Orangutan wind turbine access system

Orangutan wind turbine access system

The wind energy market continues to grow as does the capacity of the turbines, particularly offshore. Euan Youdale reports.

The World Wind Energy Association (WWEA) says a double digit growth in the wind energy market is still forecast for 2009, despite the worldwide economic downturn.

The estimate backs up the figures supplied in June at the 8th World Wind Energy Conference on Jeju island, South Korea.

They are based on a survey of 11 WWEA member associations from 15 countries representing more than 80% of the world market.

They recorded 5,374 MW of newly installed capacity in the first quarter of 2009, equaling an increase of 23% on the same countries in 2008.

In November 2009, WWEA said it would keep to its forecast of 152,000 MW of installed capacity worldwide by the end of 2009.

This represents a new record of over 30,000 MW newly installed capacity within one year and a market growth of 25%, compared with 2008.

"These figures confirm wind energy as a stable, profitable and low-risk investment. Although some wind energy projects are postponed due to financing challenges, the overall market development can still compensate such delays showing great signs of vitality.

"A substantial share of the slow down in some regions are a consequence of new regulations and bureaucratic delays that undermine the development of new wind parks rather than of financing difficulties," says a WWEA spokesman.

Capacity rise

Wind energy has been a fast growing market for crane rental and services companies over the last few years, and this trend will continue, says Peter Libert at Sarens.

As far as Libert is concerned, the experimental period of large-capacity turbine erection is now over and the company is ready to provide the full services needed to tackle future projects on a grand scale.

One recent groundbreaking project was the onshore erection of 6 MW Enercon E-126 turbines in Hamburg Altenwerder, Germany (see linked article). The nacelle alone weighs 365 tonnes and the axle height is 136 m, requiring the biggest cranes possible, says Libert.

"The existing cranes that can do this lift take several weeks to dismantle and the same to re-erect, resulting in 1.5 to two months for intermediate mobilisation," explains Libert.

In an onshore wind park consisting of 11 E-126 turbines, this means the crane must be remobilised ten times, amounting to 20 months for only the remobilisations. The operational time is additional to this.

"Therefore, Sarens asked Demag to develop a crane that had the correct capacity, but still could be remobilised fast between two turbines. The CC 9800 is a crane that can be considered as truly mobile," says Libert.

Complete dismantling and erection of the CC 9800 takes 17 days. If the crane is driven between turbine sites, and only partly dismantled, this can be reduced to eight days.

Evolution

Sarens has also erected six 5 MW turbines at the Thornton Bank wind farm project 28 miles off the Belgian coast in 2008 and another six 5 MW Repower units for Alpha Ventus in the North Sea off Germany in 2009.

According to Libert, Sarens now has a contract to erect 30 turbines for the Irish Sea-based Ormonde Project in 2010 and will erect a further 80 turbines in 2011.

"The experimental time is over," says Libert. Sarens now offers entire wind turbine erection management for on and offshore provisions.

As these projects become larger and more widespread, developments will include dedicated vessels for offshore installations, says Libert, meaning that project preparation and co-ordination will become even more important.

Europe is still the main market for onshore projects, although the rest of the world is catching up, with Brazil and Australia being two examples.

"Onshore will keep growing as before. The 2 MW class is a mature business at the moment and will continue, but we will see an upgrade of these turbines to an average of 3 MW without significant changes in dimensions or weights.

"In this way, this class of turbine will survive for many years. The 5 to 6 MW turbines will not take over the leading position in onshore applications."

For this reason, existing cranes will continue in the same way, adds Libert, perhaps with small upgrades for increasingly high towers.

"The offshore business, however, will see an evolution from the standard 5 MW to 6.5 MW today and will even be improved to 7 to 9 MW in a few years. 10 MW [turbines] are being developed, however, we will not see prototypes for the next five years," concludes Libert.

New maintenance

The increase in turbine erection is accompanied by the need to service them. Maintenance is a significant part of the overall cost and, as such, wind farm operators seek new ways of working, to reduce costs. The majority of the lifting work involved is performed by cranes.

However, competition is looming from alternative forms of lifting.

According to the developers of the Orangutan wind turbine access system from ITI Energy, the fact that wind farms are often sited on remote hilltop locations, can make the use of cranes costly due to transportabity and weight. They can also only be deployed in low-level wind conditions, argues Orangutan.

The access system is made up of two friction clamps, connected by an hydraulic structure that allows caterpillar-like motion. It works by climbing the turbine tower, carrying whatever tooling package is required for the maintenance operation.

ITI Energy has completed this programme and has invested more than UK£ 2 million (US$ 3 million) in de-risking the clamping and climbing technology.

ITI is now confident that if such a device was built it would rival conventional crane technology for gearbox, generator and blade changes on land-based turbines 1.5 MW and above.

Innovation in spotlight

Roderik van Seumeren, Mammoet CEO, has a few words of warning when it comes to innovations in the crane industry and he uses the wind market as an example.

He says that while innovations provide new business opportunities, a crane rental company can find that it is pushed into a corner. He explains that the trend for narrow track crawler cranes designed to move easily through wind farms is an example.

"The narrow track crawler crane for the wind industry is a good idea. But you have smaller crawler bases and the centre of gravity is higher, so it is more unstable when travelling with the main boom than it normally would be," says van Seumeren.

This, he explains, can lead to accidents. A recent example took place in Sweden when the road caved in under a narrow track crawler and the crane collapsed. Following this kind of incident the rental company looks to the insurer to pay for the damage.

But when the insurance company looks at the narrow track crane being used, instead of a more stable configuration, it will inevitably ask questions.

"In the end the insurance [company] has to pay - but they say, 'hey, what kind of business is this?' So we are concerned."

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