Results:

The role of the UK Energy Research Centre Marine Energy Research Network in developing a route map for marine renewable energy research is described and put into the context of previous and current marine energy research at a national and EU level. A summary of the route mapping process is given based upon the Batelle approach. Justification is provided for route mapping in terms of encouraging cooperation and collaboration within the community to develop a coherent reseach, development and demonstration strategy, which will be used to inform policy makers and funding bodies. Some preliminary outputs from the network are presented in the paper to encourage discussion.

This document is a project report for the project titled 'A wave/current flume for research on offshore renewable energy devices: with the first application on multiple heavy point wave absorbers.'

This project is concerned with marine energy in the form of waves and tidal streams which may in principle supply more energy than the UK needs. The main consideration when developing devices which utilise wave and tidal power in order to generate electricity is economic viability. In order to assess whether potential devices will be economically viable to produce and run, as well as to maximise their performance, it is crucial to rigorously test physical prototypes.

The aim of this project is provide a wave/current facility (flume) in which marine power devices can be properly tested because the influence of currents on wave devices and waves is often overlooked. For this project a wave maker was added to an existing 5m wide and 20m long environmental flume. The wave maker can generate regular, random and directional seas which is vital because the power generated is much reduced by random directional waves which occur in reality.

This briefing paper examines how renewables in Scotland are shaped by decisions taken by the Scottish Government, the UK Government and the EU. Drawing on interviews with stakeholders, it explores the potential impact of Brexit on Scottish renewables.

Brexit has the potential to disrupt this relatively supportive policy environment in three ways in regulatory and policy frameworks governing renewable energy; access to EU funding streams; and trade in energy and related goods and services.

Our briefing identifies varying levels of concern among key stakeholders in Scotland. Many expect policy continuity, irrespective of the future UK-EU relationship. There is more concern about access to research and project funding, and future research and development collaboration, especially for more innovative renewable technologies. The UK will become a third country forthe purposes of EU funding streams, able to participate, but not lead on renewables projects, and there is scepticism about whether lost EU funding streams will be replaced at domestic levels.

While there is no real risk of being unable to access European markets even in a No-Deal Brexit scenario, trade in both energy and related products and services could become more difficult and more expensive affecting both the import of specialist labour and kit from the EU and the export of knowledge-based services. Scotlands attractiveness for inward investment may also be affected.

• Using a systems engineering approach to the development of wave energy technologies
• Using ESME (ETI’s modelling tool)
• Least Cost Optimisation - Wave
• Least Cost Optimisation - Tidal
• Installed Capacity
• Analysis
• Conclusions

This document is a profile for the project titled 'Development of a 5^th Scale Tidal Turbine - SRTT'.

The objectives for this project are:

This project aims to design and construct a 5^th scale engineering model of a tidal turbine system. The system will be tested under controlled and actual conditions and in doing so a numerical model will be developed. Ultimately enough information will be acquired to allow the future development of a full scale demonstrator system.

The objectives of this project are:

Having demonstrated the fundamental proof of concept for the EB Frond Wave Energy Collector through the Phase one project, the next step (the Phase two project) was proposed to further assess the technical and commercial viability of the EB Frond concept through the development of the existing mathematical and physical modelling methods.

The EB Frond project is the wave energy programme developed by The Engineering Business Ltd (EB), following on from an original idea conceived at Lancaster University.

To meet the identified objectives, and take the EB Frond programme forward along the preferred development route, a number of specific tasks were identified for Phase two. These encompassed:

1. Introduction
2. Small-Scale Testing
3. Test Results
4. Mathematical Modelling
5. Analysis and Interpretation
6. Survivability
7. Economic Model
8. Development Route to Full-Scale Production
9. Conclusions

The following points emerged as the most important:

• There needs to be a link between physical modelling of devices and biological models or data sets
• The impact on sea-mammals, birds and fish should be urgently addressed
• Any Environmental Monitoring should be in 3 stages: before, during and after device installation, and each stage should ideally take place over at least 12 months to take into account seasonal effects. Time is not on the device developer’s side
• There is very little data available on the movement of birds and sea mammals, and nothing can be ascertained about their interactions with devices until in situ data/observations are made (e.g. at EMEC)
• Continuous monitoring is very expensive, time consuming and difficult. At present there is little funding available and what funding there is, is very difficult to release
• The boundaries of acceptability have to be defined to assist developers.
• There should be an agreed environmental monitoring programme that all developers are encouraged to follow at all sites (bearing in mind particular sensitivities of site)
• It is not clear what parameters should be measured and what is the best technology available for an environmental monitoring programme.
• A monitoring programme should concentrate on possible showstoppers for marine developers

• There is a demonstrable route to making tidal stream energy competitive with other low carbon technologies;tidal stream has the potential to be a material part of the future UK energy system
• Tidal energy is capable of supplying 20-100TWh of the 350TWh of the UK’s annual electricity demand
• Potential impact of the tidal industry on UK GDP is estimated to be in the range of £1.4 - 4.3billion
• The cost of energy from tidal stream arrays can compete with other low-carbon sources
• The sector has transitioned in recentyears from small-scale prototype devices, through to full-scale demonstration and early commercial arrays are now in development
• The UK leads the rest of the world in the development of tidal devices
• Significant cost reduction will require coordinated investment in supply chain innovation, processes and peopleArray and device design integration is vital

• Even with aggressive cost reduction and innovation activities, current attenuator wave energy technologies are highly unlikely to meet the ETI/UKERC marine energy roadmap targets, and are therefore unlikely to make a significant contribution to the UK energy system in the coming decades
• Radical new wave energy extraction and conversion system approaches are needed to reduce cost and increase energy extraction and reliability.This will provide a trajectory towards lower cost solutions in the long term.

This document is a summary for the project titled 'Flume modernisation and refurbishment'.

In order for the UK to meet its ambitious targets for energy production from renewable sources (10% of electricity by 2010, 15% by 2020) it needs to expand its capacity to generate all forms of renewable energy and marine energy is a big part of this. The development and production of new solutions for generating renewable energy, as well as contributing to meeting the UK's energy targets, provides business opportunities internationally.

This project is concerned with marine energy in the form of tidal streams and it is reasonably straightforward to generate power from moving water, the difficult bit is doing it efficiently and at lowest cost. In order to assess whether potential devices will be economically viable to produce and run, as well as to maximise their performance, it is crucial to rigorously test physical prototypes. Model testing in the field can be difficult, expensive and time consuming with variables such as weather affecting results considerably on a daily basis. For this reason it is much easier to recreate controlled conditions within a laboratory where repeatable experiments can be set up. Similar to a wind tunnel for air flow and study of aeroplanes, a water flume can be used to study tidal flows and how devices will interact to generate electricity. To do this the conditions created in the various near shore locations the devices would operate have to be replicated in a laboratory environment. The aim of this project is provide a wave/current facility in which tidal power devices can be properly tested.

