The biggest ocean-based wind farm is currently being constructed in the North Sea. ABB has the task of linking the new wind farm to the German grid – a task that requires effective water cooling.
“Continuous improvements are being made in the water-cooling system and Sapa have an active role in this,” says Pontus Mellung, who handles purchasing from Sapa at ABB’s HVDC division in Ludvika, Sweden.
German energy company EON is responsible for constructing the wind farm that will supply power to the German grid. The output from the wind farm is equivalent to that of the average coal-fired power plant, or half a Swedish nuclear plant.
ABB’s role in the project is to transfer power from the wind farm. This is one of the biggest single contracts for ABB in 2007, with a value of SEK 2.7 billion. The contract is for an HVDC Light system, a transmission technology in which ABB has a strong lead.
“It is proven technology, but this is the first time we are using it on our own offshore platform with an unmanned operating centre,”
explains Tommy Lövehagen, overall project manager at ABB.
“This requires other solutions, since offshore installations increase the need for automation and communications. The platform is 128 kilometres offshore. We have to be able to carry out most of the inspection and maintenance without travelling out to the platform. Information on status and any faults is sent to a manned centre onshore by fibre optic communication links.”
On the platform, electricity from the windfarm is converted from alternative current to direct current and then fed by cable to an onshore receiving station, where it is converted back to AC.
Electricity is converted at either end of the cable by converters known as valves. This process generates heat, which has to be carried away by cooling profiles made by Sapa in Finspång, Sweden.
“The high precision that is required for efficient cooling is achieved using profiles that are joined by friction stir welding (FSW),” says Rolf Pettersson, sales representative for cooling profiles at Sapa.
A large number of water coolers of different types are needed to keep temperatures down. Sapa therefore maintains close contact with ABB
so that products can be continuously developed. Numerous other aluminium products are also being supplied for the project.
“We’re working together to develop new products and to refine existing ones. A team from ABB meets up regularly with representatives of Sapa,” says Pontus Mellung.
According to Tommy Lövehagen there is a great deal of optimism about offshore wind farms:
“It’s the first time such a big installation has been built offshore and it’s important that it is successful. This is a growing market and we’re working very hard to establish a strong position in this field. We also have a unique technology for this type of project.”
Text: Mats Lundström