Hydropower, Project Development, Wind Power

Wind Unveiled: Technology on Show at EWEC 2009

Issue 3 and Volume 12.

At this spring’s gathering of the European wind industry at the European Wind Energy Conference and Exhibition (EWEC), the mood was upbeat. There was little evidence that the economic downturn will spell long-term stagnation for the wind sector. Indeed, far from an industry pensive at waning levels of interest, the general atmosphere can be best described as ‘positive’ as far as the future global prospects of wind power are concerned.

In this optimistic view, wind power development will continue to flourish as a highly dynamic growth industry and job motor, despite the current dip. Wind is also believed to perform well against its main competing renewable energy sources – with regard to a favourable cost-benefit ratio and matured technology. One speaker predicted that emerging technologies, like energy from marine currents and waves, are only likely to become serious competitors to wind power in about 15–20 years time. Wind power is also increasingly recognized as key-contributing instrument towards levelling-off the impact of today’s economic recession and in alleviating the threat of climate change running out of control. Equally important, wind can make a substantial contribution towards a long-term goal to achieve energy supply security.

Surplus stock

Other EWEC 2009 sources remained more cautious, pointing to the sizable number of turbines now flooding the wind market in search of new buyers. Often these turbines were originally part of developer framework contracts, but have now turned into surplus stock due to project-financing difficulties. Pessimists point towards August/September 2009 as a crucial wind market evaluation period. For instance, as one wind industry analyst commented: ‘Wind turbine suppliers that are stockpiling unsold turbines, whilst hoping for a major market upswing later this year, will prove either visionary or end up in serious financial trouble.’

As one of the world’s largest suppliers – with last year’s total installations amounting to some 5500 MW – GE Energy anticipates that the US market volume will shrink this year. That, in turn, will certainly affect GE’s US wind business volume too, said managing director of GE Wind Energy Europe, Rainer Bröring in Marseille. However, Bröring added: ‘But for Europe, we expect to grow faster than the market, mainly due to brisk demand for our 2.5 MW 2.5xl. At the end of 2009 about 400 2.5xl turbines will be in operation, a total that includes a project in Romania comprising of 139 turbines. This May/June we will inaugurate the new 2.5xl assembly plant in Noblejas, Spain. This facility features a redesigned moving line, similar to the latest 2.5xl production technology pioneered and implemented in our German Salzbergen-based Centre of Excellence. A 60 Hz 2.5xl version will be introduced next year in the US, where it offers an alternative for the 1.5 MW turbine series in densely populated areas with land constraints like New York state.’

Today a record 13,000 units of GE’s 1.5 MW series are now in operation worldwide, with an order backlog of 3000 turbines.

Commenting on GE’s position with regard to offshore wind, Bröring said that this is still a niche market, noting: ‘Our business strategy is high volume production concentrated on a limited number of products. Seriously entering the offshore market requires huge investments in ‘real offshore technology,’ but we continue to actively observe US and global market developments.’

Aerospace entrance

In what many wind industry insiders consider a major trend in development, French aerospace companies EADS Astrium and EADS Composite Aquitaine announced their formal entrance into the wind industry at EWEC 2009. The two organizations offer the wind industry ‘more than 30 years’ aeronautics and space industry experience in developing large-scale structures using high performance composites.’ They also bring in advanced capabilities in the fields of engineering (new blade development and existing blade optimization), manufacturing, testing and control (i.e. non-destructive inspections). Equally important are the major synergies envisaged between the wind power sector and EADS Astrium aerospace core business, like mass and cost reduction, safety and reliability requirements, and high loads under extreme environmental conditions such as those experienced offshore.

‘With our new rotor blade business we chose a careful step-by-step approach in order to reduce overall risk,’ explained Thierry Bonnefond, Wind Turbine Blades Product Line manager at Astrium, during the conference. Bonnefond added: ‘It is not our intention to become a competitor to LM Glasfiber, but instead to develop the first step of a state-of-the-art blade manufacturing capability, integrating our background gained in the aerospace applications together with a world-class engineering capability.’

A blade manufacturing plant at an existing site is already operational and is dedicated to this activity, and the company says that a first order has been obtained from a French wind farm operator, consisting of a batch of replacement blades.

