DEVELOPING LEADING-EDGE PROTECTION FOR WIND TURBINE BLADES
Aerospace technology is being used to develop a novel wind turbine blade protection system for the leading edges of offshore turbine blades.
The research project believes that this solution could lead to lighter wind turbine blades and drivetrains, whilst eliminating the need for intervention related to rain erosion.
The longer, lighter turbine blades have higher tip speeds, thereby reducing the cost of energy generated by each wind turbine over its operating lifetime.
Erosion of wind turbine blades is caused by the combined effect of rain impact and general weathering. This eventually compromises the blade’s underlying composite structure, by degrading and ultimately removing the protective coating, exposing the blade.
The erosion reduces aerodynamic efficiency and leads to losses in the operational output of the turbine. This manifests as a significant drag increase as the blades turn, causing a reduction in energy output for each wind turbine.
Rain erosion is currently the leading cause of damage to wind turbine blades. It is a significant issue for both turbine manufacturers and owner/operators as they look to improve a blade’s operational life to match the 25-years active service life of the turbines.
Erosion of blade leading edges is reported as occurring within two years of a turbine’s operation offshore. A wind farm in the North Sea reported severe erosion on the blades in all its 270 turbines within six years.
Improving erosion protection for offshore wind turbine blades could significantly reduce turbine blade repair costs and the costs/losses in power production through the downtime of turbines requiring repair.
The Leading Edge for Turbines (LEFT) project, part-funded by Innovate UK, is a two-year, £1 million collaboration between PES Performance, Engineered Solutions (PES) Ltd; Sheffield-based specialist aerospace component manufacturer, Doncasters Bramah and the Offshore Renewable Energy Catapult; the UK’s leading technology innovation and research centre for offshore renewable energy.
The PES design engineers are using their experience in composites optimisation and component performance for the project. This includes their expertise in lightweight materials and aerodynamic design.
Doncasters is applying its aerospace expertise for leading-edge erosion shields for aircraft and helicopters, to solutions for the offshore wind industry. Doncasters utilise a variety of forming and fabrication processes. These include electroforming; an electro-deposition based additive manufacturing process, like electroplating.
Parts are grown in a chemical bath onto a preformed mandrel to produce near net shape parts, removing the need for multi-stage forming operations associated with conventional metal forming techniques.
Benchmark rain erosion testing at ORE Catapult has indicated that the nickel-cobalt solution under test could be expected to give 30 years protection when continuously tested to offshore wind specifications. This exceeds the performance of products currently available on the market, and with a 25 year typical turbine lifetime, this solution could provide lifetime protection against leading-edge erosion.
The LEFT project aims to validate an optimal method of attaching such a solution to offshore wind blades, in addition to considering how to integrate the design of a nickel-cobalt leading edge into the overall design and functionality of wind turbine blades.