Iberdrola, a Spanish renewable energy firm, and 50Hertz, a German transmission system operator, have agreed to collaborate on the design, installation, and commissioning of the offshore substation for the Baltic Eagle wind farm, which is being developed in German Baltic Sea waters.
The jointly used offshore substation will house the technical equipment collecting the electricity produced by the wind turbines and will connect to the onshore transmission grid in Lubmin, Germany.
Iberdrola also said it had awarded contracts to the joint venture Iemants-Fabricom, responsible for the manufacturing of all structural elements of the substation, and to marine contractor Heerema, who will transport and install the substation on the Baltic Eagle site. Siemens Gas and Power is responsible for the delivery of all main electrical equipment for Iberdrola`s low-voltage part of the OSS.
The substation will consist of a foundation and a topside housing the transformers as well as electrical equipment. The four-legged steel jacket foundation weighs approximately 2,900 tonnes and will be fastened with two hammered piles at each leg. The topside consists of a closed multi-story module of 5 decks with a total estimated net weight of around 4,250 tonnes.
"Fabrication is already progressing at different locations in Europe and platform manufacturing has already started at Belgian yards. Sail out to the site is planned for 2022, while completion of the offshore installation and commissioning is expected to take place in 2023," Iberdrola said.
When the Baltic Eagle wind farm is connected to the grid, the wind turbines will deliver electricity via the inter-array cables to the offshore substation where it is then transformed from 66 kV to 220 kV and transmitted via two high voltage subsea cables across the 90 km distance to the landing point at Lubmin.
"The substation is one of the key elements of the wind farm, tasked with collecting and exporting the entire electricity produced by 50 wind turbines -estimated to account for ca. 1.9 TWh per year. With this energy production it will be possible to sustainably meet the demand of 460,000 homes and to avoid the emission of 800,000 tonnes of CO2 into the atmosphere each year," Iberdrola said.
The Baltic Eagle offshore wind farm is located northeast of the Rügen island off the Pomeranian coast in the Baltic Sea in a water depth of 40-45 meters. Iberdrola was awarded 476 MW of capacity during the transitional auction held in 2018.
The wind farm will comprise 50 wind turbines of 9.525 MW capacity to be installed on monopile foundations and will cover an area of 40 km2. Commissioning is expected in 2024.
Reuters in March reported that due to an increased interest in renewables asserts, Iberdrola was getting unsolicited bids for some of its wind farms, including the 476 MW Baltic Eagle project.
Citing unnamed sources, Reuters said that the company was looking for partners to finance the construction of Baltic Eagle, but it was aiming to retain full ownership. Iberdrola did not comment on the Reuters report.