 33 kV Cable from Wave Normal 33kV underground 3 x single core cables from the Wave Hub substation metering circuit Deployment hub Substation to WPD 22.0 24.0 26.0 breaker to the WPD 33kV substation compound. Priced as £65/m x 120m x 3 singles. Costs include Main 33kV Substation burial. Busbars
Costs are developed from the following operations: 1) Supply of special HV cable joint - Provision of experienced HV cable jointing personnel to prepare 33kV Sub-sea Cable to 33kV Onshore cable, joint and test (best estimate = £6.5k). 8.2 9.0 10.0 Cable Joint 2) Concrete cable jointing block - A dry concrete block constructed to encapsulate the cable joint at least 4m under the beach at Hayle. Likely to be constructed in situ under the beach above the Mean High Water line where the directional drill terminates (best estimate = £2.5k).
Sub total 754.4 837.7 1092.4 Manufacture of Four 5 MW The lower cost represents a preliminary quote for four 5MVA sub-sea transformers without any (33/11 kV) Sub-sea 400 800 1200 peripheral support equipment at $150 000 US per unit and six months delivery. The upper cost is taken Transformers from a more comprehensive but again preliminary quote from another supplier. Manufacture and Assembly of a Four Way Termination Wave Hub Delivery of complete system will take an estimated 8 months. Because the equipment will be in only Distribution Unit (TDU), – Sub-sea ~60m of water it is proposed that all connections are dry made at the surface rather than using Sub-sea- Umbilical Cables Solution expensive wet mateable plugs and sockets. Each of the four transformer units will have two secondary (11 and 33 kV), Trawl 2450 2975 3500 – outgoing 11kV cables approximately 80m long for connection at the surface to wave generator Protection and Support arrays. While it may be optimistic at this stage, there is considered to be significant scope for value Structures for the engineering of this element, therefore this price is considered to be the upper cost bound with the best Transformers and TDU, and estimate as 85% and lower bound as 70% of this. Includes delivery and insurance. Control System/Remote Switchgear. To be positioned on the vertices of the 'Area To Be Avoided' to delineate the area in which the developer's devices will be moored. Best cost estimate is based on £17k per buoy for a HIPPO Super Four Area Marker Buoys ("Special" 48.0 68.0 80.0 Lite 3m Special Mark buoy including moorings. Lowest cost based on a FPM Henderson 2.2m buoy at Marks) £12k per buoy including moorings. Note - navigational safety equipment specification is subject to a navigational risk assessment and consents.
E Best cost estimate is based on the recommendation that Class 2, Steel, 3m buoys with light are used R @ £17k per buoy including moorings. RACON /AIS transponder on a single buoy at an additional £2k. O
H Lowest cost based on a FPM Henderson 2.2m buoy at £12k per buoy including moorings. Note - S
F navigational safety equipment specification is subject to a navigational risk assessment and consents. F Four Cardinal Buoys with RACON / AIS The initial IALA recommendation on marking of Offshore Renewable Energy Sites (wave and tidal O
50.0 70.0 98.0 -
Transponder on Western Buoy turbines) is currently being drafted but it is possible that Wave Hub will need to be marked with Class 1 s t Buoys ("Superbuoys") as Cardinal Marks with 9+ nautical mile lights and one Racon. As the Superbuoy n
e concept is new and still under development, the additional cost (Class 1 buoys estimated @ £24k per m
e buoy including moorings, superstructure, counterweight, and solar lighting system) are shown only in l E
the upper bound. n o
i Wave Rider Buoy plus peripheral equipment at ⁄40805. Conversion rate applied = 0.69. Based on t Single Waverider Buoy 26.0 30.0 35.0 c figures provided by Datawell BV, manufacturers of Waverider Buoys. Includes deployment costs. u r t s
n Navigation Buoy Deployment 42.0 46.0 51.0 Assumes the use of a single Anchor Handling Tug for 4 days at a charter cost of £11.5k per day. o C
l
a Additional Offshore Monitoring / Survey Includes procurement and installation. See the Environmental Management System (EMS) document t
