scholarly journals Investigation of the Error of Mean Representative Current Velocity Based on the Method of Bins for Tidal Turbines Using ADP Data

2020 ◽  
Vol 8 (6) ◽  
pp. 390
Author(s):  
Udara Rathnayake ◽  
Matt Folley ◽  
S.D.G.S.P. Gunawardane ◽  
Carwyn Frost
Keyword(s):  
Current Velocity ◽  
Technical Specification ◽  
Tidal Energy ◽  
International Electrotechnical Commission ◽  
Power Performance ◽  
Tidal Turbines ◽  
Extraction Site ◽  
A Tec ◽  
Acoustic Doppler Profiler ◽  
Relationship Of

Representing the velocity at a tidal energy extraction site in a standardized manner is essential for the development of the tidal energy sector. The International Electrotechnical Commission (IEC) have issued a technical specification to determine the mean representative current velocity (MRV) relative to a tidal energy converter (TEC). This method determines the MRV using an acoustic Doppler profiler (ADP). This is used to evaluate the power performance of a TEC and so can have a significant influence on the power performance uncertainties, due to the cubed relationship of the MRV and power. This paper investigates these uncertainties in the MRV by considering four sources of uncertainty in the ADP. These are turbulence intensity, tilt, Doppler noise and beam misalignment of an ADP. A synthetically generated dataset is used to define current velocity and profile using the characteristics of currents and ADP. The generated synthetic dataset is processed to calculate the MRV based on the standard IEC method. An alternative method to calculate the MRV, called the temporal-spatial method (TSM), is proposed and the two methodologies are used to assess the error of the MRV. A sensitivity analysis shows that the errors of the MRV based on the standard IEC method are always higher than the TSM. The biases in the MRV based on the different combinations of the uncertainty are investigated and it is found that the bias for the MRVs based on the TSM method is generally less than that of the IEC method.

Power Performance Assessment of the Tidal Turbine Sabella D10 Following IEC62600-200

2016 ◽  
Author(s):  
Stéphane Paboeuf ◽  
Pascal Yen Kai Sun ◽  
Laura-Mae Macadré ◽  
Gaël Malgorn
Keyword(s):  
Performance Assessment ◽  
Technical Specification ◽  
Tidal Energy ◽  
Electrical Network ◽  
Power Performance ◽  
Electricity Grid ◽  
Tidal Turbines ◽  
Site Characteristics ◽  
Tidal Turbine ◽  
Power Curves

Recently, the tidal turbine Sabella D10 has been installed in the Fromveur Passage, off Ushant Island, in France. Sabella D10 is a 1 MW tidal turbine fully submerged and laid on the seabed with a horizontal axis and 6 blades. It is the first French tidal turbine producing electricity and connected to the electrical network. As tidal turbines are emerging technologies, the demonstration of the power performance in real conditions is vital for designers. Currently, few full scale prototypes have been tested at sea and even less have been integrated into the electricity grid. Due to this context, the standard IEC62600-200 Electricity producing tidal energy converter - power performance assessment has been applied only on a limited number of turbines and, as a consequence, industrials have a limited feedback on the use of the IEC62600-200. The aim of this paper is to detail the IEC62600-200 requirements for the power performance assessment, and the application case on the tidal turbine Sabella D10. The technical specification IEC62600-200 was issued in 2013 and describes the procedure for the power performance assessment of the tidal converters. This technical specification gives requirements for the site and test conditions, the measurement procedures and their exploitation to obtain the power curves. Finally, the reporting format of the results, is detailed to provide a complete document to the certification body. In the framework of the project Sabella D10, funded by ADEME, the power curves of the tidal turbine prototype D10 of Sabella have been established in cooperation with Sabella and Bureau Veritas according to IEC62600-200. They worked together for the interpretation of the technical specification, the exploitation of the measurements and the presentation of the results. The global procedure of IEC has been followed however some adaptations have been made to take into account the Sabella D10 specifics and site characteristics. Indeed, the Sabella D10 project started before the IEC62600-200 publication and some requirements have not been anticipated at the beginning of the project. The first objective of this analysis is to challenge the IEC methodology with an analysis of a real set of production data and to demonstrate the applicability of the technical specification. Additionally, the assumptions and the deviation with the IEC will be presented and some improvements of the standard will be proposed in conclusion.

