Despite the considerable efforts the international research community has made over the last decades, wave energy technologies have failed to achieve the desired design convergence to support their future market growth. Many technical challenges remain unresolved, leading to high costs of energy in comparison with other renewable energy sources. It becomes apparent that incremental innovation alone cannot fill the gap between the current techno-economic estimates and the medium-term policy targets established for wave energy. A systematic problem-solving approach must be embedded from the outset of technology development to meet the high sector expectations. This approach should support the engineering design processes, facilitate traceability of engineering analysis, and provide practical tools for understanding the wave energy context, formalising wave energy system requirements, guiding techno-economic design decisions, and overcoming technical challenges. Systems Engineering methods have been successfully applied to developing complex commercial products in many sectors. Among the many tools developed in Systems Engineering, it is worthwhile mentioning two structured innovation techniques: Quality Function Deployment (QFD) for problem formulation and selection [1]; and the Theory of Inventive Problem Solving (TRIZ) for concept generation [2]. Unfortunately, their use in wave energy is still limited and fragmented. Taking as a starting point the technology-agnostic assessment of wave energy capabilities performed in previous research work [3] for the problem formulation and concept selection, the authors have applied QFD to obtain the prioritisation of the technical characteristics that may offer the greatest impact to the overall design for a wave energy system. The main Functional Requirements are mapped to an equal number of Design Parameters extracted from the 39 technical parameters provided by TRIZ. The TRIZ toolkit is then employed to suggest three alternative innovation strategies to overcome wave energy cost and performance limitations. Firstly, separation principles are used to deal with physical contradictions. Examples of potentially effective strategies involving separation in time, space, scale or condition are proposed. Subsequently, inventive principles are employed to solve technical contradictions and trade-offs. The four most promising inventive principles that have been found in this implementation are "Local quality", "Dynamism", "Pneumatics or hydraulics", and "Physical or chemical properties". These principles prompt the user to consider a broader range of alternatives and improve creative thinking. Additional examples are given on how these inventive principles could be applied in wave energy. Finally, a system transition strategy is needed for the most complex challenges. Bypassing contradictory demands involves more radical changes in the functional allocation of requirements to the physical embodiment. Therefor
{"title":"Successful innovation strategies to overcome the technical challenges in the development of wave energy technologies","authors":"P. Ruiz-Minguela, Jesús María Blanco, V. Nava","doi":"10.36688/ewtec-2023-144","DOIUrl":"https://doi.org/10.36688/ewtec-2023-144","url":null,"abstract":"Despite the considerable efforts the international research community has made over the last decades, wave energy technologies have failed to achieve the desired design convergence to support their future market growth. Many technical challenges remain unresolved, leading to high costs of energy in comparison with other renewable energy sources. It becomes apparent that incremental innovation alone cannot fill the gap between the current techno-economic estimates and the medium-term policy targets established for wave energy. \u0000A systematic problem-solving approach must be embedded from the outset of technology development to meet the high sector expectations. This approach should support the engineering design processes, facilitate traceability of engineering analysis, and provide practical tools for understanding the wave energy context, formalising wave energy system requirements, guiding techno-economic design decisions, and overcoming technical challenges. \u0000Systems Engineering methods have been successfully applied to developing complex commercial products in many sectors. Among the many tools developed in Systems Engineering, it is worthwhile mentioning two structured innovation techniques: Quality Function Deployment (QFD) for problem formulation and selection [1]; and the Theory of Inventive Problem Solving (TRIZ) for concept generation [2]. Unfortunately, their use in wave energy is still limited and fragmented. \u0000Taking as a starting point the technology-agnostic assessment of wave energy capabilities performed in previous research work [3] for the problem formulation and concept selection, the authors have applied QFD to obtain the prioritisation of the technical characteristics that may offer the greatest impact to the overall design for a wave energy system. The main Functional Requirements are mapped to an equal number of Design Parameters extracted from the 39 technical parameters provided by TRIZ. The TRIZ toolkit is then employed to suggest three alternative innovation strategies to overcome wave energy cost and performance limitations. \u0000Firstly, separation principles are used to deal with physical contradictions. Examples of potentially effective strategies involving separation in time, space, scale or condition are proposed. \u0000Subsequently, inventive principles are employed to solve technical contradictions and trade-offs. The four most promising inventive principles that have been found in this implementation are \"Local quality\", \"Dynamism\", \"Pneumatics or hydraulics\", and \"Physical or chemical properties\". These principles prompt the user to consider a broader range of alternatives and improve creative thinking. Additional examples are given on how these inventive principles could be applied in wave energy. \u0000Finally, a system transition strategy is needed for the most complex challenges. Bypassing contradictory demands involves more radical changes in the functional allocation of requirements to the physical embodiment. Therefor","PeriodicalId":201789,"journal":{"name":"Proceedings of the European Wave and Tidal Energy Conference","volume":"5 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114188960","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Cross-flow turbines show great promise for extracting power from water currents since their rectangular projected area allows them to achieve high blockage. As a turbine’s blockage ratio—the ratio of the rotor projected area to the channel cross-sectional area—increases, its efficiency and structural loading increase since both kinetic and potential energy in the freestream are converted to mechanical power. For an array of turbines deployed in a river or tidal channel, the array blockage ratio will vary due to daily or seasonal fluctuations in the water level, as well as when individual turbines are deactivated for maintenance. Consequently, understanding how the performance characteristics of the array change as confinement is varied is of practical interest. Here, we characterize the performance of a laboratory-scale two-turbine array at various levels of confinement in a recirculating water channel. The array blockage