scholarly journals Research on a Comprehensive Maintenance Optimization Strategy for an Offshore Wind Farm

Energies ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 965
Author(s):  
Yang Lu ◽  
Liping Sun ◽  
Yanzhuo Xue
Keyword(s):  
Wind Farm ◽  
Wind Farms ◽  
Weather Conditions ◽  
Offshore Wind ◽  
Monte Carlo Algorithm ◽  
Maintenance Cost ◽  
Offshore Wind Turbine ◽  
Offshore Wind Farm ◽  
Proposed Model ◽  
Maintenance Activities

Offshore wind is considered a crucial part in the future energy supply. However, influenced by weather conditions, the maintenance of offshore wind turbine system (OWTs) equipment is challenged by poor accessibility and serious failure consequences. It is necessary to study the optimized strategy of comprehensive maintenance for offshore wind farms, with consideration of the influences of incomplete equipment maintenance, weather accessibility and economic relevance. In this paper, a Monte Carlo algorithm-improved factor is presented to simulate the imperfect preventive maintenance activity, and waiting windows were created to study the accessibility of weather conditions. Based on a rolling horizon approach, an opportunity group maintenance model of an offshore wind farm was proposed. The maintenance correlations between systems and between equipment as well as breakdown losses, maintenance uncertainty, and weather conditions were taken into account in the model, thus realizing coordination of maintenance activities of different systems and different equipment. The proposed model was applied to calculate the maintenance cost of the Dafengtian Offshore Wind Farm in China. Results proved that the proposed model could realize long-term dynamic optimization of offshore wind farm maintenance activities, increase the total availability of the wind power system and reduce total maintenance costs.

scholarly journals The Relation between Migratory Activity of Pipistrellus Bats at Sea and Weather Conditions Offers Possibilities to Reduce Offshore Wind Farm Effects

Animals ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 3457
Author(s):  
Robin Brabant ◽  
Yves Laurent ◽  
Bob Jonge Poerink ◽  
Steven Degraer
Keyword(s):  
Wind Turbines ◽  
Wind Farm ◽  
Negative Relationship ◽  
Wind Farms ◽  
Weather Conditions ◽  
Seasonal Migration ◽  
Offshore Wind ◽  
Offshore Wind Farm ◽  
Offshore Wind Farms ◽  
Migratory Activity

Bats undertaking seasonal migration between summer roosts and wintering areas can cross large areas of open sea. Given the known impact of onshore wind turbines on bats, concerns were raised on whether offshore wind farms pose risks to bats. Better comprehension of the phenology and weather conditions of offshore bat migration are considered as research priorities for bat conservation and provide a scientific basis for mitigating the impact of offshore wind turbines on bats. This study investigated the weather conditions linked to the migratory activity of Pipistrellus bats at multiple near- and offshore locations in the Belgian part of the North Sea. We found a positive relationship between migratory activity and ambient temperature and atmospheric pressure and a negative relationship with wind speed. The activity was highest with a wind direction between NE and SE, which may favor offshore migration towards the UK. Further, we found a clear negative relationship between the number of detections and the distance from the coast. At the nearshore survey location, the number of detections was up to 24 times higher compared to the offshore locations. Our results can support mitigation strategies to reduce offshore wind farm effects on bats and offer guidance in the siting process of new offshore wind farms.

An opportunistic maintenance strategy for offshore wind turbine based on accessibility evaluation

2019 ◽  
Vol 44 (5) ◽  
pp. 455-468
Author(s):  
Xie Lubing ◽  
Rui Xiaoming ◽  
Li Shuai ◽  
Hu Xin
Keyword(s):  
Wind Turbine ◽  
Preventive Maintenance ◽  
Wind Farm ◽  
Weather Conditions ◽  
Offshore Wind ◽  
Offshore Wind Turbine ◽  
Maintenance Strategy ◽  
Offshore Wind Farm ◽  
Opportunistic Maintenance ◽  
Operation And Maintenance

