INNWIND.EU is a project with a budget of nearly €20 million and with 28 partners. Its objectives include the conceptual design of beyond-state-of-the-art 10-20 MW offshore wind turbines and hardware demonstrators of their critical components. Thus far, the project has developed several innovative rotor designs, drivetrain components, and fixed and floating substructures that greatly reduce the Levelized Cost of Energy (LCOE) for 10-20 MW offshore wind turbines. No technological “show-stoppers” for the development of wind turbines between 10-20 MW wind turbines are seen, but manufacturing processes for critical components such as the hub and blade bearings are not fully developed and need to be matured.
Large integrating projects such as INNWIND.EU facilitate effective consortia working on multi-disciplinary innovations. The INNWIND.EU consortium consists of large wind turbine manufacturers, certification bodies, consulting companies, research institutions and leading universities. An assessment of the entire wind turbine with different innovations has been made at the 10 MW and 20 MW scales by applying performance indicators and a comprehensive cost model developed in the project. Moving from conventional 5 MW offshore turbines to lightweight 10 MW- 20 MW scale allows a reduction in LCOE due to the larger turbine size along with the use of an efficient lightweight rotor and the shift from traditional three-stage geared drive trains to a medium speed drive. Significantly further reduction of LCOE can be expected for both 10 MW and 20 MW designs, due to the advanced concepts researched in INNWIND.EU, getting LCOE close to 80 €/MWh for 20MW turbines and 85 €/MWh for 10MW turbines. This corresponds to an overall reduction of more than 30% in LCOE compared to the reference value of 106.9 €/MWh corresponding to 5 MW turbine sizes, thus bringing 20 MW offshore wind turbines closer to the market.
Some of the key promising innovations as developed in the project that reduce LCOE and increase efficiency include:
- The Low Induction Rotor (LIR), which constrains the extreme loads at the blade root and allows large rotor diameters with increased energy capture;
- Optimized aerodynamic and structural platforms of blades for reduced blade root fatigue and tower base fatigue;
- Active control with a focus on blade trailing edge flaps and blade trailing edge section morphing for load alleviation;
- High temperature superconducting generators to increase efficiency;
- Pseudo-Magnetic Direct drives (PDD) that also significantly increase transmission efficiency;
- Advanced optimal jacket designs at 50 m water depths to support wind turbines at 10 MW and 20 MW capacities;
- Guyed articulated sub structure at 50 m water depth that avoids resonant excitation for 2-bladed and 3-bladed rotors;
- Novel triple-spar semi-submersible floating wind turbine for 10 MW wind turbines.
To develop and validate the design basis of floating wind turbines, several wave tank tests have been made in the project that test semi-submersible and tension leg platforms. The floater response and parameters of waves measured in the tests are available to the public upon request. Met-ocean conditions required for the design of future large wind turbines up to 300 m in height, with wind velocity profiles and associated wave climate have been constructed using advanced models and validated with data from the FINO3 platform. This met-ocean database allows the set-up of an external conditions design basis for 10-20 MW wind turbines. All the above are available on request.