ratio was varied from 30% to 60%—the upper end of what might be realizable in a natural channel. Two experimental approaches for varying the blockage were considered: 1) altering the channel cross-sectional area via a change in water depth, and 2) altering the array projected area by changing the blade span. Across all tested blockage ratios, the nominal chord-based Reynolds number (4.0 x 104) and nominal depth-based Froude number (0.22) were held constant, and the submergence-based Froude number was minimized to avoid ventilation of the turbine rotors at the upper end of the tested blockages. At each blockage ratio, the turbine performance was evaluated across a range of tip-speed ratios under a counter-rotating, phase-locked control scheme, wherein the turbines rotate at the same, constant speed but in opposite directions, with a constant angular phase offset, Δθ, between them. We focus this work on Δθ = 0°, an operating case in which the lateral forces and reaction torques for a pair of turbines are equal and opposite, which is advantageous for support structure design. As the array blockage ratio is increased, we observe significant increases in the array performance and thrust coefficients, as well as an increase in the range of tip-speed ratios over which the array produces power. For the highest confinements, peak power coefficients exceed unity and thrust coefficients are substantially higher than in conventional array designs. We observe disparities between the power and thrust coefficients for arrays with the same blockage ratio, but different blade spans. We attribute the higher performance for longer blade spans to differences in the relative magnitude of parasitic support structure losses between the two rotors, as well as free surface effects. Further, we explore the effectiveness of techniques for accounting for these performance differences through the estimation of blade-level performance. Overall, our results provide a solid foundation for understanding how the performance of cross-flow turbine arrays change
横流涡轮机显示出从水流中提取能量的巨大希望，因为它们的矩形投影面积允许它们实现高阻塞。随着涡轮的堵塞比(转子投影面积与通道横截面积之比)的增加，由于自由流中的动能和势能都转化为机械能，涡轮的效率和结构载荷也随之增加。对于部署在河流或潮汐通道中的一组涡轮机，由于水位的每日或季节性波动，以及单个涡轮机因维护而停用时，阵列阻塞比将会变化。因此，了解阵列的性能特征如何随着约束的变化而变化是有实际意义的。在这里，我们描述了实验室规模的双涡轮阵列在循环水通道中不同程度的约束下的性能。阵列阻塞比从30%到60%不等，这是在自然通道中可能实现的上限。考虑了两种改变阻塞的实验方法:1)通过改变水深来改变通道横截面积，2)通过改变叶片跨度来改变阵列投影面积。在所有测试的堵塞比中，基于弦的标称雷诺数(4.0 x 104)和基于深度的标称弗劳德数(0.22)保持不变，而基于淹没的弗劳德数被最小化，以避免在测试堵塞的上端涡轮转子通风。在每个堵塞比下，涡轮性能在一个反向旋转的锁相控制方案下通过一系列的叶尖速比进行评估，其中涡轮以相同的恒定速度在相反的方向上旋转，它们之间有恒定的角相位偏移Δθ。我们的工作重点是Δθ = 0°，在这种情况下，一对涡轮机的侧向力和反作用力相等且相反，这有利于支撑结构的设计。随着阵列堵塞比的增加，我们观察到阵列性能和推力系数的显著增加，以及阵列产生功率的叶尖速比范围的增加。在最高约束条件下，峰值功率系数大于1，推力系数大大高于常规阵列设计。我们观察了相同堵塞比但不同叶跨的阵列功率和推力系数之间的差异。我们将更长的叶片跨度的更高性能归因于两个转子之间寄生支撑结构损失的相对大小的差异，以及自由表面效应。此外，我们通过叶片级性能的估计来探讨计算这些性能差异的技术的有效性。总的来说，我们的研究结果为理解横流涡轮阵列性能随阵列堵塞比的变化提供了坚实的基础，并突出了横流涡轮实验设计的注意事项。
{"title":"Experimental techniques for evaluating the performance of high-blockage cross-flow turbine arrays","authors":"Aidan Hunt, B. Polagye","doi":"10.36688/ewtec-2023-203","DOIUrl":"https://doi.org/10.36688/ewtec-2023-203","url":null,"abstract":"Cross-flow turbines show great promise for extracting power from water currents since their rectangular projected area allows them to achieve high blockage. As a turbine’s blockage ratio—the ratio of the rotor projected area to the channel cross-sectional area—increases, its efficiency and structural loading increase since both kinetic and potential energy in the freestream are converted to mechanical power. For an array of turbines deployed in a river or tidal channel, the array blockage ratio will vary due to daily or seasonal fluctuations in the water level, as well as when individual turbines are deactivated for maintenance. Consequently, understanding how the performance characteristics of the array change as confinement is varied is of practical interest. \u0000Here, we characterize the performance of a laboratory-scale two-turbine array at various levels of confinement in a recirculating water channel. The array blockage ratio was varied from 30% to 60%—the upper end of what might be realizable in a natural channel. Two experimental approaches for varying the blockage were considered: 1) altering the channel cross-sectional area via a change in water depth, and 2) altering the array projected area by changing the blade span. Across all tested blockage ratios, the nominal chord-based Reynolds number (4.0 x 104) and nominal depth-based Froude number (0.22) were held constant, and the submergence-based Froude number was minimized to avoid ventilation of the turbine rotors at the upper end of the tested blockages. At each blockage ratio, the turbine performance was evaluated across a range of tip-speed ratios under a counter-rotating, phase-locked control scheme, wherein the turbines rotate at the same, constant speed but in opposite directions, with a constant angular phase offset, Δθ, between them. We focus this work on Δθ = 0°, an operating case in which the lateral forces and reaction torques for a pair of turbines are equal and opposite, which is advantageous for support structure design. \u0000As the array blockage ratio is increased, we observe significant increases in the array performance and thrust coefficients, as well as an increase in the range of tip-speed ratios over which the array produces power. For the highest confinements, peak power coefficients exceed unity and thrust coefficients are substantially higher than in conventional array designs. We observe disparities between the power and thrust coefficients for arrays with the same blockage ratio, but different blade spans. We attribute the higher performance for longer blade spans to differences in the relative magnitude of parasitic support structure losses between the two rotors, as well as free surface effects. Further, we explore the effectiveness of techniques for accounting for these performance differences through the estimation of blade-level performance. \u0000Overall, our results provide a solid foundation for understanding how the performance of cross-flow turbine arrays change","PeriodicalId":201789,"journal":{"name":"Proceedings of the European Wave and Tidal Energy Conference","volume":"11 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123871116","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Rachael E. Smith, Bryn Townley, Bevan Wray, A. Mason-Jones
In this work, the impact of local blockage on the power production of a tidal array due to multiple turbines positioned in close proximity is studied. A numerical model of the HydroWing tidal energy device, which features multiple turbines on a retrievable wing, is being developed using geometry-resolved computational fluid dynamics (CFD). For this paper, the influence of two turbines at several spacings is considered. The CFD model is used to perform quasi-static steady-state simulations of two turbines in a twin rotor configuration, where a multiple reference frame (MRF) approach is used to simulate rotor rotation. The lateral spacing between the rotors is varied and the resulting impact on the axial loads and power performance of the two turbines is studied, with the aim of identifying the optimal turbine spacing for the HydroWing device. The results will be used in future design optimisation work to minimize the levelized cost of energy of a large scale array using HydroWing technology at the proposed site for the Morlais tidal energy project.
