perpetuus tidal energy · 2015. 10. 28. · smd responded straum as no response 3.3 axial flow...

PERPETUUS TIDAL ENERGY

CENTRE LTD PTEC Developer Consultation

Date – October 2013

ITP/REF – UKP 1191

PTEC Developer Consultation Report

UKP1191 i October 2013

This project has been co-funded by ERDF under the INTERREG IVB NWE programme. The report

reflects the author’s views and the Programme Authorities are not liable for any use that may be made

of the information contained therein.

Perpetuus Tidal Energy Centre Ltd

IT Power reference: UKP1191

October 2013

Contractor:

IT Power

St. Brandon’s House

29 Great George Street

Bristol, BS1 5QT, UK

Tel: +44 117 214 0510

Fax: +44 117 214 0511

E-mail: [email protected]

www.itpower.co.uk

Document control

File path & name I:\Data\0WorkITP\0Projects\1191 PTEC Phase 1 Delivery FEED &

EIA\2 Work\Developer consultation\

Author J. Hussey, M. Leybourne

Project Manager J. Hussey

Approved

Date October 2013

Distribution level Final

mailto:[email protected]://www.itpower.co.uk/


UKP1191 ii October 2013

TABLE OF CONTENTS

1 INTRODUCTION .............................................................................. 1

1.1 PTEC ................................................................................. 1

2 SCOPE AND METHODOLOGY ............................................................... 1

2.1 Scope ................................................................................ 1

2.2 Key Objectives ..................................................................... 1

2.3 Methodology ........................................................................ 2

2.4 Parameters for Discussion ........................................................ 2

3 DEVELOPERS ................................................................................. 3

3.1 Turbine Neutral Platforms ........................................................ 4

3.2 Floating Devices (Axial Flow) ..................................................... 5

3.3 Axial Flow (Bottom Mounted) .................................................... 5

3.4 Cross Flow (Bottom Mounted) .................................................... 6

3.5 Other ................................................................................. 7

4 CONSULTATION RESPONSES ............................................................... 8

4.1 Interest in PTEC and Timing ...................................................... 8

4.2 Site Design / Layout ............................................................... 9

4.3 Device Design / Configuration ................................................... 9

4.4 Foundations / Moorings ........................................................... 10

4.5 Electrical Infrastructure .......................................................... 11

4.5.1 Ratings and Voltage ....................................................... 11

4.5.2 Power Electronics ......................................................... 11

4.5.3 Isolation ..................................................................... 11

4.5.4 Communications ........................................................... 11

4.5.5 Low voltage / Back-up Electricity Supply .............................. 12

4.6 Installation Approach .............................................................. 12

4.6.1 Vessels ...................................................................... 12

4.6.2 Installation Port Requirements .......................................... 12

4.7 Operation and Maintenance Considerations .................................... 12

4.8 Other ................................................................................. 13

5 FUTURE MARKET GROWTH PREDICTIONS ................................................ 13

5.1 First Arrays .......................................................................... 13

5.2 Larger ‘Commercial’ Projects .................................................... 14

6 CONSIDERATIONS FOR PTEC INFRASTRUCTURE AND ROCHDALE ENVELOPE ......... 15

6.1 Size and number of berths / cables ............................................. 16

6.2 Voltages ............................................................................. 16

6.3 Progress towards Design Freeze ................................................. 17

APPENDIX A: DEVELOPER QUESTIONNAIRE ....................................................... 0

7 INTRODUCTION .............................................................................. 1

7.1 Scope ................................................................................ 1

7.2 Key Objectives ..................................................................... 1

8 QUESTIONNAIRE ............................................................................. 2


UKP1191 1 October 2013

1 INTRODUCTION

This document summarises the results of the developer consultation carried out as part of

the FEED work for the PTEC project.

The developer consultation will be used to determine the technical requirements and level

of interest in the site by the leading tidal technologies. Also, importantly the consultation

will be used to determine the preliminary site layout, outline Rochdale Envelope, and input

into the EIA, infrastructure requirements and project design statement.

Thirty nine of the most advanced or promising tidal technology developers were contacted

as part of this exercise, these comprise companies who are already in discussions with PTEC

about potential deployments as well as other companies identified as potential customers.

The full list of developers approached can be found in Section 3.

A copy of the questionnaire used can be found attached as Appendix A. The answers to these

questions are summarised, analysed and discussed anonymously in Section 4.