The flume was opened on the 10th August 2009 and can produce currents simultaneously with any type of wave condition. The first project to make use of the facility was the nationally renowned Manchester Bobber which is a floatation device which generates electricity through a grid of floats which 'bob' up and down with the motion of the sea. There are also several other projects using the facility such as one being carried out by a group of MEng students which is sponsored by Yorkshire water.

This Marine Energy Technology Roadmap, jointly developed by the Energy Technologies Institute (ETI) and the UK Energy Research Centre (UKERC) represents a major update to the ETI/UKERC 2010 Marine Energy Technology Roadmap, a document created to identify and prioritise the key technology and deployment issues faced by the marine renewable energy sector in the UK. This update has primarily been created to reflect the changes and advancements within the marine energy sector that have taken place since 2010, but it also recognises the engineering challenges that remain and that must be overcome to enable the industry to progress rapidly to early array deployments.

The Office of the Deputy Prime Minister ('the ODPM') has commissioned this research into Planning for Renewable Energy as part of its New Horizons research programme. The New Horizons programme aims to introduce new research ideas, develop innovative, cross-cutting approaches to research and offer a forward-thinking perspective on medium- to long-term policy issues pertaining to the ODPM.

The specific objectives of the Planning for Renewable Energy research have been:

The research programme was devised in May 2002 and the research was conducted over the course of eleven months, commencing in October 2002.

The research is especially timely because the results are able to inform the revision of Planning Policy Guidance 22 (renewable energy) and the accompanying documentation for the new Planning Policy Statement 22 (renewable energy). The research has also been able to take account of the Energy White Paper, Our Energy Future, Creating a Low Carbon Economy (2003) and The Sustainable communities Plan (2003), both of which were published during the course of the project.

Perhaps the single most important concluding remark for ODPM is to point out that its extensive responsibilities for the built environment mean that it cannot avoid a significant role in the development of policies on renewables over the course of the next five to ten years. Indeed, given the potentially vital role of the linkages between planning, regeneration and governance, and the ODPM's responsibilities across these areas, the Department could reasonably be considered to be the most important in helping the country to become a low carbon economy

1. Introduction
2. Context of the research
3. The planning system and renewable energy
4. Community renewables and urban regeneration
5. Governance of renewable energy
6. Final conclusions and recommendations

The objectives for this project are:

Tidal energy is a largely untapped natural renewable energy resource and approximately 92% of available UK tidal energy resource exists in deep water.

SMD Hydrovision (SMDH) is a company with over 30 years experience designing subsea machinery and has developed the TidEl concept to exploit this resource.

TidEl consists of a pair of turbine/generators that are fixed together by a cross beam and secured to the seabed using a novel mooring system.

It is planned in this project to install a 1MW TidEl device at the EMEC facility off Eday in the Orkney Isles in 2006, where it will be subject to extensive testing over a prolonged period.

Numerical modelling of a WEC is presented in this paper along with some details of the experimental setup. Issues related to the numerical modelling of the single DOF (degree-of-freedom) motion of a surging point absorber WEC (wave energy converter) are outlined and a comparison with experimental data is presented. A commercial CFD code Flow-3D has been used for the numerical modelling and the ability of the code to simulate free surface linear waves and wavestructure interaction is evaluated in this paper.

The work is aimed at simulating a surging wave energy converter to achieve an optimized shape and to predict output power at a higher or full scale. The findings of this study may also serve as a reference point for the use of a commercial code such as Flow-3D for simulating such problems.

1. Introduction
2. Wave Tank Experiments
3. Numerical Modelling
4. Results
5. Conclusions and Future Work

The Pelamis Wave Energy Converter (WEC) is an innovative concept for extracting energy from ocean waves and converting it into a useful product such as electricity, direct hydraulic pressure or potable water. The system is a semi-submerged, articulated structure composed of cylindrical sections linked by hinged joints. The wave-induced motion of these joints is resisted by hydraulic rams that pump high-pressure oil through hydraulic motors via smoothing accumulators. The hydraulic motors drive electrical generators to product electricity. The complete machine is flexibly moored so as to swing head-on to the incoming waves and derives its 'reference' from spanning successive wave crests.

The Pelamis WEC development programme OPD identified a requirement for an intermediate scale 'systems' demonstrator with which to develop and prove the full-scale Pelamis hydraulic, control and data acquisition systems. A 7^th scale model was conceived to satisfy the OPD ethos of systematically tackling each aspect of technical risk before committing to a full-scale prototype. It is seen as absolutely critical to the overall success of the technical programme that as little immature technology as possible is incorporated within the first full-scale prototype.

In addition, during the programme of work undertaken here it was felt that further control studies using and updated version of the 20^th scale model also had considerable merit.

The overall objectives of the project were:

• A1. Summary
• A2. 7^th Scale Model General Configuration
• A3. Model Upgrades
• A4. Transport & Installation
• A5. Testing & Analysis
• A6. Conclusions
• B1. Introduction
• B2. Testing & Analysis
• B3. Model Decommissioning & Maintenance
• B4. Conclusions
• Project Conclusions
• Recommendations for Future Work

• First, variation in the levels of ambient turbulence has little effect on the power and thrust coefficient, and a minimal effect also on the velocity profiles in the immediate wake.
• Second, the differences that are observed in the wake velocity profiles with varying levels ofthe ambient turbulence intensity occur further downstream, and become more significant progressing downstream before beginning to fade out. Such differences should be accounted for by a far-wake model which is sensitive to turbulence, as is indeed the case with GL Garrad Hassan’s existing WindFarmer software

• First, we verify that the FORTRAN subroutine (DRAGFO) used to simulate a tidal turbine in Telemac2D produces the same results when launched with one processor as it does with several processors.
• Next, a simple flow than the wake downstream a tidal turbine is analyzed: this simple case is the wake of a flow around a cylinder, which is simulated for two models of turbulence in Telemac2D (k-epsilon model and constant viscosity model). The validated results from this analysis (mesh size, turbulence model ...) were used to get some guidance in our study which concerns the flow around the tidal turbines and not around cylinders.
• �Third, the wake of a tidal turbine in a flume is simulated and validated in Telemac2D using laboratory measurements made by the LNHE department of EDF. The methodology for simulating one tidal turbine is defined, in particular a drag force is applied on a rectangular box in order to simulate the drag force due to the turbine.
• Once it was established that a single tidal turbine in a flume could be modeled, two varying alignments of tidal turbine arrays were simulated in Telemac2D using the same two models of turbulence.At this stage, two methodologies are defined:
  • the first one for the method where a rectangular box is used for each turbine, and
  • the second methodology for the global box containing allturbines method. In this second case, the methodology also explains how to calculate an equivalent drag coefficient to simulate a set of turbines in a large scale basin.
• In both methodologies, the way of choosing the mesh size (near and far from the rectangular box(es) and in the transition area ranging from a fine mesh to a larger mesh), the turbulence model, the drag coefficient, and the limitations are given.