{"title":"Impact of lateral turbine spacing on the performance of a multi-rotor tidal energy device","authors":"Rachael E. Smith, Bryn Townley, Bevan Wray, A. Mason-Jones","doi":"10.36688/ewtec-2023-334","DOIUrl":"https://doi.org/10.36688/ewtec-2023-334","url":null,"abstract":"In this work, the impact of local blockage on the power production of a tidal array due to multiple turbines positioned in close proximity is studied. A numerical model of the HydroWing tidal energy device, which features multiple turbines on a retrievable wing, is being developed using geometry-resolved computational fluid dynamics (CFD). For this paper, the influence of two turbines at several spacings is considered. \u0000The CFD model is used to perform quasi-static steady-state simulations of two turbines in a twin rotor configuration, where a multiple reference frame (MRF) approach is used to simulate rotor rotation. The lateral spacing between the rotors is varied and the resulting impact on the axial loads and power performance of the two turbines is studied, with the aim of identifying the optimal turbine spacing for the HydroWing device. The results will be used in future design optimisation work to minimize the levelized cost of energy of a large scale array using HydroWing technology at the proposed site for the Morlais tidal energy project.","PeriodicalId":201789,"journal":{"name":"Proceedings of the European Wave and Tidal Energy Conference","volume":"105 ","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114089757","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Tidal turbines are sensitive to the high turbulence of tidal flows. Large and intense vortices are generated at the seabed and cause extreme loads, fatigue damage and degraded power production. Thus, these vortices must be characterised prior to the turbine installation. The flow characteristics can be assessed through ADCP measurements, but these measurements are sparse. The vortex characteristics are strongly affected by the seabed macro-roughness (rocks, faults) that induces spatial variations of the flow characteristics at a local scale. These local variations are difficult to catch through measurements [1]. Numerical simulations, that cover large areas, can fill in the gaps of measurements. Reynolds Averaged Navier Stokes simulations cover wide domains, but do not simulate the turbulent motions. Large Eddy Simulations (LES) do simulate the turbulent motions, but are computationally expensive, which reduces their spatial and temporal coverages. LES has been validated for the simulation of turbulence at a tidal power site, with a spatial coverage of about 0.5 km² and a temporal coverage of about 30 minutes [2,3]. However, the high turbulence intensity complicates the analysis of turbulent motions. The tracking and characterisation of vortices is complex and time-consuming. New methods to automate this work would be very welcome. In this work, we use Large Eddy Simulations to simulate the vortices generated at the rocky seabed of the Paimpol-Bréhat tidal turbine test site (France). A tracking method is used to follow the movement of turbulent motions (see Figure 1). This tracking highlights the long durability of turbulent motions. The impact of the most intense motions on fictive turbines is assessed and extreme flow variations are observed. This confirms the interest of the method for an easy detection of the most troublesome vortices and the locations where they are generated. It paves the way for the identification of the locations where turbine installation should be avoided due to potential damaging turbulent motions. [1] Togneri, M. & Masters, I. Micrositing variability and mean flow scaling for marine turbulence in Ramsey Sound. Journal of Ocean Engineering and Marine Energy, 2016, 2, 35-46 [2] Mercier, P.; Grondeau, M.; Guillou, S.S.; Thiébot, J. & Poizot, E. Numerical study of the turbulent eddies generated by the seabed roughness. Case study at a tidal power site. Applied Ocean Research, 2020, 97 [3] Mercier, P. & Guillou, S.S. The impact of the seabed morphology on turbulence generation in a strong tidal stream. Physics of Fluids, 2021, 33
{"title":"Tracking a large vortex at a tidal power site","authors":"P. Mercier, Sylvain S. Guillou","doi":"10.36688/ewtec-2023-339","DOIUrl":"https://doi.org/10.36688/ewtec-2023-339","url":null,"abstract":"Tidal turbines are sensitive to the high turbulence of tidal flows. Large and intense vortices are generated at the seabed and cause extreme loads, fatigue damage and degraded power production. Thus, these vortices must be characterised prior to the turbine installation. The flow characteristics can be assessed through ADCP measurements, but these measurements are sparse. The vortex characteristics are strongly affected by the seabed macro-roughness (rocks, faults) that induces spatial variations of the flow characteristics at a local scale. These local variations are difficult to catch through measurements [1]. Numerical simulations, that cover large areas, can fill in the gaps of measurements. Reynolds Averaged Navier Stokes simulations cover wide domains, but do not simulate the turbulent motions. Large Eddy Simulations (LES) do simulate the turbulent motions, but are computationally expensive, which reduces their spatial and temporal coverages. \u0000 LES has been validated for the simulation of turbulence at a tidal power site, with a spatial coverage of about 0.5 km² and a temporal coverage of about 30 minutes [2,3]. However, the high turbulence intensity complicates the analysis of turbulent motions. The tracking and characterisation of vortices is complex and time-consuming. New methods to automate this work would be very welcome. \u0000 In this work, we use Large Eddy Simulations to simulate the vortices generated at the rocky seabed of the Paimpol-Bréhat tidal turbine test site (France). A tracking method is used to follow the movement of turbulent motions (see Figure 1). This tracking highlights the long durability of turbulent motions. The impact of the most intense motions on fictive turbines is assessed and extreme flow variations are observed. This confirms the interest