Bonnefond continued: ‘With regard to longer-term development plans, as a first step 1–2 MW class ‘conventional’ rotor blades, with lengths between 25 and 45 metres, will be developed for the onshore market. A second step involves the development of innovative ‘light weight’ rotor blades for 4–5 MW (and more if needed) offshore turbines, with a key focus at reliability aspects. We also currently look into other options like segmented blades and blade health monitoring, solutions which can already be applied on the first blades to be produced.’

During the period 2011–2012, and depending on customer demand, a new rotor blade manufacturing plant is expected to become operational in Aquitaine, southern France.

Potential sites close to transportation infrastructure and adapted for large-size components have already been identified next to the Gironde River and estuary, Bonnefond concludes.

New details emerge

In the field of offshore wind, two interesting contributions came from civil engineering contractor Ballast Nedam of the Netherlands. The first is a so-called One Lift Concept whereby a complete offshore wind turbine top head (nacelle + rotor + tower) can be lifted and installed at sea on a ready-made foundation structure. The One Lift system is incorporated in the huge 100 metre-high Svanen installation vessel. The second development, at a less advanced product development stage, is a drilled concrete monopile foundation comprising of multiple prefab rings (Look out for an article on this in a forthcoming issue of REW).

The actual number of completely new multi-megawatt-sized wind turbines presented in Marseille was limited, but several wind companies did reveal fresh details of their latest products.

German company PowerWind, initially established in 2007 as Conergy’s wind power division, presented its 2.5 MW gear driven PowerWind 90 (rotor diameter 90 metres). The new turbine expands the company’s product range, joining a 900 kW model assembled in Bremerhaven. The PowerWind 90 features a main shaft supported by two main bearings. This design is aimed at protecting the gearbox against rotor-induced bending moments, explained the company’s head of R&D, Frank Fisher. ‘We, in addition, incorporated an air-cooled permanent magnet-type (PM) generator with full converter as this ensures the highest possible power quality with excellent grid failure ride-through capabilities,’ he says. Fisher adds that PowerWind’s R&D department currently comprises 25 engineers, but this will increase to 40 by the end of 2009. Besides mechanical and electrical systems, the design team is also specialized in rotor blade development and dynamic simulations, he notes. A 2.5 MW version with an enlarged 100+ metre rotor diameter is planned, while a hot/cold climate version is also under development. Two PowerWind 90 prototypes are expected at the end of the year, and series production is due to start in 2011.

Duisburg-based Eviag AG was founded late 2007 and currently employs a staff of about 20, a number that will increase to around 50 by the end of 2009. Eviag acquired a license for the 2.5 MW Fuhrländer FL 2500 (rotor diameters of 80, 90, and 100 metres), of which around 30 turbines were operational in March. The agreement between the two German companies includes an exclusive licence for France, non-exclusive licences for Poland and North Africa, and options for the US and Italian markets. Eviag MD Wilhelm Hecking says that series assembly will commence in early 2010 at a location in the Duisburg harbour. ‘Our company’s main objective is to offer customers the lowest cost of ownership. From a business point of view, 2009 is a difficult time to enter the wind market. Convincing insurance companies is … the easy part, as these parties are already familiar with the qualities of our wind turbine technology. The difficulty is obtaining project finance,’ he adds.

New models and turbine developments

Global Wind Power (GWP) of India plans to erect a new direct-drive 2 MW prototype within the next few months in the Netherlands. The turbine, named GWP-82-2000kW, has been developed by Dutch wind pioneer Henk Lagerwey and his design team. The brochure distributed at EWEC 2009 shows both the GWP logo and the name ‘Lagerwey’ prominently displayed on the nacelle. Interesting, from a wind technology point of view, is an in-house developed permanent magnet-type annular generator which uses passive air-cooling. This main component appears as a clearly visible disk located between the tower and three-blade rotor, together with the rotor bearing assembly. The rotor diameter is 82.5 metres and the turbine will become available with two tubular steel towers offering hub heights of 80 and 105 metres. A 120+ metre steel/concrete hybrid tower is a potential option for later stages of development. The calculated cut-in wind speed is 2.7 m/s and the rated power level is reached at 12.5 m/s.