1.1 PTEC

The Perpetuus Tidal Energy Centre (PTEC) is a managed demonstration facility for tidal

energy developers; suitable for the deployment of up to full scale single units and small

arrays from prototype to pre-commercial demonstrators. The offshore facility will be a

20MW demonstration site located approximately 2.5km to the south of St. Catherine’s Point,

and will include grid connection via subsea cables as well as navigation aids and monitoring

equipment.

2 SCOPE AND METHODOLOGY

2.1 Scope

The purpose of the consultation was to obtain a coherent list of requirements from

technology developers that can inform the FEED study for the design of the electrical system

and integrate effectively with the consenting process. The outputs from this consultation

will be captured in the preliminary site layout, outline Rochdale Envelope, and input into

the EIA, infrastructure requirements and project design statement.

IT Power asked 40 developers, in high level terms, about their potential timescales for

deployment, as well as a series of technical questions relating to their technology.

IT Power did not discuss any commercial matters relating to the developers or PTEC.

2.2 Key Objectives

The four main objectives for the developer consultation were as follows:

1. Obtain information to define requirements for the FEED Study, comprising:

Technical data relating to the device.

Infrastructure requirements.

Deployment plans and requirements.

O&M plans and requirements.

Data to define the Rochdale Envelope and project design statement.



2. Understand the approximate deployment timescales expected by the developers.

3. Understand the ideal services that they would require from PTEC.

4. Understand the ideal port and onshore support infrastructure requirements on the

Isle of Wight.

2.3 Methodology

A document detailing the developers to be contacted, information about each, and the

approach to be used (who and how contacted) was produced for approval by PTEC.

A questionnaire was developed, based on the information described in section 2.4. This

questionnaire was filled in from the result of face-to-face meetings or during phone

conversations where possible, and was sent out by email where this was not the case. The

contents of the questionnaire were used to loosely guide conversations with the developers

in order to capture all of the necessary information and was agreed by PTEC before it was

issued. The questionnaire is attached as Appendix B.

In addition, an information document providing an introduction to PTEC was produced which

outlined the work that has been carried out to date and general information about the

project including key headline data such as bathymetry and typical flow velocities. This was

sent to the selected developers to help sell the concept of PTEC, show how well advanced

the project is and to raise their awareness and interest in PTEC. This document was also

agreed by PTEC before it was issued.

2.4 Parameters for Discussion

IT Power discussed the following parameters with the developers:

Site design

Layout of berths within PTEC

Potential layout of devices and infrastructure within the berths

Connection to transmission infrastructure

Number of devices, if deployed in an array

Timing

Approximately when will the device(s) be deployed

What would be the intended length of deployment

Device design

Device configuration (axial/transverse/other)

Surface piercing/floating/sub surface

Foundation/mooring type and design (GBS/piled)

Footprint of deployment

Blade number, dimensions and rotation speed

Electrical output – rated capacity and voltage

Control (specifically location of converters), communications and electrical

isolation methodology

Installation approach

Duration and seasonality of offshore installation activity



Installation equipment and vessels to be used

Methodology

Port requirements

Hard standings and road access

Operational and maintenance considerations

Personnel and vessels required

Frequency of scheduled maintenance interventions

Frequency and type of scheduled surveys

Unscheduled maintenance

Back-up electricity supply requirement

Port requirements

Decommissioning

Approach to decommissioning

Other onshore support infrastructure requirements

Ideal services that a developer would expect PTEC to provide

Other

Personnel involved during deployment

Health & safety considerations

Key results of any prior EIA studies

Willingness for sharing of data (environmental monitoring)

The answers to these questions and all additional comments were tabulated for ease of

collation and comparison.

These are summarised and discussed in Section 4; to ensure confidentiality, this is done

without reference to the developers themselves or the source of any particular response.

Where developers were uncertain about their approach or the detail required, IT Power has

endeavoured to fill in the data as accurately as possible, based on our knowledge of similar

systems. Where this has been done, it is noted in the report.

3 DEVELOPERS

The following 40 tidal technology developers were contacted during this work. These

represent advanced developers whose further development timescales are likely to fit those

of PTEC, as well as promising early stage technologies, and those who have expressed an

interest in the site.

For the purposes of this report, the developers have been categorised into the flowing:

Turbine Neutral Platforms

Floating Devices (Axial Flow)

Axial Flow (Bottom Mounted)

Cross Flow (Bottom Mounted)

Other

Comments on the applicability of these technologies and their level of interest in the site

are summarised in Sections 3.1 to 3.5.



