Review
Energy & Fuels
Benjamin Pakenham, Anna Ermakova, Ali Mehmanparast
Summary: This study aims to investigate decommissioning and life extension strategies in the offshore wind sector through technical discussions and financial modeling. By employing a techno-economic approach, it provides insights for the offshore wind industry on the best course of action for current wind farms based on size and age.
Review
Energy & Fuels
Ali Jadali, Anastasia Ioannou, Athanasios Kolios
Summary: This study aims to develop a framework for end-of-life strategies of offshore wind turbines, considering multiple criteria in decision-making, and translating strategies like service life extension, repowering, and decommissioning into applicable processes for offshore wind farms. A SWOT analysis is conducted to compare the proposed processes, and factors contributing to process uncertainty as well as lessons from the oil & gas industry are discussed.
ENERGY SOURCES PART B-ECONOMICS PLANNING AND POLICY
(2021)
Article
Green & Sustainable Science & Technology
Gustavo de Novaes Pires Leite, Franciele Weschenfelder, Joao Gabriel de Farias, Muhammad Kamal Ahmad
Summary: This study conducts technical and economic analyses for a wind farm in Brazil, exploring the economic benefits of the strategies of repowering and lifetime extension. The findings reveal that lifetime extension has improved feasibility in terms of economic indicators, even though it has fewer positive economic indexes.
RENEWABLE & SUSTAINABLE ENERGY REVIEWS
(2022)
Article
Engineering, Marine
Mikel Serrano-Antonanazas, Jesus-Enrique Sierra-Garcia, Matilde Santos, Maria Tomas-Rodriguez
Summary: Compared to onshore turbines, floating offshore wind turbines have advantages but also face challenges in terms of vibration and lifespan. This study proposes a general method to automatically study the relationship between vibration frequencies and the degrees of freedom of turbines, aiming to facilitate the design of structural control systems.
JOURNAL OF MARINE SCIENCE AND ENGINEERING
(2023)
Article
Automation & Control Systems
A. M. Jadali, A. Ioannou, K. Salonitis, A. Kolios
Summary: Offshore wind turbines are designed with a nominal service life of 20 to 25 years; the decision on selecting the most appropriate end-of-life scenario, such as decommissioning, repowering, or service life extension, depends on criteria, techno-economic, and risk assessment. This paper compares repowering and decommissioning through a techno-economic model, showing that full repowering reduces LCoE by nearly 35% compared to partial decommissioning and 36.5% compared to full decommissioning in a hypothetical offshore wind farm scenario.
INTERNATIONAL JOURNAL OF ADVANCED MANUFACTURING TECHNOLOGY
(2021)
Article
Green & Sustainable Science & Technology
Jessica Ceolin de Bona, Joao Carlos Espindola Ferreira, Julian Fernando Ordon
Summary: This study investigates the repowering potential of wind farms in Brazil and examines various technical and economic factors affecting repowering projects. The results suggest that repowering should focus on wind turbines with less than 2.0 MW. Financial indicators and energy selling tariffs play a crucial role in determining the feasibility of repowering projects.
RENEWABLE & SUSTAINABLE ENERGY REVIEWS
(2021)
Article
Green & Sustainable Science & Technology
Shuai Cong, Sau-Lon James Hu, Hua-Jun Li
Summary: A comprehensive strategy is developed in this study for modeling monopiled offshore wind turbines using finite element methods, which involves optimal sensor placement and cross-model updates to correct major sources of error. The proposed method shows effectiveness in simultaneously updating model parameters and improving accuracy in dynamic analysis and design.
Article
Energy & Fuels
Arthur Leandro Guerra Pires, Paulo Rotella Junior, Sandra Naomi Morioka, Luiz Celio Souza Rocha, Ivan Bolis
Summary: The present study provides a systematic review of the main trends and methods used in the economic feasibility studies of offshore wind energy. It highlights the growing interest in offshore wind power generation and identifies the key areas of focus in this field. The article offers a broad view of the methodological possibilities and specificities for investors and researchers interested in studying the economic feasibility of offshore wind generation.
