Flexible rubber blades for tidal turbines

Abstract The global transition towards sustainable energy systems has identified tidal power as a uniquely predictable and substantial renewable energy resource 1 . However, the highly unsteady sea environment subjects turbines to severe hydrodynamic loads, greatly increasing capital and maintenance costs 2,3 . Large-scale state-of-the-art turbines at present rely on complex, expensive active pitch systems to mitigate these fluctuations. Here we present a reliable, passive alternative: flexible rubber blades featuring chordwise trailing-edge deformation. We experimentally demonstrate that these flexible blades achieve an equivalent total energy yield over simulated tidal cycles compared with rigid blades with active pitch control, while mitigating high-frequency fatigue-inducing load fluctuations by up to one-third. This passive load regulation arises from aeroelastic deformation that flattens blade camber under load, enabling structural robustness without added mechanical complexity. These findings suggest that chordwise-flexible blades can enhance the durability and performance of tidal turbines, offering a promising pathway towards more reliable and cost-effective tidal energy generation.