By Prof Tony Lewis, Chief Technology Officer, OceanEnergy
WEDUSEA has recently completed its latest round of wave tank testing at Lir, Ireland’s flagship National Ocean Test facility.
Located in the University College Cork Environmental Research Institute, the Lir National Ocean Test Facility provides world-class laboratory testing for offshore wind, wave and tidal energy devices. The state-of-the-art facilities at Lir include four wave tanks that can replicate real ocean conditions and enable testing of various marine innovations, technologies and structures at different scales.
In January 2023, OceanEnergy, the Irish company which is co-ordinating the €19.6m WEDUSEA partnership project, tested a scaled model of the OE35 at the Deep Ocean Basin at Lir.
This was a scale model of the OE35 that will be deployed for sea trials at the European Marine Energy Centre (EMEC) site in the Orkney Isles for a two-year period at a later stage of the WEDUSEA project.
This recent round of wave tank testing is the latest in a significant programme of systematic testing carried out by OceanEnergy as we have developed our OE35 technology (the OE Buoy) over the years. We have taken a rigorous approach to testing at each stage of development and the project has thus been built on robust scientific foundations throughout.
OceanEnergy follows the Technology Readiness Level (TRL) methodology for validating technology development, which is now the industry standard. The goal is to de-risk the technology and drive down the levelized cost of energy (LCOE). The philosophy of OceanEnergy has been to approach the development of the OE Buoy by progressing sequentially up the TRL levels – passing stage gates during this process. This allows significant de-risking of the development and confidence in scaling up to tests with higher costs.
The first concepts were tested at a scale of 1:50 (TRL1-3) at the Hydraulics and Maritime Research Centre (HMRC) in University College Cork, Ireland. This testing programme, which used a device model to a scale of 1:50, was designed to optimise the hull configuration and maximise the power output. During this phase, the device was tested in a variety of hull configurations and wave conditions representative of the real seas, which the OE Buoy would work in when deployed commercially.
For the second phase of testing, a detailed design was produced by a team of naval architects. Testing at a scale of 1:15 (TRL4) was completed in the large wave basin at Ecole Central de Nantes, France. HMRC staff were used to carry out the tests at Nantes to ensure full continuity within the development process. During these larger scale trials more detailed information was obtained as well as confirmation of the predicted energy capture and device behaviour in larger sea states.
Following the successful outcome of the controlled tests in Cork and Nantes, the third phase of testing saw the move to the intermediate size testing of the OE Buoy (TRL5) in the open sea in Galway Bay, Ireland. The quarter scale device, a 28 tonne model was fabricated in Cork and following the successful completion of stability sea trials in Cork Harbour, it was towed to the Galway Bay Test Site. These tests were carried out with different air turbine and power take-off configurations and culminated in a collaborative project (CORES) funded by the European Union’s Seventh Framework programme.
This open sea test programme confirmed the ability of the device to behave and operate stably, safely and reliably in real sea conditions.
Further technology development was carried out when the 500kW OE35 device (TRL6) was constructed and towed to the US Navy Wave Energy Test Site in Hawaii for deployment.
So, it can be seen that our recent wave tank tests at Lir are the latest example of our long term commitment to a rigorous development approach, which places systematic scientific testing and analysis at the very heart of our R&D.
The WEDUSEA project will continue to follow robust scientific testing principles and the latest industry protocols as we advance the commercialisation of wave energy.
You can see a video of the Lir wave energy testing here.