Abstract
This report intends to provide guidelines to compare different types of tidal energy converters. The first section of the report shows the different groups and sub-groups of converters that can be found currently in the literature. Parameters such as scale factors and blockage corrections that need to be considered when testing tidal energy converters are also discussed briefly in the report. Methods currently adopted to measure structural loads and performance of tidal devices can be found in the report with recommendations on topics such as: data collection, instrumentation and post-processing of data.
The report then gives suggestions on the parameters that can be employed to carry out the comparisons between types of tidal converters (e.g. performance vs. solidity). Other parameters such as blade deflection or wake structure are also suggested as parameters that can be utilised for comparative studies; however, the collection of such data is always dependent on the testing objectives of the experimental session.
A case study is presented at the end of the report. A three bladed horizontal axis turbine was tested in four different facilities as part of the Round Robin testing programme of MARINET. In the results of the study, it can be observed that the performance characteristics of the turbine were slightly influenced by the testing facilities used, especially when the turbine was installed in facilities with turbulent flows. It was concluded that turbulence intensity did not influence the performance of the devices severely. However, the examination of other flow characteristics (e.g. turbulence length scales or wave-current interactions) should be studied in detail in the future.