The maintenance costs of offshore wind turbines operated under the irregular, non-stationary conditions limit the development of offshore wind power industry. Unlike onshore wind farms, the weather conditions (wind and waves) have greater impacts on the operation and maintenance of offshore wind farm. Accessibility is a key factor related to the operation and maintenance of offshore wind turbine. Considering the impact of weather conditions on the maintenance activities, the Markov method and dynamic time window are applied to represent the weather conditions, and an index used to evaluate the maintenance accessibility is then proposed. As the wind turbine is a multi-component complex system, this article uses the opportunistic maintenance strategy to optimize the preventive maintenance age and opportunistic maintenance age for the main components of the wind turbine. Taking the minimum expectation cost as objective function, this strategy integrates the maintenance work of the key components. Finally, an offshore wind farm is taken for simulation case study of this strategy; the results showed that the maintenance cost of opportunistic maintenance strategy is 10% lower than that of the preventive maintenance strategy, verifying the effectiveness of the opportunistic maintenance.

Sea-Keeping Analysis of an Offshore Wind Farm Installation Vessel During the Jack-Up Process

2014 ◽  
Author(s):  
Philip H. Augener ◽  
Hannes Hatecke
Keyword(s):  
Wind Farm ◽  
Wind Farms ◽  
Weather Conditions ◽  
Offshore Wind ◽  
Shallow Waters ◽  
Offshore Wind Farm ◽  
Offshore Wind Farms ◽  
The North ◽  
The North Sea ◽  
Jack Up

Offshore wind farms are not planned in sheltered and shallow waters any longer. Especially in the North Sea there exist many approved offshore wind farm projects at water depth between 30 and 50 meters. In particular the installation process of these projects is strongly influenced by weather conditions and the sea-keeping capabilities of the installation vessels. For reliable planning of the entire project, not only the weather statistics, but also the vessel’s sea-keeping capabilities need to be known accurately. For this purpose different kinds of sea-keeping analyses can be conducted. In this paper a sea-keeping analysis is presented, where the focus is upon the jack-up process. For the numerical computation the sea-keeping code E4ROLLS is applied. The results of this sea-keeping analysis are operational limitations for the jack-up process, caused by two different criteria derived from jack-up classification requirements.

Optimization of O&M for Offshore Wind Farms Modelling for WMTC Conferences

2015 ◽  
Author(s):  
Thomas Nivet ◽  
Ema Muk-Pavic
Keyword(s):  
Wind Farm ◽  
Wind Farms ◽  
Cost Effective ◽  
Offshore Wind ◽  
Offshore Wind Turbine ◽  
Offshore Wind Farms ◽  
Climate Conditions ◽  
Operation Analysis ◽  
Cost Effective Approach ◽  
Failure Evaluation

Offshore wind energy is one of the most upcoming sources of energy, and it is already partially replacing the fossil fuelled power production. However, offshore wind turbine technology is also associated with harsher weather environment. Indeed, it experiences more challenging wind and wave conditions, which in turn limits the vessels capabilities to access the wind farms. Additionally, with the constant rise of power utilization, improvements in the Operation Maintenance (O&M) planning are crucial for the development of large isolated offshore wind farms. Improvements in the planning of the O&M for offshore wind farms could lead to considerable reduction in costs. For this reason, the interest of this research paper is the investigation of the most cost effective approach to offshore turbine maintenance strategies. This objective is achieved by implementing a simulation approach that includes a climate conditions analysis, an operation analysis, a failure evaluation and a simulation of the repairs. This paper points out how different O&M strategies can influence the sustainability of a wind farm.

Fatigue Life Analysis of Offshore Wind Turbine Support Structures in an Offshore Wind Farm

2018 ◽  
Author(s):  
Bryan Nelson ◽  
Yann Quéméner
Keyword(s):  
Wind Turbine ◽  
Wind Turbines ◽  
Wind Farm ◽  
The Body ◽  
Offshore Wind ◽  
Offshore Wind Turbine ◽  
Analysis Tool ◽  
Support Structures ◽  
Offshore Wind Farm ◽  
Actuator Disk