of the method for an easy detection of the most troublesome vortices and the locations where they are generated. It paves the way for the identification of the locations where turbine installation should be avoided due to potential damaging turbulent motions. \u0000[1] Togneri, M. & Masters, I. Micrositing variability and mean flow scaling for marine turbulence in Ramsey Sound. Journal of Ocean Engineering and Marine Energy, 2016, 2, 35-46 \u0000[2] Mercier, P.; Grondeau, M.; Guillou, S.S.; Thiébot, J. & Poizot, E. Numerical study of the turbulent eddies generated by the seabed roughness. Case study at a tidal power site. Applied Ocean Research, 2020, 97 \u0000[3] Mercier, P. & Guillou, S.S. The impact of the seabed morphology on turbulence generation in a strong tidal stream. Physics of Fluids, 2021, 33","PeriodicalId":201789,"journal":{"name":"Proceedings of the European Wave and Tidal Energy Conference","volume":"54 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114358006","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Casey Nichols, Scott Lambert, Rebecca Fao, Robert Raye
There are many organizations working towards the commercialization of wave energy converter technologies and are advancing their designs through the technology readiness levels (TRLs). A critical step before the field deployment of prototype wave energy converters is the validation of the subsystems and components that are contained in the wave energy converter through laboratory testing and performance characterization. In 2021, the National Renewable Energy Laboratory (NREL) developed and demonstrated a system for testing power takeoffs (PTO) with a low-speed, high-torque dynamometer and a grid-tied high-power DC power source and sink before field deployment. The hydraulic dynamometer allows for the simulation of PTO actuation from wave motion and is capable of a wide range of wave periods and heights which are represented as various speeds and torques from the dynamometer. The high-power bidirectional power supply allows for hardware in the loop and controller in the loop testing to be conducted on WEC power electronics. This presentation was made to describe the methods used by NREL research staff to test all components and sub-systems in the PTO of a novel wave energy converter before field deployment.
{"title":"Wave Energy Power Take-off Validation with a Hydraulicly Actuated Rotary Dynamometer and a Bi-directional High-power DC Supply","authors":"Casey Nichols, Scott Lambert, Rebecca Fao, Robert Raye","doi":"10.36688/ewtec-2023-169","DOIUrl":"https://doi.org/10.36688/ewtec-2023-169","url":null,"abstract":"There are many organizations working towards the commercialization of wave energy converter technologies and are advancing their designs through the technology readiness levels (TRLs). A critical step before the field deployment of prototype wave energy converters is the validation of the subsystems and components that are contained in the wave energy converter through laboratory testing and performance characterization. In 2021, the National Renewable Energy Laboratory (NREL) developed and demonstrated a system for testing power takeoffs (PTO) with a low-speed, high-torque dynamometer and a grid-tied high-power DC power source and sink before field deployment. The hydraulic dynamometer allows for the simulation of PTO actuation from wave motion and is capable of a wide range of wave periods and heights which are represented as various speeds and torques from the dynamometer. The high-power bidirectional power supply allows for hardware in the loop and controller in the loop testing to be conducted on WEC power electronics. This presentation was made to describe the methods used by NREL research staff to test all components and sub-systems in the PTO of a novel wave energy converter before field deployment.","PeriodicalId":201789,"journal":{"name":"Proceedings of the European Wave and Tidal Energy Conference","volume":"42 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116197799","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Wanan Sheng, C. Michailides, E. Loukogeorgaki, George Aggidis
The Lancaster in-house code is a time-domain analysis code, developed especially for the TALOS wave energy converter, a novel wave energy conversion technology. The TALOS wave energy converter is a point absorber-like wave energy converter, but with a unique power take-off (PTO) system. The whole PTO system is fully enclosed within the structure, hence no moving parts are exposed to the harsh marine environments. The PTO of the TALOS WEC consists of a mass ball within the structure, with a number of springs and dampers (for instance, direct drives or hydraulic systems) connecting between the mass ball and the structure. Such an arrangement of the PTOs would make the PTO essentially non-linear, regardless whether the actual PTO dampers are linear or nonlinear as well as the linear springs. Therefore, a time domain analysis must be established for the TALOS WEC. Towards the goal, an in-house time-domain model has been developed at Lancaster University, and now it is to be validated via the delicated numerical models built using well-established commercial software (and in the future via experimental data). Within this framework, the present paper presents an effort for validation using the DNV SESAM commercial hydrodynamic and structural analysis software. To build a numerical model for TALOS WEC, the Lancaster in-house time domain code is based on the hybrid frequency-time domain approach. That is, the basic hydrodynamic parameters are analysed using the panel methods (WAMIT, HAMS, NEMOH), and then the relevant parameters are transformed for the Cummins’ time-domain equation, such as the added mass at infinite frequency, and the memory effect (the convolution terms). This work is an extension of the comparison between the in-house code and the DNV SESAM software, and the comparisons would include the relevant hydrodynamic analyses, the time-domain analyses with and without the TALOS PTO system, with the aims towards developing the validated tools of both the in-house code and the commercial software.
