Offshore wind turbine maintenance access: a closed‐form probabilistic method for calculating delays caused by sea‐state

Feuchtwang, Julian; Infield, David

doi:10.1002/we.1539

Cited by 31 publications

(31 citation statements)

References 10 publications

(9 reference statements)

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“…Strathclyde University, Centre for Doctoral Training offshore wind OPEX model This model has been developed at the Centre for Doctoral Training in Wind Energy Systems to provide a complementary analysis tool to a previously developed probabilistic model [14]. The initial model development focussed on the use of specialist heavy-lift vessels for offshore wind and to inform decision support for operational strategies [15].…”

Section: University Of Stavanger Offshore Wind Simulation Modelmentioning

confidence: 99%

Reference Cases for Verification of Operation and Maintenance Simulation Models for Offshore Wind Farms

et al. 2015

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Due to lack of operating experience in the field of offshore wind energy and large costs associated with maintaining offshore wind farms, there is a need to develop accurate operation and maintenance models for strategic planning purposes. This paper provides an approach for verifying such simulation models and demonstrates it by describing the verification process for four models. A reference offshore wind farm is defined and simulated using these models to provide test cases and benchmark results for verification for wind farm availability and O&M costs. This paper also identifies key modelling assumptions that impact the results. The calculated availabilities for the four models show good agreement apart from cases where maintenance resources are heavily constrained. There are also larger discrepancies between the cost results. All the differences in the results can be explained by different modelling assumptions. Therefore, the models can be regarded as verified based on the presented approach. INTRODUCTION MotivationOffshore wind energy is a new area for operation and maintenance (O&M) research, and the operational legacy of the industry is only just over a decade. Operation and maintenance cost modelling software tools are being developed to support activities in this field. Because of the novelty of offshore wind energy generation and lack of real data, there are limited options for validation and verification of these models. Verification and validation of a simulation model is essential if the model is to say something useful about the system it is meant to represent. We define verification as ensuring that the simulation model is implemented according to the specifications of the conceptual model of the system; validation is defined as ensuring that this conceptual model is in fact a faithful representation of the real system for the purposes of the model [1]. It may prove difficult for researchers to acquire suitable data to perform model validation. For full operational validation [1], necessary historical data would include repair and logistical costs, statistical information on component reliability and performance indicators such as total operations costs or availability. This type of information is possessed by the farm owner/operator, turbine manufacturer or non-existent for new generation wind turbines. BackgroundSeveral O&M simulation models for offshore wind farms have been developed, of which Hofmann [2] provides a thorough overview. Often, the intended applications of the models differ slightly. For example, one model will focus on assessing heavy-lift vessels, whereas another will be used for maintenance strategy optimisation. [3]. One position is that models are never entirely validated because it is not practicable to assess correspondence between the system and the model for its entire domain of applicability [1]. Even if the system is observable and a comparison of model output and system output is possible, one is often interested in predicting system behaviour under circumst...

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Section: University Of Stavanger Offshore Wind Simulation Modelmentioning

confidence: 99%

Reference Cases for Verification of Operation and Maintenance Simulation Models for Offshore Wind Farms

et al. 2015

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“…Offshore wind farm operation and maintenance (O&M) cost models need resource requirements for repair as inputs to the models. These models can be highly sensitive to the accuracy of this data and that data is not currently in the public domain . In some cases onshore input data is used to estimate offshore outputs in these models .…”

Section: Introductionmentioning

confidence: 99%

“…These models can be highly sensitive to the accuracy of this data and that data is not currently in the public domain. 4,5 In some cases onshore input data is used to estimate offshore outputs in these models. 2,6 Inputs such as failure rates, repair times, number of technicians required for repair and average cost of repair are required.…”

Section: Introductionmentioning

confidence: 99%

Failure rate, repair time and unscheduled O&M cost analysis of offshore wind turbines

2015

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Determining and understanding offshore wind turbine failure rates and resource requirement for repair are vital for modelling and reducing O&M costs and in turn reducing the cost of energy. While few offshore failure rates have been published in the past even less details on resource requirement for repair exist in the public domain. Based on ~350 offshore wind turbines throughout Europe this paper provides failure rates for the overall wind turbine and its sub-assemblies. It also provides failure rates by year of operation, cost category and failure modes for the components/sub-assemblies that are the highest contributor to the overall failure rate. Repair times, average repair costs and average number of technicians required for repair are also detailed in this paper. An onshore to offshore failure rate comparison is carried out for generators and converters based on this analysis and an analysis carried out in a past publication. The results of this paper will contribute to offshore wind O&M cost and resource modelling and aid in better decision making for O&M planners and managers

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“…Feuchtwang and Infield [15] developed a closed form probabilistic method for calculating delays caused by sea scale in offshore wind turbine system. Arshad and O'Kelly [2] reviewed different offshore windturbine structures giving different ideas with respect to maintenance operation and costs.…”

Section: Previous Researchmentioning

confidence: 99%

Minimizing maintenance cost for offshore wind turbines following multi-level opportunistic preventive strategy

2016

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a b s t r a c tCost of energy generated from offshore wind is impacted by maintenance cost to a great extent. Cost of maintenance depends primarily on the strategy for performing maintenance. In this paper a maintenance cost model for offshore wind turbine components following multilevel opportunistic preventive maintenance strategy is formulated. In this strategy, opportunity for performing preventive actions on components is taken while a failed component is replaced. Two kinds of preventive actions are considered, preventive replacement and preventive maintenance. In the former, components that undergo that action become as good as new (i.e., the replaced components, are not just as good as new, but are actually new), but in the latter, ages of components are reduced to some degree depending on the level of maintenance action. Total cost associated with maintenance depends on the setting of age groups that determine which component should be preventively maintained and to what degree. Through optimum selection of the number of age groups, cost of maintenance can be minimized. A model is formulated where total maintenance cost is expressed as a function of number of age groups for components. A numerical study is used to illustrate the model. The results show that total cost of maintenance is significantly impacted by number of age groups and age thresholds set for components.

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Offshore wind turbine maintenance access: a closed‐form probabilistic method for calculating delays caused by sea‐state

Cited by 31 publications

References 10 publications

Reference Cases for Verification of Operation and Maintenance Simulation Models for Offshore Wind Farms

Reference Cases for Verification of Operation and Maintenance Simulation Models for Offshore Wind Farms

Failure rate, repair time and unscheduled O&M cost analysis of offshore wind turbines

Minimizing maintenance cost for offshore wind turbines following multi-level opportunistic preventive strategy

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