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The improvements in electricity-based availability and cost of energy compared to the base case for different numbers of CTVs.
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This paper presents a cost-benefit evaluation that investigates the potential economic benefits of using remote inspection technology for offshore wind farms. Remote inspection consists of a robot system inside the turbine nacelle that can perform inspections on behalf of an operator located on land. Such a system can reduce the need for expensive...
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Citations
... Previous studies in this domain have focused on exploring robotics-based inspection from various angles. For instance, Netland et al 10 have proposed the use of a robot inside the nacelle. The proposed robot moves on a rail and is able to conduct inspection with high-resolution camera, thermal sensor, and microphones. ...
Operations and maintenance (O&M) of floating offshore wind farms (FOWFs) poses various challenges in terms of greater distances from the shore, harsher weather conditions, and restricted mobility options. Robotic systems have the potential to automate some parts of the O&M leading to continuous feature‐rich data acquisition, operational efficiency, along with health and safety improvements. There remains a gap in assessing the techno‐economic feasibility of robotics in the FOWF sector. This paper investigates the costs and benefits of incorporating robotics into the O&M of a FOWF. A bottom‐up cost model is used to estimate the costs for a proposed multi‐robot platform (MRP). The MRP houses unmanned aerial vehicle (UAV) and remotely operated vehicle (ROV) to conduct the inspection of specific FOWF components. Emphasis is laid on the most conducive O&M activities for robotization and the associated technical and cost aspects. The simulation is conducted in Windfarm Operations and Maintenance cost‐Benefit Analysis Tool (WOMBAT), where the metrics of incurred operational expenditure (OPEX) and the inspection time are calculated and compared with those of a baseline case consisting of crew transfer vessels, rope‐access technicians, and divers. Results show that the MRP can reduce the inspection time incurred, but this reduction has dependency on the efficacy of the robotic system and the associated parameterization e.g., cost elements and the inspection rates. Conversely, the increased MRP day rate results in a higher annualized OPEX. Residual risk is calculated to assess the net benefit of incorporating the MRP. Furthermore, sensitivity analysis is conducted to find the key parameters influencing the OPEX and the inspection time variation. A key output of this work is a robust and realistic framework which can be used for the cost‐benefit assessment of future MRP systems for specific FOWF activities.
... The overall objective is to improve performance metrics such as a reduction in asset downtime and the LCOE. An overview of the existing cost models prior to 2011 is presented in Hofmann et al. 12 with more recent reviews presented by Welte et al. 95 and Judge et al. 96 A cost-benefit assessment of remote inspection of nacelle is presented by Netland et al., 71 where NOWIcob tool is used to simulate the O&M costs. It is demonstrated that for an offshore wind farm, a remote inspection system combined with condition monitoring improves availability and reduces the LCOE, as compared to the condition monitoring alone. ...
Marine operations required to transfer technicians and equipment represent a significant proportion of the total cost of offshore wind. The profile of sites being considered for floating offshore wind farms (FOWFs), e.g., further from the shore and in harsher environments, indicates that these costs need to be assessed by taking into account the maintenance requirements and restricted weather windows. There is an immediate need to investigate the potential use of robotic systems in the wind farm's operations and maintenance (O&M) activities, to reduce the need for costly manned visits. The use of robotic systems can be critical, not only to replace repetitive activities and bring down the levelised cost of energy but also to reduce the health and safety risks by supporting human operators in performing the desired inspections. This paper provides a review of the state of the art in the applications of robotics for O&M of FOWFs. Emerging technology trends and associated challenges and opportunities are highlighted, followed by an outline of the agenda for future research in this domain.
... Even though the inspection planning methodology is matured and well-proven in industrial applications [25], its feasibility for the majority of offshore wind applications is questionable due to the profound inspection costs [26]. A more economically feasible alternative, in the form of condition-based monitoring, is typically investigated for offshore wind applications [27,28]. In this context, condition monitoring data can be applied to identify structural damage, and then the resulting integrity information can be employed for updating reliability [29]. ...
