Sustainable Marine’s tidal drivetrain passes German tests with flying colours

Sustainable Marine has completed ‘rigorous tests’ on its latest generation tidal turbine drivetrain at the world-renowned Center for Wind Power Drives at RWTH Aachen University, proving the technology is robust enough to take on the Bay of Fundy tides.

SCHOTTEL Hydro, Sustainable Marine’s German engineering partner, collaborated with the Center of Wind Power Drives (CWD) at RWTH Aachen University to test the latest generation SIT250 drivetrain.

The key component, manufactured by propulsion expert SCHOTTEL, forms the ‘powerhouse’ of Sustainable Marine’s pioneering floating tidal turbine, converting torque – or rotation of the blades – into electricity.

The ‘accelerated lifetime testing’ was successfully completed in a six-month period, replicating five years of operation in the Minas Passage in Nova Scotia, at Canada’s Bay of Fundy – home to the highest tides on earth.

The site will play host to Sustainable Marine’s Pempa’q project involving the world’s first floating tidal energy array, delivering up to 9MW of energy to Nova Scotia’s grid, and powering around 3,000 homes per year.

A unique, tailor-made test rig was built within the University’s CWD, to test the drivetrain. It formed part of the ‘OsT’ project, led by SCHOTTEL Hydro and funded by the German Federal Ministry for Economic Affairs and Energy.

Ralf Starzmann, vice president of business development at Sustainable Marine, said: “Our latest testing project with Aachen University marks another significant step forward for our tidal energy technology and the broader Pempa’q Project. The durability and survivability of our platforms is paramount alongside their energy generating capacity at competitive costs.

“It was particularly important to prove the drivetrain could withstand five years of operation at the Minas Passage site, with this being the planned maintenance interval period. Rigorous independent assessments with world-class institutes like Aachen University play a key role providing credibility and confidence in the technology”.

Sustainable Marine’s SIT250 drivetrain has a grid-ready electrical power rating of 70kW. The system consists of a rotor hub, slow speed shaft, planetary gearbox and asynchronous generator.

As part of the novel test procedure a total of four independent hydraulic cylinders were used to apply simultaneous testing involving multiple load components. Further a 125kW motor was used to substitute the torque generated by the rotor, according to Sustainable Marine.

Following 2467 hours on the test rig, 152MWh of electrical energy was fed back by the drivetrain, equating to around one year’s electricity supply for 50 German homes. Post testing the drivetrain was decommissioned and subjected to a thorough inspection.

Dennis Bosse, managing director at the Center for Wind Power Drives, said: “The test program was divided into two main sequences. The first period focused on the rotating components, including the bearings and gearbox, where fatigue damage is caused by constant loads, involving torque, thrust as well as transverse force and bending moments were applied. During this period the drivetrain ran for 1800 hours at rated power.

“The second period focused on the static components including the drivetrain housing where fatigue damage is caused by variation of the loads. Components oscillated simultaneously with multiple combinations and load amplitudes.

“Ultimately, the testing proved that the SIT250 drivetrain is capable of withstanding the significant challenges posed by the FORCE Test Site in the Bay of Fundy”.