Article
Green & Sustainable Science & Technology
Samuel Torres-Rincon, Emilio Bastidas-Arteaga, Mauricio Sanchez-Silva
Summary: Floating offshore wind farms with flexible installed capacity can reduce energy costs, potentially up to 18% using an adaptable platform strategy. However, the benefits of flexibility depend on new legislation and proper flexibility management policies.
Article
Engineering, Marine
Xin Jin, Yong Yue, Yiming Chen, Jing Du, Maosi Wen, An Wu, Jianjun Tan
Summary: In this study, GH Bladed and MATLAB software were combined on Python to solve the low efficiency problem in design and analysis. The relation between structural parameters and raceway stress of the bearings was investigated using finite element analysis and sub-modelling refinement techniques. The structural parameters were optimized using the Artificial Fish Swarm Algorithm (AFSA) to reduce maximum contact stress and increase fatigue life of the bearings.
Review
Green & Sustainable Science & Technology
Javier Lopez-Queija, Eider Robles, Josu Jugo, Santiago Alonso-Quesada
Summary: This paper provides a critical review of the current state-of-the-art in floating wind turbine control technologies, discussing the advantages and drawbacks of the most commonly used control algorithms and summarizing future research trends.
RENEWABLE & SUSTAINABLE ENERGY REVIEWS
(2022)
Review
Engineering, Environmental
Su Mei Woo, Jonathan Whale
Summary: Renewable energy generation and increased electrification are crucial for reducing greenhouse gas emissions and addressing climate change. The global deployment of wind turbines is increasing rapidly, but the management of their end-of-life waste poses challenges. The research found that wind turbine EoL management is dynamic and complex, requiring consideration of multiple factors.
WASTE MANAGEMENT & RESEARCH
(2022)
Article
Green & Sustainable Science & Technology
Chao Chen, Philippe Duffour, Paul Fromme, Xugang Hua
Summary: This study presents a computationally efficient methodology combining aerodynamic decoupling and modal reduction techniques for predicting the fatigue life of offshore wind turbine support structures. The method accurately predicts fatigue life and significantly reduces computational costs.
Review
Green & Sustainable Science & Technology
N. Y. Sergiienko, L. S. P. da Silva, E. E. Bachynski-Polic, B. S. Cazzolato, M. Arjomandi, B. Ding
Summary: The wind energy industry is shifting towards offshore installations, allowing for larger wind turbines to be deployed in deep-water regions with higher and steadier wind speeds. This article provides an overview of the trends in wind energy systems for offshore applications, reviews existing semi-submersible platforms, and analyzes techniques proposed to upscale floating support structures for larger wind energy systems, with a focus on system dynamics.
RENEWABLE & SUSTAINABLE ENERGY REVIEWS
(2022)
Article
Green & Sustainable Science & Technology
Sung-ho Hur
Summary: A new control strategy of sharing controllers/converters for wind turbines is proposed to improve reliability and energy yield, especially for offshore wind turbines. The Matlab/Simulink model is utilized for simulation of each turbine, as well as for simulating clusters of multiple turbines.
Article
Energy & Fuels
Shaikha Al-Sanad, Jafarali Parol, Lin Wang, Athanasios Kolios
Summary: An integrated structural optimization framework for onshore wind turbine towers was developed in this study, combining a parametric finite element analysis model with a genetic algorithm to minimize tower mass while meeting design requirements. The framework was validated and applied to a representative 2.0 MW onshore wind turbine tower, demonstrating significant mass reduction potential.