scholarly journals Passive flow control mechanisms with bioinspired flexible blades in cross-flow tidal turbines

2021 ◽  
Vol 62 (5) ◽  
Author(s):  
Stefan Hoerner ◽  
Shokoofeh Abbaszadeh ◽  
Olivier Cleynen ◽  
Cyrille Bonamy ◽  
Thierry Maître ◽  
...  
Keyword(s):  
Turbine Blades ◽  
Cross Flow ◽  
Tidal Energy ◽  
Control Mechanisms ◽  
Passive Flow Control ◽  
Turbine Efficiency ◽  
Tidal Turbines ◽  
Passive Flow ◽  
Axial Turbines ◽  
The Cost

Abstract State-of-the-art technologies for wind and tidal energy exploitation focus mostly on axial turbines. However, cross-flow hydrokinetic tidal turbines possess interesting features, such as higher area-based power density in array installations and shallow water, as well as a generally simpler design. Up to now, the highly unsteady flow conditions and cyclic blade stall have hindered deployment at large scales because of the resulting low single-turbine efficiency and fatigue failure challenges. Concepts exist which overcome these drawbacks by actively controlling the flow, at the cost of increased mechatronical complexity. Here, we propose a bioinspired approach with hyperflexible turbine blades. The rotor naturally adapts to the flow through deformation, reducing flow separation and stall in a passive manner. This results in higher efficiency and increased turbine lifetime through decreased structural loads, without compromising on the simplicity of the design. Graphic abstract

scholarly journals ESTIMATION OF ELECTRICITY GENERATED FROM TIDAL ENERGY IN BEDONO VILLAGE OF DEMAK REGENCY

2020 ◽  
Vol 4 (9) ◽  
pp. 13-17
Author(s):  
Agus Margiantono ◽  
Titik Nurhayati ◽  
Wahib Hasbullah
Keyword(s):  
Electric Power ◽  
Current Velocity ◽  
Tidal Current ◽  
Tidal Energy ◽  
Tidal Currents ◽  
Active Power ◽  
Tidal Current Velocity ◽  
The Village

In some places in the village of Bedono Demak Regency there is a location with high tidal current velocity, the coordinates of the Location is 6 ° 55'29.0 "S 110 ° 29'11.4" E. In this study estimated the amount of electric power that can be generated from tidal currents in the village Bedono. Estimates are made by modeling the location and the Darrieus turbine using the CFD (Computating Fluid Dinamyc) Software. From the research that has been done to get the results of electric power that can be produced in the village Bedono highest at 14-16 times 3469.413W and lowest 39.002W at 22-24 hours according to the CFD is the highest active power occurred at 14-16 at 3197.064W and the lowest 35.941W at 22-24 hours.

scholarly journals Passive acoustic methods for tracking the 3D movements of small cetaceans around marine structures

2020 ◽  
Author(s):  
Douglas Gillespie ◽  
Laura Palmer ◽  
Jamie Macaulay ◽  
Carol Sparling ◽  
Gordon Hastie
Keyword(s):  
Marine Mammals ◽  
New Technologies ◽  
Three Dimensional ◽  
Tidal Energy ◽  
Time Of Arrival ◽  
Marine Animals ◽  
Tidal Turbines ◽  
Wide Range ◽  
Tidal Turbine ◽  
Passive Acoustic

