Passive Pitch Control Mechanism for Tidal Turbine Blades

This technology enables the independent passive pitching of individual turbine blades in response to uneven and variable loading. When compared with state-of-the-art solutions, it offers high resilience and reliability by reducing the unsteady loading and limiting the maximum power at rated flow velocity on tidal turbines with the potential to significantly decrease the levelized cost of energy production.

Application

• Passive control mechanism for tidal turbine blades

Development Status

• Prototype demonstrator and results

IP Status

• International (PCT) Patent Application

Commercial Offerings

• Commercial development and licensing

Opportunity

The potential of tidal energy to contribute to future energy decarbonisation strategy as a predictable renewable source is substantial. To realise this, however, advancements in technology are required to reduce the levelized cost of energy and enhance the competitiveness of these sectors in the energy market.

A key aspect where technology can make a difference is by mitigating hydrodynamic load fluctuations, and controlling the maximum power transmitted to the generator, thereby enhancing operational efficiency and also increasing the turbine's fatigue life.

One such approach is to deploy blade pitching mechanisms that mitigate exposure to varying loads. However, current methods for pitching control typically rely on active mechanisms that are not desirable in harsh environments, are limited to low-frequency fluctuations, are costly and require high maintenance.

Technology Overview

To address this, Professor Viola and colleagues at the University of Edinburgh have developed a new mechanical solution to control the pitching of blades. The Edinburgh technology enables individual blades of a turbine system to passively pitch in response to instantaneous loads.

This is achieved through an assembly that allows a turbine blade to pitch around a spanwise axis, with the pitching motion being constrained by a torsional spring. It can either be used in addition to pitch control systems to enhance unsteady loading mitigation, particularly at high frequency, or can entirely substitute active pitch systems by controlling only the turbine speed.

The mechanism is agnostic of blade design, so suitable for use with existing and future systems. Importantly the implementation is mechanically simple and does not include active components or complex linkages making it inherently durable and offering the potential for higher resilience, better reliability, longer lifetimes, lower susceptibility to structural fatigue and ultimately reducing the levelized cost of energy.

Benefits

• Fully passive mechanical pitching mechanism

• Independent pitching of individual blades in response to localised loading conditions

• Projected to decrease levelized cost of energy by more than 10%

• Applicable to most blade designs

• Suitable for retro-fitting to existing blades, as well as new blade designs

Publications

https://VOILAb.eng.ed.ac.uk/publications#Energy

Please note, the header image is purely illustrative. Source: imaginima via GettyImages

Quote: TEC1104494