During EWEC 2009, Siemens Energy introduced its new SWT-2.3-101 model. The company says the machine is ideally suited for sites with low- to medium-speed winds, and that it supplements the existing 2.3 MW SWT-2.3-93 volume model and SWT-2.3-82 VS. Featuring a 101 metre rotor diameter, the new wind turbine is ready for delivery – and a first major order from Turkey comprising 13 units was announced in early April. Siemens further expects the low- to medium-speed wind market segment to grow substantially in the future, representing as much as one third of the total global wind power market in the coming years. The SWT-2.3-101 wind turbine is equipped with new 49 metre rotor blades, developed and manufactured using to the company’s seamless ‘IntegralBlade’ process.

Reflecting the trend for larger rotor sizes for a given capacity, Vestas of Denmark announced two new models during February 2009, a new 3 MW V112-3.0MW (rotor diameter 112 metres) as well as a V100-1.8MW turbine. Compared with the current V90-3.0MW, the rotor swept area has increased by 55%, while the power rating has remained unchanged. The smallest 1.8 MW turbine model builds on the V80-2.0MW platform. Externally the new models are both clearly recognizable by a prominent (generator) CoolerTopTM cooler assembly on top of the box-type nacelle, most likely representing the new 2009 corporate Vestas product style. The CoolerTop arrangement channels wind into the heat exchanger, enabling the number of moving parts and electrical components to be reduced. This improves reliability and acts to reduce noise, according to the technical specifications.

Several wind industry experts in Marseille suggested that the V112-3.0MW might, in time, come to replace the current Vestas V90-3.0MW flagship. When introduced in 2003, the latter’s innovative lightweight concept was widely admired in the wind industry, but unfortunately suffered from a series of (gearbox-related) issues. From an engineering perspective it is therefore interesting to note that the mechanical V112-3.0MW marks a switch away from the V90-3.0MW drive concept with its compact integrated gearbox and main bearing assembly. In contrast, the spacious V112-3.0MW nacelle incorporates a conventional three-point gearbox support drive solution, as applied in former 2.75 MW and 4.2 MW NEG Micon turbines and multiple geared competitor models, among others. Interestingly, the ‘three-point’ solution is also applied in the new 3.3 MW REpower 3.XM (see REW March/April 2009). Vestas’s Rob Sauven said that for the V112-3.0MW product development, a key design objective was low lifetime costs, leading to a choice for a gearbox based on both reliability and supply chain considerations.

Technology challenges

Applying a permanent magnet-type (PM) generator with full converter system in the V112-3.0MW is new for Vestas, but not for the wind industry. This generator solution is also applied in the Clipper Liberty, PowerWind 56 and 90, GE (2.5xl), and Unision’s new 2 MW U-88 and U-93 series, among others. However, during EWEC’s technical expert session, titled ‘Taking wind power technology to the next level,’ Kenersys

CEO Andreas Reuter counselled caution in applying PM generators in wind turbines. Reuter said: ‘Applying permanent magnets is still a new generator technology that, in our view, lacks [the] necessary long-term track record. For the moment conventional generator technology is therefore our preference.’ Kenersys uses synchronous generators with electrical field excitation. It erected a 2.0 MW K82 2.0MW prototype in Göteborg, Sweden during February 2009 and the larger 2.5 MW K100 2.5MW in Gotland, Sweden a month later.

With regard to direct drive turbine fortunes, expert opinions varied between ‘still a challenge,’ to highly positive, pointing at ‘increased simplicity and higher efficiency,’ and back to rather negative by claiming ‘20% higher capital investment costs.’

Henrik Stiesdal, Siemens Wind Power (SWP), warned of creating a ‘monster’ out of gearboxes, referring to an inventory of many (former Bonus) wind turbines installed during the 1980s, the majority of which are still operational. However, he added that size matters as larger components are more difficult to manufacture.

Optimum size

Heiko Roβ (BARD Engineering) reported good results from an endoscopic gearbox analysis conducted on two 5 MW BARD 5.0 (2007) offshore prototypes. He further said that there are now a number of commercial 5 MW wind turbine makes available, but that when size increases to 8–10 MW the corresponding drivetrain loads will be huge, requiring major system innovations.

Prof. Gijs van Kuik of Delft Technical University said he believes that there is no real optimum wind turbine size, and that the generating cost

per kWh is the key driver. But, on the question whether a bigger wind turbine makes cheaper electricity, Sauven said that it is not size, but reliability that is the main issue. Commenting, Roβ wondered why the need for bigger-sized offshore wind turbines is even questioned. He drew parallels with onshore product development, in which the ‘optimized size’ has continuously shifted upwards from 300 kW, to 600 kW, 1.5 MW, 2.5–3 MW, and upwards today.

