The International Husum WindEnergy 2008 event took place in September. More than 700 companies, research and scientific institutions from 35 countries presented their latest products and services, while the almost 30,000 attendees visited from 40 nations. Eize de Vries reports on the latest innovations.
Since first opening its doors in 1989, Husum has offered a vibrant and yet relaxed informal meeting place for the industry. This biennial event has grown from humble beginnings into a world-leading wind industry fair. For the first time Husum WindEnergy 2008 was organised as a co-operative venture between Messe Husum and the Hamburg Messe (squeezing in a 2008 event to quick-step onto a new, even-numbers two-yearly cycle). Nonetheless, as in previous years, exhibitor booths were again spread throughout the main hall and three large temporary structures.
While the sunny and relatively high early September temperatures heated up the tents considerably during the day, there was no evidence of this affecting record number of international exhibitors. With over 23,000 of the total 30,000 attendees coming from abroad, not only was all available space inside the four halls occupied, but also a large section of available ‘free’ walking space on the fair grounds. With space at a premium, one alternative solution saw Dutch exhibitor Advanced Tower Systems (ATS) displaying a huge concrete element from its new concrete-steel-hybrid tower prototype on a trailer in the car park of a nearby Chinese restaurant.
Another possible indication of the run on space comes from the observation that while not so long ago it was normal for main suppliers to display complete wind turbine nacelles in Husum, for various reasons fewer companies undertook such efforts this year. ATS foundation aside, a 900 kW Conergy PowerWind 56 wind turbine nacelle with a 45-tonne mass was the heaviest single piece of equipment on display. Yet as part of a major restructuring, at the beginning of the fair that German company sold its remaining wind division, comprising the PowerWind 56, to US-based private equity investor Warburg Pincus. Under the wings of the new owner, commercial operations will continue under the trade name PowerWind, with turbine assembly again concentrated in Bremerhaven, Germany. PowerWind employs about 70 staff and plans to manufacture 100 turbines in 2009 and up to 300 in 2010. Besides PowerWind, a sizable number of other wind companies are active in the sub-megawatt class segment, which shows substantial market potential, especially in regions with a less developed infrastructure. For instance, both Vestas and Gamesa sell an 850 kW model introduced around 2000, while Enercon has developed two 800 kW turbines and one 900 kW sister model in recent years. Since 2004 Enercon has erected over 2100 of these direct-drive, sub-megawatt turbine series worldwide. The latest addition to Enercon’s product portfolio is the 30 kW E-10, a direct-drive variable speed stall turbine with three metal rotor blades of which a prototype was erected back in 2007. With a rotor diameter of only 10 metres this machine represents a huge contrast with the company’s largest model, the 6 MW E-126 (rotor size 127 metres) which is now regarded as a series product.
One of the largest single object displays at Husum WindEnergy 2008 was a ‘mock-up’ nacelle from REpower’s latest 3.3 MW geared 3.XM onshore turbine. This turbine type has a rotor diameter of 104 metres and a conventional geared drive train that builds on experiences with the 2 MW MM82 and MM92 volume models.
Also new in REpower’s portfolio is the 6 MW 6M turbine, which is an evolutionary upscaling of the 5 MW 5M utilizing the substantial built-in design reserves. The rotor diameter remains unchanged at 126 metres, but REpower has developed a new RE 61.5 metre rotor blade for the 6M in-house. Three 6M prototypes will be erected later this year at an onshore site in Germany near the Danish border, and this more powerful turbine will succeed the pioneering 5M in coming years. 5M/6M wind turbine assembly and REpower rotor blade production are now concentrated in Bremerhaven, where two new assembly/manufacturing facilities are now operational. Including the prototype erected in 2004, there were 10 operational 5M turbines at the start of 2008, of which two installations operate offshore in a record 44-metre water depth off the Scottish coast. As a further milestone, this year REpower erected six 5M turbines in the C-Power Thornton Bank project off the Belgian coast. The final rotor was installed by 19 September. Another six 5Ms are destined for the German Alpha Ventus offshore project in 2009.
Integrated drivetrain advances
GE Drivetrain Technologies, a division of GE Transportation, is a North American supplier of megawatt-class wind turbine gearboxes. During the past few years the Drivetrain Technologies division has designed and developed a new gearbox for GE Energy’s popular 1.5 MW series. Some 10%–15% of all 1.5 MW GE Energy turbines are already fitted with this gearbox, and this percentage is expected to increase by as much as two or three times by 2010. Novel features of this two-stage compound planetary gearbox include the skipping of a common third spur gear stage, and positioning the planet gear bearings outside the actual wheels. The first measure is designed to reduce internal efficiency losses by minimizing the number of bearings and gear meshes.
