Name: DanTysk: Offshore Wind Farm Development and Operations in the North Sea
Address: DE

Overview

DanTysk is an operational offshore wind farm located in the North Sea, representing a significant component of Germany’s renewable energy infrastructure. The facility is situated within the German Exclusive Economic Zone (EEZ), positioned approximately 70 kilometres west of the island of Sylt, near the maritime border with Denmark. As a major wind energy installation, DanTysk contributes to the broader energy mix of the region by harnessing consistent wind resources characteristic of the North Sea basin.

The wind farm has a total installed capacity of 288 MW. This capacity is generated by an array of 80 wind turbines. Each turbine is a Siemens Wind Power SWT-3.6-120 model, with an individual nameplate capacity of 3.6 MW. The selection of the SWT-3.6-120 technology reflects the engineering requirements for offshore environments, balancing power output with structural resilience against marine conditions. The uniformity of the turbine fleet simplifies operational maintenance and grid integration strategies for the site.

Vattenfall serves as the primary operator of the DanTysk wind farm. As a leading energy company, Vattenfall manages the day-to-day operations, maintenance, and energy output optimization of the facility. The operational status of the farm is currently active, having been commissioned in 2014. This commissioning date marks the transition of DanTysk from a development project to a key contributor to the German offshore wind portfolio. The facility’s location in the North Sea allows for efficient transmission of generated electricity to the mainland grid, supporting regional energy demand.

The strategic placement of DanTysk near the Danish border highlights the international nature of North Sea energy resources. While situated in the German EEZ, its proximity to Denmark underscores the shared maritime environment and potential for cross-border energy cooperation. The wind farm’s operational parameters, including its 288 MW capacity and 80-turbine configuration, are consistent with mid-sized offshore wind installations developed during the early 2010s. These specifications enable DanTysk to deliver a steady output of wind-generated power, contributing to the decarbonization efforts within the German energy sector.

Development and Ownership History

The DanTysk offshore wind farm project originated with Geo Gesellschaft für Energie und Ökologie, which served as the initial developer for the site located in the North Sea. The project's early development phase involved securing the concession for the area situated 70 kilometres west of the island of Sylt, within the German Exclusive Economic Zone (EEZ) near the border with Denmark. Geo Gesellschaft für Energie und Ökologie played a pivotal role in the preliminary stages, laying the groundwork for what would become one of the significant offshore installations in the region.

Acquisition by Vattenfall

Vattenfall acquired the DanTysk project, transitioning it from the initial development phase led by Geo Gesellschaft für Energie und Ökologie to a major operational entity. Under Vattenfall's ownership, the project advanced through construction and commissioning, culminating in its operational status in 2014. The wind farm features 80 Siemens Wind Power SWT-3.6-120 turbines, each with a capacity of 3.6 MW, contributing to the total installed capacity of 288 MW. Vattenfall's management has overseen the ongoing operations of the facility, ensuring its integration into the regional energy grid.

Stake Sale to Stadtwerke München

Following the commissioning of the DanTysk wind farm, Vattenfall initiated a stake sale to Stadtwerke München, diversifying the ownership structure of the asset. This transaction allowed Stadtwerke München to secure a portion of the 288 MW capacity, enhancing their renewable energy portfolio. The sale reflects the strategic financial planning often employed in large-scale offshore wind projects to distribute investment risks and returns among key energy providers. Vattenfall retained operational control, maintaining the role of the primary operator for the facility.

Year	Event
Initial Phase	Project development by Geo Gesellschaft für Energie und Ökologie
Pre-2014	Acquisition by Vattenfall
2014	Commissioning of the 288 MW wind farm
Post-2014	Stake sale to Stadtwerke München

Technical Specifications and Infrastructure

The DanTysk offshore wind farm utilizes a fleet of 80 wind turbines manufactured by Siemens Wind Power. This configuration represents a standardized approach to offshore generation in the North Sea during the mid-2010s, balancing individual turbine output with array density.

Turbine Specifications

The SWT-3.6-120 turbines are three-bladed, horizontal-axis wind turbines designed for offshore environments. The "3.6" in the model name denotes the rated power output in megawatts, while "120" refers to the rotor diameter in meters. These turbines are mounted on monopile foundations, which are driven into the seabed to support the nacelle and rotor assembly. The specific technical parameters of the turbine model are detailed in the following table.

Parameter	Value
Manufacturer	Siemens Wind Power
Model	SWT-3.6-120
Rated Capacity per Turbine	3.6 MW
Total Number of Turbines	80
Total Installed Capacity	288 MW
Rotor Diameter	120 m
Foundation Type	Monopile

Grid Connection and Substation

Electrical energy generated by the 80 turbines is collected via underwater cables and transmitted to a central offshore substation. This substation is located on the SylWin transformer platform, which serves as the primary connection point for the DanTysk array. The platform steps up the voltage for efficient transmission across the North Sea seabed towards the German mainland grid. The location of the wind farm, approximately 70 km west of the island of Sylt, places it within the German Exclusive Economic Zone (EEZ) near the border with Denmark, influencing the routing of the export cables.

How does the DanTysk wind farm connect to the grid?

The DanTysk wind farm transmits its generated electricity to the onshore grid through a dedicated subsea cable system anchored by the SylWin platform. This platform serves as the primary offshore collection and transformation hub for the 288 MW of power produced by the 80 Siemens SWT-3.6-120 turbines. This location allows for efficient aggregation of power from the turbine array before long-distance transmission.

