An Evaluation of Blade Repair Techniques and Applicability for Tidal Turbines

Abstract

The number of tidal stream energy installations is set to rise rapidly as countries deploy increased renewable energy capacity to meet net zero targets. The year 2023 was a pivotal year for the tidal stream industry in the UK, with 11 Contracts for Difference being awarded to tidal stream projects in Allocation Round 5. This will grow UK deployed capacity to nearly 100MW by 2028. In wind energy, an estimated 3800 incidents of blade damage occurred for 700,000 installed turbines in 2020. This has resulted in significant attention on optimisation of repair procedures to minimise operational downtime. As a result, this is now supported by a skilled and experienced repair industry with developed practices. Wind and tidal blades share significant similarities in composite material construction and design, and as tidal energy scales, similar attention to blade repair will likely be required to ensure that tidal turbine blades can be kept in service with minimal downtime. This study reviews and contrasts the observed and expected damage experienced by in-service composite wind and tidal turbine blades to establish a baseline for transfer of existing techniques between the industries. The tidal-specific repair requirements and impacts of blade design and operating conditions are assessed, enabling assessment of the applicability and suitability of developed wind industry procedures, techniques, and tools for tidal blade repair. The challenges surrounding the unique design features of tidal blades such as thick sections, ply tapering, and large curvature are assessed to identify areas requiring novel repair approaches. The study acts as a primer to allow tidal stream project developers and operators to anticipate blade maintenance requirements and better understand the transferability of existing wind repair practices to bolster future growth in the tidal stream industry.