Building on the latter development, GE Drivetrain Technologies unveiled its ‘next generation’ geared wind turbine drivetrain concept, named IntegraDrive, at the Husum show. The new drive system is aimed at GE as well as non-GE clients and integrates a two-stage planetary gearbox with a medium-speed generator in a compact flange-on single assembly. Among the advantages of such a design is that it requires fewer gears and bearings, and misalignment risks between the gearbox and generator are virtually eliminated. Both these factors add to overall systems reliability, says Robert Ciszak, Advance Systems leader. Furthermore, elimination of the high-speed stage increases gearbox efficiency where, Ciszak explains: ‘Third gear stage losses can amount to 1.5%. A second advantage linked to eliminating the fast speed gear stage is that thicker oil with superior lubrication performance can be applied.’
Superimposing an IntegraDrive on a standard 1.5 MW nacelle shows the compactness of the new drive concept when compared with conventional designs. Says Ciszak: ‘The IntegraDrive saves an average of 2 tonnes on gearbox mass alone. This does not even take into account additional weight savings made possible by eliminating the otherwise required generator support chassis and/or the weight-saving option of a shorter nacelle.’
GE Drivetrain Technologies engineers also put a lot of effort in IntegraDrive serviceability. For instance, with the aid of a so-called ‘rail-slide system’ the generator can be easily removed by just one person in less than an hour, without a crane. ‘Our IntegraDrive concept is suitable at least for wind turbine power ratings up to 8 MW. We are also confident that geared drive systems in general, and the IntegraDrive in particular, offer a superior solution in terms of costs and efficiency compared to direct drive systems’, Ciszak concludes.
Meanwhile, in a similar development, Innovative Windpower AG displayed a Falcon 1.25 MW main chassis with an integrated drive system at Husum.
The compact unit assembly comprises an integrated geared drive train with a flange-on low speed generator.
The Dubai-based company operates an assembly facility for the smart-looking Falcon turbines in Bremerhaven.
Europe’s new technology crop
Project developer e.n.o. Energy, based in Rostock and in Rerik, Germany, presented its new 2 MW e.n.o. 82 wind turbine at Husum. The conventional pitch-controlled variable speed concept features a three-point gearbox support with a double-fed induction generator. The rotor diameter is 82.4 metres, and hub heights will be available up to 101 metres. The turbine has been developed by former German engineering consultancy RSB Consult, which is now part of the Indian company Kenersys Group (see below). The overall product development goals were cost-effectiveness and a high availability, explained e.n.o.’s managing director Karsten Porm: ‘We erected a prototype near Rostock this April  and in the third month the turbine already achieved 98% availability. The main reason for us as a wind farm developer to engage in turbine manufacture is that we wish to obtain a better supply chain control. However, this objective does not conflict with our simultaneous aim to continue purchasing third-party turbines in parallel for our future wind projects.’ Turbine manufacture was due to start in October with ten 0-series turbines, and by the end of 2008 e.n.o Energy envisages a staff of 50. This will be followed by a further 40 units in 2009 and 60–80 in 2010.
Elsewhere, new Multibrid owner Areva of France displayed a model nacelle of the new offshore version of its M5000. The original concept was characterized by a highly compact nacelle cover, with relatively limited working space for service personnel. As with the onshore version, the M5000 offshore concept contains a fully integrated machine housing incorporating single-stage gearbox, a permanent magnet type low-speed generator and a single rotor bearing. New in the offshore version, this compact housing has now been fully encapsulated by a spacious steel frame that expands to the rear side. The rectangular structure with a plastic composite cover features a helicopter-hoisting platform on top. Among the other added features is a built-in hatch in the nacelle floor to lower staff to safety in case of an emergency. The new offshore model version is slightly heavier than the original, and will be applied first at the Alpha Ventus project. However, erection of the six turbines has now been postponed until 2009.
Meanwhile, engineering consultancy Wind-to-Energy (W2E) is perhaps best known for designing Fuhrländer’s innovative 2.5 MW FL 2500 turbine, which is now assembled in Germany and is soon to be joined by installations in eastern China and Montana in the US. The new German FL 2500 assembly plant at Siegerland airport became operational earlier this year and serves as a model for similar facilities elsewhere in the world. The FL 2500 itself is turning into a commercial success with over 300 units scheduled for installation worldwide by 2010.
The FL 2500 is available with rotor diameters of 80, 90, and 100 metres. Even larger rotor sizes are likely in the 2.5 MW class, and in fact most volume classes during the coming years. Siemens Wind Power serves as a good example of this ongoing trend. Earlier this year the German power-engineering giant announced a new 101 metre rotor for the 2.3 MW main volume model, which is currently mainly supplied with a 93 metre rotor.