This study evaluated, by time-domain simulations, the fatigue lives of several jacket support structures for 4 MW wind turbines distributed throughout an offshore wind farm off Taiwan’s west coast. An in-house RANS-based wind farm analysis tool, WiFa3D, has been developed to determine the effects of the wind turbine wake behaviour on the flow fields through wind farm clusters. To reduce computational cost, WiFa3D employs actuator disk models to simulate the body forces imposed on the flow field by the target wind turbines, where the actuator disk is defined by the swept region of the rotor in space, and a body force distribution representing the aerodynamic characteristics of the rotor is assigned within this virtual disk. Simulations were performed for a range of environmental conditions, which were then combined with preliminary site survey metocean data to produce a long-term statistical environment. The short-term environmental loads on the wind turbine rotors were calculated by an unsteady blade element momentum (BEM) model of the target 4 MW wind turbines. The fatigue assessment of the jacket support structure was then conducted by applying the Rainflow Counting scheme on the hot spot stresses variations, as read-out from Finite Element results, and by employing appropriate SN curves. The fatigue lives of several wind turbine support structures taken at various locations in the wind farm showed significant variations with the preliminary design condition that assumed a single wind turbine without wake disturbance from other units.

scholarly journals A cross-sectional survey of physical strains among offshore wind farm workers in the German exclusive economic zone

BMJ Open ◽  
2018 ◽  
Vol 8 (3) ◽  
pp. e020157 ◽  
Author(s):  
Marcial Velasco Garrido ◽  
Janika Mette ◽  
Stefanie Mache ◽  
Volker Harth ◽  
Alexandra M Preisser
Keyword(s):  
Wind Farm ◽  
Wind Farms ◽  
Exclusive Economic Zone ◽  
Offshore Wind ◽  
Upper Body ◽  
Offshore Wind Farm ◽  
Cross Sectional Survey ◽  
Cross Sectional ◽  
Heavy Loads ◽  
Under Construction

ObjectivesTo assess the physical strains of employees in the German offshore wind industry, according to job type and phase of the wind farm (under construction or operation).DesignWeb-based cross-sectional survey.SettingOffshore wind farm companies operating within the German exclusive economic zone.ParticipantsMale workers with regular offshore commitments and at least 28 days spent offshore in the past year (n=268).Outcome measuresPhysical strains (eg, climbing, noise, working overhead, with twisted upper body or in confined spaces, vibration, heavy lifting, humidity, odours).ResultsThe most frequently mentioned physical strain was ’climbing’ with 63.8% of the respondents reporting to be always or frequently confronted with climbing and ascending stairs during offshore work. Work as a technician was associated with a greater exposition to noise, vibrations, humidity, cold, heat, chemical substances, lifting/carrying heavy loads, transport of equipment, working in non-ergonomic positions and in cramped spaces, as well as climbing.Indeed, statistical analyses showed that, after adjusting for phase of the wind farm, age, nationality, offshore experience, work schedule and type of shift, compared with non-technicians, working as a technician was associated with more frequently lifting/carrying of heavy loads (OR 2.58, 95% CI 1.58 to 4.23), transport of equipment (OR 2.06 95% CI 1.27 to 3.33), working with a twisted upper body (OR 2.85 95% CI 1.74 to 4.69), working overhead (OR 2.77 95% CI 1.67 to 4.58) and climbing (OR 2.30 95% CI 1.40 to 3.77). Working in wind farms under construction was strongly associated with increased and decreased exposure to humidity (OR 2.32 95% CI 1.38 to 3.92) and poor air quality (OR 0.58 95% CI 0.35 to 0.95), respectively.ConclusionsWorkers on offshore wind farms constitute a heterogeneous group, including a wide variety of occupations. The degree of exposure to detrimental physical strains varies depending on the type of job. Technicians are more exposed to ergonomic challenges than other offshore workers.

