Wind farms

This section provides information on offshore wind farms in the area of the German Exclusive Economic Zone. The wind turbines are connected to a transformer platform via the so-called internal cabling. On the transformer platform, the electricity produced in the park is transformed to a voltage level of 155 kV. From there it is forwarded to the converter platform of the grid operator, where the electricity is converted for transport on land (see also Grid connection systems).


The first offshore wind turbines had a capacity of 3.6 to 5 megawatts (MW). Larger rotors and more stable substructures have led to an increase in performance over time. Currently, capacities of at least 8 MW are the standard. However, it is to be expected that the capacity of offshore wind turbines will continue to increase in the coming years.

Foundation structures

Offshore wind turbines are currently mainly built on so-called monopiles. These are steel tubes that are rammed into the seabed and on whose upper end the towers and turbines are mounted. As the water depth increases and the wind turbine becomes heavier, multi-leg structures are used as an alternative. During ramming, considerable noise is generated, which can affect the underwater animal world, especially marine mammals. A number of alternative foundation types are therefore being developed or are even being tested. The diagram gives an overview of the various foundation structures.

Pilot plants

In order to promote innovative developments in offshore wind turbines, the legislator has issued special provisions for so-called pilot plants (see Part 5 of the Wind Energy at Sea Act). Pilot plants are the first three offshore wind turbines of a type with which an essential innovation that goes far beyond the state of the art is demonstrably tested. The innovation can in particular pertain to the generator output, the rotor diameter, the hub height, the tower type or the foundation structure.

Innovative foundation structures are currently being tested, namely so-called suction bucket foundations. Such foundations consist of a cylindrical open steel foundation that is sucked into the ground with the opening facing downwards by creating a vacuum.

Approval regime

For the construction of an offshore wind farm, the project-executing entity requires a permit. The competent authority is the Federal Maritime and Hydrographic Agency (BSH). The construction of the wind turbines and the transformer platform is usually applied for and approved as one project. Due to the high complexity of these projects, the legislator has given the BSH the opportunity to permit individual measures for construction or the commissioning subject to individual approval. As a result, part of the official review is shifted to the enforcement procedure.

Since 1 January 2017, the legal basis for approval has been the Wind Energy on Sea Act (WindSeeG). Before the Wind Energy at Sea Act came into force, approval was granted on the basis of the Offshore Installations Ordinance (Seeanlagenverordnung). The WindSeeG and the Offshore Installations Ordinance stipulate that a planning approval procedure must be carried out before the official approval is granted. Only in exceptional cases can such a procedure be waived and a so-called plan approval be granted. As a rule, an environmental impact assessment must also be carried out as part of the planning approval procedure. This means that the public must be involved and it must be carefully considered whether the environmental impacts associated with the project are acceptable. The planning approval is accompanied by a number of ancillary provisions that ensure that construction and operation do not have a negative impact on the safety of shipping and air traffic or on the marine environment.

For the implementation of the planning approval procedure, the developer must submit several documents and drawings. The following overview of the minimum application and planning documents and the associated annexes contains a detailed list for projects on areas that have not been centrally pre-surveyed.

The plan may only be approved if certain requirements are met. These include, among other things, the so-called declaration of commitment for the surrender and transfer of ownership of the wind farms to any subsequent users in the event that the plan approval decision becomes invalid. The BSH has prepared a form for this purpose, the use of which is mandatory: (Formular Verpflichtungserklärung gemäß § 90 Absatz 2 WindSeeG).

Enforcement procedures

Once the planning approval has been issued, the project is subject to supervision by the BSH. If necessary, the BSH may issue orders to ensure proper implementation. In particular, technical stipulations according to the standard design, which specifies which specific certified documents are to be submitted to the BSH, are part of the enforcement.