Ontology | Virtual City Model

Introduction

Offshore wind turbines represent an important technology for generating renewable energy technology and use the power of the wind to generate clean and sustainable electricity. Offshore wind turbines are complex systems of components carefully designed to withstand the demanding environmental conditions of the sea and wind. The construction of offshore wind turbines requires a multifaceted approach that includes mechanical, electrical and structural principles. The towering structures are made up of various key components, each playing a crucial role in the overall functionality of the system. This report focuses on the development of a parametric model for offshore wind turbines for different environmental conditions. Two significant high-performance criteria (HPC in the following) are energy output and structural stability. The parametric model provides a straightforward approach for different design options, which are required due to changing wind loads, water depths and soil conditions. Figure 1 shows a schematic representation of offshore wind turbines with different foundations.

Fig. 1: Schematic representation of an offshore wind turbine with different foundations [6] — **Fig. 1: Schematic representation of an offshore wind turbine with**
**different foundations [6]**

The Federal Republic of Germany’s national goal of becoming one of the first climate-neutral industrialized countries to try by 2045 calls for an energy transition in Germany. Wind power is an important instrument for achieving this goal. By 2030, offshore wind energy should amount to at least 30 gigawatts (hereinafter GW), by 2035 at least 40 GW and by 2045 at least 70 GW. [2] According to [3], the current expansion of wind power is around 23% below the desired plan. In practice, these goals and necessity mean that wind turbines are becoming larger and wind farms are being built in deeper waters, as the wind speeds are higher there and therefore greater energy production per system is possible. While in 1991 an offshore wind turbine was able to harvest around 0.45 MW, in 2017 it was already 8 MW — and the trend is rising. [1] [4] To meet the requirements of high wind speeds, harsh marine environments, dynamic soil properties and corrosive salt water, the system design of an offshore wind turbine must always be adapted individually (or per wind farm). [4] Different support structures and rotor diameters and corrosion protection techniques must therefore be taken into account (see Figure 2).

Figure 2: Evolution of wind turbine sizes within the last 26 years.[1] — **Figure 2: Evolution of wind turbine sizes within the last 26 years. [1]**

The research report from [7] captures a very detailed engineering approach that is looking for design solutions to allow certification of offshore wind turbine design. In this report, an approach to capture systematically the system in its components and interrelations is provided (see Figures 3 and 4).

What is the purpose?

The ontology is developed to demonstrate an example of the conceptual design of offshore wind turbines to provide an easy-to-understand design framework and make this much-needed renewable energy generation technology more accessible. In addition to the various shown system elements, an attempt is also made to illustrate their interrelationships.

What is the scope?

The domain shows a concept for offshore wind turbine systems in different water depths and soil conditions. The ontology also includes information like the structure, the components, and the materials. In this ontology, the scope will be to show three different offshore wind turbines with different foundations.

Who are the intended users?

The intended end-users are engineers, researchers, and construction and maintenance contractors for offshore wind turbines or renewable energies. With the use of this ontology, they can access comprehensive information about the system, its components, and materials and the different foundation types, which are necessary for different water depths.

What is the intended use?

The intended use is to assist in designing different types of offshore wind turbines. In the ontology, it is possible to add a lot more details — f.e. facts about materials or corrosion protection.

An extension of the domain could open up the possibility of adding additional information about, for example, the failure rates of the components. This could be used further to carry out life cycle analyses or maintenance
planning. The development of an ontology always lacks a universal methodology; each approach contributes to an ontology with improved clarity, understandability, and error resolution. By [5], an essential aspect of ontology creation is to establish boundaries, preventing user overwhelm or confusion. They provide a wide array of suggestions that can be employed during ontology development.

Components

Figure 3: Schematic representation of a system recording of the off- shore wind turbine. [7] — **Figure 3: Schematic representation of a system recording of the off-**
**shore wind turbine. [7]**

Ontograf

**Figure 4: Ontology of the offshore wind turbine created with Protegé.**

Engineering Examples

Optimizing Offshore Wind Turbine Foundation Design:

Scenario: A project involves the installation of offshore wind turbines in an area with varying seabed conditions and water depths. Engineers need to optimize the foundation of design to ensure stability and efficient energy production.
Use Case: The ontology serves as a guide for engineers, providing insights into suitable foundation types and materials based on seabed characteristics and water depths. It assists in selecting the most appropriate design elements, such as pile types and dimensions, considering factors like water depth and soil properties. Engineers could utilize ontology to create a parametric model for structural analysis, ensuring the optimized foundation design meets the required performance standards.

Integration of Advanced Monitoring Systems for Offshore Wind Turbines:

Scenario: A wind farm operator wants to implement advanced monitoring systems on offshore wind turbines to enhance performance monitoring and maintenance efficiency.
Use Case: Engineers use the ontology to understand the components and technologies available for advanced monitoring systems. The ontology offers insights into sensor types, communication protocols, and data analysis methods suitable for offshore wind turbines. By utilizing the ontology, engineers design a comprehensive monitoring system, considering factors like turbine health, environmental conditions, and predictive maintenance needs (The ontology needs to be expanded for this case).

References

[1] Afewerki, S., 2019. Firm agency and global production network dynamics. European Planning Studies 27, 1483–1502.

[2] Deutschland, B., 2023. Mehr energie aus erneuerbaren quellen -energiewende beschleunigen.

[3] GmbH, Z.O., 2023. Energiemonitor – die wichtigsten daten zur Energieversorgung.

[4] Goudarzi, N., Zhu, W., 2012. A review of the development of wind turbine generators across the world, in: ASME International Mechanical Engineering Congress and Exposition, American Society of Mechanical Engineers. pp. 1257–1265

[5] Noy, N.F., McGuinness, D.L., et al., 2001. Ontology development 101: A guide to creating your first ontology.

[6] Petrini, F., Manenti, S., Gkoumas, K., Bontempi, F., 2010. Structural design and analysis of offshore wind turbines from a system point of view. Wind Engineering 34, 85–107.

[7] Vorpahl, F., Schwarze, H., Fischer, T., Seidel, M., Jonkman, J., 2013. Offshore wind turbine environment, loads, simulation, and design. Wiley Interdisciplinary Reviews: Energy and Environment 2, 548–570.

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