1. Andritz Hydro Hammerfest

2. Aquascientific

3. Atlantis Resources Corporation

4. BioPower Systems

5. Blue Energy Canada

6. Bluewater Energy Services B.V.

7. Blue Tidal Energy

8. Clean Current Power Systems

9. Ecomerit Technologies - Aquantis

10. ETI

11. Flumill

12. Green-Tide Turbines

13. Hyundai Heavy Industries

14. Kawasaki Heavy Industries

15. Kepler Energy

16. Marine Current Turbines (MCT)

17. Minesto

18. Nautricity Ltd

19. Nova Innovation Ltd

20. Ocean Flow Energy

21. Ocean Renewable Power Co. LLC

22. OpenHydro

23. Sabella SAS

24. Scotrenewables

25. SeaPower Gen Ltd

26. SMD Hydrovision

27. SME

28. Straum - Hydra Tidal

29. Sub Sea Turbines

30. Swan Turbines

31. Tidal Energy Limited

32. Tidal Generation Ltd (TGL)

33. Tidal Sails AS

34. Tidal Stream Limited

35. Tocardo BV

36. Toshiba

37. Verdant Power

38. Verderg

39. Voith Hydro

40. QED Naval

3.1 Turbine Neutral Platforms

Turbine neutral platforms provide a means to mount several turbines and associated

electrical systems on a common platform. The platforms are designed to accept different

types of turbines from different developers. There are a wide variety of approaches used

for the platform, from surface piercing, floating to sub-surface bottom mounted. Therefore

different anchoring methods are used, with most opting for either piles or gravity anchors.

Turbine neutral platforms are well suited to the PTEC site given the water depths and berth

sizes. These platforms could also provide the opportunity to demonstrate several different

turbines without the need to completely change the platform itself over the lifetime of the

project.

The turbine neutral platforms consulted as per of this exercise were:

Developer Response Received

Bluewater Energy Services B.V. Responded

SME Responded

Tidal Stream Ltd Responded

QED Naval Responded



3.2 Floating Devices (Axial Flow)

Floating devices are intended to exploit the faster flow speeds encountered near the

surface; the designs can reduce the foundation infrastructure required, but require

integrated mooring and anchoring solutions. The anchors have to be selected based on the

seabed conditions at the site. There is often some surface piercing element to the design.

The deeper water at PTEC, when compared to many good tidal sites, makes it ideal for

floating technology. Their deployment at the site may however have implications for

consenting from a navigation and visual impact point of view.

Floating devices consulted as per of this exercise were:


Ecomerit Responded

Nautricity No response

Ocean Flow Energy Responded

Scotrenewables Responded

SMD Responded

Straum As No response

3.3 Axial Flow (Bottom Mounted)

These devices are often referred to as horizontal axis tidal turbines (HATTs).They are similar

to technologies used in wind energy. Generally, axial flow turbines are composed of a

number of blades which are connected to a hub which rotates about a horizontal axis. Axial-

flow turbines extract energy from moving water in much the same way as wind turbines

extract energy from moving air. The turbine is aligned so that it points into the flow with

the rotational axis parallel to the flow. The turbine rotor may be housed within ducts to

create secondary flow effects by concentrating the flow and altering the flow velocity of

the water passing through the turbine to focus the extractable energy.

There are also various approaches to control - rotors with fixed pitch (stall controlled) and

variable pitch turbine blades are both under development in the industry.

Axial flow turbines are the most well developed type of tidal energy converter technology,

with a number of device concepts at a pre-commercial stage.

These developers use monopoles, tripods, quadrapods, or a similar type of jacket / frame

to mount their turbines and are held in place using either piles or weights.

Most current 1MW, bottom mounted turbines are looking for water depths of 40 to 50m,

although a few are looking to deploy larger machines in even deeper water. The range of

water depths at the site provide a number of locations for such deployments. A number of

these developers however are concentrating on smaller machines, and the lack of areas

shallower than 35m at the site could prove difficult for these.



Axial flow, bottom mounted turbines consulted as per of this exercise were:


AndritzHydro Hammerfest Responded

Atlantis Resources Corporation Responded

Clean Current Responded

Green-Tide No response

Hyundai Heavy Industries No response

Kawasaki Heavy Industries No response

MCT (Siemens) Responded

Nova Innovation Responded

OpenHydro Responded

Sabella SAS No response

Sub Sea Turbines No response

Swan Turbines No response

TGL (Alstom) Responded

Tidal Energy Limited Responded

Tocardo Responded

Toshiba No response

Verdant Isles Responded

3.4 Cross Flow (Bottom Mounted)

These devices have a cross-flow design with the blades rotating about an axis perpendicular

to the direction of the tidal flow mounted either vertically or horizontally. Cross-flow

turbines have not reached the same level of development as axial flow turbines, with no

full scale, pre-commercial devices deployed. A cross-flow turbine rotates in one direction

making it suitable for bidirectional tidal flows. As with axial-flow turbines, some designs

also make use of ducts to enhance flow. Devices typically have a lower hydrodynamic

performance than axial-flow turbines, but have other benefits such as rectangular swept

area, better suited to shallow tidal flows, and scalability (up to multi-MW devices).