AbstractA wide range of anthropogenic structures exist in the marine environment with the extent of these set to increase as the global offshore renewable energy industry grows. Many of these pose acute risks to marine wildlife; for example, tidal energy generators have the potential to injure or kill seals and small cetaceans through collisions with moving turbine parts. Information on fine scale behaviour of animals close to operational turbines is required to understand the likely impact of these new technologies. There are inherent challenges associated with measuring the underwater movements of marine animals which have, so far, limited data collection. Here, we describe the development and application of a system for monitoring the three-dimensional movements of cetaceans in the immediate vicinity of a subsea structure. The system comprises twelve hydrophones and software for the detection and localisation of vocal marine mammals. We present data demonstrating the systems practical performance during a deployment on an operational tidal turbine between October 2017 and October 2019. Three-dimensional locations of cetaceans were derived from the passive acoustic data using time of arrival differences on each hydrophone. Localisation accuracy was assessed with an artificial sound source at known locations and a refined method of error estimation is presented. Calibration trials show that the system can accurately localise sounds to 2m accuracy within 20m of the turbine but that localisations become highly inaccurate at distances greater than 35m. The system is currently being used to provide data on rates of encounters between cetaceans and the turbine and to provide high resolution tracking data for animals close to the turbine. These data can be used to inform stakeholders and regulators on the likely impact of tidal turbines on cetaceans.

scholarly journals Performance and Wake Characterization of a Model Hydrokinetic Turbine: The Reference Model 1 (RM1) Dual Rotor Tidal Energy Converter

Energies ◽  
2020 ◽  
Vol 13 (19) ◽  
pp. 5145
Author(s):  
Craig Hill ◽  
Vincent S. Neary ◽  
Michele Guala ◽  
Fotis Sotiropoulos
Keyword(s):  
Reynolds Number ◽  
Reference Model ◽  
Angular Position ◽  
Tidal Energy ◽  
Wake Flow ◽  
Height Velocity ◽  
Scale Model ◽  
Speed Ratio ◽  
Power Performance ◽  
Energy Converter

The mechanical power and wake flow field of a 1:40 scale model of the US Department of Energy’s Reference Model 1 (RM1) dual rotor tidal energy converter are characterized in an open-channel flume to evaluate power performance and wake flow recovery. The NACA-63(4)-24 hydrofoil profile in the original RM1 design is replaced with a NACA-4415 profile to minimize the Reynolds dependency of lift and drag characteristics at the test chord Reynolds number. Precise blade angular position and torque measurements were synchronized with three acoustic Doppler velocimeters (ADV) aligned with each rotor centerline and the midpoint between the rotor axes. Flow conditions for each case were controlled to maintain a hub height velocity, uhub= 1.04 ms−1, a flow Reynolds number, ReD= 4.4 × 105, and a blade chord length Reynolds number, Rec= 3.1 × 105. Performance was measured for a range of tip-speed ratios by varying rotor angular velocity. Peak power coefficients, CP= 0.48 (right rotor) and CP= 0.43 (left rotor), were observed at a tip speed ratio, λ= 5.1. Vertical velocity profiles collected in the wake of each rotor between 1 and 10 rotor diameters are used to estimate the turbulent flow recovery in the wake, as well as the interaction of the counter-rotating rotor wakes. The observed performance characteristics of the dual rotor configuration in the present study are found to be similar to those for single rotor investigations in other studies. Similarities between dual and single rotor far-wake characteristics are also observed.

Assessment of Zooplankton Injury and Mortality Associated With Underwater Turbines for Tidal Energy Production

2013 ◽  
Vol 47 (4) ◽  
pp. 142-150 ◽  
Author(s):  
David R. Schlezinger ◽  
Craig D. Taylor ◽  
Brian L. Howes
Keyword(s):  
Size Distribution ◽  
Particle Density ◽  
Collaborative Work ◽  
Tidal Energy ◽  
Energy Potential ◽  
Marine Renewable Energy ◽  
Tidal Turbines ◽  
Video Images ◽  
Significant Difference ◽  
Tidal Turbine