{"title":"Development and validation of the in-house hydrodynamics code and the DNV software for TALOS wave energy converter","authors":"Wanan Sheng, C. Michailides, E. Loukogeorgaki, George Aggidis","doi":"10.36688/ewtec-2023-460","DOIUrl":"https://doi.org/10.36688/ewtec-2023-460","url":null,"abstract":"The Lancaster in-house code is a time-domain analysis code, developed especially for the TALOS wave energy converter, a novel wave energy conversion technology. The TALOS wave energy converter is a point absorber-like wave energy converter, but with a unique power take-off (PTO) system. The whole PTO system is fully enclosed within the structure, hence no moving parts are exposed to the harsh marine environments. \u0000The PTO of the TALOS WEC consists of a mass ball within the structure, with a number of springs and dampers (for instance, direct drives or hydraulic systems) connecting between the mass ball and the structure. Such an arrangement of the PTOs would make the PTO essentially non-linear, regardless whether the actual PTO dampers are linear or nonlinear as well as the linear springs. Therefore, a time domain analysis must be established for the TALOS WEC. Towards the goal, an in-house time-domain model has been developed at Lancaster University, and now it is to be validated via the delicated numerical models built using well-established commercial software (and in the future via experimental data). Within this framework, the present paper presents an effort for validation using the DNV SESAM commercial hydrodynamic and structural analysis software. \u0000To build a numerical model for TALOS WEC, the Lancaster in-house time domain code is based on the hybrid frequency-time domain approach. That is, the basic hydrodynamic parameters are analysed using the panel methods (WAMIT, HAMS, NEMOH), and then the relevant parameters are transformed for the Cummins’ time-domain equation, such as the added mass at infinite frequency, and the memory effect (the convolution terms). This work is an extension of the comparison between the in-house code and the DNV SESAM software, and the comparisons would include the relevant hydrodynamic analyses, the time-domain analyses with and without the TALOS PTO system, with the aims towards developing the validated tools of both the in-house code and the commercial software. ","PeriodicalId":201789,"journal":{"name":"Proceedings of the European Wave and Tidal Energy Conference","volume":"179 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116340267","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Mckenzie Love, Aiswarya Vellappally, Pierre Roy, Kate Smith, Gavin McPherson, David Gold
Environmental interactions of marine renewable energy (MRE) projects are challenging to monitor, and key questions remain about their potential impacts. Processing large volumes of environmental data acquired from submarine monitoring and the use of machine learning to identify presence and interactions of marine wildlife with MRE infrastructure are powerful tools for assessing the environmental response to MRE infrastructure. The use of automated image analysis for species identification and enumeration using algorithms like convolutional neural networks can vastly reduce the time required to extract usable data from submarine imagery compared to manual expert processing. We present a novel industry-ready image processing workflow for automated wildlife detection developed using 1000+ hours of underwater video footage obtained by Nova Innovation Ltd. from their operational tidal stream turbine array at Bluemull Sound in Shetland, Scotland. The objective of this work was to develop a workflow and associated algorithms to automatically filter many hours of underwater video, remove unwanted footage, and extract only video containing marine mammals, diving birds or fish. The workflow includes object detection through advanced image analysis, image classification using machine learning, statistical analyses such as quantification of data storage reduction and number of detections, and automated production of a summary report. Blind tests were undertaken on a subset of videos to quantify and iteratively improve the accuracy of the results. The final iteration of the workflow delivered an accuracy of 80% for the identification of marine mammals, diving birds and fish when a three-category (wildlife, algae, and background) classification system was used. The accuracy rose to 95% when a two-category system was used, and objects were classified simply as ‘target’ or ‘non-target’. The entire workflow can be run from video inception to production of an automated results report in approximately 30 minutes, dependent on size of input data, when environmental conditions such as water clarity and key species of interest are familiar to the algorithm. The accuracy and runtime speed of the workflow can be improved through expanding the training dataset of images used in the development of this initial tool by including additional species and water conditions. Application of this workflow significantly reduces manual processing and interpretation time, which can be a significant burden on project developers. Automated processing provides a subset for more focused manual scrutiny and analysis, while reducing the overall size of dataset requiring storage. Auto-reporting can be used to provide outputs for marine regulators to meet monitoring reporting conditions of project licences. Integration of this workflow with automated passive acoustic monitoring systems can provide a holistic environmental monitoring approach using both underwater imagery and acoustics.
{"title":"Automated detection of wildlife in proximity to marine renewable energy infrastructure using machine learning of underwater imagery","authors":"Mckenzie Love, Aiswarya Vellappally, Pierre Roy, Kate Smith, Gavin McPherson, David Gold","doi":"10.36688/ewtec-2023-623","DOIUrl":"https://doi.org/10.36688/ewtec-2023-623","url":null,"abstract":"Environmental interactions of marine renewable energy (MRE) projects are challenging to monitor, and key questions remain about their potential impacts. Processing large volumes of environmental data acquired from submarine monitoring and the use of machine learning to identify presence and interactions of marine wildlife with MRE infrastructure are powerful tools for assessing the environmental response to MRE infrastructure. The use of automated image analysis for species identification and enumeration using algorithms like convolutional neural networks can vastly reduce the time required to extract usable data from submarine imagery compared to manual expert processing. We present a novel industry-ready image processing workflow for automated wildlife detection developed using 1000+ hours of underwater video footage obtained by Nova Innovation Ltd. from their operational tidal stream turbine array at Bluemull Sound in Shetland, Scotland. The objective of this work was to develop a workflow and associated algorithms to automatically filter many hours of underwater video, remove unwanted footage, and extract only video containing marine mammals, diving birds or fish. The workflow includes object detection through advanced image analysis, image classification using machine learning, statistical analyses such as