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Title: Advancing reliability information for Wave Energy Converters
Author: Thies, Philipp Rudolf
ISNI:       0000 0004 2737 1004
Awarding Body: University of Exeter
Current Institution: University of Exeter
Date of Award: 2012
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Marine renewable energy promises to provide a significant contribution to the future electricity supply. It is estimated that 17% of today's UK electricity demand could be generated from wave and tidal sources. The ambition to harvest this resource is in the public interest, as it eases the pressures on energy security, holds the potential to reduce carbon emissions and has the prospect to create a new UK industry sector worth £15 billion. From an engineering perspective, marine energy is one of the least developed renewable energy technologies and has to be regarded as unproven. The reliability of components and devices in the harsh marine environment is one of the main engineering challenges. Reliability assessments and the assurance of acceptable reliability levels are dependant on the adequacy of failure information, which is scantily available for marine energy. This thesis shows that large failure rate uncertainties impede the reliability assessment for wave energy converters and how a suite of experimental, numerical and statistical methods can be applied to improve scarcely available reliability information. The analysis of component load conditions identifies fatigue as failure mode of concern and the fatigue life of mooring lines and marine power cables is quantified in a floating wave energy application. A Bayesian statistical approach and dedicated service-simulation component testing is proposed, and implemented to improve the quality of reliability estimates and to provide relevant data and assurance. The methods presented, along with the results, will assist reliability assessment and design during early development stages, and will inform the prediction of maintenance requirements during operation. Reliable marine energy systems will be the technical enabler for the successful transition of prototype devices to a commercially viable marine energy industry.
Supervisor: Johanning, Lars ; Smith, George H. ; Wolfram, Julian Sponsor: Engineering and Physical Sciences Research Council (EPSRC), SuperGen Marine Phase 2 ; Peninsula Research Institute for Marine Renewable Energy (PRIMaRE) ; Institution of Engineering and Technology (IET)
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available
Keywords: Reliability ; Failure rate ; Wave energy ; Marine renewable energy ; Bayesian updating ; Reliability Block Diagram ; Mooring ; Umbilical ; Marine power cable ; Rainflow cycle analysis ; Fatigue ; Component testing ; Service simulation testing