An Investigation into the Motion Behaviour of a Wind Farm Mothership

2015 ◽  
Author(s):  
Blanca Peña ◽  
Erik P. ter Brake ◽  
Kyriakos Moschonas
Keyword(s):  
Numerical Simulations ◽  
Wind Farm ◽  
Wind Farms ◽  
Weather Conditions ◽  
Offshore Wind ◽  
Financial Benefit ◽  
Offshore Wind Farms ◽  
Motion Characteristics ◽  
Vessel Motion ◽  
Motion Behavior

A number of UK Round Three offshore wind farms are located relatively far from the coast making crew transfer to the sites time consuming, more prone to interruption by weather conditions and increasingly costly. In order to optimize the functionality of a permanent accommodation vessel, Houlder has developed a dedicated Accommodation and Maintenance Wind Farm vessel based on an oil & gas work-over vessel that has been successfully deployed for many years. The Accommodation and Maintenance (A&M) Wind Farm vessel is designed to provide an infield base for Marine Wind Farm operation. The A&M vessel is designed for high operability when it comes to crew access and performance of maintenance and repair of wind turbine components in its workshops. Also general comfort on board is of high regard. As such, the seakeeping behavior of the unit is of great importance. In this publication, the seakeeping behavior is presented on the basis of numerical simulations using 3D diffraction software. The first design iteration is driven by achieving high maneuverability and good motion characteristics for operational up-time and personnel comfort on board the vessel. Model test data of the original work-over vessel has been used to validate and calibrate the numerical simulations. On this basis, parametric studies can be performed to fine-tune a potential new hull form. In turn, this could reduce the number of required physical model tests providing a potential financial benefit and optimized delivery schedule. The vessel motion behavior was tested against the acceptability criteria and crew comfort guidelines of motion behavior for a North Sea environment.

scholarly journals ENHANCING MARINE ENERGY COMPETITIVENESS: CO-LOCATED OFFSHORE WIND AND WAVE ENERGY FARMS

2017 ◽  
pp. 4
Author(s):  
Sharay Astariz ◽  
Gregorio Iglesias
Keyword(s):  
Wave Energy ◽  
Wind Farm ◽  
Fossil Fuels ◽  
Sustainable Use ◽  
Wind Farms ◽  
Economic Benefits ◽  
Offshore Wind ◽  
Maintenance Cost ◽  
Shadow Effect ◽  
Marine Energy

If marine energy is to become a viable alternative to fossil fuels, its competitiveness must be enhanced. In this sense, combining various renewables in the same marine space is emerging as a solution. Among the different options, this paper focuses on combined wind and wave energy farms. First, the different synergies between both renewable are analysed, such as the more sustainable use of the marine resource or the opportunity to reduce costs of both technologies by sharing some of the most important costs of an offshore project. Second, this paper focuses on two technology synergies: the reduction of the inherent intermittency of renewables; and the so-called shadow effect which implies the reduction of the wave height in the inner part of the wind farm. Both effects may suppose an important reduction in the operation and maintenance cost by reducing the balancing cost when connecting the installation to the grid and increasing weather windows to access the wind turbines. However, the benefits of this combination will depend on the site characteristics and the array layout. On this basis, the power smoothing and shadow effect in co-located farms are analysed through different case studies considering real sea conditions, wind farms currently in operation and a high resolution numerical model (SWAN). Finally, conclusions about the economic benefits of co-located farms are drawn by recalculating the levelised cost of energy when both renewable are combined.

Computation of Drift Forces for Dynamic Positioning Within the Very Early Design Stage of Offshore Wind Farm Installation Vessels

2014 ◽  
Author(s):  
Philip H. Augener ◽  
Stefan Krüger
Keyword(s):  
Wind Farm ◽  
Wind Farms ◽  
Offshore Wind ◽  
Irregular Waves ◽  
Design Stage ◽  
Dynamic Positioning ◽  
Offshore Wind Farm ◽  
Early Design ◽  
Early Design Stage ◽  
Drift Forces

The German government has decided upon the changeover from fossil and nuclear based electrical power generation to renewable energies. Following from this offshore wind farms are erected in the exclusive economic zones of Germany. For the transportation and installation as well as the maintenance of the wind turbine generators very specialized vessels are needed. The capability of dynamic positioning even in very harsh weather conditions is one of the major design tasks for these vessels. For this reason it is important to know the external loads on the ships during station keeping already in the very early design stage. This paper focuses on the computation of wave drift forces in regular and irregular waves as well as in natural seaway. For validation the results of the introduced calculation procedure are compared to measured drift force data from sea-keeping tests of an Offshore Wind Farm Transport and Installation Vessel.

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