After a successful initial study to validate their tidal turbine design software Tidal Bladed, GL Garrad Hassan are preparing for the next phase of full scale validation, under the Reliable Data Acquisition Project for Tidal (ReDAPT) project. Tidal Bladed is a commercial software package which can be used to calculate the performance of, and loading on, tidal stream energy converters in the tidal stream environment.
Initial comparisons to measurements taken from the Tidal Generation Limited (TGL) 500kW tidal turbine have shown that Tidal Bladed gives very accurate predictions of the mean values of blade near-root flapwise bending loads, rotor speed, electrical power and pitch angle. Improved characterisation of the turbulent flow structure was identified as key to understanding and predicting the dynamic loading on tidal turbines.
Since its initial deployment in January 2013, the TGL 1MW turbine has been collecting high quality flow data using several Single Beam Acoustic Doppler Profilers (SBDs) mounted on the device. Many hours of flow data have already been collected and the data is currently undergoing analysis at GL Garrad Hassan. This analysis should lead to new understanding of the flow structures present in tidal stream turbulence and improved prediction of turbine dynamic loading.
The development of the GL Garrad Hassan Tidal SCADA system is allowing high frequency real time turbine performance and load data to be collected alongside the environmental conditions. This concurrent machine and environmental data is critical to the understanding of how the machine behaves in the harsh marine environment. Reducing the uncertainties in the loading and performance calculations used will allow for more cost effective tidal turbine designs.
The ReDAPT project was commissioned and funded by the Energy Technologies Institute (ETI) and aims to increase public and industry confidence in tidal turbine technologies by providing a wide range of environmental impact and performance information, as well as demonstrating a new, reliable turbine design.
Tidal Bladed is used by the majority of leading tidal turbine manufacturers as their primary tool for prediction of turbine performance and loading during the design process. The software is also used within certification and academia. GL Garrad Hassan offers training courses in the use of Tidal Bladed, to aid confident and effective use of the software and improve understanding of tidal turbine fundamental theory.
Press release, November 4, 2013; Image: Alstom