The W2E machine is also in use by Indian newcomer Lanco Wind Power (LWP), a subsidiary of the Lanco Group, the second largest conventional (natural gas, coal, biomass, hydro) electric power producer in the country. Besides power generation, stock exchange-listed Lanco is also involved in real estate and building construction. The company builds the group’s own power plants, along with those for other clients. The move into wind power is a recent business activity. The first turbine model to provide LWP with the necessary leverage to enter the global wind market is the 2 MW L93 (rotor diameter 93.2 metres). The L93 is a slightly scaled-down sister product of the FL 2500 family and again a W2E product development. The turbine has the largest rotor in its class (the REpower MM92 comes in second with a 92.5 metre rotor) and is suited for IEC class II and III wind conditions. LWP’s CEO Prasad Kandimalla said in Husum that L93 castings will be bought in China, while rotor blade production is concentrated in India. Initially, 300 blade sets will be manufactured annually, but this will increase to 600 sets by 2011–2012. Erection of a L93 prototype in Germany is planned for June 2009. Lanco has selected Germany as its turbine assembly base, while the key market focus is on Europe. Kandimalla sees Germany’s reputation for engineering excellence as a positive image-enhancing factor for his company’s aim to become the most competitive wind turbine supplier in Europe’s main wind markets.
Asia’s booming players take a stand
SEWIND of China is part of the Shanghai Electric Group, one of the largest manufacturers of electrical and mechanical equipment in the country. SEWIND’s wind business commenced with the acquisition of a licence for the 1.25 MW DeWind D6 turbine (owned by US-based CTC Corporation). Renamed the SEC-1250, SEWIND has already erected 120 units since the start of production in 2007. Under development is a larger 2 MW SEC-2000, a joint project with aerodyn of Germany. The latter will become available with rotor diameters of 87 metres and 93 metres, and prototype erection is planned for the end of 2008. Both geared ‘SEC’ turbine types operate with pitch-controlled variable speed. The next project planned by the ambitious Chinese company is a largely in-house developed 3.6 MW turbine, for which a prototype is planned for 2010–2011 and which is also aimed towards offshore applications.
Global Wind Power Ltd (GWP) is a 100% subsidiary of the Indian Reliance ADA GROUP which has a market capitalization of US$43 billion. GWP, already active in India, is expanding its activities to a worldwide level, with a special focus on the United Kingdom and Ireland, Benelux, Eastern Europe, plus North and South America. The company recently opened a state-of-the-art facility near Mumbai, India. This plant will assemble 750 kW and 1.5 MW wind turbines with a capacity of 600 MW annually. The GWP 47–750 kW is a fixed speed active-stall turbine, for which a worldwide licence was acquired from Norwind of Denmark. The GWP 77–1.5 MW pitch-controlled variable speed turbine has been licensed for the Indian market from Fuhrländer of Germany. The 750 kW wind turbine is expected to become available as REW goes to press and the 1.5 MW by mid-2009. The Indian company also manufactures a 225 kW former Micon model it acquired from NEPC of India. The new nameplate is the GWP 30–225 kW. GWP also has great expectations of the GWP 82–2.0 MW, a direct drive turbine developed by Dutch engineering consultancy Lagerwey Wind. The latter builds on experiences with the 2 MW (Lagerwey) Zephyros concept (prototype 2002). During 2009 a prototype will be tested in Lelystad, the Netherlands, and a second unit at a test site in India. Production is planned for 2010. [For more on GWP see the interview with company chief executive Sudhindra Rao on page 69.]
Another emerging wind market player is Kenersys, a renewable energy venture of the Indian company Kalyani Group. This company has a diversified business portfolio and a global workforce of more than 10,000. Andreas Reuter, managing director of Kenersys Europe, was – among others – a founder of former engineering consultancy RSB Consult. Kenersys has a wind turbine design office in Münster, Germany, where Reuter and his team developed two pitch-controlled variable speed gear-driven Kenersys wind turbines. These installations currently form the product portfolio backbone. Both these pitch-controlled, variable-speed Kenersys turbine types, like the e.n.o. 82, feature a conventional non-integrated drivetrain with three-point gearbox support.
A key difference is that the Kenersys turbines contain an electrically excited synchronous generator with full converter, a type widely applied in the power industry. By making this choice Reuter establishes a clear distinction from the popular permanent magnet generator wind industry trend. The full converter system with ‘improved electrical architecture’ is aimed at qualifying the system to deal with weaker grids as well as tougher new grid codes. Other distinct design features include external geared rotor blade pitch bearings for optimized load sharing, and externally placed pitch motors for better heat dissipation. The smallest 2 MW Kenersys K 82–2.0 further comprises an 82-metre rotor diameter, while the 2.5 MW K 100–2.5 sister product is fitted with a 100-metre rotor.
