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A Simulation Study of Feeder-Based Installation Concepts for Offshore Wind Farms
Oelker, Stephan (University of Bremen) | Ait-Alla, Abderrahim (University of Bremen) | Lütjen, Michael (University of Bremen) | Lewandowski, Marco (University of Bremen) | Freitag, Michael (University of Bremen) | Thoben, Klaus-Dieter (University of Bremen)
ABSTRACT Conventional fossil fuels are becoming more expensive and cannot cover the rising global energy needs with the remaining reserves in the future. In this context, the relevance of offshore wind energy (OWE) has increased steadily because of high wind resource availability. However, the installation of an offshore wind farm is challenging and cost-intensive because of harsh weather conditions and limited availability of resources. Therefore, a great effort has been devoted to the study of new installation concepts such as feeder concepts. In this paper, a discrete event simulation study is presented to quantify the benefit of using feeder vessels in the installation logistics of offshore wind farms. The results show that the offshore feeder concept outperforms the conventional concept under certain conditions. INTRODUCTION Due to CO-emission and climate change, renewable energies are becoming more important. By using renewable energy, such as wind energy, it is possible to make the energy supply sustainable and climate-friendly. In particular offshore wind energy is of key importance for the success of the energy transition, since for instance in Germany, the theoretically available areas for onshore wind energy installations are typically limited in size and are often already built-up. As a result, the number of offshore wind turbines (OWTs) at sea has increased significantly in recent years. In the first half of 2016, the number of wind turbines has increased to 835 OWTs with a total output of 3,552.22 MW (Deutsche WindGuard 2016). In 2017, approximately 947 wind turbines with a total output of 4,108 megawatts were in operation in the German North Sea and Baltic Sea, and projects under construction or in planning show that the goal of the German federal government will be achieved with the same development of the number of erection sites (BWE Bundesverband Windenergie 2017). However, the feed-in tariff is going down and the tendering process of offshore wind farms (OWF) in general is realized by auctions. This leads to high market pressure and needs for new saving potentials, whereby harsh weather and sea conditions complicate the planning of the offshore installation process. Due to the existing weather and sea conditions, the construction of the OWE involves logistical challenges. Besides the harsh weather and sea conditions, the installation planning has to deal with limited resource availability. Furthermore, the focus in the next years will be on the installation of high power wind turbines (>= 6MW). The installation of these high power OWTs will essentially take place in deeper water depths (30 – 50 m), and thus in wind farms located in a distance greater than 50 km from the shore (Muhabie, Rigo, Cepeda, and D'Agosto 2018). This leads to significant delays and increased costs in the installation processes. Actually, the erection of OWF is carried out based on a rigid concept, in which the components are transported from production sites to the base port and from the base port to the wind farm location. In the process, different wind turbine components are shipped via waterways from the production sites to the base port. An installation vessel loads the components, sails to the offshore wind farm location and performs the installation. Currently, the share of logistics costs for the erection of OWF is estimated to be between 15% and 20% (Muhabie, Rigo, Cepeda, and D'Agosto 2018) (Dewan, Asgarpour, Jones, and Ouelhadj 2016). This is a result of the great uncertainties at sea, caused especially by unpredictable weather conditions, which make the installation of offshore wind turbines a complex and challenging planning problem. Therefore, a great effort has been devoted to the study of new installation concepts, such as the feeder concepts, which seeks to optimize the use of costly resources like installation vessels and base ports. For this reason, it must be determined which potentials can be raised with such concepts since the technical requirements causes further investment or development costs. For the monetary assessment, economic considerations in the form of investment calculations or cost and performance calculations come to their limits because of the complexity and the restrictions of the processes. A first study of feederbased installation concepts for OWF was presented in (Ait Alla, Oelker, Lewandowski, Freitag, and Thoben 2017). The authors introduced the base port-feeder concept, in which a feeder vessel supplies an installation vessel, called "Jack-Up barge" with nacelles, towers and rotor blades directly in the base port or at shallow waters. In this paper, we extend the work presented in (Ait Alla, Oelker, Lewandowski, Freitag, and Thoben 2017) and introduce another feeder-based concept (offshore feeder concept). For this reason, a simulation study about different installation concepts for offshore wind farms by means of a multi-agent discrete event simulation model is proposed. The aim is to quantify the benefit of an offshore feeder concept. The simulation model considers process times of different operations, weather restrictions and costs. Based on empirical and experimental results, the study performs a comparison analysis. Moreover, the proposed simulation study identifies factors, that affect the offshore feeder-based installation of OWF and investigates their influence on the installation performances.
