5 research outputs found
Fatigue and fracture mechanics of offshore wind turbine support structures
Wind power, especially offshore, is considered to be one of the most promising
sources of ‘clean’ energy towards meeting the EU targets for 2020 and 2050.
However, its popularity has always fluctuated with the price of fossil fuels since
nowadays wind electricity production cannot compete with nuclear or coal
electricity production. Support structures are thought to be one of the main drivers
for reducing costs in order to make the wind industry more economically efficient.
Foundations and towers should be fit for purpose, extending their effective
service life but avoiding costs of oversizing.
An exhaustive review of the background and state of the art of the Fatigue-Life
assessment approaches has been carried out, combining analysis of the
gathered experimental data and the development of Finite Element models based
on contemporary 3D solid models with diverse Regression Analyses, in order to
identify their weakness and evaluate their accuracy. This research shows that the
guides and practices currently employed in the design and during the operation
of the offshore wind turbine support structures are obsolete and not useful for
optimisation, which generally leads to conservationism and an unnecessary
increase in costs.
The basis for a comprehensive update of the Girth Weld and Tubular Joint S-N
curves and the Stress Concentration Factors of Tubular Joints has been set out.
Furthermore, a reliable methodology for deriving the Stress Intensity Factor at the
deepest point of a semi-elliptical surface saddle crack in a tubular welded T-joint
has been proposed
A comparative study of multiple-criteria decision-making methods under stochastic inputs
This paper presents an application and extension of multiple-criteria decision-making (MCDM) methods to account for stochastic input variables. More in particular, a comparative study is carried out among well-known and widely-applied methods in MCDM, when applied to the reference problem of the selection of wind turbine support structures for a given deployment location. Along with data from industrial experts, six deterministic MCDM methods are studied, so as to determine the best alternative among the available options, assessed against selected criteria with a view toward assigning confidence levels to each option. Following an overview of the literature around MCDM problems, the best practice implementation of each method is presented aiming to assist stakeholders and decision-makers to support decisions in real-world applications, where many and often conflicting criteria are present within uncertain environments. The outcomes of this research highlight that more sophisticated methods, such as technique for the order of preference by similarity to the ideal solution (TOPSIS) and Preference Ranking Organization method for enrichment evaluation (PROMETHEE), better predict the optimum design alternative
A framework for the selection of optimum offshore wind farm locations for deployment
This research develops a framework to assist wind energy developers to select the optimum deployment site of a wind farm by considering the Round 3 available zones in the UK. The framework includes optimization techniques, decision-making methods and experts’ input in order to support investment decisions. Further, techno-economic evaluation, life cycle costing (LCC) and physical aspects for each location are considered along with experts’ opinions to provide deeper insight into the decision-making process. A process on the criteria selection is also presented and seven conflicting criteria are being considered for implementation in the technique for the order of preference by similarity to the ideal solution (TOPSIS) method in order to suggest the optimum location that was produced by the nondominated sorting genetic algorithm (NSGAII). For the given inputs, Seagreen Alpha, near the Isle of May, was found to be the most probable solution, followed by Moray Firth Eastern Development Area 1, near Wick, which demonstrates by example the effectiveness of the newly introduced framework that is also transferable and generic. The outcomes are expected to help stakeholders and decision makers to make better informed and cost-effective decisions under uncertainty when investing in offshore wind energy in the UK
Multi-criteria assessment of offshore wind turbine support structures
Wind power, especially offshore, is considered one of the most promising sources
of ‘clean’ energy towards meeting the EU and UK targets for 2020 and 2050.
Deployment of wind turbines in constantly increasing water depths has raised the
issue of the appropriate selection of the most suitable support structures’
options. Based on experience and technology from the offshore oil and gas
industry, several different configurations have been proposed for different
operational conditions. This paper presents a methodology for the systematic
assessment of the selection of the most preferable, among the different
configurations, support structures for offshore wind turbines, taking into
consideration several attributes through the widely used multi-criteria decision
making method TOPSIS (Technique for Order Preference by Similarity to Ideal
Solution) for the benchmarking of those candidate options. An application
comparing a monopile, a tripod and a jacket, for a reference 5.5 MW wind turbine
and a reference depth of 40 m, considering multiple engineering, economical and
environmental attributes, will illustrate the effectiveness of the proposed
metho
Results and data for for the selection of optimum offshore wind farm locations for deployment
Results and data acquired in the paper "A
framework for the selection of optimum offshore wind farm locations for deployment"<br