Canadian-German collaboration delivers stronger tidal turbine blades

Sustainable Marine has recorded a first major milestone in the Canadian-German EvoFoil project after completing extreme load testing on a new tidal turbine blade, designed to withstand some of the most challenging tidal environments in the world.

Sustainable Marine’s new 4.3-meter blade underwent a comprehensive ‘static-bending test campaign’ to demonstrate its future durability as it has been specifically designed to withstand conditions in the Bay of Fundy’s Minas Passage.

Located in Canadian province of Nova Scotia, the site will play host to the company’s Pempa’q Project to showcase the world’s first floating tidal energy array.

The test results on the new blade showed continued evolution with a 7% energy yield increase, compared to previous 4-meter rotors designs.

Also, the new blade was able to withstand loads of up to 3.8 tons – which is the equivalent of four old VW Beetles, according to Ralf Starzmann, head of power systems at Sustainable Marine.

“Successful extreme load testing marks an important milestone demonstrating the reliability of our new blade design, which is a key factor in tidal turbine development. Working closely with our partners, we developed a tailor-made test rig to meet the requirements of our new 4.3-meter blade.

“This verifies the short-term strength of the new blade design against the extreme loads it will experience at the Fundy Ocean Research Centre for Energy (FORCE) test site in the Minas Passage, where our tidal platform will soon be located,” said Starzmann.

Aside from Sustainable Marine, the EvoFoil project is being developed in partnership with German organizations M&D Composites Technology and Leibniz Universität Hannover Institute of Production Engineering and Machine Tools.

It aims to deliver a series of design innovations to optimize the performance of tidal turbine blades while driving down production and operation costs.

The recent testing took place at M&D Composites’ facilities in Friedeburg in Germany, which enabled direct feedback to the production team. The tests also proved the passive-adaptive pitch properties of the new design – increasing energy generating potential.

Tim Markwald, M&D Composites Technology managing director, said: “A key focus for M&D Composites involves optimizing the manufacturing process of the turbine blades and designing a novel generation of tools to reduce fabrication time and costs. By increasing the energy yield and reducing production costs we can help scale down the overall cost of energy.”

Carsten Schmidt from Leibniz Universität Hannover noted that during the latest lab test campaign, the partners also monitored blade deformation and fibre strains.

“This is helping to inform broader work to develop a new ‘multi-layer’ material which will improve the mechanical behavior of the blade and help counteract the various loads.

“We introduced a novel fibre-optic strain measuring system to improve the monitoring process, providing strain information with a very high spatial and temporal resolution all across the foils surface. We now have unique data which will be used to further improve the design concept,” Schmidt added.

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