This book evaluates and compares risk regulation and safety management for offshore oil and gas operations in the United States, United Kingdom, Norway and Australia. It provides an interdisciplinary ...approach with legal, technological and sociological perspectives on efforts to assess and prevent major accidents and improve safety performance. Presented in three parts, it begins with a review of the factors involved in designing, implementing and enforcing a regulatory regime for industrial safety. It then evaluates the four regimes exploring the contextual factors that influence their design and implementation, their reliance on industrial expertise and standards and the use of performance indicators. Finally the book assesses the resilience of the Norwegian regime, its capacity to keep pace with new technologies and emerging risks, respond to near miss incidents, encourage safety culture, incorporate vested rights of labor, and perform inspection and self-audit functions. This book is relevant for those in government, business and academia, and anyone involved in offshore safety issues.
As the size of offshore wind turbines increases, a realistic representation of the spatiotemporal distribution of the incident wind field becomes crucial for modeling the dynamic response of the ...turbine. The International Electrotechnical Commission (IEC) standard for wind turbine design recommends two turbulence models for simulations of the incident wind field, the Mann spectral tensor model, and the Kaimal spectral and exponential coherence model. In particular, for floating wind turbines, these standard models are challenged by more sophisticated ones. The characteristics of the wind field depend on the stability conditions of the atmosphere, which neither of the standard turbulence models account for. The spatial and temporal distribution of the turbulence, represented by coherence, is not modeled consistently by the two standard models. In this study, the Mann spectral tensor model and the Kaimal spectral and exponential coherence model are compared with wind fields constructed from offshore measurements and obtained from large‐eddy simulations. Cross sections and durations relevant for offshore wind turbine design are considered. Coherent structures from the different simulators are studied across various stability conditions and wind speeds through coherence and proper orthogonal decomposition mode plots. As expected, the standard models represent neutral stratification better than they do stable and unstable. Depending upon the method used for generating the wind field, significant differences in the spatial and temporal distribution of coherence are found. Consequently, the computed structural design loads on a wind turbine are expected to vary significantly depending upon the employed turbulence model. The knowledge gained in this study will be used in future studies to quantify the effect of various turbulence models on the dynamic response of large offshore wind turbines.
Summary
Wind energy conversion system, aiming to convert mechanical energy of air flow into electrical energy has been widely concerned in recent decades. According to the installation sites, the ...wind energy conversion system can be divided into land‐based wind conversion system and offshore wind energy conversion (OWEC) system. Compared to land‐based wind energy technology, although OWEC started later, it has attracted more attentions due to its significant advantages in sufficient wind energy, low wind shear, high power output and low land occupancy rate. In this paper, the principle of wind energy conversion and the development status of offshore wind power in the world are briefly introduced at first. And then, the advantages and disadvantages of several offshore wind energy device (OWED), such as horizontal axis OWED, vertical axis OWED and cross axis OWED are compared. Subsequently, several major constraints, such as complex marine environment, deep‐sea power transmission and expensive cost of equipment installation faced by offshore wind conversion technology are presented and comprehensively analysed. Finally, based on the summary and analysis of some emerging technologies and the current situation of offshore wind energy utilization, the development trend of offshore wind power is envisioned. In the future, it is expected to witness multi‐energy complementary, key component optimization and intelligent control strategy for smooth energy generation of offshore wind power systems.
Offshore wind energy conversion (OWEC) has attracted intensive attentions due to its significant advantages in sufficient wind energy, high power output and low land occupancy rate. This article firstly introduces the state‐of‐the‐art of the development status of the offshore wind energy technology worldwide, and then comprehensively analyzes the advantages and constraints of the OWEC technology. Finally, the future development trend of the offshore wind energy is envisioned.
•A model is proposed to assess the failure rate of components of floating offshore wind turbines based on onshore turbine data.•A failure rate correction model is presented for the relations of ...failure between onshore and floating offshore wind turbines.•The results indicate that the failure rates of components of floating wind turbines are higher than those of onshore devices.•A Bayesian network is constructed to analyze the failure rate and reliability of the entire floating offshore wind turbine.•The performance of the proposed model is validated by a comprehensive comparison with the existing studies and models.
A model is proposed to assess the failure rates of components of floating offshore wind turbines based on the knowledge of failure data of corresponding structures of onshore wind turbines with sufficient failure data. A failure rate correction model is first presented to map the relations of failure features between onshore and floating offshore wind turbines. Subsequently, a failure rate analogy model is established to infer the failure rates of elements of support structures that have no correspondence in onshore devices. The results indicate that the failure rates of components of floating offshore wind turbines are higher than those of onshore devices. Accordingly, a Bayesian network is constructed to analyze the failure rate and reliability of the entire floating offshore wind turbine. The uncertainty of the model is investigated to illustrate the factors that significantly affect the predicted failure rates and reliability. Moreover, the performance of the proposed model is validated by a comprehensive comparison with the existing studies and models. The model presented contributes to the risk, failure, and reliability analysis and assessment under insufficient data conditions.