• First, it is verified that the subroutine (SOURCE) used to simulate a tidal turbine in Telemac3D produces the same results when launched with one processor as it does with several processors.
• Second, a tidal turbine in a flume is simulated with Telemac3D.

• The models show good agreement in the tidal dynamics outside of Pentland Firth.
• Each model uses different parameters for seabed coefficient resulting in small differences within the Pentland Firth.
• There are significant differences in the way the tides are modelled making it difficult to compare predicted power using different turbine configurations
• There is insufficient field data available to determine which model is better reproducing the real tidal dynamics.
• There appears to be general agreement as to the magnitude of the powers each of the models are producing.
• However, a detailed comparison of the differing methodologies for the implementation of tidal turbines is difficult because of the differences in the modelling of the tidal dynamics within the Pentland Firth.

• Section 1: the potential synergies that can be achieved by developing the core modules in a fashion consistent with standard Garrad Hassan (GH) software architectures are briefly explored. The current architecture ofthe existing wave energy converter (WEC) hydrodynamic modelling tools developed by GH is also described and an overview of the envisaged structure for the tools developed under PerAWaT presented;
• Section 2: an overview of the wave input to the core modules is presented. Quantities such as the wave spectrum and the key spectral parameters are introduced and defined. Estimation techniques to derive the wave spectrum from real data are also considered, and a preliminary definition of the target capabilities is given;
• Section 3: The basis of both the frequency and the time-domain models is presented using linear (Airy) wave theory. An introduction to the principles of fluid-structure interaction modelling, with emphasis to the Boundary-Element Method, is given and applications to WEC modelling described in detail. Particular emphasis is given to the practical aspects of solving the time-domain equation of motion, the selection of a supporting hydrodynamic solver and the modelling of the external forces (namely the power take-off force, the mooring force and the impact of the control methodology). The Section is concluded with a review of the current capabilities and a preliminary implementation specification (to be further expanded in WG1 WP1 D1B);
• Section 4: the optimisation methodology is overviewed and examples of WEC array optimisation exercises conducted to date are reviewed. Different optimisation techniques are presented in preparation of the implementation stage. In addition, three scenarios which correspond to the phased development of the core layout optimiser are introduced, in a preliminary definition of the target capabilities (to be further expanded in WG1 WP1 D1B);
• Section 5: the implementation strategy (interim) for the methodology is described:
  • Key design variables (when optimising an array of WECs)
  • Description of representative scenarios to assess the functionality of the developed software
  • Overview of performance vs. survivability conditions

• the generation of ambient flow conditions,
• method of measurement of time-varying flow- and mechanical parameters,
• design of small-scale model of a tidal stream turbine and
• design of a rotor suitable for the low Reynolds number of these experiments.

• The preliminary work to better understand the turbine using more basic modellingapproaches.
• the development and application of the CFD model of the turbine.

• the development of a basic analytical model of a high solidity turbine, in order to support the design of a credible turbine rotor; and
• the CFD analysis of this design, in order to produce results for the velocity field in the wake of the turbine.

• Hydrodynamic interactions between WECs and TECs operating in arrays can be significant thereforemodelling of array effects is essential when estimating the energy yield of potential project.
• Wave tank testing of WEC arrays is extremely demanding and needs to be carefully planned and analysed. In particular the effects of reflections can be of the same order as effects of the interactions you are trying to measure. Despite the challenges, it is possible to measure significant interactions in the tank.
• Linear potential flow theory (used in WaveDyn) is sufficient to accurately model device interactions. Weakly non-linear wave kinematics (non-breaking) do not have a significant influence on device response and performance for operational conditions.
• The spectral approach in WaveFarmer is capable of accurately predicting energy yield for a large wave farm.
• Model-scale & full-scale validation of WaveDyn has been invaluable as has model scale validation of WaveFarmer. However, full-scale validation of WaveFarmer will be essential when data becomes available.
• The mean performance of a tidal device can be predicted usinga Reynolds Averaged Navier Stokes (RANS) model, however, more work is required in order to `correct’ this type of model so as to accurately capture wake recovery.
• Basin scale modelling using linear momentum actuator disc theory (LMADT) for one row of devices was successful. The limitations of the model are well understood, and the upper limit of energy extraction compares well to analytical methods. However, 3D models such as TidalFarmer are required for detailed assessment of annual energy production
• .Whilst progress has been made on the analysis of blockage effects of arrays and devices, further work is required to fully understand and model the flow reduction through the array.

• The launch of WaveFarmer & TidalFarmer is only the first step in increasing project developers’ confidence in their return on investment in WEC & TEC arrays.
• Effective commercial exploitation will be required to stimulate use of the tools.
• The resulting data generated by full scale deployments will enable further development of the tools and the reduction of uncertainty.
• The reduction of uncertainty could be accelerated by investment in trials to generate full scale data for validation

• A review of the existing literature provides an overview of the available modelling options and also provides a basis for the selection of an appropriate level of model sophistication.
• The GH Blockage model is described and the rationalised modelling approach is justified. The GH Blockage model uses Potential flow theory to evaluate the effect of bounding surfaces and/or other surrounding turbines on a tidal turbine under investigation.
• The model is used to predict the three dimensional flow field in and around the tidal turbine, which enables the change in turbine performance to be predicted. The altered flow field around the turbine is also used in modelling the wake mixing and recovery process.
• A list of key assumptions that the GH Blockage model makes is provided along with the relevant references to existing theory.
• The method by which the mathematical models are implemented into a working code is described, as is the way in which the GH Blockage model to be incorporated within the GH TidalFarmer Beta code.
• Flow diagrams of the GH Blockage model algorithms are presented and examples of the outputs are provided

• A review of the existing literature is presented which provides an overview of both the applicable modelling options and previous experimental campaigns which characterise the wake region of interest.
• The GH near wake model is described and the modelling approach justified.
• The model is used to predict the three dimensional flow field which is then passed to the GH far wake model as an input.
• The GH Blockage model feeds the model when appropriate, providing a corrected rotor thrust and an altered flow field around the turbine.
• A list of key assumptions that the GH near wake model makes is provided along with the relevant references to existing theory.
• The method by which the mathematical models are implemented intoa working code is described, as is the way in which the GH near wake model is to be incorporated within the GH TidalFarmer Beta code.
• Flow diagrams of the GH near wake model algorithms are presented and example outputs provided

1. the detailed hydrodynamic performance of rotors in turbulent flows,
2. the effect of bounding surfaces on the device performance, and
3. the wake form and structures downstream of a tidal device, as a function of flow profile, depth and ambient turbulence.

