Siemens sees 30% lower costs for offshore wind grid connections

German industrial group Siemens AG (ETR:SIE) on Monday unveiled a new direct-current solution for connecting offshore wind turbines to the grid which can lower costs by as much as 30%.

Presented at the National Maritime Conference in Bremerhaven, the new Siemens platform housing the transmission technology is much smaller and more compact than the large central converter platforms which are usually used.

The platform involves a direct-current cable that can connect several of these platforms sequentially in a wind farm and then route them to an onshore transformer substation.

The core of the new transmission technology consists of diode rectifier units (DRU), a transformer, smoothing reactor, and the rectifier – all combined in one tank. The use of the DRUs and the encapsulated DC-CS direct-current switchgear decreases the installation space by more than 80% compared with air-insulated technology.

The volume of the platform structures is reduced by four-fifths, and the weight is cut by two-thirds. As a result, costs are reduced by more than 30 %, Siemens said in a statement, adding that the new solution also enables transmission capacity to be increased by one-third, while transmission losses fall by one-fifth.

"As the only provider on the market, we have already successfully commissioned four offshore direct-current connection projects. Our new solution will play a major role in decreasing the cost of offshore wind power below ten cents per kilowatt hour by 2020. This is how we plan to make the direct-current technology used in Germany more interesting to other markets, too," said Jan Mrosik, CEO of the Energy Management Division at Siemens.

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