The electric energy matrix in Brazil mostly comprises energy from hydroelectric power plants, approximately 60.8%. This large participation presents some vulnerability in periods of drought and often ...the country’s electric energy matrix is complemented by the use of other energy sources, such as thermoelectric. Even though it is currently among the largest onshore wind power producers in the world, Brazil has not yet started developing this energy source in the offshore segment. However, this study shows that offshore wind energy can be a complementary energy source for the country’s electric energy matrix, and thus replace other energy sources which have more impact on the environment. Therefore, this study sought to develop a methodology that can be easily replicated using free access tools, aiming to contribute to the development of offshore wind technology and future research in the country. The results show a large production of offshore wind energy in the southeastern region of Brazil. The "Cabo Frio 2″ data collection point presented the highest annual production of offshore wind energy. However the study opted for the "Arraial do Cabo-A606″ collection point located in the state of Rio de Janeiro and at ocean depths that can be reached by fixed foundations.
•A simplified methodology is presented to estimate offshore wind energy potential.•The energy potential is calculated in different sites in the southeast of Brazil.•The developed methodology is user-friendly and has free access tools.•The offshore wind energy can contribute to complement the energy matrix of Brazil.•This paper expands the scarce literature about offshore wind energy in Brazil.
Anchor piles and suction anchors have been used for anchoring different types of offshore structure in the past four decades. The recent growing interest and demand for wind energy has motivated the ...industry to evaluate the use of Offshore Wind Turbines (OWT) in deep waters for which floating wind turbine is a good alternative to bottom-fixed solutions particularly in seismic regions with possibility of soil liquefaction. Extensive research has been carried out to assess the consequences of soil liquefaction for buildings and onshore structures; however, this phenomenon has not been sufficiently studied for offshore foundations. This paper aims at investigating the use of advanced liquefaction modeling in assessment of the performance of anchor piles for offshore facilities and in particular floating offshore wind turbines. The software FLAC3D is used to carry out the nonlinear dynamic analyses using SANISAND constitutive model for saturated sand. The analyses indicate that SANISAND model is capable of correctly simulating the excess pore water pressure in the free-field as observed in centrifuge tests. Pore pressure build-up due to earthquake shaking together with earthquake-induced displacements are computed at various points in the soil medium containing an anchor pile in different scenarios. The numerical results indicate that anchor piles may experience permanent lateral displacements and tilt due to the combined action of static mooring load and earthquake shaking leading to soil liquefaction.
•Verification of constitutive model using soil test data.•Verification of centrifuge test results for earthquake shaking.•Inclusion of a structural element (anchor) in computational model.•Response of suction piles under combined actions of environmental and earthquake loads during liquefaction.•Sensitivity of anchor response to several parameters and practical observations.
Modern offshore wind turbines are susceptible to blade deformation because of their increased size and the recent trend of installing these turbines on floating platforms in deep sea. In this paper, ...an aeroelastic analysis tool for floating offshore wind turbines is presented by coupling a high‐fidelity computational fluid dynamics (CFD) solver with a general purpose multibody dynamics code, which is capable of modelling flexible bodies based on the nonlinear beam theory. With the tool developed, we demonstrated its applications to the NREL 5 MW offshore wind turbine with aeroelastic blades. The impacts of blade flexibility and platform‐induced surge motion on wind turbine aerodynamics and structural responses are studied and illustrated by the CFD results of the flow field, force, and wake structure. Results are compared with data obtained from the engineering tool FAST v8.
The present paper provides an overview of the current state and future trends of the offshore wind farms worldwide along with the technological challenges, especially the wind farm layout and the ...main components. First, this paper provides a review of the operative wind farms, main components characteristics and the wind farms dimensions. This is followed by a correlation analysis between offshore wind farm layout parameters such as the number of turbines, the installed capacity, the distance from shore and the water depth. Moreover, the present paper reviews the available data regarding the future projects’ portfolio. The evolution of offshore wind technology related to the pre- and under-construction projects is discussed. The data showed an increase in the wind farm dimensions and the capacity of the turbines for wind power generation more in line with that from other energy resources, which is, thereby, enhancing the potential and attractiveness of offshore wind industry for future investors. Finally, a discussion of future previsions related to offshore wind farm layout and capacity concludes the paper.
•The paper provides an overview of the current state and future trends of the offshore wind farms worldwide.•This paper provides a review of the operative wind farms, main components characteristics and the wind farms dimensions.•Offshore wind farm parameters, as the number of turbines, installed capacity, distance from shore and water depth.•a discussion of future previsions related to offshore wind farm layout and capacity is included.
To be competitive in offshore wind energy production, safe and economical foundation design is essential. In recent years, tripod suction bucket foundations have been considered as an alternative to ...conventional foundations owing to their unique features suitable for offshore construction environments, economic installation, and high overturning resistance. However, it is difficult to accurately predict the behavior of tripod foundation because the load acting on the tripod is complex in HVM (i.e., horizontal, vertical, and moment loads) and the response varies depending on the size and direction of the load. Moreover, it is harder to analyze because the effects of cyclic loads must be considered in an offshore environment. This study, therefore, has investigated the behavior of the tripod suction bucket foundation under cyclic loadings. To analyze the complex responses of the tripod foundation in detail, the overall behavior of the tripod foundation system was observed based on the compression–pullout behavior of a single bucket. Moment–rotation responses, the cyclic stiffness, and permanent displacements of the tripod foundation are evaluated by analyzing the vertical behavior of the single‐bucket foundations as well as the rotational behavior of the tripod foundation. A number of centrifuge model tests were carried out with different loading conditions (i.e., loading amplitudes and directions). It was confirmed that the cyclic behavior of the tripod bucket foundation is significantly affected by loading amplitudes and directions. Furthermore, this study emphasized the importance of considering load characteristics when designing the tripod foundation.
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