Straight bladed configurations are often referred to as Darrieus turbines in recognition of

the original patent holder Georges Jean Marie Darrieus. A helical bladed configuration of

the Darrieus turbine (often referred to as a Gorlov turbine after their original patent holder

- Alexandar m. Gorlov) can improve consistency of shaft torque output as well as improving

rotor self-starting characteristics.



As with the bottom mounted axial flow devices, the developers use monopoles, tripods,

quadrapods, or a similar type of jacket / frame to mount their turbines and are held in

place using either piles or weights.

A key advantage of cross flow turbines is the ability to deploy them in shallower water than

a similarly rated axial flow machine. As such, most developers of this technology are

targeting shallow water regions (less than 30m), the lack shallow water at PTEC could be a

problem for many of these.

Cross flow, bottom mounted turbines consulted as per of this exercise were:


Ocean Renewable Power Company Responded

Blue Energy Canada Responded

Blue Tidal Energy Responded

SeaPower Gen Responded

Kepler Energy Responded

3.5 Other

This category covers all other technologies that do not fit into the categories above.

Operating principals include, oscillating or ‘traversing’ hydrofoils, venturies, Archimedes

screws and novel applications of ‘standard’ turbine types.

The foundation systems envisaged for these technologies are broadly similar to those

employed by the classifications above.

Developer consulted as per of this exercise were:


Minesto Responded

Aquascientific No response

BioPower Systems No response

Flumill Responded

Tidal Sails No response

Verderg Responded

ETI Responded



4 CONSULTATION RESPONSES

IT Power obtained responses from 27 of the 40 developers consulted; the remainder declined

to do so or did not respond to approaches. Where known, IT Power have filled in details for

those who did not respond.

16 of the developers consulted have already constructed and deployed a full or near-

full scale prototype machine.

26 have tested a scale turbine in realistic conditions.

14 are still at the concept or preliminary design stage.

A summary of these developer’s responses is provided in the reminder of this section. To

ensure confidentiality, this is done without reference to the developers themselves or the

source of any particular response.

4.1 Interest in PTEC and Timing

Interest shown in PTEC by respondents was as follows:

18 developers stated they were interested in deploying technology at PTEC.

11 were very keen and / or are already in discussions with PTEC themselves about

such deployments.

7 saw the site as a possible back-up to their existing strategies if they didn’t go

according to plan.

7 developers were not interested in the site because they were only looking for

commercial sites or they had no intention of building projects.

Only 1 developer ruled out PTEC on the grounds of the electrical system. This was a

developer that required a single cable to shore for each turbine deployed.

Most respondents said they would be looking to deploy their first array project between

2016 and 2018. This was the case even for those who had not yet built their first full-scale

prototype; IT Power does not believe these timescales are realistic for these early stage

developers.

Table 1 below shows possible deployment scenarios for the site, based on those who have

expressed an interest in the site and have indicated a size project they would like to deploy.

The ‘possible projects’ column includes those who see PTEC as a back-up as well as early

stage developers with expressed very ambitious plans. ‘Realistic Projects’ only includes

advanced developers who have expressed a real interest or those who have the potential to

meet their stated timescales.

It is important to note that for the vast majority of devices, deployment is contingent on

funding to build the turbines for the site. In several cases, funding is still required to design

or prove their technology.



Table 1: Possible Deployment Scenarios for PTEC

Year Possible Projects (MWs) deployed Realistic Projects (MWs) deployed

2016 10 Projects, 23.575 MW 6 Projects, 12.475 MW

2017 4 Projects, 18.6 MW 3 Projects, 15 MW

2018 5 Projects, 10 MW 2 Projects, 6 MW

2019 3 Projects, 9 MW 1 Project, 4 MW

2020 1 Project, 3 MW 1 Project, 3 MW

Most of the developers questioned were looking for a lease term of at least 10 years, but

ideally as long as possible.

4.2 Site Design / Layout

Only 4 developers were interested in deploying small / single machines at the site, although

this is to some extent driven by how the site has been presented and the most advanced

developers questioned.

The developers of small devices had turbines rated between 30kW and 200kW. In some cases

this was due to a deliberately slow scaling up process, others see a substantial market for

small turbines, so do not intend at this stage to scale up their turbines. IT Power is aware

of at least 12 developers looking to exploit this market. There is therefore scope to have a

1MW berth available for a nursery site within the site.

