TenneT is currently exploring modular and scalable offshore subsea technologies as potential next innovative step to simplify large scale offshore wind grid connection systems and enabling further technical options for the offshore grid topology. As a first of a series of relevant innovation steps, a subsea power transformer shall be developed with the goal to have a full-scale prototype ready until 2028.

The awarding client is TenneT Offshore GmbH.

The objective of this Project is to develop a HVDC SUBSEA Transformer, which is currently not available on the market and cannot be achieved by incrementally improving currently available technologies. This HVDC SUBSEA Transformer system shall be a locally detached part of an HVDC system, ideally in or adjacent to offshore wind park areas which can be used in the TenneT offshore connections or future offshore grids.

The modular system shall comprise in its core components basically a ground connecting installation plate (mud mat), an assembly frame for the electrical high voltage equipment, a transformer compatible to existing state of the art HVDC technologies, busbars, dry/wet mat-ed connectors, instrumentation and controls as well as an 400kV AC cable capable to with-stand HVDC offset induced voltage levels.

The Parties enter into an innovation partnership, which foresees the following phases:

1. Research & Development (R&D) Phase

(a) Basic Design

(b) Detailed Design

(c) Prototype built and Testing

2. Commercial Phase

The phases are subdivided by setting intermediate goals. On the basis of the intermediate goals, the client can decide at the end of each development stage whether to end or continue the innovation partnership.

Upon successful completion of the Phase 1 (c) and thus of the R&D Phase as a whole, TOG shall have the right to conclude the Framework Agreement with the Contractor for the Commercial Phase. The Contractor is obliged to conclude a corresponding Framework Agreement with TOG.

There is no obligation for the contracting authority to award individual contracts under the framework contract. In addition to the Client, affiliated companies within the meaning of Section 15 of the German Stock Corporation Act (AktG) or other companies shall be able to access and use the respective phases (both the R&D phase and the performance phase) as well as the results achieved in each case as "Associated Partners". These "associated partners" shall be entitled to access and use the results accordingly.