Also on turbine size, Reuter commented that a key issue for offshore wind applications is the number of foundations required, and that 5 MW and 10 MW class turbines are both expensive installations. Stiesdal added that, in his view, a commercial 10 MW turbine is not feasible within the next five years.

On a question of whether the size of the offshore wind market is large enough to support the development of dedicated offshore wind turbines, Stiesdal said that the stringent reliability requirements of offshore machines are just as essential onshore, noting: ‘New offshore experiences will be incorporated in onshore wind turbines.’ Sauven believes that in future offshore wind innovations will originate from onshore developments.


Finally, a controversial issue was whether real technical breakthroughs can be expected from large wind companies. Professor van Kuik believes this is not the case and that real innovations start with individuals. Stiesdal disagreed and quoted the example of hybrid cars that originate from the world’s largest manufacturer, Toyota from Japan.

However, set against historic and current wind industry developments, this is far from a black and white issue. Enercon is a key example of a major wind industry innovator when the company was small (i.e. its 500 kW E-40). That innovative tradition has been kept alive until now, with the E-ship, a new ‘high-performance’ rotor blade shape in 2003–2004, and segmented steel/plastics composite hybrid blades for the E-126. MULTIBRID (~1995–1997) is another typical example of a major technology innovation in wind generation developed by a specialized engineering consultancy (aerodyn) that at the time only employed a staff of around 25–30 engineers.

Meanwhile, Siemens Wind Power’s (2008) 3.6 MW direct-drive Concept turbine is a key example of a potential new series product developed by one of the world’s largest power-engineering giants and a major wind industry player.

Thomas Ackermann of Energynautics commented that wind technology progress would accelerate if the wind industry could co-operate on issues that are not company-specific. Roβ suggested a move to develop common standards for offshore maintenance now that the offshore market is opening up. In other fields, Intellectual Property (IP) rights can sometimes prove an issue, according to the expert panel.

Jean-Michel Germa, Compangnie du Vent, remarked that technological breakthroughs are impossible without political commitment. A living example in support of these words is the success of the German EEG energy feed-in law; a system which is now being copied and introduced in many countries and regions of the world.

A second key example includes the rapid growth of the wind industry and wind market development in China, India and South Korea. These impressive achievements would not have been possible without the forward-looking long-term vision and active support of individual governments and the many entrepreneurs that make these things happen. Wind developments in the US, the world’s biggest market, were also remarkable in 2008 and for the coming years, hopes are high for wind power and other renewables under the leadership of new President Barack Obama.

Eize de Vries is Wind Technology Correspondent for Renewable Energy World.
e-mail: [email protected]

Nobel winner’s message

During the traditional Global leaders’ vision session, Dr. Rajendra Pachauri was one of the prominent panellists. As he could not be present in Marseille, the 2007 Nobel Peace Price winner (shared with Al Gore) and member of the Intergovernmental Panel on Climate Change, gave his address by video-link from India. Pachauri warned that in order to limit the earth’s temperature increase to a critical 2°C–2.4°C, the volume of CO2 greenhouse gas released into the atmosphere should reach its peak before 2015. He called for an accelerated application of renewable energy sources, while especially highlighting the major role of wind power. Most important, he said, was to get this message across to politicians and other decision-makers. Pachauri explained that when the world succeeds in curbing climate change in time, while combining it with the rapid expansion of renewable energy capacity, the cumulative benefits are huge. Positive effects include lower pollution levels, higher agricultural output, increased energy security, and a huge boost to global employment.

However, another speaker on the panel warned that the current economic situation does hold a risk of reduced commitments to boost renewable energy. The latter indirectly pinpointing the discrepancy between short-term and long-term objectives on energy and climate issues.

Across the three halls, exhibitors dealing with today’s challenges did not deny a business slowdown due to problems linked with obtaining project finance. There also appeared to be some consensus that this year’s global wind market volume may shrink by 20%–25% compared to the boom year of 2008. However, some optimistic equipment suppliers already envisage a substantial upturn during the second half of 2009, starting in the US. In their view, this positive development will be as a direct result of the US Recovery and Reinvestment Act – the economic stimulus package introduced earlier this year by the newly elected US President.