Sizes of berths that developers were interested in were as follows:

5 wanted a berth of 6MW or more

3 wanted a berth between 3.1MW and 5.9MW

5 Wanted a berth between 1.1MW and 3MW

5 wanted a berth up to 1MW

8 developers required deep water (greater than 35 - 40m), whilst 11 required shallow areas

(less than 30m) at the northern boundary of the site.

4.3 Device Design / Configuration

This element of design was understandably the most well considered, with developers

having put a lot of time and effort into the design and layout of their rotors and power take

off system.



The majority of developers consulted were using axial flow turbines. These were also

generally the most advanced:

24 of the developers consulted were developing axial flow turbines.

5 were developing cross flow turbines.

6 were exploiting some other power take off configuration.

4 were developing turbine neutral platforms.

8 developers have or are intending to use large rotors of 16m diameter or more. All but 6

had rotational speeds of 15rpm or less; these 6 had rotational speeds above25rpm. The

majority (18) were 3 bladed.

9 developers employed pitch control of the rotors.

17 developers had a design employing more than one rotor on their structure; this includes

the developers of turbine neutral platforms

11 of the 39 developers approached would intend to deploy surface piercing technology at

the site.

4.4 Foundations / Moorings

Only 17 of the 39 developers consulted had a definite foundation / anchor design. 9

developers indicated that foundation choice was site specific, this was particularly the case

with the floating systems. Most of the early stage developers had not yet fixed this element

of their design.

A few developers are also concentrating on the turbine element only, and will be relying on

others to supply mounting (foundation) systems such as the developers of ‘turbine neutral

platforms’

The breakdown of foundation / mooring concepts for those with a definite solution was as

follows:

Monopile: 7 developers

Multi-pile (pin piles) : 16 developers

Tripod - 8 developers

Qudrapod - 1 developer

Other - 7 developers (includes pinned anchors for mooring lines of floating

systems)

Gravity base: 7 developers

It should be noted that there is some overlap between these categories, i.e. a few

developers make use of a tripod gravity base (tripod support structure secured with ballast

weights).

The footprint of deployment varied significantly between the developers, with single,

bottom mounted turbines requiring a small seabed area per device (



4.5 Electrical Infrastructure

4.5.1 Ratings and Voltage

Most machines were rated at 1MW or more. 11 developers were intending to develop

machines rated at over 2MW, the majority of these will use multiple turbines on a single

platform to achieve this. Only 3 developers are intending to build individual turbines rated

2MW or more.

Most developers did not have a definite export voltage in mind, this was largely because

most had not yet reached a point where they had to specifically define this. Others were

currently exporting at a relatively low voltage, and intended to scale this with device size.

Most of the advanced developers (11) were currently exporting at 6.6kV. This is largely

driven by the system voltage at EMEC, which is 6.6kV, and to some degree by the cost and

availability of subsea connectors certified for higher voltages. Many of the advanced

developers stated that they intended to export at 11kV, in the long run, but were not yet

at that stage.

13 developers said they were able to export at either 11kV or 6.6kV (possibly even 33kV),

depending on the requirements of the PTEC infrastructure, through appropriate transformer

choice.

Only 3 developers were intending to export at their generator voltage (with no on-board

transformer), and were therefore looking for voltages of less than 6.6kV.

The majority of developers would connect to the PTEC cable infrastructure by a dry mate

connection, 7 device developers preferred a wet mate connection.

4.5.2 Power Electronics

Most developers intend to incorporate converters and power electronics into the ‘nacelle’

of their machine. 6 were planning converters onshore or in their own sub-sea hub. 13 had

not considered this element in detail and were therefore unsure.

4.5.3 Isolation

Most developers (14) were planning a circuit breaker on each individual machine, although

all developers expected their cable / connection to be isolated for connection and removal

of machines. The remainder are unsure or did not respond. Only 3 developers are not

intending a circuit breaker on-board their machine.

4.5.4 Communications

All but 2 of the developers questioned intended to use fibre optic cables for communication

with their device. Most of those who had previously deployed a large scale machine (at

EMEC) also intended to use Wi-Fi or a radio link as a backup.

The 2 developers who expressed a preference not to use fibre optics preferred to use a

copper data cable due to the expense of fibre optic converters, slip rings etc.



4.5.5 Low voltage / Back-up Electricity Supply

10 developers said they required a low voltage, auxiliary / backup electricity supply. 6

stated that this was a ‘nice to have’ but could be obtained from their own on-board

transformer or batteries if necessary. Few developers consulted were able to give an

indication of what this supply should be; responses ranged from 1kV to 20kW.