AbstractCollaborative work between the UMASS-Marine Renewable Energy Center, the Town of Edgartown, and the Coastal Systems Program is focused on developing the tidal energy potential of Muskeget Channel. We have undertaken detailed oceanographic and environmental surveys to optimize in-stream turbine power generation and to quantify potential environmental effects. In 2011 and 2012, tidal turbine demonstration projects were conducted in Muskeget Channel to determine the combined effects of blade strikes, shear stress, turbulence, and cavitation on zooplankton. Single turbines may minimally impact zooplankton populations; however, full-scale projects may potentially alter zooplankton populations forming the base of coastal food webs. Static plankton tows were performed up- and downstream of the operating turbine axis. Integral flow meters allowed adjustment of tow duration to optimize zooplankton density in the concentrate. Samples were held at in situ temperatures, and sequential photomicrographs and video images were taken to determine particle density, size distribution, and the number of live organisms in samples taken up and down gradient of the operating tidal turbines within 3 h of collection. Statistical analysis showed no significant difference in the total number or size distribution of motile zooplankters, indicating tidal turbine operation did not cause significant mortality and suggested that impacts of commercial size tidal energy projects upon zooplankton populations in Muskeget Channel may be negligible.

scholarly journals Comparative Investigations of Tidal Current Velocity Prediction Considering Effect of Multi-Layer Current Velocity

Energies ◽  
2020 ◽  
Vol 13 (23) ◽  
pp. 6417
Author(s):  
Bo Feng ◽  
Peng Qian ◽  
Yulin Si ◽  
Xiaodong Liu ◽  
Haixiao Yang ◽  
...  
Keyword(s):  
Machine Learning ◽  
Current Velocity ◽  
Tidal Current ◽  
Learning Algorithms ◽  
Critical Role ◽  
Tidal Energy ◽  
Machine Learning Algorithms ◽  
Tidal Current Velocity ◽  
Velocity Prediction ◽  
Prediction Approach

Accurate tidal current prediction plays a critical role with increasing utilization of tidal energy. The classical prediction approach of the tidal current velocity adopts the harmonic analysis (HA) method. The performance of the HA approach is not ideal to predict the high frequency components of tidal currents due to the lack of capability processing the non-astronomic factor. Recently, machine learning algorithms have been applied to process the non-astronomic factor in the prediction of tidal current. In this paper, a tidal current velocity prediction considering the effect of the multi-layer current velocity method is proposed. The proposed method adopts three machine learning algorithms to establish the prediction models for comparative investigations, namely long-short term memory (LSTM), back-propagation (BP) neural network, and the Elman regression network. In the case study, the tidal current data collected from the real ocean environment were used to validate the proposed method. The results show that the proposed method combined with the LSTM algorithm had higher accuracy than both the commercial tidal prediction tool (UTide) and the other two algorithms. This paper presents a novel tidal current velocity prediction considering the effect of the multi-layer current velocity method, which improves the accuracy of the power flow prediction and contributes to the research in the field of tidal current velocity prediction and the capture of tidal energy.

scholarly journals Accuracy of the actuator disc-RANS approach for predicting the performance and wake of tidal turbines

2013 ◽  
Vol 371 (1985) ◽  
pp. 20120293 ◽  
Author(s):  
W. M. J. Batten ◽  
M. E. Harrison ◽  
A. S. Bahaj
Keyword(s):  
Large Scale ◽  
Scale Effects ◽  
Tidal Energy ◽  
Rans Model ◽  
Tidal Turbines ◽  
Actuator Disc ◽  
Element Approach ◽  
Tidal Stream ◽  
Turbine Wake ◽  
Horizontal Axis Turbine

