Iberdrola : Andalusia substation now installed at german Wikinger offshore wind farm

It arrived in the Baltic Sea last Friday after a 14-day journey covering the 4,700 km from Cádiz

• This electricity distribution infrastructure weighing about 8,500 tonnes will be the energetic core of this renewable facility, which has a capacity of 350 megawatts and for which the overall budget is €1.4 billion.

• The Andalusia substation will be in charge of collecting all of the electricity produced by the wind turbines in the open sea - enough to meet the needs of 350,000 German homes and avoid some 600,000 tonnes of CO emissions into the atmosphere each year - and preparing it for transmission to the mainland

• Prior to the installation of the substation, the special crane vessel Oleg Strashnov spent a week assembling the three-piece structure that supports its weight

Last weekend IBERDROLA successfully installed the Andalusia substation at the Wikinger offshore wind farm, which is to be located in the waters of the Baltic Sea off Germany.

This electricity distribution infrastructure reached its destination last Friday, 35 km from the port of Mukran on the island of Rügen, after a 14-day journey covering a distance of 4,700 on the tug vessel Smit Sentosa. It arrived before the scheduled time and there were no incidents along the way.

The offshore substation, which was given the name 'Andalusia' at a ceremony held at the port of Cádiz in early August, will be used on a joint basis by IBERDROLA and 50Hertz, the operator of the electricity system in the Baltic Sea off Germany.

All of the structural components of the substation - with the exception of the electrical equipment - were manufactured at Navantia's shipyard in Puerto Real (Cádiz). The foundation, which is referred to as a 'jacket', started its journey on a barge on 10 August. The two 'topsides' followed on a different vessel a few days later.

Prior to the installation of the substation, the special crane vessel Oleg Strashnov spent just under a week assembling the three-piece structure that supports its weight.

First of all, the six-legged jacket was placed on top of the foundation piles that had been driven into the seabed previously. It was then fixed to the piles using a special type of concrete. Once the concrete had hardened, the two topsides were installed and attached to the jacket.

Once the topsides were assembled, it was time to start commissioning the electrical components in the substation, such as the transformers, switches and protection and control systems. Parallel to this, the uploading cable belonging to 50Hertz and the internal cable for the wind farm, which will connect the substation to the wind turbines, were also installed.

When the Wikinger wind farm is connected to the grid, the voltage of the energy produced by the wind turbines will be increased from 33,000 to 220,000 volts at the substation and then transmitted via the high voltage undersea cable across the 90 km distance to the Lubmin electrical substation.

The Andalusia substation weighs about 8,500 tonnes, which is heavier than the Eiffel Tower and the Statue of Liberty together. It will be the energetic core of the Wikinger offshore wind farm, a 350 MW renewable energy facility being built by IBERDROLA in German waters with an overall budget of some €1.4 billion. The Andalusia substation will be in charge of collecting all of the electricity produced by its wind turbines in the open sea - enough to meet the needs of 350,000 German homes and avoid some 600,000 tonnes of CO emissions into the atmosphere each year - and preparing it for transmission to the mainland

This major feat of engineering is designed by IBERDROLA to withstand the extreme weather conditions it will have to endure. It consists of two sections or superstructures, which will be used by IBERDROLA and by 50Hertz.

The Wikinger offshore wind farm will have an installed capacity of 350 megawatts (MW), provided by the 70 wind turbines with a unit capacity of 5 MW to be installed on the site covering an area of about 34 km. It is being developed by IBERDROLA in the Baltic Sea, where the water depth ranges between 37 and 43 metres. It is expected to be commissioned by the end of next year.

'Pull' effect of IBERDROLA on Spanish companies

In his speech at the ceremony to mark the delivery of this infrastructure, IBERDROLA's Chairman Ignacio Galán highlighted the 'pull' effect that IBERDROLA exerts on Spanish companies in this renewable initiative: 'The leading role of Spanish industry in this project is very clear: the substation and its platform were built at this Navantia shipyard, the 29 platforms for the turbines were built at the Navantia shipyard in the Ferrol Estuary, the piles that will fix these platforms in place and the masts of the turbines were built in Avilés by the company Windar from Asturias, and finally, the wind turbines themselves were built by Gamesa. In the case of Puerto Real, the contract has provided jobs for hundreds of people and over 120 companies from the area have been involved as suppliers'.

Technical features of the substation:

• 90,000 hours of engineering devoted to the design stage.
• First offshore wind farm to be built with two topsides.
• First substation designed using a jacket foundation with six pre-piled legs.
• Substation with an operating capacity that is fully automatic and remotely controlled.
• Steel structure almost 2.3 times heavier than that of a combined cycle power plant (4,500 tonnes vs. 2,000 tonnes).
• The cabling laid is about five times longer than that of a onshore substation (150 km vs. 32 km). To be more specific, the Spanish company installed 70 new megawatts (MW) in the months of June and July of this year, using this renewable technology in two of its strategic markets: United Kingdom and United States.