Assessment of novel WEC with rubber-air-water interface; performance validation, optimization and demonstration of associated cost benefits
Abstract
AWS Ocean Energy completed rigorous due diligence of the original AWS Mark II Waveswing in 2008/2009 in a process which included independent assessment and competitor analysis by Black and Veatch [commissioned by AWS]. Although technical viable the internal and independent assessments both concluded that the AWS II system could not be economically viable in terms of market revenue support [5 ROCs] or longer term electricity prices. Existing studies indicate that the key to achieving economic viability is through a series of transformational technology steps rather by attempting to achieve economies of scale from first generation technology. From this stand point, and with a clear view of short term and long-term economic and performance requirements, AWS developed the AWS III device. This system has similarities with the Coventry Clam developed in the 1980s and includes a number of distinct novel features. These novel features include the development of a novel rubber diaphragm air-water interface. AWS has developed this new technology to readiness level 3/4. A number of key areas relating to performance require further development in order to demonstrate economic viability. Garrad Hassan has developed a numerical performance simulation model of the AWS III, while AWS has installed a 9th scale model of the device in Loch Ness. In order to demonstrate the performance benefits of the AWSIII it is vital that the Garrad Hassan model is robustly validated via 50th scale model tests. It is also important to link these models with the empirical performance data acquired from the Loch Ness trials. This can be achieved by also testing and optimizing a 9th scale single cell model in a highly controlled and repeatable wave tank environment. Cross validation of performance models and linking model tests with Loch Ness trials will enable informed and focused optimization of the Loch Ness system. All findings will be consolidated and then explicated to qualify and assess the capacity to improve the performance of the AWS III system. Findings will also be used to demonstrate the potential to drive down the long term cost of wave power through performance improvement. In addition to the specific goals of optimizing the performance of the current device design, a key additional benefit of the proposed programme is the opportunity to gain a greater understanding of the uncertainties involved in the relationships between small scale model test data, moderate scale model test data, moderate scale field trial data, and numerical simulations, and hence achieve an understanding of how to improve the design of an integrated tank-test and field trial programme for device characterization, design, and optimization. This part of the study will address a range of issues including programme planning, design, instrumentation, scaling, data analysis, and integration.
Organisations
Description | The project was asociated with an award from the Technology Strategy Board to the company developing the technology. The project was intended to examine and optimise a wave energy device which had previously been tested on Loch Ness at a notional scale of 1:10. The device previously tested was approximinately 6m in diameter and consisted of a number of modules arranged in an annular (doughnut-shaped) structure. The intention was to test the whole device at smaller scale (notionally 1:40) in the tank, and to carry out tests of device modules at 1:10 scale. with the aim of better characterising and understanding the device performance and understanding the realtionship between the small-scale tank test results and the tests on the loch. After some initial studies the intention to test at 1:40 scale was abandoned as it was concluded that the small scale modules would be too small to give correctly scaled results. This would have provided one of the key academic outputs, addressing the key challenge of extrapolation from model to full-scale. Attention was then focussed on the module testing. A series of test campaigns were undertaken successfully, allowing the characterisation of the performance and validating numerical models. Focus then switched to some tests in support of a planned deployment of a single full scale module. This deployment was simulated successfully, and the results contributed to the design of the full-scale stucture. It was hoped that the 1/10 scale model results could then be compared with the full-scale results to yield an alternative insight into extrapolation issues, but unfortunately the company faced funding challenges towards the end of the project and the full-scale demonstrator was not constructed. Some further studies were carried out on a commercial basis on the survivability of a modified version of the device after the end of this project, but the company downsized dramatically some time after that. Due to the commercial nature of the project, a number of results were unable to be published in the academic literature. |
Exploitation Route | The direct findings are of little use to others since they relate specifically to the device being developed, which ahs not been taken on by other developers so far. However the experience and skills gained during the program has contributed to the development of a publically-available set of best-practice guidelines for model testing of wave energy devices which has now been adopted by a worldwide association of large scale test facilities. |
Sectors | Aerospace Defence and Marine Energy |
Description | The findings were used to develop the device, and a series of further studies were subsequently carried out in collaboration with the industrial partner. During the test campaigns conducted for this project, the team at the Kelvin Hydrodynamics laboratory developed experience in a number of techniques for model testing of flexible wave energy devices which have contributed to subsequent studies with other devices. The experience gained has also contributed to the project PI writing a set of best practice guidelines for model-testing of wave energy devices. These guidelines have now been adopted by the International Towing Tank Conference, the key international body representing large-scale marine hydrodynamics test facilities worldwide. |
First Year Of Impact | 2012 |
Sector | Aerospace, Defence and Marine,Energy |
Impact Types | Economic Policy & public services |
Description | Development of Best Practice Guidelines for Model Testing of Wave Energy Converters |
Geographic Reach | Multiple continents/international |
Policy Influence Type | Membership of a guideline committee |
Impact | During the test campaigns conducted for this project, the team at the Kelvin Hydrodynamics laboratory developed a number of techniques for model testing of flexible wave energy devices which have contributed to subsequent studies with other devices, and have also contributed to the project PI chairing a committee tasked with writing a set of best practice guidelines for model-testing of wave energy devices. These guidelines have now been adopted by the International Towing Tank Conference (2014), the key international body representing large-scale marine hydrodynamics test facilities worldwide. |
URL | http://ittc.info/downloads/Generel%20files/pdfprocedures2014/7.5-02-07-03.7.pdf |
Description | AWS Ocean Energy Ltd |
Amount | £39,090 (GBP) |
Funding ID | AWS/2012/1 |
Organisation | AWS Ocean Energy |
Sector | Private |
Country | United Kingdom |
Start | 07/2012 |
End | 09/2012 |
Description | AWS Ocean Energy Ltd |
Amount | £39,090 (GBP) |
Funding ID | AWS/2012/1 |
Organisation | AWS Ocean Energy |
Sector | Private |
Country | United Kingdom |
Start | 09/2012 |
End | 12/2012 |
Title | Improved testing for flexible / pneumatic WECs |
Description | In the course of the project, the team developed a number of improved techniques and approaches for carrying out physical model tests of flexible WECs, in particular related to the modelling and scaling of the pneumatic systems of this device, but in a more general sense relating to improved approaches for the testing of wave energy converters |
Type Of Material | Improvements to research infrastructure |
Provided To Others? | No |
Impact | As described in another section, the experience gained from this study has contributed towards a set of best-practice guidelines now adopted by a key intenrational testing body. |