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Areva's offshore ambitions

UK: The French nuclear-energy firm is eyeing local and UK offshore markets.

Anil Srivastava, senior executive vice president, Areva Business Group Renewable Energies
Anil Srivastava, senior executive vice president, Areva Business Group Renewable Energies

Anil Srivastava of Areva renewable energies division, talks about bid plans and confidence in its turbines.

French nuclear giant Areva is getting serious about wind. Currently it has just six 5MW turbines off the German coast but that figure will surge to 126 - more than 600MW of capacity - by the end of 2013, realising the company's ambition to be the third-biggest offshore-turbine manufacturer.

Areva plans to break into the French and UK markets, bringing local turbine and blade manufacture with it, says Anil Srivastava, the senior executive vice president of Areva Business Group Renewable Energies.

The latest turbine deal to be finalised is the 400MW Global Tech 1 wind farm off the coast of Germany in the North Sea. The EUR1.3 billion project-finance package is the biggest in the sector to date.

In June, Areva entered into an agreement with Spanish wind developer Iberdrola to build offshore projects in its home market of France. The consortium is bidding for two of the five wind zones in the country's first 3GW phase of offshore wind development. Areva is also targeting the UK's Scottish round of offshore projects, which totals 6.4GW, and the much bigger - 20GW altogether - UK-wide Round 3 of offshore development.

The company is capable of shipping 100 5MW turbines a year from its factory in Bremerhaven, Germany, Srivastava says. "We plan to double that in 12 months."

Areva entered the wind-turbine manufacturing industry in 2007 when it acquired the Multibrid design drawn up by German wind specialist Aerodyn.

Multibrid uses a medium-speed generator with a one-stage gearbox. It is a hybrid of the fast-speed three-stage geared systems - which currently make up the bulk of the offshore fleet - and the more recently evolved gearless direct-drive systems increasingly favoured by offshore-turbine makers. These remove the need for a gearbox between the rotor and fast-turning generator by employing a slow-speed generator.

Harsh lesson

Areva's first six offshore machines were commissioned in November 2009 at the Alpha Ventus test project, 45km off the German coast. The construction process provided a bruising lesson, Srivastava admits. Just months after completion, an overheating of the gearbox's slide bearings in one turbine caused it to fail. Gearbox supplier Renk had changed the bearing material to an aluminium-zinc alloy, which expanded at double the rate of the original when heated. Areva replaced all six turbines.

"Only one machine died," insists Srivastava. "We could have changed the gearbox of just that one machine, but we wanted to find out why the other machines did not fail. It was better to ask difficult questions at that early stage rather than when thousands of wind turbines are in the water."

The whole machine was tested and Areva decided to put all future turbines through full-load testing. As a result, Areva will open its new drive-system test facility at Bremerhaven in September.

The company is not in a hurry to upscale from its 5MW model. "First of all let everyone see that it's the best and most reliable offshore machine in the world," says Srivastava. He is critical of the trend to increase turbine size while moving to direct-drive technology. Although they have fewer rotating parts, direct-drive machines have more interfaces and therefore more potential for failure, he maintains.

The Multibrid design is the best compromise between having moving parts in fast-speed geared drive systems and no moving parts in direct-drive systems, he says. He sees Vestas' move to a medium-speed geared system for its new 7MW turbine as evidence of that.

Srivastava stresses that the industry needs to industrialise the production of wind turbines, while improving reliability. Not only will it lower the cost of capital, but it will also reduce provision for "contingencies", he points out.

Contingency provisions to cover payments for problems such as failing to deliver a project on time typically amount to 5% of a project's total cost. Five per cent of a EUR1.2 billion project is huge, he says.

But, he adds, the biggest savings can come from increasing the energy yield of wind turbines.

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