SylWin Platform and Subsea Cabling

The SylWin platform functions as the central node for the DanTysk interconnection. It collects the medium-voltage power from the individual turbine strings and steps it up to high voltage for efficient subsea transmission. The platform is connected to the onshore grid via a high-voltage direct current (HVDC) or high-voltage alternating current (HVAC) cable, depending on the specific grid integration strategy employed for the SylWin cluster. The subsea cable runs from the platform across the North Sea floor to the landing point on the island of Sylt. This cable infrastructure is critical for minimizing transmission losses over the 70-kilometre distance between the wind farm and the shore. The robustness of this cabling is essential for maintaining operational status in the often turbulent conditions of the North Sea.

Role of the Accommodation Platform

In addition to the electrical infrastructure, the DanTysk site includes an accommodation platform that supports the operational and maintenance activities of the 288 MW facility. This platform provides living and working quarters for the crew, including engineers and technicians from the operator, Vattenfall. The accommodation platform is crucial for ensuring rapid response times for maintenance and repairs, which is vital for maximizing the energy yield of the 80 turbines. It serves as a logistical base, reducing the need for frequent ferry trips from the shore, thereby enhancing the overall efficiency of the wind farm's operations. The presence of this platform underscores the integrated approach to managing large-scale offshore energy infrastructure in the German EEZ.

What are the operational challenges of offshore wind farms like DanTysk?

The operational profile of the DanTysk wind farm, located in the North Sea within the German Exclusive Economic Zone, presents specific logistical and engineering challenges inherent to offshore renewable energy infrastructure. As a facility operating 80 Siemens Wind Power SWT-3.6-120 turbines, the maintenance regime requires precise coordination to minimize downtime for each 3.6 MW unit. The remote location, situated 70 kilometres west of the island of Sylt, necessitates robust on-site support systems to ensure continuous power generation and efficient turbine servicing.

On-Site Accommodation and Logistics

A critical component of DanTysk’s operational strategy is the construction of a dedicated accommodation platform. This infrastructure element is directly inspired by the design principles applied to the Horns Rev 2 wind farm. The platform serves as a central hub for technical personnel, allowing engineers and maintenance crews to reside near the turbine array rather than relying solely on daily ferry transport from the mainland. This proximity significantly reduces the "weather window" dependency for minor repairs, as crews can respond to turbine alerts more rapidly than if they had to commute from the shore each shift.

The accommodation platform enhances operational efficiency by providing living quarters, control rooms, and storage facilities for spare parts and tools. By mirroring the successful model of Horns Rev 2, the operators at DanTysk have optimized the balance between capital expenditure on infrastructure and the long-term operational expenditure on labor and turbine availability. This setup is particularly valuable in the North Sea, where sea states can vary significantly, affecting the accessibility of individual turbine foundations.

Maintenance and Power Supply

Maintenance operations for the 80 turbines involve complex logistical planning. The use of diesel generators plays a vital role in the maintenance workflow. These generators provide auxiliary power to the turbines during servicing, allowing the main generator to be disconnected or the turbine to be placed in a specific operational mode without drawing excessive power from the grid or relying entirely on battery reserves. This ensures that the turbine can be kept in a stable state while technicians access the nacelle or the hub for inspections and repairs.

The integration of diesel generators supports the reliability of the 288 MW total capacity. By ensuring that each of the 80 Siemens SWT-3.6-120 units can be maintained efficiently, the operator, Vattenfall, can maximize the annual energy production. The operational challenges are thus managed through a combination of strategic infrastructure investment, such as the accommodation platform, and tactical use of auxiliary power systems to streamline the maintenance of individual turbine components in the harsh North Sea environment.

Why it matters

DanTysk represents a significant milestone in the development of Germany’s offshore wind energy infrastructure, particularly within the North Sea basin. As an operational facility with a total installed capacity of 288 MW, the wind farm contributes directly to the regional energy mix and the broader German strategy to diversify power generation sources away from traditional fossil fuels. The project is operated by Vattenfall, a major energy company that has played a central role in expanding offshore wind assets in the German Exclusive Economic Zone (EEZ). The commissioning of DanTysk in 2014 marked the entry of a substantial generation asset into the grid, helping to stabilize supply and increase the share of renewable electricity in the northern German states.

Strategic Location and Cross-Border Context

The geographical positioning of DanTysk is a defining feature of its operational and strategic importance. Located 70 kilometres west of the island of Sylt, the wind farm sits precisely at the border between the German EEZ and the Danish territorial waters. This proximity to Denmark is not merely geographical; it places DanTysk within a key corridor for North Sea energy interconnection. The border location facilitates potential grid integration and power exchange with neighboring Scandinavian energy systems, which are increasingly interconnected through high-voltage direct current (HVDC) links and alternating current (AC) networks. For energy analysts and grid operators, DanTysk serves as a case study in how offshore assets can leverage cross-border proximity to enhance grid stability and optimize energy trading between Germany and Denmark.

Technical Contribution to the Regional Grid

From a technical perspective, DanTysk’s configuration of 80 Siemens Wind Power SWT-3.6-120 turbines, each with a capacity of 3.6 MW, reflects the engineering standards prevalent during the mid-2010s offshore wind boom. The aggregate output of 288 MW provides a reliable baseload contribution during peak wind conditions, supporting the local transmission infrastructure on the Jutland peninsula and the Schleswig-Holstein coast. The use of established turbine technology from Siemens Wind Power ensured operational reliability and maintenance efficiency, which are critical factors for long-term asset performance in the harsh North Sea environment. By adding 288 MW to the regional capacity, DanTysk helped reduce the reliance on imported coal and natural gas power, thereby lowering the carbon intensity of the local energy mix. Its continued operation underscores the enduring value of early-generation offshore wind farms in Germany’s ongoing energy transition, known as the Energiewende.

DanTysk: Offshore Wind Farm Development and Operations in the North Sea