Report: Plug-and-Play Offshore Transformer Modules Cut Costs

The Siemens-led research partnership in Denmark has demonstrated that there are significant benefits to gain from introducing a simpler plug-and-play connection for offshore wind turbines, reports.

To improve offshore wind energy competitiveness, Siemens Wind Power, Øglænd System and ALL NRG are working on a project that seeks to reduce the cost of offshore transformer modules by making them simple to build, and easier and faster to install.

The new Offshore Transformer Module (OTM) plug-and-play concept, facilitated by Siemens Wind Power and supported by, is developed for 220kV connectors to offer simpler offshore wind installation. The project has made it possible to install a transformer and switchgear pack using a combination of straight connectors and electrical actuators. A transformer is ready to operate within hours, said.

The project also examined the design of and developed and tested prototype cable-handling tools and systems, cable stripping and a HVAC booster station guiding system. All these solutions are promising, said Jesper Møller, Head of Offshore Concept and Solutions at Siemens Wind Power.

“Our project demonstrates that, using relatively simple means, standard cables and materials, we can create a plug-and-play solution that allows us to connect a transformer to the station and power it up fast. It could in the long run make the current transformer stations redundant,” said Møller.

In the project description, Siemens estimated that a simpler transformer module with a plug-and-play connection can improve a future business model (CAPEX+OPEX) by DKK 300 million (EUR 40.3 million) per 400MW of offshore energy installed.

“It currently costs more than DKK 1 million to install a transformer module, including the cable-handling,” said Esben Rocatis Nielsen, Head of the Technical Department at ALL NRG.

“The new solution significantly reduces installation time, which not only minimises the risk of windy days that make installation work impossible, but also (and importantly) gets the turbine up and running and supplying energy to the shore quicker. The faster you install, the sooner you can connect your wind farm to the grid and produce power.” 

Fast and efficient installation is decisive to reducing costs, according to the developers. If you can reduce the time taken to connect and commission a wind farm, you can transport power ashore sooner. This in itself is a significant cost reduction.

Claus Vilhelmsen, Sales Director, Øglænd System Denmark, said: “Cable-handling and connecting booster stations to the wind farms and electricity grid are costly because each installation is unique. The newly developed plug-and-play solution significantly reduces costs while also ensuring rapid, efficient and precise transformer station installation.” has a coordinating role in the project. On behalf of the participating companies, this Danish cluster organisation compiled a single application that described the concept of simpler connection and faster production start. The Energy Technology Development and Demonstration Program (EUDP) backs projects that, through new and innovative energy technologies, can contribute to meeting Denmark’s national energy and climate goals.

Since the application was approved, Siemens has assumed technical leadership of the project group, while has taken care of administration and contact between EUDP and the project group.

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