This paper presents a probabilistic framework for updating the structural reliability of offshore wind turbine substructures based on digital twin information. In particular, the information obtained from digital twins is used to quantify and update the uncertainties associated with the structural dynamics and load modeling parameters in fatigue damage accumulation. The updated uncertainties are included in a probabilistic model for fatigue damage accumulation used to update the structural reliability. The updated reliability can be used as input to optimize decision models for operation and maintenance of existing structures and design of new structures. The framework is exemplified based on two numerical case studies with a representative offshore wind turbine and information acquired from previously established digital twins. In this context, the effect of updating soil stiffness and wave loading, which constitute two highly uncertain and sensitive parameters, is investigated. It is found that updating the soil stiffness significantly affects the reliability of the joints close to the mudline, while updating the wave loading significantly affects the reliability of the joints localized in the splash zone. The increased uncertainty related to virtual sensing, which is employed to update wave loading, reduces structural reliability.
... This is a significant cost saving in one project since the global loss due to inefficient blades of the turbine is reported to be over $4 billion per year [219]. Another study evaluating the costbenefits of remote inspection of offshore wind farms is reported in [220]. The scenario consisted of an offshore wind farm of 100 wind turbines, each of which has 3MW rated power at the cost of €2400 per KW. ...
The domain of Robotics is a good partner of renewable energy and is becoming critical to the sustainability and survival of the energy industry. The multi-disciplinary nature of robots offers precision, repeatability, reliability, productivity and intelligence, thus rendering their services in diversified tasks ranging from manufacturing, assembling, and installation to inspection and maintenance of renewable resources. This paper explores applications of real robots in four feasible renewable energy domains; solar, wind, hydro, and biological setups. In each case, existing state-of-the-art innovative robotic systems are investigated that have the potential to create a difference in the corresponding renewable sector in terms of reduced set-up time, lesser cost, improved quality, enhanced productivity and exceptional competitiveness in the global market. Instrumental opportunities and challenges of robot deployment in the renewable sector are also discussed with a brief case study of Saudi Arabia. It is expected that the wider dissemination of the instrumental role of robotics in renewable energy will contribute to further developments and stimulate more collaborations and partnerships between professionals of robotics and energy communities.
... Offshore wind turbines are exposed to harsh maritime conditions, which often cause damages and failures. In the literature, the technical availability of offshore wind energy (OWE) is between 60 and 90 % (Scheu et al 2012;Netland et al 2014), which is very low compared to onshore wind energy (97-99%) (Institut für Solare Energieversorgungstechnik, 2008). One reason for this fact is that the logistics processes for the maintenance of OWT are very complex and, therefore, cost-intensive compared to the onshore variants, because downtimes are usually longer in the case of a failure. ...
Offshore wind turbines are exposed to harsh maritime conditions. This makes the planning of the maintenance processes more challenging and therefore cost-intensive compared to onshore wind turbines. To deal with these challenges, it is important to investigate the impact of different maintenance strategies, e.g. reactive and predictive maintenance on the turbines’ performance. In this context, the availability of turbines, the energy production and the overall maintenance costs are considered. This paper addresses the impact of different maintenance strategies by presenting a parametric multi-agent-based discrete-event simulation. Based on this simulation, we study the variation of failure detection on the performance of the turbines. The results of the simulations show that through a better predictability of the maintenance measures, both, the downtime of wind turbines and the failure consequences can be reduced. Saving potentials lie primarily in the reduction of the material costs and lower production losses.
... High voltage direct current (HVDC) technology is currently drawing the researchers' attention as a cost-effective solution for efficient power transmission, especially for offshore sites that use transmission cables [1]. Offshore wind turbines are expected to have 3000 full load hours per year compared to 2000 hours in case of onshore ones [2]. Therefore, operation and maintenance (O&M) is considered a dominant element in HVDC power grids to maintain stable power generation. ...
... Compared to onshore sites, O&M of offshore wind farms is more expensive, since onshore O&M strategy relies on conducting frequent maintenance visits to the onshore sites and holding routine maintenance tasks, which seems to be impractical in the case of offshore sites [2]. This gives a rise of investigating a robotic inspection solution for offshore HVDC power stations [3], which can guarantee high accessibility to offshore assets with minimum human intervention. ...
Offshore high voltage DC (HVDC) wind farms offer a promising solution to growing energy demands in the future. Condition monitoring of substation assets is essential for reliable and resilient operation of electrical networks. Existing condition monitoring techniques for onshore substation and electrical network assets include regular and scheduled on-site visits by trained personnel to substation sites. However, such routine inspection is not a cost-effective solution for offshore sites. In cases where the accessibility to network assets becomes difficult, robotic and autonomous condition monitoring provides a solution. Such a robotic/autonomous solution would need to interact with the surrounding substation environment, without increasing the risk of electrical breakdown and flashovers between different energized components. In Part A of this paper, the effect of high electrostatic fields on an inspection unmanned aerial vehicle (UAV) is analyzed, with respect to: 1) AC corona emissions interference on the UAV, and 2) Air breakdown clearance characteristics. Both simulations and experiment results presented in the paper show the impact of corona emissions interference to both UAV autopilot and actuation sections, which requires a shielding mitigation solution. Also, experiment results show the limited effect of introducing a shielding solution on increasing the flashover risk between valve hall towers.