- Europe > United Kingdom > North Sea (0.24)
- Europe > Norway > North Sea (0.24)
- Europe > Netherlands > North Sea (0.24)
- (2 more...)
- Health, Safety, Environment & Sustainability > Sustainability/Social Responsibility > Sustainable development (1.00)
- Health, Safety, Environment & Sustainability > Environment (1.00)
- Information Technology > Modeling & Simulation (1.00)
- Information Technology > Artificial Intelligence > Representation & Reasoning > Agents (0.48)
A Study of New Installation Concepts of Offshore Wind Farms by Means of Simulation Model
Ait-Alla, Abderrahim (University of Bremen) | Oelker, Stephan (University of Bremen) | Lewandowski, Marco (University of Bremen) | Freitag, Michael (University of Bremen) | Thoben, Klaus-Dieter (University of Bremen)
ABSTRACT Wind energy has become an established technology for the generation of electricity from renewables. However, in Germany, suitable areas for the installation of onshore wind power plants are limited or often already built-up. As a result, offshore wind energy farms will play a fundamental role in the generation of electricity from renewable energies in the future as well as for the energy supply in general. The installation of an offshore wind farm is challenging and cost-intensive due to harsh weather conditions and limited availability of resources. Accordingly, concepts for the installation of offshore wind parks have to be developed and evaluated. In this paper, we investigate the impact of different installation concepts on the logistic costs using a multiagent and discrete event simulation model. The results show that the size of the offshore wind farm, as well as the weather data, have a substantial impact on the selection of the installation concept. INTRODUCTION During the last decade, the relevance of offshore wind energy (OWE) has increased steadily. In 2015, the total cumulative installations of offshore wind turbines reached more than 10 GW. It remains notable that 92% of these global facilities have been realised in Europe (Pineda 2015). Compared to OWE, the suitable areas for the construction of new onshore wind power plants in Germany are often already used (Zheng, Li, Pan, Liu and Xia et al. 2016). In addition, offshore wind turbines (OWT) can produce significantly more electricity due to more constant and higher wind conditions at sea. As a result, OWE generation will become a major factor in the production of electricity from renewable energies in the future (Rohrig, Richts and Bofinger 2013). The development of wind power farms is also advancing in the German North Sea and Baltic Sea. Thus, the federal government's target of 6.5 gigawatts of installed offshore wind power performance seems to be realistic by 2020 (Deutsche WindGuard 2016). In the first half of 2016, the number of plants has increased to a total of 835 OWTs with a total output of 3,552.22 MW and projects under construction or in planning show that the goal will be achieved with the same development of the number of erection sites (Deutsche WindGuard 2016). At the same time, costs for the generation of energy on the water are significantly higher in comparison to other technologies, in particular, compared to onshore wind energy (Kost., Mayer and Thomsen 2013). According to estimates the total logistics costs for an offshore wind farm have a proportion of about 15-20% of the total investment costs (Dewan 2016). This is a result of the significant uncertainties at sea, caused especially by weather conditions that moreover are not predictable with respect to planning of tasks. It is assumed that a cost reduction is possible with regard to the electricity production costs of more than 3% in the entire installation process (Fichtner and Prognos 2013). The installation methods are also heavily dependent on the weather and sea conditions, which can lead to significant delays and increasing costs during the installation process. The installation of offshore wind turbines accordingly leads to a complex planning problem. In this context, the available resources must be utilised as well as possible, and further new concepts for the installation of offshore wind farms (OWF) must be developed and evaluated. In this context, it must be determined which potentials can be raised with such concepts since the technical feasibility causes further investment or development costs. For the monetary assessment, economics considerations in the form of investment calculations or cost and performance calculations come to their limits due to the complexity and the restrictions of the processes.
- Europe > United Kingdom > North Sea (0.24)
- Europe > Norway > North Sea (0.24)
- Europe > Netherlands > North Sea (0.24)
- (2 more...)
- Health, Safety, Environment & Sustainability > Sustainability/Social Responsibility > Sustainable development (1.00)
- Health, Safety, Environment & Sustainability > Environment (1.00)
- Facilities Design, Construction and Operation > Offshore Facilities and Subsea Systems (1.00)
- Information Technology > Modeling & Simulation (1.00)
- Information Technology > Artificial Intelligence > Representation & Reasoning > Agents (0.48)