REpower Offshore wind turbines at Thornton Bank and alpha ventus achieve first class operational results

Almost one year after final commissioning of the Thornton Bank wind farm in Belgium, REpower Systems AG (WKN 617703) is in a positive mood.

The availability of the six REpower 5M wind turbines has been consistently above 97% over a period of six months, and with that – despite the adverse conditions in the open seas – at the level of onshore wind turbines. Since the wind turbines were officially commissioned, over 4,000 full load hours have been recorded per wind turbine.

The six wind turbines installed by REpower in the German alpha ventus wind power test field have been delivering positive results in the first weeks and months of operation and are currently working excellently as well. Several of the wind turbines installed at this wind farm have already completed their operational trials.

The initial phase of the Thornton Bank wind energy project with six REpower wind turbines was officially inaugurated at the end of June 2009 and, for the remainder of the year, achieved a technical availability rate of 94%.

The wind farm is located 28 kilometers off the Belgian coast in waters between 12 m and 27 m deep, making it one of the first such wind farms to be located so far offshore. Of course, this makes service particularly challenging.

REpower Chief Technology Officer (CTO) Matthias Schubert says: “We have deliberately prepared ourselves for these more difficult access conditions. Thanks to continuous improvement measures in service, we have managed to raise the technical availability for the current year to over 97% – a peak value that even many onshore wind energy systems cannot emulate.”

This was enabled through the ongoing optimization of the maintenance concept and the resulting reduction of downtime during inspections. Faults are immediately identified by a Permanent Monitoring System (PMS) and then quickly rectified by locally based service technicians from REpower Benelux.

A team of specialists works in parallel to the service technicians to ensure that each individual fault type is permanently eliminated. As a result, 4,000 full load hours were achieved even in the first year of operation – a figure that would be impressive enough even for onshore sites.

“This proves that we can expect much more wind power offshore than onshore and, as a result, much higher power outputs,” adds Schubert.

REpower was also able to post positive output figures for the alpha ventus wind farm. As Schubert says: “Our systems there are running without any problems and have proved their worth at the test site. The experience that we have gained with more than two dozen turbines at coastal onshore and offshore locations since the setup of the first prototype in 2004 has proved extremely useful.”

The design of the REpower offshore systems is also adapted to the special conditions associated with operation on the high seas. “Our offshore wind turbines are designed to be extremely maintenance-friendly so that all large system components such as the gearbox can, if necessary, be repaired on site – that is in the open sea far away from the coast – without the need for large pieces of equipment,” says Schubert.

REpower Systems AG is one of the leading turbine producers in the German wind energy sector with a market share in excess of 10%. REpower Systems AG is one of the leading manufacturers of wind turbines for onshore and offshore applications. REpower defines itself as a technology company whose operations are characterized primarily by effective business results, sensitively to social issues and ecological responsibility.

REpower – founded in 2001 and listed on the stock exchange just one year later – focuses on the development, production and installation of multi-megawatt wind turbines. The product portfolio comprises several types of wind turbines with rated outputs ranging between 2.05 and 6.15 megawatts.

To date, the internationally operating wind turbine producer headquartered in Hamburg, Germany, can call on the production, projecting and construction experience gained for more than 2,000 wind turbine projects. REpower’s 1.5-megawatt MD 70/77 series, in particular, set new standards and became one of the most successful turbines in its class. The company’s 2-megawatt MM 70/82/92 series, launched in 2002 and now in production, has been similarly successful on the market.

The profitable and reliable wind turbines are designed at the REpower TechCenter in Osterrönfeld (Schleswig-Holstein) and manufactured at the plants in Husum (North Frisia), Trampe (Brandenburg) and Bremerhaven. With the REpower 5M wind turbine – currently one of the largest wind turbines in the world with a rated output of 5 megawatts and a rotor diameter of 126.5 metres – the company has extended its turbine portfolio in the multi-megawatt class a couple of years ago.

Construction of the prototype of this wind turbine, which is mainly deployed in offshore wind farms, was completed in autumn 2004 in Brunsbüttel, Schleswig-Holstein. The first 5-megawatt wind turbine was installed offshore in August 2006 as part of an EU demonstration project off the coast of Scotland. The REpower 5M went into series production in winter 2008/09 at the new Bremerhaven site. The turbine house can be shipped across the globe directly from here.

In the future, its successor, the REpower 6M, will also be produced in Bremerhaven. Three initial test machines of this particularly for great water depths suitable turbine have been installed onshore at the German-Danish frontier in spring 2009.

A turbine of the latest generation extends the onshore portfolio of REpower Systems AG as of recently: The REpower 3.XM with 3.37 MW nominal power banks on the proofed and reliable technology of previous series and has especially the distinction of being service-friendly in design.

However, no machine – or company, for that matter – is perfect on its own. Ultimately, it is people that determine success. That is why REpower’s top priority is the qualification and expertise of its employees, who now number about 2,000 around the world. One fifth of these are engineers. 

REpower is represented by sales partners, subsidiaries and associates in non-German European markets such as France, Belgium, Great Britain, Italy, Portugal and Spain, but also around the world in the USA, Canada, Japan, China and Australia.