Extension of UKCMER Core Research, Industry and International Engagement

Lead Research Organisation: University of Edinburgh
Department Name: Sch of Engineering


Wave and tidal energy devices are subjected to normal everyday loadings and abnormal extreme loadings. Extreme loadings are severe and less frequent. The repetitive loadings arising from wave-device interaction or current-blade-structure interaction are lower and occur very frequently in normal operation. Economic designs that will survive have to withstand, without structural failure, a combination of these types of loading over the design life of the device and its subsystems. Cumulative fatigue damage in the wave or turbulent-current environment could occur earlier than anticipated in the life of wave or tidal current technologies and needs to be better understood to predict wear-out or failure and ensure designs are robust without entailing excessive cost. This work will explore numerically through computer modelling, and physically through preliminary model- and sea-testing, the interaction of tidal and wave devices with their sea that surrounds them, one another, their moorings and the electricity network to understand the cyclic and irregular forces acting and the structural loadings arising, ultimately aiming to reduce fatigue effects and increase reliability.

Planned Impact

Tidal and wave energy converters are being demonstrated at full-scale in UK waters, supplying the electricity network. Meeting the 2020 and later targets for installed marine energy capacity mandates that single-device installations are up-scaled into arrays, farms and parks. Concurrently fledgling and new technologies must be systematically de-risked. With increased operational service and experience, it is now timely and necessary to explore cyclic loadings and consequent fatigue effects and their consequences for reliability to avoid early component or device failure.

The work proposed will model, predict and measure the repetitive cyclic and irregular forces on devices as the interact with the sea, one another, their moorings and the electricity network. The forecast loading regimes will be used to explore the cumulative fatigue damage and how this could affect wear out and failure of devices, structures, subsystems or components.

Device developers, manufacturers, installers, operating and maintenance companies, and marine energy farm owners will benefit by the findings of this research. Structures, subsystems or component parts, subject to repetitive loadings and stresses could be better designed, manufactured, installed, operated and maintained to avoid premature failure and costly downtime, or more expensive repair or replacement.

Standards and certification authorities will be advised by the findings for future evolution of design codes for the marine energy environment.

The wider sector will benefit by the prior avoidance of failure and associated reputational risk.
Description This project is now concluded. The research leading to and contributing to this grant application and our early work has shown that the effects of wave action on tidal current turbines in the water column can be as significant as incipient turbulence. This led to the objectives of testing 3 tidal turbines in an electrically and hydro-dynamically interconnected array under the action of waves and currents in the FloWave tank. It was first test programme of its type in the world. The outputs, findings, impact, collaborations and industry and policy interaction were reported at the 2018 Annual Assembly, available to download from the website. The associated publications are in press and are reported in the Phase 4 submission to Research Fish
Exploitation Route This will advise the tidal energy community on array layout and control strategies.
Sectors Energy

URL https://supergen-marine.org.uk/events/past-events/assembly-2018
Description The work of this collaboration has influenced technology, policy, standards and practice in the marine energy sector.
First Year Of Impact 2015
Sector Energy,Environment
Description Extension of UKCMER Core Research, Industry and International Engagement
Amount £1,517,202 (GBP)
Funding ID EP/P008682/1 
Organisation Engineering and Physical Sciences Research Council (EPSRC) 
Sector Public
Country United Kingdom
Start 12/2016 
End 11/2018