• Section 1: The scope of the documents and its key objectives�
• ;Section 2: The architectureof the developed code, the core aspects of a multi-body dynamic solver and key time-domain implementation details;
• Section 3: The hydrodynamics module ;
• Section 4: The wave analysis module and its functionality;
• Section 5: The moorings module and its functionality(exemplified via a case study);
• Section 6: The power take-off (PTO) and control modules and their functionality;
• Section 7: The optimiser module and its functionality;
• Section 8: Case studies that outline initial results;
• Section 9: A summary of the key features implemented to date and planned extensions

• Section 1: Introduction
  • Scope of the document and the relationship of this document to other deliverables.
  • Summary of the closely related deliverable WG1 WP2 D1, which describes the physical representation of wave energy converters in a thirdgeneration spectral wave model, is provided,
  • Acceptance criteria for this deliverable
• Section 2: Overview of development strategy
  • Methods for achieving the key desirable characteristics of the new software (flexibility, user-friendliness, and reliability)
  • How the software modification will be carried out on four separate key elements successively, and then the integration of these elements that will provide the final software tool. Key elements:
  • representation of a wave energy converter,
  • location of the wave energy converters,
  • input of wave energy converter parameters,
  • output of wave energy converter power capture.
  • The software development tools which will be used for the project are described and the reason for the specific tool choice is explained.
  • The Microsoft VisualStudio program will be used for interactive development of the code, and the Git source code management (or revisioning) software will be used to manage changes to the code.
• Section 3: Selection of spectral wave model
  • Two open source models, SWAN andTOMAWAC, are identified as good candidates and a close comparison of the two models is carried out.
  • The comparison includes an assessment of the physical processes represented in the models and their ease of use and modification.
  • Two test cases are implemented in both models to aid in the comparison.
  • Although the models solve the same equation in a totally different way, it is shown that the results are very similar, and that neither model can be eliminated as a potential candidate based on physical process representation.
  • The final model choice is TOMAWAC, because it was developed at EDF which is associated withthe PerAWaT project and support for interpretation of the source code is more readily available.
  • However, both models were deemed suitable for the task, and therefore should there be an unforeseen problem with TOMAWAC, it would be possible to proceed with SWAN.
• Section 4: Core elements of software tool
  • Describe seach of the four core elements in detail, and outlines the development process for each of them.
  • New subroutines, and existing subroutines and variables which require modification are identified.
  • Additionally, for each core element the method for verification that the added code is working correctly is described.
• Section 5: Validation of the SpecWec tool
  • Validation of the representation of wave energy converters in a spectral wave model.
  • Two key parameters which will be addressed during the validation process are identified as wave energy converter density, and wave energy converter performance.
  • Because there is no wave farm data available for the validation process, the spectral representation of wave energy converters will be compared with both the time-domain model WaveFarmer being developed at Garrad Hassan, and the wave tank experimental data which is due to be carried out at Queen’s University Belfast as part of the PerAWaT project.

• It is found that surface waves have a detrimental effect on the mean power of the turbine,which is reduced by c. 20% for the waves considered, which is very similar to the power reduction for the bare turbine.
• Mean thrust is also reduced but to a lesser extent.
• Blade thrust and power are observed to fluctuate with significant amplitude as the blade rotates (far more so than for the case of shear flow with no waves reported in D4).
• Blade thrust fluctuates by c. �10% about its mean value, whilst blade power fluctuates by c. �100% about its mean value.
• These fluctuations are smaller than those for the bare axial flow turbine(by a factor of around two).
• The maximum blade torque fluctuation is around the same as the mean blade torque, such that the instantaneous torque is rarely negative, compared to the bare axial flow turbine, the blades of which experience long periods of negative power contribution.
• Thus the ducted turbine in sheared flow with waves delivers lower power yield but its blades experience substantially reduced fluctuating load
  
  

• Section 1: Software architecture
• Section 2: Wave inputs to the simulation
• Section 3: Core hydrodynamic modelling algorithms behind the simulation
• Section 4: Core algorithms behind the farm optimisation module
• Section 5: A set ofrepresentative scenarios to assess the applicability of the models and the key steps for the development and implementation of the software

1. model the interaction of three dimensional unsteady flow and turbine wakes within an array;
2. verify available numerical models; and
3. implement an appropriate free surface model within Code_Saturne.

This report provides the reader with an introduction, methodology and guide to implementation of the work conducted to provide a suitable means of tidal stream modelling. The tidal stream modelling is seen as an important component to the whole project since it provides the necessary upstream boundary condition to a small array of marine current turbines at the meso-scale using EDF’s Computational Fluid Dynamic (CFD) solver ‘Code_Saturne’

• Introduction
  • The Level Set Method
  • Ghost Fluid Method
• Methodology
  • Calculation of Level Set with re-distancing
  • Calculation of slop and curvature and free surface
  • Calculation methodology for the Ghost Fluid Method
• Implementing unsteady upstream boundary condition
• Implemention
  • A review on previous Connectivity modelling
  • A review on previous Re-Distancing modelling
  • Current programming strategy
• New Modules
• Results

• The Hydrodynamic Environment
  • Base-line Flow field
  • Bare Flume Simulations
  • Free-surface Capture
• Rotor Model Verification
  • Geometry Generation
  • Rotor Blade Component Verification
  • Rotor Tower Component Validation
• Composite Simulation
  • Meshing Strategy
  • Computational Setup
  • Flow Field Analysis
• Conclusions

• The key objectives of this study are to compare the results of fully nonlinear simulations to weakly nonlinear results, in particular in the case of the single cylinder, and to investigate the cylinder excitation forces and cylinder responses in an array of four cylinders subject to regular incident waves.
• The report outlines how these objectives have been met and describes any issues arising from their completion.
• The similarities and differences between the fully nonlinear time-domain solutions and the linear frequency domain solutions are considered in detail.
• A number of validation studies were also conducted in parallel with and as preparation for the completion of the main aimsof the deliverable.
• These case studies contain independent verifications of the fully nonlinear potential flow solver and are included in the report to illustrate the full capabilities of the fully nonlinear approach

• The report first introduces the two-dimensional Shallow Water Equations (SWEs) and the chosen numerical method (discontinuous Galerkin finite element method) used to solve these equations.
• The methodology is then explained for couplingLinear Momentum Actuator Disc Theory (LMADT) to the two-dimensional hydrodynamic model DG-ADCIRC by means of including a line sink of momentum within the discontinuous Galerkin scheme.
• The verification of the algorithm is undertaken for a number of problems where an array of tidal devices is located in an idealised channel, with different configurations and problem settings.
• Lastly, preliminary results are given for the Anglesey Skerries, using the modified DGADCIRC code that uses LMADT tocalculate the relevant line sink of momentum in the solution domain

