​MET-CERTIFIED visits seven marine energy test facilities at four locations in one day

June 26, 2018
Is it possible to visit 1 offshore wave energy test site, 3 flumes, 2 wave basins and 1 component test facility at 4 locations in one day? Yes, we did!  On 20th June, a dedicated group got submerged in the test facilities that Cornwall and Devon have to offer. 

During this jam-packed 24 hours, MET-CERTIFIED project partners (Ghent University & DMEC) met representatives of the University of Exeter, Wave Energy Scotland, Carnegie UK, Wave Ventures, Interreg 2 Seas and Plymouth University, all sharing the same enthusiasm for marine energy resulting in interesting discussions about the role of test facilities in certification, risk mitigation and making the technology bankable.
  
  
MET-CERTIFIED facilitates access to test facilities, please contact pieter.mathys@ugent.be   or dominique.dhondt@ugent.be for more information.



After a safety briefing on the A&P terminal of Falmouth, DMaC project manager Pete Halswell of Exeter University welcomed us at DMaC, where (synthetic) ropes or mooring lines and power cables can be tested on fatigue as well as ultimate strength tests.  The test device allows to put the moorings under stress in 4 degrees of freedom:

  • The length actuator allows a static force of 45 tonnes or a dynamic force of 30 tonnes;
  • The X and Y displacements allow free bending with a displacement of 30° and a frequency of 0.25 Hz;
  • And finally torsion along its length axis.

This can be done both in dry and wet conditions, which is a significant advantage of this test facility.  The data acquisition is based on the National Instruments Compaq Rio platform, which makes it very modular.  DMaC is ISO-9001 accredited and also part of the Marinet-2 programme, where testing is facilitated. Peter also explained the “Exeter tether”, a dynamic mooring system which has shock absorbing capabilities, in order to reduce stresses on the anchoring points of e.g. floating tidal energy devices. 

Peter demonstrated a destructive test of a synthetic mooring line that snapped at approximately 15 tons of static load.  The mooring line didn’t snap completely, and still retained 6 tons.  Getting insight on both fatigue loads and ultimate limit state loads is of extreme importance in floating energy devices.  What couldn’t be captured on the pictures or in the video is the smell of the ropes: due to the internal friction along the fibres, the mooring line heats up very quickly, which produces a particular smell.

We concluded the visit with a short discussion on why standardisation (62600-10 moorings and tidal scale testing 62600-202) provides mutual benefits.

Quote of Pete Halswell, DMaC project manager of Exeter University 
 "We had a successful and enthusiastic site visit of DMaC test facility with detailed discussions on testing of MEC devices and components, and the importance of certification to increase reliability.   I personally think certification is a vital step in proving reliability of marine energy, which in turn reduces running cost and insurance costs."
  
  


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After the DMaC visit, George Crossley, test site manager of FaBTest, University of Exeter, invited us on a pilot boat to sail to the 2.8km² zone with 4 non-grid connected test births for wave energy.  This is considered to be a relatively sheltered “nursery” site, but make no mistake as the extreme wave climate here is still high, with waves up to 9m.  Depths vary from 20 to 40m.

After a short sailing of approximately 10 minutes into Falmouth bay, we arrived at site, where Marine Power Systems had recently installed their wave energy device (submerged) and supporting/DAQ buoy.  Previously, Fred Olsens Lifesaver and Polygen have been testing there.
George indicated that the collaboration with the University of Exeter and the harbour authority (including e.g. the local marine contractors) provided the best of both worlds in terms of effective and efficient support for this site.

The fact that this site is preconsented allows wave energy developers to focus on their core business, instead of going through the time-consuming and sometimes cumbersome consenting procedures.

FaBTest provides wave early developers with a very important TRL6-7 test facility, in order to gain on-site experience in real sea conditions.

Quote of George Crossley, test site manager of FaBTest, University of Exeter
"It was exciting to be able to welcome a highly motivated group of marine energy experts from around the 2SEAS region of Europe to the Falmouth Bay Test site. The trip out into Falmouth Bay, where the Marine Power Systems WaveSub is installed, inspired in-depth discussion and collaboration in research, demonstrating Cornwall’s ability to meet the needs of industry and emphasising the vision of Interreg to share and build knowledge and relationships across Europe.”
  
 
  













































After a quick lunch, including Cornish mussels, our delegation headed back east for a short stop at the Penryn campus of Falmouth/Exeter where we visited the tidal flume and met with Magnus Harrold who works for Exeter University and supports Tocardo.  Relevant research there included the hydrodynamic effect of marine growth and fouling on e.g. buoys, open cage oyster and lobster research, and new tests for vortex induced vibrations were being prepared.  The latter was performed in conjunction with the DMaC test facility, in order to understand both the hydrodynamic and mechanical sides of this phenomena. 


 4. Plymouth Coast Lab

Our last stop was at the Plymouth Coast Lab.  This wave basin allows for wave generation with perpendicular or parallel currents.  Martyn Hann explained the test facility and the research performed for wave energy and the upcoming market of floating wind. 

A wave energy scale model was being tested during our visit, but due to confidentiality, no further information could be shared.  Martyn explained an image recognition system with multiple cameras that logs the exact position of the (floating) wave scale model, in order to fully monitor the 6 degrees of freedom.  Our representative of Interreg 2Seas even saw some poetry in those 6 degrees of freedom, namely surge, sway, heave, roll, pitch and yaw. 

We concluded our visit with at the smaller scale flumes, where fundamental research was performed to gain insight in the combined effects of landslide in conjunction with a tsunami.  Alongside, research was performed to quantify the residual movement of microplastics (and the effect of particle size on the Stokes drift).  This  clearly indicates that this test facility allows to address multiple societal challenges whether it’s renewable energy, ocean litter or coastal defence.   






























































  









Conclusion

 The site visits gave a better understanding of the potential of test facilities to detect and mitigate technical issues early on.  The informal setting on site allowed open discussions on the role of test facilities for marine energy with regard to standardization, certification, and accreditation.  Awareness within  test facilities is rising, but as the market currently is still premature,  engagement within certification schemes can be improved, in order to capitalize on the experience in test facilities and gain investment trust.  Furthermore, MET-CERTIFIED will organize visits and facilitate access to test sites in the near future, so subscribe to our newsletter or follow us on twitter for the latest announcements.​