Datasets for turbulence characterization collected with AD2CPs in potential tidal energy sites in Australia.

Sites with great potential for electricity generation from tidal stream energy are often characterized by high levels of turbulence and severe wave climates. These characteristics are known to substantially increase turbine blade loadings fluctuations, which may lead to premature device failure and blade fatigue. In order to be commercially competitive, tidal energy devices must function in turbulent environments for approximately 25 years without requiring major maintenance operations. Hence, knowledge of turbulence parameters prior to device deployment is crucial to avoid unnecessary costs with overengineering and maintenance. Aiming to support the development of tidal energy in Australia, the Tidal Energy in Australia (AUSTEn) Project identified two sites with potential for tidal energy: Banks Strait, Tasmania and Clarence Strait, Northern Territory. The datasets presented here reveal high-frequency current velocity measurements taken throughout the water column with Nortek Signature new generation Acoustic Doppler Current Profilers (AD2CPs) at one measurement station in Banks Strait and two in Clarence Strait. Measurement periods are between 2 and 3 months, which are significantly long deployment periods for turbulence characterization in tidal energy sites compared to other datasets available in the literature. Processing steps include the removal of bad quality data points using the manufacturer's software Ocean Contour, considering low correlation, side lobe interference and high amplitude spikes. These data have been used by Perez et al.(2021) to calculate turbulent kinetic energy (TKE), turbulence intensity (TI), Reynolds stresses, integral length scales, TKE dissipation and production rates as well as to discuss wave-turbulence interaction and the application of decomposition methods. In the dataset collected in Banks Strait, velocity fluctuation enhancements caused by wave orbital velocities were mitigated using the Synchrosqueezing Wavelet Transform (SWT) decomposition method. Turbulence estimates were organized by month and are revealed in the post-processed data files. Here we provide raw, processed and post-processed data files, which were made publicly available through the University of Queensland UQ eSpace repository. These datasets may be reused to further advance the understanding of turbulence and its impacts on tidal turbine performance as well as to help establish international guidelines for turbulence measurements in tidal energy site assessments.

Reliability of multi-purpose offshore-facilities: Present status and future direction in Australia.

Sustainable use of the ocean for food and energy production is an emerging area of research in different countries around the world. This goal is pursued by the Australian aquaculture, offshore engineering and renewable energy industries, research organisations and the government through the "Blue Economy Cooperative Research Centre". To address the challenges of offshore food and energy production, leveraging the benefits of co-location, vertical integration, infrastructure and shared services, will be enabled through the development of novel Multi-Purpose Offshore-Platforms (MPOP). The structural integrity of the designed systems when being deployed in the harsh offshore environment is one of the main challenges in developing the MPOPs. Employing structural reliability analysis methods for assessing the structural safety of the novel aquaculture-MPOPs comes with different limitations. This review aims at shedding light on these limitations and discusses the current status and future directions for structural reliability analysis of a novel aquaculture-MPOP considering Australia's unique environment. To achieve this aim, challenges which exist at different stages of reliability assessment, from data collection and uncertainty quantification to load and structural modelling and reliability analysis implementation, are discussed. Furthermore, several solutions to these challenges are proposed based on the existing knowledge in other sectors, and particularly from the offshore oil and gas industry. Based on the identified gaps in the review process, potential areas for future research are introduced to enable a safer and more reliable operation of the MPOPs.

Dataset for concurrent echosounder and ADCP measurements at a tidal energy candidate site in Australia.

Interaction uncertainties between tidal energy devices and marine animals have the potential to impede the tidal energy industry as it moves closer towards commercial-scale array installations. Developing standardised environmental impact assessment (EIA) practices would allow for potential impact concerns to the marine environment to be identified and mitigated early during project development. In an effort to help formulate a standardised EIA framework that addresses knowledge gaps in fish-current interactions at tidal energy candidate sites, Scherelis et al. [1] presented a case study for investigating changes in fish aggregations in response to changing environmental conditions including tidal currents at a tidal energy candidate site in Australia prior to turbine installation. Here, we present the dataset utilised for this study titled "Investigating biophysical linkages at tidal energy candidate sites: a case study for combining environmental assessment and resource characterisation" [1]. The dataset includes tidal current information from an Acoustic Doppler Current Profiler (ADCP), volume backscattering measurements from a four-frequency biological echosounder (Acoustic Zooplankton and Fish Profiler - AZFP) as an indicator for fish biomass, and fish aggregation metrics calculated from volume backscatter in post-processing. ADCP and AZFP were installed on a bottom-mounted mooring and engaged in a concurrent sampling plan for ∼2.5 months from December 2018 to February 2019. The mooring was deployed in the Banks Strait, a tidal energy candidate site located in the northeast of Tasmania, Australia, at a location favourable for tidal turbine installations considering current speed, depth, substrate, sediment type and proximity to shore. The ADCP dataset includes current velocity and direction measurements at 1 m vertical and 1-min time intervals. The raw AZFP dataset includes volume backscattering strength collected in 4-s time intervals with a vertical resolution of 0.072 m in raw, and 0.1 m in pre-processed form. Several post-processing steps were implemented to mitigate changes in background noise due to current speed and wind stress, and to isolate acoustic fish returns from remaining scattering sources. Once isolated, volume backscatter containing fish targets underwent post-processing to determine fish aggregation metrics including density, abundance, centre of mass, dispersion,% water column occupied, evenness, and index for aggregation. Each aggregation metric was then binned by minute matched with corresponding environmental conditions for current speed, shear, temperature, diel stage, and tidal stage. Raw and processed datasets for the AZFP and ADCP are provided. Post-processed data includes the derived fish aggregation metrics along with corresponding environmental conditions. The described datasets are freely available on the Australian Ocean Data Network (AODN).