4.6 Installation Approach

Installation strategies varied widely depending on the foundation / mooring approach of the

developer.

7 developers intend to install foundations, then lower, ballast or pull the nacelles /

turbines down onto the foundation.

9 developers intend to use floating systems that remain on the surface attached to

pre-installed anchors and mooring lines.

11 developers plan to install their foundation and turbine as a complete unit.

4.6.1 Vessels

The most common installation vessel required was a DP vessel; 19 developers required one

for at least part of their installation. 8 developers required multicat or tug boats, although

most of these required a DP vessel (or moored barge) for their foundation or anchor

installation. Only 1 developer intended to use a bespoke installation vessel.

This drove sea-state restrictions, which was generally a maximum of 1.5m Hs. Only one

developer believed they may be able to install their technology in larger sea-states than

this.

4.6.2 Installation Port Requirements

Most developers who have considered this aspect required a laydown area of at least 60m2,

a quay with hardstandings to lift at least 200t (up to 400t) and a draft suitable for the DP

installation vessel used (approximately 8m).

6 developers intend to mobilise their machines directly from the fabrication yard, so did

not see an installation port as a requirement.

The majority of developers consulted had not considered this factor in enough detail to

meaningfully answer.

4.7 Operation and Maintenance Considerations

O&M strategies also varied considerably, with developers falling into one of two camps.

Those with an intervention period of several years (generally between 2 and 5) – 8

developers.

Those who intend to access their machines for maintenance planned and unplanned)

many times during the years – 8 developers.

The remainder had not considered this aspect in detail or did not respond.



The first group, consisted largely of those advanced developers with very simple technology,

the majority of their complex systems onshore and with more complex access requirements.

There were also a few early stage developers in this category, with possibly unrealistic

expectations around reliability of systems and components.

Access to machines for maintenance was planned in a manner broadly similar to their

installation process.

7 developers were intending to carry out all but the most major of maintenance

activities on-board machines whilst on site.

22 intend to remove machines to an O&M port to carry out this work.

4.8 Other

Additional services, infrastructure or requirements from developers were as follows:

Support for consenting. Reduction of regulatory burden.

Relationships with universities (or similar) for pre and post construction monitoring.

Agreed monitoring strategy across the site / all projects, supplied by PTEC as part

of services.

Metocean conditions - particularly tidal flow monitoring, but also realtime wave

monitoring and forecasting for the floating devices.

Metering of electrical output from devices / arrays.

A range of suitable, general vessels and equipment available, including experienced

crews with knowledge of the area, for all developers to hire as and when required.

Office space.

A site manager that can co-ordinate work and emergency plans across the site.

Engineering design services available.

Third party performance assessments, for standards & certification.

Nearly all developers indicated that they were in principle happy to share monitoring data.

5 FUTURE MARKET GROWTH PREDICTIONS

To date, the UK Government has not set an official target for marine energy but the latest

roadmaps and studies have indicated a potential to install anywhere from 100MW to 400MW

of tidal energy by 2020.

5.1 First Arrays

The industry at present is in a strong position and is poised to begin deploying the first small

commercial arrays. These are intended to prove that multiple devices can operate together

in the same location and supply power to the grid at a rate close to utility scale. The

successful demonstration of these first arrays will be critical in the progression of the

industry and will result in larger, fully commercial arrays being deployed with a significant

increase in the total installed capacity. Based on the current state of the industry and

knowledge of the activities of technology and project developers, IT Power believes that it

is likely to be at least 2 – 3 years before these first, small arrays are installed and grid

connected in the UK.



Demonstration sites like PTEC that allow such array projects to be built without each

developer having to bear the full cost of the electrical infrastructure and development risk

will have a key role to play in these early projects.

During the demonstration and proving of first generation tidal devices, new second

generation technologies are starting to be developed with the aim of reducing costs and

increasing output. This will build on the learning achieved through the operational

experience gained from the first generation turbines. Such advances will see larger turbines,

multiple units being deployed on a common structure, improved deployment and recovery

methods and lower installation costs. This will allow developers to access a large proportion

of the UK’s tidal stream resource with technologies that are able to be installed at deep

water, high velocity and hostile sites. Third generation machines are expected to target at

low flow sites; very deep water or very shallow water. This will open up a huge area of

resource, often ignored in estimates of exploitable potential. Exploitation of these sites has

even more potential outside of the UK.

