Offshore wind energy: Rising wind power activity observed in French waters

EDF, in partnership with Alstom and Dong, has won the major part of France’s first offshore wind farm tender, the first round in a series designed to kick-start the offshore sector in France. These projects are intended to help reduce the gap in renewable energy capacity with Germany, Spain and (in terms of offshore wind turbines) the UK, as well as reduce its dependence on nuclear power.

France’s onshore wind power generation currently meets 2.5% of consumption with 7000 MW installed, far behind Germany, the European Union’s top wind energy producer with 28,000 MW. But even with the planned offshore wind farm projects, France has a lot of catching up to do, according to a European Wind Energy Association (EWEA) report published in November. The report showed that total installed offshore wind farm capacity in Europe in 2020 would be 40 GW, compared with less than 3 GW at the end of 2010. Britain already has current and planned projects for 47 GW and Germany for 31 GW.

Winners

EDF won three of the tenders, while a fourth was won by Spanish renewables major Iberdrola in partnership with France’s state-owned nuclear company Areva. The two consortia will build 2000 MW of offshore wind farm capacity, with an investment of 7 billion euros ($9.1 billion),

EDF won the tenders for sites at Saint-Nazaire, Courseulles-sur-Mer and Fecamp, while Iberdrola and Areva will build a fourth wind farm at Saint-Brieuc. Power production at the four sites is scheduled to start in 2020.

‘This decision will lead to the development of a new industrial sector with a global reach, with 10,000 jobs created, and position France among the leaders of the offshore industry,’ energy minister Eric Besson told a news conference on 6 April.

The French government launched the tender last July, for a maximum capacity of 3000 MW by 2015, as part of a plan to increase its renewable power to meet 23% of domestic energy demand by 2020. The remaining 1000 MW is expected to be allotted later this year when France’s GDF Suez and Germany’s Siemens, which were unsuccessful in a bid to build an offshore wind farm at a fifth site at Le Treport, can hope to find their project included in the second tender package, according to a statement from M. Besson.

The consortium that won the tender for the development of the Saint-Brieuc (Cotes-d’Armor) wind farm off the Normandy coast is led by Iberdrola and EOLE-RES. It was the most competitive field with three different technologies proposed. It will contain 100×5 MW Areva M5000 turbines and is scheduled to enter into operation between 2017 and 2019.

These tenders offered what is probably a unique opportunity to develop a wind turbine industry based on French technology, built and assembled in France, employing a substantial number of local industrial contractors and benefiting from technological partnerships with various bodies. The EDF project alone will involve nearly 200 suppliers to the offshore wind turbines sector.

The Saint-Brieuc site

The selection of the Areva M5000 WTG by Iberdrola and RES is likely to have been influenced by a recognition of Areva’s experience over some years in offshore installations. In the North Sea, Areva started up the Alpha Ventus pilot wind farm in 2009 and, by the end of 2013, will have installed more than 120 offshore turbines.

To meet this new demand Areva will create two plants at Le Havre, one to manufacture turbines and the other for blades. This industrial base is well placed to supply the largest offshore wind power market in the world, the Channel and the North Sea. The company’s wind power activities are likely to create some 2000 jobs, through its network of partners and suppliers throughout France, mainly concentrated in Brittany. Iberdrola and RES have signed agreements with other French industrial players, including STX in Saint-Nazaire, to build the wind turbine foundations.

Alstom’s new giant

‘These projects, corresponding to up to 1500 MW of new installed capacity, go hand in hand with an ambitious industrial plan which should create about 7500 direct and indirect jobs, notably with the manufacturing of Alstom’s Haliade 150 wind turbine,’ said EDF and Alstom in a joint statement.

A key factor in Alstom’s success, aside from the fact of being a France-based company, would have been the company’s promise to establish up to four plants in north-western France through an investment of 100 million euros to support the production of the turbines in the event of a successful bid. Now Alstom plans to establish the four factories (they will actually be four cluster sites) to produce components for and assemble the WTGs in the port areas of Saint-Nazaire (Loire-Atlantique) for the nacelles and alternators, and in Cherbourg (Manche), in partnership with LM Wind Power, for the blades and towers.

As stated earlier, the EDF consortium plans to install Alstom’s Haliade 150, the largest offshore wind turbine in the world with a rotor diameter of nearly 150 metres. The prototype was inaugurated on 19 March at Carnet, St Nazaire, at a ceremony attended by the energy minister, M. Besson. Although the largest, the new machine is not the most powerful offshore WTG. That honour belongs to REpower’s 6.15 MW unit installed in March at Thornton Bank.

The 6 MW unit was developed specifically as a response to the French government’s call for tenders in July 2011. In preparation for its certification, the first Haliade 150 will undergo a series of year-long tests on land at the Carnet site, before a second turbine is placed in the sea off the Belgian coast in autumn 2012. Pre-series production is planned for 2013 with production in series due to start in 2014.

The Carnet site, located near Saint-Nazaire on the shores of the Loire estuary, was chosen for its geological characteristics which are very similar to the submarine environment in which the wind turbines will eventually be installed. The 25 metre sub-structure (known as the jacket) was installed on pillars driven more than 30 metres into the ground on which the 75 metre high tower was then mounted, its nacelle towering over the landscape 100 metres from the ground. The wind turbine and its support structure have a total combined weight of 1500 tons.

The first nacelle for the Haliade 150 was assembled at Saint-Nazaire, in a temporary pre-series workshop which will produce about 40 units over the next three years. The second unit is currently being assembled there. About 40 Alstom engineers and operators are employed in these assembly operations.

Besides the industrial cluster to be developed by Alstom, the consortium plans to establish, in the ports of Saint-Nazaire, Brest, Cherbourg and Le Havre, up to eight sites at which the foundations for the wind turbines will be built, as well as four operation-maintenance centres in the nearby ports of La Turballe, Saint-Quay-Portrieux, Caen-Ouistreham and Fecamp, thereby creating an additional 2500 jobs. The entire project will create a total of nearly 7500 jobs.

Design challenges

To meet the severe challenges posed by the marine environment, and to improve the competitiveness of offshore wind power, Alstom has aimed at a simple, robust and efficient design. It will function without a gearbox (ie by direct drive) and is fitted with a permanent magnet generator, to reduce operating and maintenance costs. It employs Alstom’s ‘Pure Torquer’ technology which protects the generator by diverting unwanted stresses from the wind to the turbine’s tower. And it is claimed to offer more efficiency with its 150m rotor (the 73.50m blades are the longest of any WTG available) because of its improved load factor.

Initial testing will be carried out onshore. Analysis of the turbine’s power curve to determines its capacity to produce electricity efficiently according to wind availability, is central to this certification procedure. These tests will also, once additional sensors have been installed, enable validation of the various simulations (stress, temperature, life span) carried out during the Haliade 150′s research and development phase.

The electrical equipment installed in the tower (converters, transformers, low-voltage electricity network, and computer data processors and communications networks) will also undergo advanced validation tests. The generator will be subjected to tests which measure operating temperature, vibrations, current and voltage. After that the turbine’s various mechanical components will be tested for vibration, stresses (notably for the blades) and reaction times. Lastly, and still during this onshore test phase, the turbine’s global performance and piloting software parameters will be analysed.

Offshore testing will begin in autumn 2012, allowing the testing of various aspects of maintenance and connection under real operating conditions.