i 6.0 8.0 15.0
p Equipment for details. a C Eight marker buoys at an estimated £4k per buoy. These mark the endpoint positions of the 11kV Eight Array Connection Marker Buoys 24.0 32.0 40.0 umbilicals to which the device arrays will be spliced. The cable will consist of three cores (one per phase), be XLPE insulated, and be armoured and protected for sub-sea submersible operation. It will also contain a fibre optic link. Estimated at £96.5 Offshore 33kV Armoured Sub-sea Cable 2295 2800 3360 per meter. Indicative cable length = 27,680 m as set out in Drawing WGEHUB/001. A cable length of 29 km gives the best estimate cost. The cost for sub-sea cable laying and route finding was prepared by Global Marine Systems. Cable laying vessel mobilisation is 10% of the total cost. Upper cost boundary includes extra £830k for winter Sub-sea Cable Deployment Cost 2 9 2 5 3250 4080 operations risk (Oct - April). Best estimate assumes May to September installation. These costs include insurance and management elements as well as operational risk contingency. Provisional preparation of sea bed for mud mat and sub sea hardware deployment. Subject to offshore Seabed Preparation 0.0 50.0 100.0 Vessel Support marine geotechnical survey. During Hardware Transformer and Installation Installation from floating platform with 25 tonne capacity crane facilities. These costs assume the use of a single Anchor Handling Tug at a charter cost of £11.5k per day. Budgeted are two days for each Umbilical Cable Connections 129.0 161.0 194.0 Deployment transformer and its peripheral equipment to be installed, two days for the installation of the sub-sea Connection Marker distribution unit, plus four days for mobilisation and contingency. Buoy Installation Sub total 8,395.0 10,290.0 12,753.0
Cost of fitting out the Wave Hub Management Company (WHMC) business office (location to be WHMC Office Furniture and Equipment 10.0 15.0 20.0 decided), with furnishings, computers, communications equipment, and welfare facilities as required.
t n
e Pick-up or utility vehicle for the transport of the ROV, fuel, and other equipment from storage in the Wave Hub Support Vehicle 20.0 25.0 30.0 m compound to a charter vessel and elsewhere as required. p i
u For the inspection of sub-sea cables and equipments, and the continued environmental monitoring of q
E the site. Best cost estimate is for a Seaeye Falcon (attached to the surface vessel and powered by a
C low drag umbilical) capable of camera inspection (a high resolution colour camera) and fitted with a five
M Inspection ROV 70.0 80.0 82.0 function manipulator capable of connector mating/de-mating. Lower cost bound represents the same H ROV capable of camera inspection but with a single function manipulator only (capable of retrieving W
d items by attaching lifting equipment, and cleaning by attaching cleaning tools). Includes £2k for n
a commissioning tests to approve capabilities.
s
e Miscellaneous Support and Maintenance Allowance for additional tools, materials and equipment for use during wave hub operations. E.g. first c
i 8.0 10.0 12.0
v Equipment aid equipment, safety equipment, and communications equipment. r e
S Initially, it is proposed that a standby Waverider Buoy, and two array connection point Marker Buoys
t
r (easily handled and most likely to go astray) will be stored as spares. This forms the best estimate cost o
p (with an additional £4k for other minor items) and assumes a replacement Cardinal Buoy can be rented p
u Spares 10.0 40.0 55.0 and deployed from the Trinity House depot in Swansea in the event one is lost. The smaller and more
S manageable Special Marks are not of the same importance as Cardinal Buoys and supply is usually good, therefore a spare is costed only in the upper bound. Moorings are not included as they can usually be recovered. The lower bound cost assumes there is no 'hot' spare waverider buoy. Sub total 118.0 170.0 199.0 Project construction costs 9,906 12,097 15,092 Project Capital Cost Total 10,921 13,455 16,952
Note - The costs shown are estimated at November 2004.