The Crown estate has so far issued 26 leases or Agreements for Lease to tidal projects,

totalling over 1.3GW of potential capacity. 16 of these are for small array projects of 10MW

or less (totally around 50MW). Each of these projects represents a credible developer and

thus a potential customer for PTEC. Many of these projects will not get constructed for

various financial and consenting reasons, making PTEC an even stronger prospect for these

developers.

5.2 Larger ‘Commercial’ Projects

Following these initial arrays, developers will seek to optimise the energy yield from each

unit and the total combined array output. With the learning acquired from the first arrays

and the installation of second generation arrays, the improved device technology should

demonstrate cost reductions to increase the commercial competitiveness of tidal energy

against other forms of renewable generators. The magnitude of public revenue support for

tidal energy is expected to reduce over the next decades as the technologies mature and

therefore require less financial support. DECC aims for the revenue support to reach parity

with offshore wind by approximately 2027, although this is likely to be flexible, based upon

the progress of the industry. It is, however, imperative that the cost of energy decreases

rapidly in order for the tidal industry to become cost competitive with offshore wind and

other large scale, renewable generating technologies before 2030.



Figure 1: IT Power’s predictions for the deployment of tidal energy converters,

including capital and revenue support mechanisms.

(Adapted from the Marine Energy Action Plan Report, DECC 2009

The roadmaps that have been generated have been useful in guiding Governmental policies

and conveying the needs and requirements of the industry however, the predicted

timescales and magnitudes of the deployment of marine energy have all been optimistic. IT

Power’s timescale predictions for the deployment of tidal energy are shown in Figure 1 are

based on the company’s experience in the industry and involvement with many tidal

development projects. Whilst these may seem pessimistic, in terms of timescales, than

many of the roadmap predictions made over the recent years, they represent a more

realistic timescale over which significant engineering challenges will be overcome and the

large scale deployment of TECs at a utility level will be made.

6 CONSIDERATIONS FOR PTEC INFRASTRUCTURE AND ROCHDALE ENVELOPE

The responses obtained during this consultation prove that PTEC will have to be very flexible

in order to accommodate as many developers as possible, and the Rochdale Envelope would

need to be very broad. The difficulty and expense of incorporating all technologies

consulted as part of this work would not be worthwhile. The suggested ‘extremes’ that

could be covered by the Rochdale Envelope are shown in Table 2 below. This will be further

refined with appropriate sample technologies to represent these extremes selected in

collaboration with PTEC and the EIA team. As part of the Rochdale envelope and EIA process,

consideration will also need to be given to exclusion/safety zones and process for defining

and implementing these if required.



Table 2: Considerations for Rochdale Envelope

Element ‘Worst case’ Possibility

Number of machines (complete units,

which could comprise multiple rotors) Up to 30

Device configurations Axial flow, cross flow, ducted

Rotors

Up to 25m rotor diameter

Up to 70 individual rotors

Up to 60rpm

Location Bottom mounted, mid-water column,

floating / surface piercing

Foundations (structure) Monopile, tripod, frame up to (30m x

30m)

Moorings, anchors (securing system) Monopile, pinpiles, gravity base

Up to 90 individual piles installed

Cables

Up to 6 separate export cables

Up to 30 separate ‘inter-array’

(turbine) cables

With regards to the infrastructure supplied by PTEC, the following should be considered:

6.1 Size and number of berths / cables

5 developers indicated they wanted a berth of at least 6MW. These were generally the most

advanced developers with realistic possibility of coming to PTEC in the timescales indicated,

although 3 of these were only considering PTEC as a backup. The ability to accommodate at

least 2 berths of this size would seem appropriate. If the size (ratings) of each berth / cable

could be varied, this would reduce the risk of unallocated capacity at the site.

Given the projects highlighted in Table 1, 6 individual berths would seem appropriate.

6.2 Voltages

Nearly as many developers stated they would need to export power at 6.6kV as said 11kV.

Cables at both voltages, with the flexibility to change the voltage would be beneficial. This

could be achieved with multiple cables to shore and tap changers on the main transformer.

A separate cable to shore for each berth, would also enable accommodation of those

developers looking to keep their control equipment onshore or in their own hub, as well as

those not planning an isolator in their own turbine.

Given the number of developers who stated they would need an auxiliary power supply in

‘their’ cable, this element should be investigated. The cost of supplying this is likely to be

small when compared to the cost of the cables.



6.3 Progress towards Design Freeze

Table 2 above summarises the considerations for the Rochdale Envelope coming out of this

consultation. This will be further refined with appropriate sample technologies to represent

these extremes, selected in collaboration with PTEC and the EIA team.

