Iberdrola's Windanker offshore wind farm in the Baltic Sea is now feeding electricity into the German grid, according to transmission operator 50Hertz, which has completed commissioning tests for the Ostwind 3 grid connection.

The Windanker offshore wind farm, developed by Spanish utility Iberdrola in the Baltic Sea, has started feeding electricity into the German grid. Transmission system operator (TSO) 50Hertz announced the milestone on August 31, stating it had built the Ostwind 3 grid connection linking the wind farm to the national power network.

Commissioning tests completed

According to 50Hertz, final commissioning tests were carried out in coordination with Iberdrola, and the majority of the wind farm's 21 turbines are now feeding electricity into the German high-voltage grid. Power flows through the Jasmund offshore platform, a subsea and land cable connection roughly 100 kilometres long, before reaching the new Stilow substation near Greifswald. These developments come as the global offshore wind sector continues to record operational milestones, from new capacity coming online to technical incidents, as recently illustrated by Japan's onshore wind auction capped at 14 yen per kWh and Ørsted shutting down a turbine following a fire.

The Jasmund offshore platform was built by the HSI joint venture, comprising HSM Offshore Energy, Smulders and Iv, before being installed in the Baltic Sea earlier this year by Heerema Marine Contractors. The binding completion date for the Ostwind 3 connection is the end of September, according to 50Hertz, while full commissioning of the Windanker wind farm is scheduled for the fourth quarter of 2026, according to information Iberdrola shared on its website.

A 315 MW capacity powered by 21 turbines

Windanker, with a total capacity of 315 MW, will comprise 21 Siemens Gamesa SG 14-236 DD wind turbines, each fitted with the manufacturer's Power Boost technology, enabling roughly 15 MW of output per unit. Turbine components began arriving earlier this year at the Mukran Port on Germany's Baltic Sea coast, where they were pre-assembled before offshore installation.

In May, DEME said its new jack-up vessel Norse Energi was preparing to work on offshore wind projects in the Baltic Sea and North Sea, with its first assignment on Windanker scheduled to start in June 2026. DEME has been installing the Windanker turbines since acquiring Havfram, the company that was awarded the installation contract in 2024.

Part of Iberdrola's Baltic Hub cluster

The 315 MW offshore wind farm, being built northeast of the island of Rügen, is part of Iberdrola's Baltic Hub, an offshore wind farm cluster with a combined installed capacity of around 1.1 GW. The cluster also includes the company's Wikinger and Baltic Eagle offshore wind farms, both already in operation.