• A series of tests will be conducted with one turbine located in a fixed position whilst the second turbine is moved longitudinally and laterally throughout the frame of the test platform.
• The tidal turbines fabricated for this project are 1.2 metre diameter (1:10th scale) and are being assembled by Ocean Flow Energy.
• A test platform is being constructed by Wave Barrier Ltd and this will provide the frame to which the turbines and survey instruments will be attached to.
• Following this deliverable, the test rig will be constructed and assembled with rotors, then installed in the EDF flume and calibrated

• Introduction to project and work package
• Free surface methods
• Implementation
• Validaiton cases

• Section 1: Scope of the documents and its key objectives
• Section 2: Brief introduction to potential flow theory and the difficulties associated with a fully non-linear implementation
• Section 3: Brief description of first order hydrodynamic formulations
• Section 4: Detailed description of the second-order (weakly) nonlinear hydrodynamic formulation
• Section 5: Stochastic approach used to obtain irregular wave results
• Section 6: Linear and weakly non-linear hydrodynamic results associated with a single truncated cylinder WEC free to move in all DOFs
• Section 7: An extension of the linear and weakly nonlinear resultsto an array with four cylinders WEC free to move in all DOFs
• Section 8: The next steps in terms of the implementation

Against a policy background set principally by the Energy White Paper 2003 and the Sustainable Communities Plan 2003, Brook Lyndhurst's research work on "Planning for Renewable Energy" approached the issue of renewable energy from three perspectives:

The particular objectives of the research were:

Our research suggests that the issue(s) of renewable energy is, in general, restricted to a small but enthusiastic minority of players in regional and local government. For the mainstream practitioner in land-use planning and urban regeneration, energy issues generally, and renewable energy issues in particular, have a low priority.

Those practitioners with responsibility for renewables, while making some headway in forging links with regional planners, appear to operate discretely from regeneration practitioners at all levels and planners at the local level. As a result, no "critical mass" of concern has come about, so there has been no significant impetus for the development of a "community of interest" encompassing planning, regeneration and renewable energy personnel, at both regional and local levels.

In the longer term, however, it would seem that if the UK is to achieve truly dramatic reductions in its emissions of carbon dioxide (as envisaged, most obviously, by the Royal Commission on Environmental Pollution), then a more radical and far-reaching programme of change will be required.

• The Aim of MD 5.2
• The Hydrodynamic Flow Model
• Calibration and Validation
  • Reason for validation:
  • Validation 1: In the Time Domain
  • Validation 2: In the Frequency Domain
  • Conclusions from the 2D validation
  • 3D Validation:
    • What statistic to use?
    • Comparison in 3D
    • Comparison in 3D: TGL
    • ADP Shear Data: 1 – 1.2 m/s
    • Model Shear Data: 1 – 1.2 m/s
    • Direct comparison of Shear Profiles: 1 – 1.2 m/s
• Key Points – 2D
• Key points – 3D comparison

• Aims of Work Package ME8: Anti fouling systems for tidal energy devices
• Broad Aims
• Design Stage
• ReDAPT Coating Test List
• Approach 2012
• Results: Seabed pod panels May 2014 - 24 months
• Niche areas
• Results: Seabed pod panels 24 months – Hydrodynamic Drag
• Results: Seabed pod panels 24 months - Corrosion
• Results: Which coating?
• Achievements
• Take Home Messages & Lessons Learned
• Next Steps

• The background on the standard
• The challenges
• Standard scope
• Risk and Technology Qualification
• The risk based method for the generic tidal turbine
• Main features
• The Service Specification for Certification of Tidal Turbine and Arrays
• Conclusions and future developments

• MD1: Development of a CFD model of the TGL turbine at the EMEC site.
• Methods:
  • Sliding Mesh Method developed for RANS and LES
  • Synthetic Eddy Method used to represent depth profile of mean and unsteady flow
  • LES with sliding mesh method and SEM inflow to predict 1 MW turbine loads
• Findings
  • Accurate prediction of power and thrust
  • Measured shear significantly affects cyclic blade loading
  • LES with SEM inflow predicts blade root bending moment affecting fatigue design
• Aim Achieved: To establish capability of CFD for unsteady load prediction in realistic flows
• Lessons and Next Steps

• site measurements;
• hydrodynamic modelling;
• turbine and electrical design;
• testing;
• operation;
• maintenance and site working; and
• marine operations and environment

• Requirements
• Life Cycle Assessment (LCA) System Definitions
• Life Cycle Impact (LCI) Assessment
• Life Cycle Processes
• Technology Level Rationale
• Tidal Stream Array Siting Considerations
• Specific Modelling Considerations
• Calculation of Carbon Payback Interval
• Evaluation and Reviewing of Results
• Reporting and Interpretation of Results
• Appendices
  • A: System Boundary Details
  • B: Waste Disposal
  • C: Transport Details
  • D: Tidal Current Probability Data
  • E: Data Collection Considerations
  • F: Global Warming Potential

The objectives for this project are:

This project is the first phase of work for the SeaGen project, which is a wet renewable tidal turbine system for extracting energy from the sea's currents.

Tidal turbine systems are possibly the only wet renewable project concept that can generate electricity on predictable basis, and therefore augments the variable power generation nature of other renewable technologies. With the UK government's objectives towards sustainable energy, the SeaGen concept could provide a proportion of the government's renewable energy targets.

The project also allows for further instrumentation and testing of the Seaflow system currently installed off Lynmouth in North Devon. This testing will include correlation of the turbine blade loads with the sea's current variations to verify the fatigue prediction techniques used for the SeaGen system.

Since 1997, The Engineering Business Ltd (EB) has been developing tidal stream generation technology. In 2002 EB designed, built and installed the worlds first full-scale tidal stream generator, the 150kW Stingray demonstrator. The Stingray concept is that the energy within tidal currents can be harnessed through oscillating hydroplanes. A full description of the concept and technology is presented in the Phase 1 and Phase 2 reports. Stingray was reinstalled in Yell Sound in the Shetland Islands between July and September 2003 for Phase 3 of the project. This report presents an overview of this phase of the project, the results obtained and outlines the implications of those results on the potential for commercial electricity generation.

The fundamental objective of the project was to demonstrate that electricity could be generated at a potentially commercially viable unit energy cost utilising Stingray technology. In addition to this, a number of measurable targets for the Phase 3 operations were agreed with the DTI.

The aim of the marine operations was to undertake a series of tests, at slack water and on the flood tide, to reconfirm basic machine characteristics, develop the control strategy and demonstrate performance and power collection through periods of continuous operation.

A summary of the main test work findings is as follows:

Although compliance with the targets set by the DTI was at a lower level than would have been hoped, the broader aims were met in the majority of cases. There is evidence to suggest that the technology is capable of full compliance with all targets that remain relevant.

