Fitting tidal turbines with flexible rubber blades can generate cheaper power by making the machines simpler and tougher, AZoCleantech reported.
Fast-flowing tidal channels batter turbine blades with constant turbulence and waves, causing fatigue and costly unplanned downtime. Conventional designs rely on active pitch control systems featuring motors, sensors, and bearings to twist blades away from strong flows. These mechanical systems are expensive and prone to underwater breakdowns.
Engineers from the University of Edinburgh and Michelin designed a 1.26-meter test turbine featuring three flexible rubber blades with a stiff internal steel spar. As currents strengthen, the trailing edge bends to automatically shed excess load without hinges or actuators. Nature inspired the approach, mirroring how fish and trees bend in strong wind and water flows.
The team tested the model turbine at the University of Edinburgh’s FloWave Ocean Energy Research Facility, a 25-meter circular tank recreating real tidal turbulence. The basin operated in current-only mode with a working water depth of 1.92 meters during the campaign. Submerged cameras filmed the blades changing shape as the rotor spun at hub height.
Measurements combined with full tidal cycle simulations showed the rubber-bladed turbine produced the same electricity amount as conventional pitch-controlled turbines. The flexible design reduced rapid load fluctuations by up to 29 percent. Rubber shares a water-like density, allowing neutrally buoyant blades that further limit load variations.
“Tidal energy is one of the most predictable renewable resources we have, but the sea is so unforgiving that turbines have needed complex machinery just to survive it,” said Professor Ignazio Maria Viola, who co-led the study at the University of Edinburgh School of Engineering.
Computer simulations of a 20-meter turbine indicate that full-size rubber blades could exceed the 20-year service life of current machines. The reduction in complex machinery could lead to lighter support structures and cheaper maintenance, lowering the cost of tidal electricity.
“The idea is simple: let the blades adapt to the flow, rather than relying on complex mechanical systems to withstand harsh ocean currents,” Dr. Zhehong Zhang told AZoCleantech.
Michelin brought its manufacturing expertise to the project.
A stiff internal steel spar runs from root to tip while the rubber trailing edge automatically bends and flattens under pressure. This natural deformation sheds excess force without requiring motors or actuators.
Researchers tested a 1.26-meter horizontal-axis turbine at the FloWave Ocean Energy Research Facility, a 25-meter circular wave-current basin at the University of Edinburgh.
The work remains at the research stage, and further development and testing are required before any potential industrial application or commercialization, the team stated.