08 May 2017
The Siemens partnership in the EUDP Project has demonstrated that there are significant benefits to gain from introducing a simpler plug-and-play connection for offshore wind turbines.
As offshore wind turbines and offshore wind farms have grown, transformer platforms have grown accordingly. Today, many transformer platforms are so large and complex that the cost of the transformer platform itself amounts to a significant part of the total cost of deploying an offshore wind farm.
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 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 Offshoreenergy.dk, 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.
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, says 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," says Jesper Møller.
Faster off the mark
Fast and efficient installation is decisive to reducing costs. 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.
"It currently costs more than DKK 1 million to install a transformer module, including the cable-handling," says 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," he says.
Claus Vilhelmsen, Sales Director, Øglænd System Denmark, sees similar benefits:
"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," says Claus Vilhelmsen.
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 per 400 MW of offshore energy installed.
Offshoreenergy.dk has a coordinating role. On behalf of the participating companies, OEDK 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 OEDK has taken care of administration and contact between EUDP and the project group.
The HVAC Booster concept cooperation is a textbook example of how to reduce costs through innovation," says Director of Renewables Hans A. Pedersen from Offshoreenergy.dk.
"When problem-owners work with problem-solvers, they create ground-breaking concepts, techniques and methods. When specialists pool their expertise, new, innovative, cost-saving solutions come to light," says Hans A. Pedersen.
Benefits of the OTM concept
- Rapid installation of the transformer module onto a foundation dispenses with the need for a separate transformer foundation and simplifies the transformer system itself.
- The back-to-basics transformer module design saves time in the design phase and lowers both production and maintenance costs.
- Simpler installation logistics reduces waiting time.
- The lightweight transformer module means that there is no need for very expensive heavy lifting cranes.
- Much simpler installation and faster commissioning – the wind farm produces power sooner.
- Guided plug-and-play connection reduces the risk of errors.
- Fewer transformer parts mean that replacement is easier in the event of a breakdown.
- Fewer turbines fail due to a defect on a transformer.