1. Introduction
2. Design and Production
3. Marine Operations Summary
4. Stakeholders and the Environment
5. Test Results- Machine Characteristics & Sensor Performance
6. Test Results - Overview Power Cycle Analysis
7. Test Results - Detailed Power Cycle Analysis
8. Test Results - Overall Power Collection
9. Test Results - Transmission Performance & Efficiency
10. Test Results - Current Data Analysis
11. Validation of Mathematical Model
12. Economic Analysis - Background
13. Cost Modelling
14. DTI Targets
15. Conclusions
16. Acknowledgments

This document is a summary for the project titled 'Sustainability Energy Infrastructure and Supply Technologies - Offshore HVDC Grids'.

In order for the UK to meet its ambitious targets for energy production from renewable sources (10% of electricity by 2010, 15% by 2020) it needs to expand its capacity to generate all forms of renewable energy and the largest proportion of this is expected to come from wind. The UK currently generates more energy than any other country in the world from wind (700MW) and the third stage of the UK Governments wind energy plan is expected to deliver another 25GW by 2020.

This project involved carrying out a critical assessment of prior and developing technology in the field, it also involved developing a mathematical and software model of an off-shore wind farm connected to shore by a HVDC grid.

This project was carried out in collaboration with TNEI, who produce a commonly used software tool for utility companies, and it has helped expand their capability into HVDC grids. This puts the company in an ideal place to capitalize on what is an extremely fast growing market both in the UK and internationally. A total of £4.88m funding has been obtained, from the Engineering and Physical Sciences Research Council and the Northern Wind Innovation Programme (in partnership with Siemens T&D), for follow on projects. It was only possible to obtain this funding because of the initial funding for this project from the Joule centre.

The geographical location of the United Kingdom and the seas that surround it provide internationally enviable renewable resources. Technologies for wind power extraction are now mature and an increasing role for the opportunistic capture of this intermittent energy source for the electricity grid is firmly established. Marine wave energy offers even greater scope for the future, with somewhat slower temporal variability but with necessary technological advances still outstanding. Even more exclusive, however, is the potential for tidal energy extraction from around the UK coastline. The most attractive locations for harnessing tidal power are estuaries with a high tidal range for barrages, and other areas with strong tidal currents (e.g. straits and headlands) for free-standing tidal stream devices. Barrage schemes, drawing on established low-head hydropower technology, are fully proven. The La Rance plant in France has now passed its 40th year of operation.

Of about 500-1000TWh/year of tidal energy potentially available worldwide (Baker, 1991), Hammons (1993) estimated the UK to hold 50TWh/year, representing 48% of the European resource, and few sites worldwide are as close to electricity users and the transmission grid as those in the UK. Following from a series of government-funded studies commissioned by UKAEA in the 1980s, 8 major estuaries were identified where tidal barrages would be capable of procuring over 40TWh/year. In rank order of scale, they were the Severn, Solway Firth, Morecambe Bay, Wash, Humber, Thames, Mersey and Dee (see UKAEA, 1980 and 1984, Baker, 1991). Thus, about half of this energy was located in the North West of England (House of Commons, 2008).

Also within the Eastern Irish Sea, exploitable tidal stream resources have been identified to the north of Anglesey and to the north of the Isle of Man, with more localised resources in the approaches to Morecambe Bay and the Solway Firth (DTI, 2004). Note, however, that in estuaries it is unlikely that tidal stream options can come close to the energy yield of barrage alternatives. Recent assessments for the Mersey offer estimates of 40-100GWh/year for tidal stream arrays, contrasting with 1200GWh/year estimated for a barrage at an equivalent location (RSK Environmental Ltd, 2007). In a similar vein, whilst tidal lagoons are often mooted as a viable alternative to estuary barrages, offering a similar operational function, it is highly unlikely that they could be realised at a comparable scale and remain competitive on cost against the major barrage schemes cited above.

Barrages on the Solway Firth, Morecambe Bay, Mersey and Dee, operating in ebb-only generation with 1xDoEn turbine provision could meet about 5% of UK demand. With further scheme optimisations and refined representation of pumping efficiencies, a figure close to 6% might be achieved. Based on the scale of the North West's 'economy' at approximately 12% of the UK total, this energy capture should supply about half the North West's present electricity needs.

In economic terms, this study has shown that the North West schemes should be no more than 70% more expensive in unit cost of energy produced when compared to that achievable from the Severn with, in each case, lowest costs arising from installations consistent with the Department of Energy's 1980s studies (1xDoEn turbine installations).

Increasing turbine provision substantially (to up to 3 times the default provision) would increase energy capture and enable retention of more of the intertidal area in the estuarial basin, so alleviating some of the environmental concerns, but at extra cost of electricity produced.

2-D modelling significantly alters the energy predictions from the 0-D modelling, so demonstrating the necessity of the more rigorous approach. As a consequence of this, further investigation is required to determine how much of the substantial energy increases predicted from 0-D modelling of 3xDoEn installations can be realised in the 2-D modelling. Presently, only about a 20% enhancement has been achieved, in part because of the reduction of tidal amplitudes at the barrage locations.

Earlier studies (DoEn, 1989) reported the potential for an outer line for the Severn barrage producing an additional 6.80TWh/year and barrages on the Wash, Humber and Thames capable of yielding 3.75, 1.65 and 1.37TWh/year, respectively (UKAEA, 1980). Combining these with the 33TWh/year obtained herein for the North West barrages and the Cardiff-Weston Severn barrage scheme (for similar 1xDoEn ebb-mode operation) would achieve a total of about 46.5TWh/year. This should be capable of uplift to around 50TWh/year by addition of positive head pumping, representing 13% of the UK (2005) electricity consumption of 387TWh/year.

1. Introduction
2. Preliminary Studies
3. Energy from Major Barrage Schemes (0-D Modelling)
4. Conjunctive (Multi-Scheme) Energy Capture (2-D Modelling)
5. Environmental Implications
6. Conclusions and Recommendations
7. References and Bibliography

• A.1.1 The research team
• A.1.2 House of Commons evidence
• A.1.3 Tidal stream energy extraction from estuaries
• A.2.1 Theoretical background to energy computations (0-D modelling)
• A.2.2 Implication of entry and exit losses in turbine conduits
• A.2.3 Validation of Turgency/Generation Matlab computational routines
• A.2.4 Preliminary studies - potential from barrages on major UK estuaries
• A.2.5 Constructional aspects
• A.3.1 Barrage lines, cross sections and bathymetries
• A.3.2 Energy computation spreadsheets
• A.3.3 Costing calculations
• A.4.1 ADCIRC background
• A.4.2 Barrage operation in ADCIRC
• A.4.3 Tidal stream farms in ADCIRC
• A.4.4 Validation of simulation grid

• It owes a duty to the international community to exploit these resources in the global battle against climate change and towards sustainability.
• Tidal barrages in the estuaries of the Northwest would be capable of meeting about half the region's electricity need.