... One is combining the maintenance activities in order to save setup costs by sharing vessels and maintenance tools, and another one is that dependence exists between WTs with high risk of failure. Haddad et al. (2014) and Netland et al. (2014) developed simulation models to maximize the cost benefits of inspection and prognostics. Ding and Tian (2012) proposed a preventive maintenance model for wind farms. ...
The existing maintenance strategies of offshore wind energy are reviewed including the specific aspects of condition-based maintenance, focusing on three primary phases, namely, condition monitoring, fault diagnosis and prognosis, and maintenance optimization. Relevant academic research and industrial applications are identified and summarized. The state of art, capabilities, and constraints of condition-based maintenance are analyzed. The presented research demonstrates that the intelligent-based approach has become a promising solution for condition recognition, and an integrated data platform for offshore wind farms is significant to optimize the maintenance activities. © 2019, Harbin Engineering University and Springer-Verlag GmbH Germany, part of Springer Nature.
... Remote inspection systems address these issues and can improve the efficiency of inspection operations [11]. A study with offshore wind farms [12] for example showed that using a remote inspection system, significantly reduces the required manned operations and the related costs. ...
... 81 Minuten braucht. Durch den Vergleich zwischen der in der Simulation erzielten Verfügbarkeit mit der Verfügbarkeit einer OWEA in Norddeutschland und der in der Literatur zitierten OWEA-Verfügbarkeiten wird das Simulationsmodell validiert(Scheu et al. 2012;Netland et al. 2014). ...
This paper describes a multi-agent-based discrete-event simulation of the maintenance processes of offshore wind turbines. First, a brief overview of the challenges for the operation and maintenance of offshore wind turbines in general will be given and the state of the art in the field of simulation of offshore operation and maintenance processes will be expressed. Subsequently, the structure of the simulation model will be explained and the simulation results for reactive and predictive maintenance strategies will be discussed. Based on the simulation model, the contribution of a better failure forecast to the maintenance costs will be investigated.
... O&M strategy is becoming more important as offshore wind farms move towards large-scale projects (Karyotakis and Bucknall, 2010). O&M costs refer to the wind farm's daily management costs which includes labour, spare parts, transportation to the wind farms' sites, lease of equipment for repair and maintenance, employment of jack-up vessels for replacement of major components, monitor systems, cable repairs and foundation inspection and repair (Dalgic et al., 2015;El-Thalji and Liyanage, 2012;Karyotakis and Bucknall, 2010;Netland et al., 2014;Scheu et al., 2012). O&M costs are directly influenced by the design of the wind farm, the environment and the selected maintenance strategy. ...
Purpose
There is increasing research interest in the expansion of the offshore wind energy sector. Recent research shows that operations and maintenance (O&M) account for around 20-35 per cent of the total energy costs in this sector. The purpose of this paper is to provide an overview of O&M issues in the offshore wind energy sector to propose initiatives that can help reduce the cost of energy used by offshore wind farms.
Design/methodology/approach
The paper is based on an in-depth literature review and a Delphi study of a panel of 16 experts on O&M.
Findings
Consisting primarily of conceptual papers and/or modelling papers, the extant literature identifies several challenges for O&M in the offshore wind energy sector. These challenges can be grouped into four categories: issues related with industry immatureness; distance/water depth; weather window; and policy issues. The Delphi study identified three other major issues that lead to increased O&M costs: too many predefined rules that limit development; lack of coordinated planning of the different services offered at the wind farms; and lack of a common approach on how O&M should be managed strategically.
Research limitations/implications
The present study is based only on Danish respondents. Future research needs to include various respondents from different countries to identify country-specific contingencies.
Practical implications
The paper provides an overview of the O&M issues in the offshore wind energy sector to prioritize where future resources should be invested and, thus, reduce O&M costs.
Originality/value
This is the first paper on O&M issues that bridges both literature studies and industry expert opinions.