quantification of data storage reduction and number of detections, and automated production of a summary report. Blind tests were undertaken on a subset of videos to quantify and iteratively improve the accuracy of the results. The final iteration of the workflow delivered an accuracy of 80% for the identification of marine mammals, diving birds and fish when a three-category (wildlife, algae, and background) classification system was used. The accuracy rose to 95% when a two-category system was used, and objects were classified simply as ‘target’ or ‘non-target’. The entire workflow can be run from video inception to production of an automated results report in approximately 30 minutes, dependent on size of input data, when environmental conditions such as water clarity and key species of interest are familiar to the algorithm. The accuracy and runtime speed of the workflow can be improved through expanding the training dataset of images used in the development of this initial tool by including additional species and water conditions. Application of this workflow significantly reduces manual processing and interpretation time, which can be a significant burden on project developers. Automated processing provides a subset for more focused manual scrutiny and analysis, while reducing the overall size of dataset requiring storage. Auto-reporting can be used to provide outputs for marine regulators to meet monitoring reporting conditions of project licences. Integration of this workflow with automated passive acoustic monitoring systems can provide a holistic environmental monitoring approach using both underwater imagery and acoustics.","PeriodicalId":201789,"journal":{"name":"Proceedings of the European Wave and Tidal Energy Conference","volume":"24 5","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114025287","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract A technique to optimize the response of Wave Energy Converters (WECs) by maximizing the amplitude of motion along the surge direction is presented. This is achieved by utilizing an adaptable mooring tightening technique for a floater moored with tension legs (tendons). To gain a deeper understanding of the effect of sea states and mooring cable lengths on the surge response of the system, a series of numerical simulations were conducted for various wave conditions while varying the length of the mooring cables. WEC-Sim [1] was used to solve the multi-body dynamics of a rectangular cuboid floater by solving the equations of motion using a time-domain formulation. The dynamics of the mooring cables were simulated using the MoorDyn model with a lumped-mass formulation [2]. To validate the accuracy of the numerical methods, a series of experimental tests were performed in a small-scale wave tank. It was observed that tightening the mooring cables by decreasing their length amplifies the surge motion of the floater while the mooring forces in the heave direction rise due to the increased tension in the cables. Stretching the cables further was found to (i) decrease the surge amplitude and (ii) drastically increase the mooring forces, threatening the integrity of the cables. Therefore, there is an optimum value of the length of the cables that maximizes the surge amplitude of the floater while ensuring that the cables will not break. The impact of other mooring cable parameters such as diameter and material properties were also evaluated. More specifically, increasing the stiffness by increasing the diameter or the tensile modulus of elasticity was found to reduce the floater’s surge amplitude. For the geometry used in this study, the optimum length, diameter and properties of the cables are provided for several sea states. The current results lay the foundations for the design of new types of WECs that harness the surge motion of a floater rather than the heave which is the most common approach for floating WECs. References [1]: Kelley Ruehl, David Ogden, Yi-Hsiang Yu, Adam Keester, Nathan Tom, Dominic Forbush, Jorge Leon, Jeff Grasberger, and Salman Husain. (2022, September), WEC-Sim (Version v5.0.1), DOI: 10.5281/zenodo.7121186. [2]: Hall, M., & Goupee, A. (2015). Validation of a lumped-mass mooring line model with DeepCwind semisubmersible model test data. Ocean Engineering, 104, 590–603. https://doi.org/10.1016/j.oceaneng.2015.05.035
摘要提出了一种优化波浪能变换器响应的方法，即最大化波浪能变换器沿浪涌方向的运动幅值。这是通过使用一种适应性的系泊紧固技术来实现的，该技术适用于使用张力腿(肌腱)系泊的浮子。为了更深入地了解海况和系泊索长度对系统浪涌响应的影响，在改变系泊索长度的情况下，对各种波浪条件进行了一系列数值模拟。利用WEC-Sim[1]求解长方体漂浮体的多体动力学，采用时域公式求解运动方程。采用集总质量公式的MoorDyn模型[2]模拟锚泊索的动力学。为了验证数值方法的准确性，在小型波浪槽中进行了一系列试验。通过减小锚链长度来收紧锚链，可以放大浮子的浪涌运动，同时由于锚链张力的增加，在升沉方向上的锚链力也会上升。进一步拉伸缆索，发现:(1)降低浪涌幅值，(2)大幅增加系泊力，威胁缆索的完整性。因此，存在一个最优的电缆长度值，既能使浮子的浪涌幅值最大化，又能保证电缆不断裂。此外，还对其他系泊电缆参数(如直径和材料性能)的影响进行了评估。更具体地说，通过增加直径或拉伸弹性模量来增加刚度可以降低浮子的喘振幅度。对于本研究中使用的几何形状，提供了几种海况下电缆的最佳长度、直径和性能。目前的研究结果为设计利用浮子的浪涌运动而不是浮子的升沉运动的新型WECs奠定了基础。参考文献[1]:Kelley Ruehl, David Ogden, Yi-Hsiang Yu, Adam Keester, Nathan Tom, Dominic Forbush, Jorge Leon, Jeff Grasberger, Salman Husain。(2022年9月)，WEC-Sim (v5.0.1版本)，DOI: 10.5281/zenodo.7121186。[2]:王晓明，王晓明。(2015)。利用DeepCwind半潜式模型试验数据验证集总质量系泊线模型。海洋工程学报，2004,19(4):559 - 563。https://doi.org/10.1016/j.oceaneng.2015.05.035
{"title":"Maximizing the surge amplitude of a floater through an adaptable mooring tightening technique","authors":"Andreas Asiikkis, D. Grigoriadis, A. Vakis","doi":"10.36688/ewtec-2023-274","DOIUrl":"https://doi.org/10.36688/ewtec-2023-274","url":null,"abstract":"Abstract \u0000A technique to optimize the response of Wave Energy Converters (WECs) by maximizing the amplitude of motion along the surge direction is presented. This is achieved by utilizing an adaptable mooring tightening technique for a floater moored with tension legs (tendons). To gain a deeper understanding of the effect of sea states and mooring cable lengths on the surge response of the system, a series of numerical simulations were conducted for various wave conditions while varying the length of the mooring cables. WEC-Sim [1] was used to solve the multi-body dynamics of a rectangular cuboid floater by solving the equations of motion using a time-domain formulation. The dynamics of the mooring cables were simulated using the MoorDyn model with a lumped-mass formulation [2]. To validate the accuracy of the numerical methods, a series of experimental tests were performed in a small-scale wave tank. It was observed that tightening the mooring cables by decreasing their length amplifies the surge motion of the floater while the mooring forces in the heave direction rise due to the increased tension in the cables. Stretching the cables further was found to (i) decrease the surge amplitude and (ii) drastically increase the mooring forces, threatening the integrity of the cables. Therefore, there is an optimum value of the length of the cables that maximizes the surge amplitude of the floater while ensuring that the cables will not break. The impact of other mooring cable parameters such as diameter and material properties were also evaluated. More specifically, increasing the stiffness by increasing the diameter or the tensile modulus of elasticity was found to reduce the floater’s surge amplitude. For the geometry used in this study, the optimum length, diameter and properties of the cables are provided for several sea states. The current results lay the foundations for the design of new types of WECs that harness the surge motion of a floater rather than the heave which is the most common approach for floating WECs. \u0000References \u0000[1]: Kelley Ruehl, David Ogden, Yi-Hsiang Yu, Adam Keester, Nathan Tom, Dominic Forbush, Jorge Leon, Jeff Grasberger, and Salman Husain. (2022, September), WEC-Sim (Version v5.0.1), DOI: 10.5281/zenodo.7121186. \u0000[2]: Hall, M., & Goupee, A. (2015). Validation of a lumped-mass mooring line model with DeepCwind semisubmersible model test data. Ocean Engineering, 104, 590–603. https://doi.org/10.1016/j.oceaneng.2015.05.035","PeriodicalId":201789,"journal":{"name":"Proceedings of the European Wave and Tidal Energy Conference","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124340386","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Geetam Saha, Diogo Neves Ferreira, N. Srikanth, Lei Zuo