This presentation covers:

In order for the UK to meet its ambitious targets for energy production from renewable sources (10% of electricity by 2010, 15% by 2020) it needs to expand its capacity to generate all forms of renewable energy and marine energy. This project is concerned with marine energy in the form of tidal power, specifically tidal barrages, and the UK's geographic location makes it ideal for these schemes. Indeed it was recently estimated that of the 500-1000TWh/year of energy believed to be available worldwide from barrage schemes, the UK holds 50TWh/year which is about half of the European resource. The North West of England has many suitable sites for barrage schemes and therefore has potential to generate a great deal of its electricity this way. Of all the potential UK sites, the Mersey is adjudged to be most feasible with its very narrow mouth meaning it needs a relatively short barrage and therefore has lower capital costs than other sites

This project involved examining the effectiveness of the different modes of operation (flood flow, ebb flow, dual which is a combination of ebb and flood) at potential North West sites and assessing the performance of alternatives to barrages. Each mode permits energy generation for typically between 8 and 11 hours a day. This study found that the most effective mode for tidal barrages to operate in is ebb flow mode, it also found that turbine installations operating in this mode could produce up to 10% of present UK electricity need. Potential schemes on the Solway Firth, Morecambe Bay, Mersey and the Dee, in the North West, could provide about half of the regions electricity requirement which is about 5% of the UK total demand. It was also found that the generation times from these potential North West schemes compliment another planned barrage scheme on the Severn estuary thereby extending the daily generation window from 11 hours to 20 hours. Other developments elsewhere in the country may enable a 15% contribution to electricity demand to be made from tidal range energy. There are a number of alternatives to barrage structures which don't require fixed structures however these were found to generate only a fraction of the power of barrages and in many cases were economically uncompetitive.

This project has been instrumental in building awareness of the potential renewable energy resource in the estuaries of the North West to both professional bodies and the interested public. In doing so it helped lead to the launch of the North West Tidal Energy Group (NWTEG).

1. tidal stream foundations
2. low-cost wave energy structures
3. optimised tidal stream blade technologies
4. optimised power take-off systems (wave & tidal)
5. wave energy sensors for control system optimisation and yield improvement.

• ETI TEC Project
• Design Process
• HydrodynamicModel Testing
• Summary
  • B&V are currently finalising the detailed design of an innovative subsea support structure for the tidal energy industry –StreamTec™
  • This concept has been borne out of industry experience and a holistic approach to optimising tidal stream technology
  • The design process has been developed from a comprehensive understanding of the dependency of the economic feasibility of the concept on the various system components and their respective design drivers
  • The solution to a complex problem, composed of an array of smaller complex problems, does not necessarily need to be a complex one!

• How will the impacts of tidal range and tidal current energy schemes positioned around the UK combine to form an overall effect?
  -- Optimisation for environmental/human impact, energy output, economics or power smoothing is needed if the overall tidal resource is to be exploited to its full potential.
• Will the extraction of tidal energy resources in one area affect the tidal energy resources at distant sites around the UK and Europe?
  -- The CSM scenario run outputs give a clear indication as to the impact at far-field UK sites. The impacts across Europe vary depending on the scenario but the most extreme case of both tidal range and tidal current deployment, shows that there would be an impact on the European coastline.
• What constraints might these interactions place on the design, development and location of future systems?
  -- The interactions within and between schemes shows that the level of tidal range deployment (for near-field and far-field effects) and tidal current deployment (mainly near-field to regional impacts) would place constraints on the schemes. Both effects could potentially impact the success of projects. Importantly, the installation of later schemes could have an impact (positive or negative) on an existing scheme or its effects.

1. How will the interactions between tidal range and tidal current systems positioned around the UK’s waters combine to form an overall effect.
2. Will the extraction of tidal energy resource in one area impact the tidal energy resource at distant sites around the UK and Europe.
3. What constraints might these interactions place on the design, development and location of future systems.

• Part A: Tidal Range
  Potentially feasible locations for tidal range schemes that could give peak power output greater than 100MW have been identified giving:
  • 10 barrage alignments – selected based on a literature review of previous studies; and
  • 11 lagoon alignments – selected based on the tidal range, water depth and coastline shape.
• Part B: Tidal Current (including Tidal Fences) 
  The original scope was to identify farms over 100MWp. However, this criteria was relaxed (to 60MWp) to account for most potentially economic locations in UK waters.
  • 20 known tidal current farm locations were selected from literature review.

• That any credible tidal current development does not impact on the tidal range sites.
• That there is only a minimal impact of tidal range sites on tidal current sites, in the most extreme cases. In less extreme cases, there is essentiallyno impact.
• Extreme scenarios suggest that the Severn Outer barrage has a significantly more severe far-field impact (on tidal current sites) in comparison with the combination of the Cardiff-Weston barrage and Bridgewater Bay lagoon.
• ‘Mega’ schemes with dual generation (Severn Outer, Solway Firth) do not work as intended, and effectively cannot move the water away fast enough, impeding generation. Noticeable benefits in using Rolls-Royce turbines in dual-mode schemes were observed for the Solway Firth, Mersey, and the Wash as there are reduced impacts on downstream tidal range than equivalent dual schemes.
• Large reduction in downstream tidal range for major barrages/lagoons in estuaries (Bridgwater Bay, Cardiff-Weston, Mersey, Thames, Wash, Humber) reduces their energy output compared to 0D modelling, as expected.
• Much less effect on downstream tidal range for lagoons on open coastlines (Rye, Dymchurch, Cumbria, Wigtown) or smaller lagoons, suggesting these may be worth further investigation.
• The increased tidal range which is visible, in particular in the Irish Sea and surroundings, when there is large scale deployment of tidal range schemes in that area, is unlikely to be acceptable in terms of environmental (and safety) impacts.
• Significant interactions (i.e. a negative effect on tidal range and potential energy) within the Severn – e.g. the Cardiff-Weston barrage reduces energy output for lagoons downstream.
• Almost no interaction between tidal range schemes in Irish Sea, despite the impacts on increased tidal range discussed earlier.
• In UK waters, large scale utilisation of the tidal resource requires significant optimisation to avoid potentially unacceptable cumulative impacts and to ensure the most energy can be extracted from the resource (potentially at least cost, with least impact on the grid etc.).

• Part A - The TELEMAC system: Installation Guide,
• Part B - The CSM Functional and Testing Report,
• Part C - The CSM Web User Interface: User Guide.

1. An Excel model with parametric representations of cost drivers such as size and arrangements of civils works, turbine choices, O&M choices etc;
2. A model report describing the model, assumptions and case study examples, and
3. A user guide.

• Part A: Assesses the potential Tidal Range sites and identifies 10 barrage and 11 lagoon sites;
• Part B Assesses the potential Tidal Current sites and identifies 18 sites.

This UKERC Research Landscape provides an overview of the competencies and publicly funded activities in marine renewable energy research, development and demonstration (RD&D) in the UK. It covers the main funding streams, research providers, infrastructure, networks and UK participation in international activities.