The actuator disc-RANS model has widely been used in wind and tidal energy to predict the wake of a horizontal axis turbine. The model is appropriate where large-scale effects of the turbine on a flow are of interest, for example, when considering environmental impacts, or arrays of devices. The accuracy of the model for modelling the wake of tidal stream turbines has not been demonstrated, and flow predictions presented in the literature for similar modelled scenarios vary significantly. This paper compares the results of the actuator disc-RANS model, where the turbine forces have been derived using a blade-element approach, to experimental data measured in the wake of a scaled turbine. It also compares the results with those of a simpler uniform actuator disc model. The comparisons show that the model is accurate and can predict up to 94 per cent of the variation in the experimental velocity data measured on the centreline of the wake, therefore demonstrating that the actuator disc-RANS model is an accurate approach for modelling a turbine wake, and a conservative approach to predict performance and loads. It can therefore be applied to similar scenarios with confidence.

A Simplified Design Method of Horizontal Axis Tidal Energy Turbine Blade

2014 ◽  
Vol 525 ◽  
pp. 240-246
Author(s):  
Xiao Hang Wang ◽  
Li Zhang ◽  
Liang Zhang
Keyword(s):  
Design Method ◽  
Tidal Energy ◽  
Horizontal Axis ◽  
Speed Ratio ◽  
Flow Angle ◽  
Momentum Theory ◽  
Tidal Turbines ◽  
Computational Fluid Dynamics Cfd ◽  
Simulation Results ◽  
Blade Element

Horizontal axis tidal turbines (HATTs) are efficient in converting tidal energy. Improvements in the design of the HATTs require a thorough understanding of the energy conversion process. In this paper, the design of a HATT with two blades is conducted by blade element momentum theory (BEM). In this simplified method, the eddy current induced by the rotors hub and tips were considered while ignoring the blade elements drag items. Based on the assumption of maximum power of blade elements, the distribution of blade elements flow angle and the chord length coefficient along the radius can be assumed to be associated only with the blade elements tip speed ratio (TSR) which is dimensionless. This approach was validated by comparing the simulation results with computational fluid dynamics (CFD). A good qualitative match between the expected value and simulation results was observed, indicating that the design method is feasible and reasonable.

Experimental study of the duct-effects of the tidal current turbines in multi-row-staggered layout

2020 ◽  
Author(s):  
Yaling Chen ◽  
Binliang Lin ◽  
Jinxi Guo
Keyword(s):  
Tidal Current ◽  
Turbine Rotor ◽  
Power Performance ◽  
Tidal Current Energy ◽  
Tidal Turbines ◽  
Initial Stage ◽  
Tidal Turbine ◽  
Wake Zone ◽  
The Stability ◽  
Current Energy

<p>Tidal turbine array was optimized to increase the power production in order to improve the commercial competitivity of tidal current energy with other forms of energy generation. Due to duct-effects, the power performance of turbines in the staggered layout was better than that of the aligned layout. However, shear layer with enhanced turbulence occurred between the duct zone and isolated wake zone downstream, which had influence on the performance stability and increased the fatigue failure of tidal turbines. The study conducted a series of laboratory experiments to investigate the duct-effects of tidal turbines located in multi-row array with staggered layout. The turbine rotor was represented by porous disc. The flow thrust and time-varying velocity were measured using micro strain gauge and acoustic doppler velometer, respectively. Results showed that the flow was accelerated between turbines with the increment around 20% behind the first row, while the duct-effects were weakened as distance increased downstream. The shear-induced turbulence was enlarged by the duct-effect when it diffused mainly towards individual wake zone at the initial stage. As the turbulence filled the whole individual wake zones, it diffused rapidly to lateral sides and jointed together, and the turbulence intensity across the array wake was significantly higher than that of the free flow. Correspondingly, the performance of turbine rotor located downstream was improved limitedly by the duct-effects, and the stability was reduced clearly. It indicated that the advantage of the duct-effect induced in the staggered layout was limited in the near wake as the lateral interval between two turbine centres was 2 times of rotor diameter.</p><p>Keywords<strong>:</strong> Turbine rotor array; Staggered layout; Duct-effects; Turbine performance; Shear-induced turbulence</p>

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