INTERNATIONAL JOURNAL OF SUSTAINABLE ENERGY
(2022)
Article
Engineering, Marine
Abdulhakim Adeoye Shittu, Ali Mehmanparast, Peyman Amirafshari, Phil Hart, Athanasios Kolios
Summary: This study presents a sensitivity analysis of offshore wind turbine support structures and emphasizes the importance of a probabilistic design approach. The results highlight the significant role of wind speed uncertainty in driving structural design, with hydrodynamic load effects being secondary. Additionally, considering the correlation between variables has a notable impact on structural reliability in ultimate limit state design.
INTERNATIONAL JOURNAL OF NAVAL ARCHITECTURE AND OCEAN ENGINEERING
(2022)
Article
Engineering, Multidisciplinary
D. Cevasco, J. Tautz-Weinert, M. Richmond, A. Sobey, A. J. Kolios
Summary: This study aims to investigate the feasibility of detecting and locating anomalies in the jacket support structure of an offshore wind turbine. A monitoring scheme is proposed based on a database of simulated modal properties, and a supervised Fisher's linear discriminant analysis is used to transform modal indicators for anomaly identification. A fuzzy clustering algorithm is trained to predict the membership of new data. A case study demonstrates the effectiveness of the global monitoring in detecting and locating simulated scenarios.
ASCE-ASME JOURNAL OF RISK AND UNCERTAINTY IN ENGINEERING SYSTEMS PART B-MECHANICAL ENGINEERING
(2022)
Article
Engineering, Mechanical
Peyman Amirafshari, Athanasios Kolios
Summary: Estimation of probability detection curves for non-destructive evaluation (NDE) can be time-consuming and costly. This study proposes a method based on Bayesian theorem to estimate POD curves, and validates its applicability using an existing database. The study finds that the predictions of the Bayesian model are consistent with the commonly used hit/miss model.
INTERNATIONAL JOURNAL OF FATIGUE
(2022)
Review
Green & Sustainable Science & Technology
L. Wang, A. Kolios, X. Liu, D. Venetsanos, C. Rui
Summary: This paper presents a state-of-the-art reliability assessment of offshore wind turbine (OWT) support structures, highlighting the importance of considering uncertainties in soil properties and environmental loads. It provides a comprehensive review on structural reliability, reliability-based calibration of codes, fatigue reliability, and the implementation of reliability assessment. The paper also discusses current and future developments in reliability assessment, such as reliability-based design optimization, multi-hazard reliability analysis, and risk-based inspection.
RENEWABLE & SUSTAINABLE ENERGY REVIEWS
(2022)
Article
Engineering, Civil
Nandar Hlaing, Pablo G. Morato, Jannie S. Nielsen, Peyman Amirafshari, Athanasios Kolios, Philippe Rigo
Summary: This paper investigates the optimal management approach for offshore wind structures under fatigue deterioration conditions. By integrating fatigue failure criteria with Bayesian networks and Markov decision processes, more optimized and informed maintenance interventions can be formulated.
STRUCTURE AND INFRASTRUCTURE ENGINEERING
(2022)
Review
Multidisciplinary Sciences
Javier Contreras Lopez, Juan Chiachio, Ali Saleh, Manuel Chiachio, Athanasios Kolios
Summary: This paper provides a cross-sectoral view of the current and potential maintenance strategies for composite structures, addressing their use and limitations, the impact of maintenance on the whole-life cycle, the application of health and condition monitoring techniques, and the benefits and limitations of currently used and potential maintenance strategies. It also identifies trends, divergences, and research gaps in the health and condition monitoring techniques and maintenance approaches used by different industries.
SN APPLIED SCIENCES
(2022)
Article
Green & Sustainable Science & Technology
Javier Contreras Lopez, Athanasios Kolios, Lin Wang, Manuel Chiachio
Summary: Blades are crucial and costly components of wind turbines. This study presents a framework for estimating leading edge erosion and energy production degradation over time. It utilizes synthetic wind and rain data, erosion protection coatings, and aerodynamic polar curves to simulate erosion and calculate energy losses. Applying this framework to a case study of a 5MW wind turbine in the North Sea, it was found that the maximum annual energy production losses range from 1.6% to 1.75% and the first erosion failure occurs between years 2 and 6.