In oscillating water column wave energy converters, the aerodynamic losses caused by flow misalignment between the rotor outlet and the outlet guide vane of self-rectifying impulse turbines are a significant design problem. The symmetrical positioning of guiding vanes on both sides of the rotor is the reason for it. In comparison to the equivalent Wells turbine, the efficiency of impulse turbines is lower because of these losses in the outlet guide vane. This paper presents a strategy to develop animproved design of an axial impulse turbine to reduce the losses in the outlet guide vane along with the residual kinetic energy loss by integrating a diffuser between the rotor and guide vanes. The proposed model was investigated numerically using RANS simulations. Multiple diffuser geometries were tested against the reference turbine for comparison of the performance characteristics. The results support the hypothesis behind the proposed design. The performance was compared extensively with the reference case in terms of the dimensionless loss coefficients for a better insight into the contribution of all the turbine sectors. The current work shows a possible design path for the performance improvement of the turbine. Results also support the fact that the guide vanes need to beredesigned for obtaining maximizing efficiency with the proposed design. The losses in the outlet guide vane were reduced by approximately 50% with an overall efficiency rise of around 2%.
{"title":"Enhancing the efficiency of an axial impulse turbine with a diffuser","authors":"Geetam Saha, Diogo Neves Ferreira, N. Srikanth, Lei Zuo","doi":"10.36688/ewtec-2023-185","DOIUrl":"https://doi.org/10.36688/ewtec-2023-185","url":null,"abstract":"In oscillating water column wave energy converters, the aerodynamic losses caused by flow misalignment between the rotor outlet and the outlet guide vane of self-rectifying impulse turbines are a significant design problem. The symmetrical positioning of guiding vanes on both sides of the rotor is the reason for it. In comparison to the equivalent Wells turbine, the efficiency of impulse turbines is lower because of these losses in the outlet guide vane. This paper presents a strategy to develop animproved design of an axial impulse turbine to reduce the losses in the outlet guide vane along with the residual kinetic energy loss by integrating a diffuser between the rotor and guide vanes. The proposed model was investigated numerically using RANS simulations. Multiple diffuser geometries were tested against the reference turbine for comparison of the performance characteristics. The results support the hypothesis behind the proposed design. The performance was compared extensively with the reference case in terms of the dimensionless loss coefficients for a better insight into the contribution of all the turbine sectors. The current work shows a possible design path for the performance improvement of the turbine. Results also support the fact that the guide vanes need to beredesigned for obtaining maximizing efficiency with the proposed design. The losses in the outlet guide vane were reduced by approximately 50% with an overall efficiency rise of around 2%. ","PeriodicalId":201789,"journal":{"name":"Proceedings of the European Wave and Tidal Energy Conference","volume":"40 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124072568","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
France benefits from an important tidal energy resource, with the second largest potential in Europe, and one of the biggest in the world. In addition, France has an important industrial and academic fabric, with several tidal developers, shipyards, and research centers, creating, theoretically, an attractive environment. However, though some tidal turbines already installed, such as Sabella demonstrator at Ouessant Island, or Guinard energy turbine in the Etel river, the sector still has a large development potential. One limitation of such a development is the lack of available data to assess the total potential. Previous studies mainly focused on the most energetic sites, such as the Alderney Race or the Fromveur Passage, while other sites are neglected. Yet, those sites, such has rivers or estuaries, offer softer conditions, lowering the risks. Moreover, although identifying a suitable area for tidal array implementation requires technical criteria (maximum current velocity, water depth, installable potential, etc.), it should also consider other aspects such as ecological indicators (migratory fishes, specific habitats, etc.), regulation specificities (Natura 2000, ZNIEFF, etc.) or human activities conflicts (fishery, UXO, etc.). On top of that, socioeconomic indicators, such as potential local content or partnerships with relevant academic stakeholders, are encouraged by authorities, and must be accounted for. Hence, this study proposes an extensive multi-criteria analysis methodology, to assess tidal energy potential of ten sites in France, including five nearshore locations (Alderney race, Fromveur passage, Raz-de-Sein, Raz-Barfleur, Paimpol-Bréhat), and five estuaries, river or similar (Gironde estuary, Gulf of Morbihan, Adour river, Etel river, Arcachon Bay). The analysis is limited to ten sites, selected based on a pre-screening analysis, which will be detailed in the study. The different criteria used will be presented, including their weight to the final score which reflect their importance during project development, and the 3-level grading system used to discriminate sites. The methodology developed to assess full-time equivalent employments created by a tidal array, using world input-output tables and other economic parameters will also be detailed. A specific focus will be proposed on methodology used to assess the installable capacity, relying on data from MARS 2D model for nearshore sites and public data for the others. First analysis shows that Raz-de-Sein and Paimpol-Bréhat are the two most suitable sites for tidal arrays implementation, while the Alderney Race is the most energetic one. Those results are driven by high scores obtained by these sites in categories such as ecological or human activities. Direct, indirect, and induced employments created during construction and operational phase by each project are also calculated, as well as potential growth value added. Hypothesis and sensitivity to them will be discussed.
