Addressing failure rate uncertainties of marine energy converters

Located off the Guérande peninsula, SEM-REV is the French maritime facility dedicated to the testing of wave energy converters and related components. Lead by Ecole Centrale de Nantes through the LHEEA laboratory, its aim is to promote research alongside the development of new offshore technologies. To this end, the 1km2, grid-connected zone is equipped with a comprehensive instruments network sensing met-ocean processes and especially waves, with two identical directional Waverider buoys deployed on the site since 2009. For the design of moored floating structures and, a fortiori, floating marine energy converters, the knowledge of the main wave resource — for regular operation — but also extreme conditions — for moorings and device survivability — has to be as precise as possible. Also, the consideration of the multiple wave systems (swell, wind sea) making up the sea state is a key asset for the support of developers before and during the testing phase. To this end, a spectral partitioning algorithm has been implemented which enables the individual characterisation of wave systems, in particular that of their spectral peakedness which is especially addressed in this work. Peakedness has been shown to be strongly related to the groupiness of large waves and is defined here as the standard JONSWAP’s peak enhancement factor γ. Statistics related to this quantity are derived from the measurement network, with a particular focus on the extreme conditions reported on SEM-REV (Joachim storm).

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Certification of Marine Energy Converters: The Experience So Far

Volume 5: Ocean Space Utilization; Polar and Arctic Sciences and Technology; The Robert Dean Symposium on Coastal and Ocean Engineering; Special Symposium on Offshore Renewable Energy ◽

10.1115/omae2007-29258 ◽

2007 ◽

Author(s):

Claudio Bittencourt Ferreira

Keyword(s):

New Technology ◽

Third Party ◽

Functional Requirements ◽

Energy Converter ◽

The Past ◽

Wave Energy Converters ◽

Marine Energy ◽

Constraints Handling ◽

The Right ◽

Energy Converters

In the past few years, DNV has been involved in a variety of projects related to marine energy converters. All projects have been characterised for the handling of technical uncertainties due to the application of new technology or proven technology in different area of application. A systematic approach based on the DNV RP-A203 Qualification of New Technology [1] was applied combined with the Guidelines for Design and Operation of Wave Energy Converters [2] to steer the third party activity, but, more importantly, to allow developers to systematically identify and deal with the risks in a rational manner with traceability of decisions throughout the development of the energy converter. From the very start of our engagement, it was clear that the handling of technical uncertainties was affected, not only by the technical barriers, but also by financial and time constraints. The establishment of the safety and functional targets to be achieved by the energy converter are to be based, not only on the safety and asset integrity aspects, but also on the financial / business model. The experience of using the Qualification process and the Guidelines on these projects, achieving the right balance between the constraints, handling of uncertainties, financial targets and safety and functional requirements, are briefly described in this paper as well as the future steps to be taken to improve the process and consolidate the experience so far. In this paper, it is also addressed the use of the DNV OSS-312 [3] on the certification process of marine energy converters.

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