UKERC ENERGY RESEARCH LANDSCAPE: MARINE RENEWABLE ENERGY

• Section 1: An overview which includes a broad characterisation of research activity in the sector and the key research challenges
• Section 2: An assessment of UK capabilities in relation to wider international activities, in the context of market potential
• Section 3: Major funding streams and providers of basic research along with a brief commentary
• Section 4: Major funding streams and providers of applied research along with a brief commentary
• Section 5: Major funding streams for demonstration activity along with major projects and a brief commentary
• Section 6: Research infrastructure and other major research assets (e.g. databases, models)
• Section 7: Research networks, mainly in the UK, but also European networks not covered by the EU Framework Researchand Technology Development (RTD) Programmes
• Section 8: UK participation in energy-related EU Framework Research and Technology Development (RTD) Programmes
• Section 9: UK participation in wider international initiatives, including those supported by the International Energy Agency

This document is a technology roadmap: it provides a guide for mobilising the wave and tidal energy community in the UK down a deployment pathway towards a target of achieving 2GW installed capacity by 2020.

The roadmap is aimed at providing a focused and coherent approach to technology development in the marine sector, whilst taking into account the needs of other stakeholders. The successful implementation of the technology roadmap depends upon a number of complex interactions between commercial, political and technical aspects.

Although this roadmap is technically focused it also considers policy, environmental and commercialisation aspects of the marine energy sector, in order to display and put in context these wider influences.

The roadmap is aimed at technology developers, project developers, policy makers, government bodies, investors (public and private)

The UK Energy Research Centre welcomes this opportunity to provide input to the BERR Consultation on the UK Renewable Energy Strategy. We have addressed a number of the questions posed in the consultation document calling on all UKERC members for input.

To meet the EU 15% renewable energy target will be a significant challenge for the UK. It is important to understand that reductions in the UKs total energy demand will produce proportional reductions in the renewable contribution required. Although self-evident, this simple fact is often overlooked. Indeed the UK has to date failed to achieve any reductions in energy use, in fact the reverse is true: energy consumption in the key sectors of electricity and energy for transport continues to rise steadily.

In addition to reducing the demand for energy, there will need to be a massive increase in the contribution of renewables to transport fuel (predominately biofuels), heat and electricity. This submission concentrates on renewable electricity because UKERC has core competency this area. In Table 1, below, UKERC presents an illustrative scenario for the contribution of renew

• Without the adoption of a more holistic approach that addresses BETTA structural reform and network regulation, it is difficult to see how a satisfactory resolution of the transmission access issue can be achieved.
• It is proposed that more strategic and unified development of the onshore and offshore network together with the provision of interconnection would be encouraged through common or at least zonal ownership of offshore transmission assets, while cost-effectiveness and the efficient delivery of assets could be achieved through tendering and outsourcing construction.
• Modern distribution networks are not typically designed to accommodate generation; a number of technical and operational challenges will need to be addressed in order for the connection of significant amounts of distributed generation on these networks.
• The consequences of intermittency or variability of input will need to be managed by a combination of retaining conventional plant and developing demand response. Additionally, interconnection with adjacent transmission systems and improved forecasting of wind resource and maintaining geographic diversity of wind generation could also reduce the impacts of intermittency.
• The role of smart grids will be to enhance the capacity and utilisation of the electricity grid (both transmission and distribution) by means other than investing in traditional transmission assets and, via the deployment of smart metering, massively increase the contribution of the demand side to system security and the decarbonisation of the heat and transport sectors.
• UKERC is concerned that a major opportunity will be missed unless there is a timely change to a regulatory regime that encourages objective and costefficient choices between investment and smart grid solutions.

Two workshops brought together around 40 experts including policy makers and advisors, scientists, businesses and civil society organisations to provide a neutral forum, under Chatham House rules, for full and frank dialogue to discuss measures for maximising the sustainability marine energy arrays within the UK government target timescales. The first workshop, Marine Planning for Arrays: Social, economic and environmental issues and implications, examined the social, economic and environmental impacts and cumulative impacts relating to siting and deployment of arrays and how to integrate the assessment and management of these using a holistic approach that considers the entire marine and coastal system. The second workshop, Marine spatial planning for the deployment of arrays, examined the marine planning policy context, simplification of consenting, locational criteria and models under development to aid decision-making.

Two workshops brought together around 40 experts including policy makers and advisors, scientists, businesses and civil society organisations to provide a neutral forum, under Chatham House rules, for full and frank dialogue to discuss measures for maximising the sustainability marine energy arrays within the UK government target timescales. The first workshop, “Marine Planning for Arrays: Social, economic and environmental issues and implications”, examined the social, economic and environmental impacts and cumulative impacts relating to siting and deployment of arrays and how to integrate the assessment and management of these using a holistic approach that considers the entire marine and coastal system. The second workshop, “Marine spatial planning for the deployment of arrays”, examined the marine planning policy context, simplification of consenting, locational criteria and models under development to aid decision-making.

There is continued interest in tidal energy generation as one of the components needed in the UK portfolio of renewable energy generation schemes. As the understanding and assessment of UK tidal energy resources progresses, it has become apparent that tidal regimes and site characteristics can vary considerably from one location to another. This, together with a survey of the state of the art in tidal energy technology, suggests that tidal energy converter schemes capable of economical operation over a wide range of site conditions would be inherently attractive. As a step towards this goal, Edinburgh Designs present in this report the result of an 11 month investigation into the technical and economical merits of a floating, variable pitch, Vertical Axis Tidal Turbine (VATT) scheme.

Tidal energy converter concepts based on conventional, fixed-pitch vertical axis tidal turbines have not shown great promise so far, owing to relatively poor efficiency, uneven loads and cavitation-limited operation. These issues can be resolved by introducing individual, active pitch control of each turbine foil. In addition, the floating vertical axis configuration offers significant advantages:

Overall, the objectives of this study have been met. In particular, we list the following conclusions:

1. Active pitch control on a vertical axis tidal turbine provides a new performance and economic benefit over the standard fixed pitch alternative. This is supported by parametric studies carried out with both a semi-analytical mode land a CFD simulation.
2. Steady-state structural loads are well understood and a simple, robust mooring configuration has been studied for the device. This area, however, would benefit from further work to determine how transient loads affect the dynamic stability of the floating structure.
3. For a single production-sized unit, electricity unit cost comparable to that forecasted for a state-of-the-art horizontal axis tidal turbine seem achievable with the variable pitch VATT concept (8-9/kWhr on the baseline site).
4. Based on the available data (2001), the results of the economic study suggest that for shallow sites (less than 25m depth, lower peak current velocities) the variable pitch VATT device may have an economic advantage over the MCT horizontal axis device.

1. Introduction
2. Review of Previous Work
3. Analytical Model
4. CFD Analysis
5. Structural Analysis
6. Optimisation and Power Prediction
7. Unit Cost Analysis