The current FEED programme should reach a design freeze in March 2014; however, there

is a requirement to accelerate this for the benefit of the EIA work; and therefore reach

design freeze as soon as possible

There may still be some flexibility after this date with regards to the size and rating of a

particular berth, including voltage; but the number of cables (and thus berths) as well as

the overall size of the project (20 or 30MW) will have to be fixed at this point. Other

elements that need to be fixed at the same time will be:

Size (extent) of site

Cables and routes as well as installation/protection measures (on and offshore)

Type of landfall

Location and size of onshore substation

Grid connection point

The Rochdale Envelope and associated technologies /number that define it

It should be noted that even after design freeze, these elements will not be set in stone

and if there is a strong enough reason for them to change then this may be accommodated.

Design freeze will be achieved following a review of the second issue of the design options

report and a design workshop with IT Power, Royal HaskoningDHV and PTEC. It will also be

dependent on an agreed strategy for the grid connection application process, the ground

conditions report and the cabling options report.



APPENDIX A: DEVELOPER QUESTIONNAIRE

PERPETUUS TIDAL ENERGY

CENTRE LTD

PTEC Developer Questionnaire

7 INTRODUCTION

The Perpetuus Tidal Energy Centre (PTEC) is a managed test / demonstration facility for tidal energy

developers; suitable for the deployment of up to full scale single units and small arrays from prototype to

pre-commercial demonstrators.

The offshore facility will be a 20MW demonstration site located approximately 2.5km to the south of St.

Catherine’s Point, and will include grid connection via subsea cables as well as navigation aids and

monitoring equipment. For further details please see the ‘PTEC Project Introduction’ document.

7.1 Scope

The purpose of this industry consultation is to obtain a coherent list of requirements from tidal developers

that can inform the FEED study for the design of the electrical system and integrate effectively with the

consenting process to determine preliminary site layout, outline Rochdale Envelope, and input into the

EIA, infrastructure requirements and project design statement.

NOTE: The FEED consultation will not include discussions of a commercial nature; this will remain the

responsibility of the PTEC team.

7.2 Key Objectives

There are four main objectives for this developer consultation:

1. Obtain information to define the project requirements for the FEED Study, which will comprise:

Technical data relating to the device.

Infrastructure requirements

Deployment and recovery plans and requirements.

O&M plans and requirements.

Data to define the Rochdale Envelope and project design statement.

2. Understand the approximate deployment timescales expected by developers.

3. Understand the ideal services that they would require from PTEC.

4. Understand the ideal port and onshore support infrastructure requirements on the Isle of Wight.

NOTE: The details given by all participants in this consultation will be held in the strictest confidence

and will not be shared outside of the PTEC project team.

IT Power and PTEC are prepared to enter into confidentiality agreements with all who wish in this regard.

8 QUESTIONNAIRE

Question Answer

Genera

l

Would you be interested in

deploying a project at PTEC?

Please summarise your testing

programmes and (3rd party)

verification to date.

Tim

ing

Approximately when would you

be looking to deploy machines

there?

What would be the intended

length of deployment for your

project?

Sit

e d

esi

gn

How may devices would you be

looking to deploy?

Comments on the number /

layout of berths within PTEC?

Potential layout of devices and

infrastructure within a berth?

Devic

e d

esi

gn

Device configuration (axial

flow/transverse/other)

Surface piercing/floating/sub

surface

Foundation/mooring type,

number and design (e.g. gravity

base/piled)

Footprint of deployment

Number of blades, dimensions

and rotation speed

Electrical output – rated capacity

and voltage

Control strategy:

Pitch/stall regulation

(active, passive, speed

etc)

Type & location of

converters

Communications and electrical

isolation methodology

Connection to transmission

infrastructure

Inst

allati

on a

ppro

ach

Installation methodology

Installation equipment and

vessels to be used

Duration and seasonality

(seastate restrictions) of offshore

installation activity

Installation port requirements

(e.g. space, hard standings and

road access, etc)

Onshore support infrastructure

requirements

Oper

ati

on

al

and

main

tena

nce

consi

dera

tions

O&M strategy

Seastate restrictions for offshore

O&M

Personnel and vessels required

Planned frequency of scheduled

maintenance interventions /

surveys

Back-up electricity supply

requirement

O&M port requirements

Decom

m

issi

onin

g

Approach to decommissioning

Oth

er

Ideal services that a developer

would expect PTEC to provide

Other onshore support

infrastructure requirements

Key results of any prior EIA

studies

Willingness for sharing of data

(environmental monitoring)

Health & safety considerations

perpetuus tidal energy · 2015. 10. 28. · smd responded straum as no response 3.3 axial flow...

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