Alpha Ventus wind turbines in the North Sea
Energy business #3: UK, a World of Possibilities
Wind energy: innovating in an emerging market
AREVA has designed a high power wind turbine specially adapted for use offshore. The group's activity includes the design, manufacture, assembly and commissioning of these wind turbines. The group also offers maintenance services over a period of five to ten years.
A pioneer in offshore technology, the group intends to become the leader in this emerging market. Nearly 250 M5000 turbines have been chosen to equip large European offshore parks.
Transforming the motive power of the wind into electricity
A wind turbine transforms wind energy into electrical energy.
It consists of the following elements:
- A mast, made up of 3 segments, supports the nacelle so that this can capture higher, and therefore stronger, winds.
- A nacelle, situated at the top of the mast, which houses the components necessary for operation of the turbine.
- The rotor, to which the three blades are fixed, begins to turn thanks to the force of the wind and so turns a mechanical shaft. The speed increaser increases the speed, and this energy is converted into electricity by the generator.
The surface area swept by the rotor is about the size of two football pitches!
The M5000, special technology
The wind energy industry has two distinct sectors, one terrestrial (or onshore) and the other marine (or offshore). Each relies on particular technology to overcome specific constraints.
AREVA is taking up a position in the fast developing offshore market with its M5000 wind turbines, turbines with a power of 5 MW specifically designed for the marine environment.
Their exclusive hybrid drive system guarantees compactness and reliability. The group designs, assembles, installs and commissions the turbines. It also designs and manufactures rotor blades, and offers maintenance services over a period of five to ten years.
Impressive dimensions:
- The mast can be as high as 130 meters.
- The rotor, to which 3 blades are fixed, reaches a diameter of 116 meters.
- Each blade weighs 16.5 tonnes.
- The mast supports the nacelle, the rotor and its three blades, that is, a total weight of more than 300 tonnes!
Alpha Ventus: a pilot project
In the summer of 2009, AREVA installed the first six M5000 turbines of the Alpha Ventus project in the North Sea. This is the first German wind energy park to be constructed out at sea.
The main phases of this pilot project - construction, assembly, operation and connection to the power grid - have provided the Alpha Ventus research committee with initial feedback. This will be used in the development of the future parks.
- The blades are manufactured by a subsidiary of AREVA in Stade, Germany. They are 56.3 m long.
- The main components - foundations, mast segments, nacelles, rotors and blades - were transported to the port of Eemshaven in The Netherlands, near the Alpha Ventus park.
- Once on site, the foundation (weighing more than 700 tonnes) is raised by a self-elevating platform equipped with a crane and transported to the anchoring point. Its structure is in the shape of a tripod, which is a major innovation and a world first.
- The 3 legs of the tripod are "bolted" onto the sea bed by piles 35 to 40 m long. The piles are cemented to the structure of the foundations.
- Once the foundations are in place, the segments of the steel tower, the nacelle and finally the rotor are fitted.
Other innovative projects
AREVA has signed a contract with Wetfeet Offshore Windenergy to supply 80 M5000 turbines of a value of over 800 million Euros for the Global Tech 1 offshore wind farm, as well as maintenance services and operations.
AREVA has also signed a Memorandum of Understanding for the provision of forty turbines for the Borkum West II wind farm (200 MW) - the second phase of the Alpha Ventus wind farm.
Finally, the group has been chosen for the construction of the first offshore project in France along the Albâtre Coast (105 MW).