Erection of the two prototypes is planned before the end of 2008, in Sweden. Reuter explains: ‘The 2.5 MW wind turbine at the location of the former Näsudden research turbine site at the Swedish island Gotland, [is to be developed] in co-operation with utility Vattenfall. Our 2 MW wind turbine prototype is destined for Göteborg, which is a joint project with Göteborg Energy.’
Reuter added that Kenersys intends to manufacture 20 K 100–2.5 and 50 K 82–2.0 turbines next year. For this purpose the company is to build two new factories, both due to become operational early in 2009 – one in Wismar, Germany, the other in India. The German plant will serve the European market, while the Indian plant will cater for its local market.
Lattice towers and other innovations
SeeBA EnergyFarming of Germany is a renowned specialist in tall lattice-type wind turbine towers. With a basic philosophy of ‘a greater hub height equates to more generation’, the company aims to offer the maximum hub height for a cost comparable with a tubular steel tower. In the past, when a maximum tip height of 100 metres was considered valid in Germany, SeeBA anticipated the market by offering a lattice-type tower with 78 metre hub height for the 600 kW Nordex N43. When maximum tip height was later raised to 150 metres, a 117 metre hub height tower was developed for the Vestas V66 (117 metres + 33 metres). SeeBA also holds a hub height world record with a Furhrländer FL 2500 on a 160 metre tower. Today there are no hub height restrictions any more, says a SeeBA specialist, and instead it is availability of high cranes that has become the limiting factor.
In Husum SeeBa presented a clever patent-pending hexagonal lattice tower concept based on an earlier octagonal design. The new tower concept is mainly distinguishable through the optimized geometry of the corner pillars, which also reduces the number of diagonals and horizontal braces. Instead of angle-iron corner pillars the hexagonal corner pillars consist of three identical prefabricated rolled steel sheets with a multi-cornered cross section. These are put together in semi-circular bolted assemblies which offer superior structural strength characteristics when compared with angle-iron type corner pillars.
The top section of the new tower design is fully closed and ends in a circular shape that can accommodate the yaw bearing. Key advantages claimed by the manufacturers include a reduction in the number of parts and bolt joints, and an 8%–15% weight saving. SeeBA plans to offer the new tower concept in the 2 MW class turbines with hub heights of 100, 120, and 140 metres, for instance.
Benefiting from a wind industry trend towards outsourcing, Zarges Aluminium Systeme (ZAS) of Germany now offers a wide range of dedicated products and services. Earlier this year ZAS opened a wind power logistics distribution centre in Peitling, where 6000 individual parts are assembled and packaged together into 430 (sub) assemblies. The warehousing concept is presented as a ‘supermarket’ for the wind industry. It operates according to ‘just in time’ delivery principles known from the automotive industry. Says ZAS senior vice-president of sales, Arnold Wagner: ‘Besides in-house production, a dedicated ZAS speciality is the supply of assemblies and standardized inner modules that easily fit inside tubular steel towers and are characterized by a minimized labour input requirement. Examples of our system solutions include climbing stairs, resting platforms, and elevators incorporating drive and controls.’
Meanwhile, German 2D/3D laser equipment developer and producer Z-Laser offers dedicated laser systems to various industries, including the wind industry. Laser systems can be applied for more precise measurement and displaying patterns and/or shapes of specific objects. One specific rather new laser technology application is already in use at Enercon, where it is applied as a manufacturing support tool for the precise positioning of glass fibre layers inside rotor blade moulds.
Markets under pressure?
Although recent, the Husum event nevertheless took place before the enormous extent of the global financial crisis had fully unfolded. The potential impact of a global downturn was therefore not a significant topic of discussion among exhibitors and visitors to the fair. The tumultuous sequence of events that followed will certainly have its impact on the wind industry too. That some wind projects will get delayed or even cancelled due to lack of finance as a result of the tight credit situation seems unavoidable. A potential positive side effect of this in the short term is that, as with other commodities, the worldwide wind equipment shortage situation may face some relief and prices may therefore come down.
But, for the medium and long term, global wind power development is expected to steam ahead as before. Indeed, perhaps anticipating an installation vessel shortage Dutch utility Essent – developer of the 80-turbine Nordsee Ost wind farm – has already contracted A2SEA’s jack-up barge SeaJack for 2011 and 2012, a well informed wind industry source said at Husum.
The simple fact is that amidst all the recent financial chaos, the threats of climate change, fossil energy shortages and the need for increased energy security all remain unchanged.