Sustainable Marine’s tidal turbine rotors fit for 20 years of continuous service

Sustainable Marine’s new turbine rotors have proven they can survive for two decades in the field, following rigorous tests at marine energy centre of the National University of Ireland.

The UK-based Sustainable Marine joined forces with the MaREI Centre at the National University of Ireland in Galway (NUI Galway), through German engineering partner SCHOTTEL Hydro, to test its new ‘ultra-durable’ turbine rotors.

The project was delivered under MaRINET2 – Horizon 2020 programme supporting offshore renewable energy testing across the EU.

The testing took place within the Ryan Institute and School of Engineering at the National University of Ireland Galway, which houses a 375-square-metres Structures Research Laboratory – said to be the largest of its kind in the Republic of Ireland.

Sustainable Marine’s novel floating tidal energy system uses a common drive train and two different rotor diameters, measuring 6.3 – 4 metres, to suit requirements at different resource sites.

Having completed extensive tests on the 6.3-metre rotors at NUI Galway, the company returned to the Irish facility to assess the performance of its shorter 4-metre rotors, specifically designed for stronger resource sites.

The state-of-the-art laboratory carried out ‘accelerated lifetime testing’ subjecting the rotors to conditions equivalent to 20 years of operation in the field, in just a matter of weeks. It covered a broad range of parameters including stress, strain and vibration.

Ralf Starzmann, vice president of business development at Sustainable Marine, said: “This international collaboration, through our German engineering partner SCHOTTEL Hydro, provides a firm indication of our ambitions to continue raising the bar and advance the field of tidal turbine technology. In order to push the boundaries, it is essential that we challenge our solutions at leading facilities that can push the limits of our technology.

“Accelerated lifetime testing is an essential process which allows us to rapidly speed up normal conditions, to better understand how structures will react over time. Our new 4-metre rotor blade has proven to be ‘ultra-durable’, providing full confidence in the design and structural integrity. Reliability is a key factor in tidal turbine development, particularly as we are now moving towards our first commercial projects”.

The complete analysis in the MaREI Centre at NUI Galway tested rotor behaviour under fatigue loading, reviewing aspects such as torsional deflection and overall structural performance.

Further in-house testing carried out by SCHOTTEL Hydro involved ultimate loading and testing the integrity of the blade until failure, according to Sustainable Marine.

The company is currently preparing to deliver the world’s first floating tidal energy array in the Bay of Fundy, Nova Scotia.

Earlier this year, it launched its new 420kW PLAT-I 6.40 floating tidal energy platform, featuring the new 4-metre rotors, which is now undergoing commissioning and testing in Grand Passage.

Sustainable Marine’s turbine design consists of a fixed pitch rotor engineered from carbon-fibre, in order to flex and pitch in overload conditions.

This ‘passive-adaptive’ quality is said to help reduce structural loads on the turbines so that smaller more cost-effective components can be used.

Jamie Goggins, director of research & innovation at NUI Galway’s School of Engineering, said: “Due to the nature of shorter blades with significantly higher loads, compared to wind blades, a specialist structural testing facility for tidal turbine blades was required to support the tidal energy industry.

“We are delighted to be able to collaborate with SCHOTTEL Hydro through the H2020 Marinet2 project to de-risk their full-scale blades to help the sector reach commercial viability. These projects also help train the next generation of energy engineers. To date, over 100 engineers have worked within our group, as either staff or students, and have gone on to work with some of the world’s leading companies”.