Article
Engineering, Industrial
Ali Saleh, Manuel Chiachio, Juan Fernandez Salas, Athanasios Kolios
Summary: With the emergence of monitoring technologies, condition-based maintenance has become a reality in the wind energy industry. This is crucial in avoiding unnecessary maintenance actions and reducing costs associated with operation and downtime. An intelligent Petri net algorithm has been developed to model and optimize offshore wind turbines' operation and maintenance, combining advanced Petri net modelling with Reinforcement Learning. The results show that this method can achieve optimal condition-based maintenance policy while considering maximum availability and minimal operational costs.
RELIABILITY ENGINEERING & SYSTEM SAFETY
(2023)
Review
Energy & Fuels
Kelvin Palhares Bastos Sathler, Konstantinos Salonitis, Athanasios Kolios
Summary: In order to become more competitive and attract investors, wind energy systems need to reduce their final cost of energy. This can be achieved by either reducing costs or increasing production, using the metric of Overall Equipment Effectiveness (OEE) to measure and improve operational losses. The introduction of this metric can enable a comparison between different wind energy assets and provide an integrated indicator linking production and losses.
INTERNATIONAL JOURNAL OF SUSTAINABLE ENERGY
(2023)
Article
Engineering, Marine
A. Kolios, M. Richmond, S. Koukoura, B. Yeter
Summary: To meet the growing demand for offshore wind energy and reduce the cost of energy, it is important to improve the effectiveness of operation and maintenance activities. This can be achieved by accurately modeling these activities, which requires more accurate weather forecasting algorithms.
Article
Engineering, Marine
Baran Yeter, Yordan Garbatov, Feargal Brennan, Athanasios Kolios
Summary: The present study develops a risk model for analysing offshore wind projects based on operational and macroeconomic data. The study investigates the parameters defining the project-specific risk premium attached to these projects and conducts a probabilistic financial analysis using Monte Carlo Simulation. The model takes into account both the operational characteristics and macroeconomic factors to estimate the project-related risk and validate the cost of capital calculations. The developed model is demonstrated on a fictitious ageing offshore wind farm under different economic circumstances, considering critical project-specific parameters.
Article
Energy & Fuels
Shaikha Al-Sanad, Jafarali Parol, Lin Wang, Athanasios Kolios
Summary: Having an optimal design of the wind turbine tower is essential for economic and safe design. The commonly used partial safety factors (PSFs) are not tailored for specific designs. By calibrating the PSFs based on reliability, using information from the condition monitoring system, precise engineering of wind turbine tower structures can be achieved. This study develops a structural optimization model for wind turbine towers using a parametric finite element analysis model and a genetic algorithm. The optimized design of the tower with calibrated PSFs achieved a 2.9% reduction in mass compared to the design with un-calibrated PSFs.
Article
Energy & Fuels
Julia Walgern, Katharina Fischer, Paul Hentschel, Athanasios Kolios
Summary: The pitch system is a critical subsystem of wind turbines, playing a key role in maximizing wind capture while protecting the turbine from excessive loads. This study analyzes the failure rates of electrical and hydraulic pitch systems based on a large population of onshore assets. The results show high failure rates for both types of pitch systems, with hydraulic systems performing slightly better. Additionally, the study identifies variations in failure rates among different turbine manufacturers and a tendency for higher failure rates in larger turbines.
Article
Green & Sustainable Science & Technology
Mareike Leimeister, Maurizio Collu, Athanasios Kolios
Summary: This paper focuses on the optimization design of spar-type platforms for floating offshore wind turbines. In situ aero-hydro-servo-elastic simulations are used to support conceptual design optimization, considering transient and non-linear loads. The results show significant cost reduction potential when alternative structural and manufacturing strategies are considered.
WIND ENERGY SCIENCE
(2022)