法国受益于重要的潮汐能资源，其潜力在欧洲排名第二，也是世界上最大的潮汐能之一。此外，法国有重要的工业和学术结构，有几个潮汐开发商、造船厂和研究中心，理论上创造了一个有吸引力的环境。然而，尽管已经安装了一些潮汐涡轮机，如Ouessant岛的Sabella示范涡轮机，或Etel河的Guinard能源涡轮机，但该领域仍有很大的发展潜力。这种发展的一个限制是缺乏评估总潜力的可用数据。以前的研究主要集中在最具活力的地点，如奥尔德尼赛跑或弗罗弗海峡，而其他地点则被忽视了。然而，那些有河流或河口的地点提供了更柔和的条件，降低了风险。此外，虽然确定一个适合实施潮汐阵的区域需要技术标准(最大流速、水深、可安装电位等)，但还应考虑其他方面，如生态指标(洄游鱼类、特定栖息地等)、法规特性(Natura 2000、ZNIEFF等)或人类活动冲突(渔业、未爆炸武器等)。最重要的是，社会经济指标，如潜在的本地内容或与相关学术利益相关者的伙伴关系，受到当局的鼓励，必须考虑在内。因此，本研究提出了一种广泛的多标准分析方法，以评估法国10个地点的潮汐能潜力，包括5个近岸地点(Alderney race, Fromveur passage, Raz-de-Sein, Raz-Barfleur, paimpoll - br hat)和5个河口、河流或类似地点(Gironde estuary, Gulf of Morbihan, Adour river, Etel river, Arcachon Bay)。分析仅限于10个地点，根据预筛选分析选择，这将在研究中详细说明。将介绍使用的不同标准，包括它们对最终分数的权重，反映它们在项目开发过程中的重要性，以及用于区分地点的3级分级系统。还将详细介绍利用世界投入产出表和其他经济参数评估潮汐阵所创造的全职等效就业的方法。将特别关注用于评估可安装容量的方法，该方法依赖于近岸站点的MARS 2D模型数据和其他站点的公共数据。首先分析表明，Raz-de-Sein和paimpol - brsamhat是两个最适合实施潮汐阵的地点，而Alderney Race是最具活力的地点。这些结果是由这些网站在生态或人类活动等类别中获得的高分所驱动的。还计算了每个项目在建设和运营阶段创造的直接、间接和诱发就业机会，以及潜在的增长价值。假设和对它们的敏感性将被讨论。本研究由H2020项目ELEMENT资助，批准号815180。
{"title":"Multi-criteria analysis to evaluate tidal energy potential in France","authors":"Florian Castillo, M. Ikhennicheu, J. Gilloteaux","doi":"10.36688/ewtec-2023-478","DOIUrl":"https://doi.org/10.36688/ewtec-2023-478","url":null,"abstract":"France benefits from an important tidal energy resource, with the second largest potential in Europe, and one of the biggest in the world. In addition, France has an important industrial and academic fabric, with several tidal developers, shipyards, and research centers, creating, theoretically, an attractive environment. However, though some tidal turbines already installed, such as Sabella demonstrator at Ouessant Island, or Guinard energy turbine in the Etel river, the sector still has a large development potential. One limitation of such a development is the lack of available data to assess the total potential. Previous studies mainly focused on the most energetic sites, such as the Alderney Race or the Fromveur Passage, while other sites are neglected. Yet, those sites, such has rivers or estuaries, offer softer conditions, lowering the risks. Moreover, although identifying a suitable area for tidal array implementation requires technical criteria (maximum current velocity, water depth, installable potential, etc.), it should also consider other aspects such as ecological indicators (migratory fishes, specific habitats, etc.), regulation specificities (Natura 2000, ZNIEFF, etc.) or human activities conflicts (fishery, UXO, etc.). On top of that, socioeconomic indicators, such as potential local content or partnerships with relevant academic stakeholders, are encouraged by authorities, and must be accounted for. \u0000Hence, this study proposes an extensive multi-criteria analysis methodology, to assess tidal energy potential of ten sites in France, including five nearshore locations (Alderney race, Fromveur passage, Raz-de-Sein, Raz-Barfleur, Paimpol-Bréhat), and five estuaries, river or similar (Gironde estuary, Gulf of Morbihan, Adour river, Etel river, Arcachon Bay). The analysis is limited to ten sites, selected based on a pre-screening analysis, which will be detailed in the study. \u0000The different criteria used will be presented, including their weight to the final score which reflect their importance during project development, and the 3-level grading system used to discriminate sites. The methodology developed to assess full-time equivalent employments created by a tidal array, using world input-output tables and other economic parameters will also be detailed. A specific focus will be proposed on methodology used to assess the installable capacity, relying on data from MARS 2D model for nearshore sites and public data for the others. \u0000First analysis shows that Raz-de-Sein and Paimpol-Bréhat are the two most suitable sites for tidal arrays implementation, while the Alderney Race is the most energetic one. Those results are driven by high scores obtained by these sites in categories such as ecological or human activities. Direct, indirect, and induced employments created during construction and operational phase by each project are also calculated, as well as potential growth value added. Hypothesis and sensitivity to them will be discussed.","PeriodicalId":201789,"journal":{"name":"Proceedings of the European Wave and Tidal Energy Conference","volume":"428 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127606511","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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