Transporters of wind energy components are facing the challenges of carrying heavier and longer loads. Euan Youdale reports
Manufacturers and rental companies have been making considerable investments in trailer systems for the wind energy market. One of them is ATS Wind Energy Services, the largest wind transporter in North America.
"The industry is already at that point where we're pushing the envelope on the size that can be transported. There were challenges to move 1.5 megawatt turbines but, for the most part, we could use existing trailer systems. But now with the 2, 2.5 and 3 megawatt turbines, it's limiting the equipment that can be used," says Alan Redding, ATS director sales and marketing.
These technological leaps coincided with a major decline of new wind energy installations in the USA in 2010. The country added 5.6 Gigawatts (GW) in 2010, down from 9.9 GW in 2009, according to a report by the World Wind Energy Association (WWEA).
One of the causes may be uncertainties over the introduction of a new national support scheme for wind power in the country. However, WWEA forecasts suggest new capacity of up to 10 GW in 2011, which would reverse the decline.
The emergence of taller towers, longer turbine blades and heavier nacelles are also contributing factors to requirements for new state-of-the-art trailer systems. "It's all getting bigger and more complicated," says Redding. "You can build bigger trailers to carry bigger components, but you can't change the infrastructure.
It's also putting more stress on the planning and permitting process, which is already a challenge from state-to-state but also between municipalities and counties. This reflects a global issue. "Due diligence is becoming more intense for transporters," says Redding. "We have to work on route studies and planning much earlier to provide a quote to the customer, but also just to see if we can get it done.
Bernd Schwengsbier, president of TII Sales, which forms the Kamag, Nicolas and Scheuerle group, says innovation is vital in these fast-moving times. "For example, 20 years ago, the wind industry did not exist. Now this sector of the market is quite big and still has a promising future and we try to get our share out of this market by developing superior systems at Nicolas and Scheuerle for economical prices."
One of them is the new Superflex semi-trailer series, available in three versions: fixed deck, single telescopic and double telescopic. It offers a technical axle load of 14 tonnes and a steering angle of 60 degrees. This makes it possible for single or double telescopic vehicles to leave the two front axle lines in a fully extended position either on the gooseneck or rear bogie. The vehicle can be adapted to suit the respective position of the payload centre of gravity, and use each axle line to its full capacity.
The low bed trailer has pendulum axles and a lift of 600 mm. "In particular, this has a very positive effect when driving on the rough terrain of construction sites or driving over railway lines and minimises any damage to the individual axle groups," says a company spokesman.
Another is TII's TK25, launched at Bauma 2010, before being introduced to the US market in the third quarter of that year. The K25 SPE version has a steering angle of +/- 60 degrees or 140 degrees. By reinforcing the main beam, the permissible bending moment has been increased by 16%, giving the K25 a higher bending moment or high load reserves, the company said. The Scheuerle side loader was launched shortly afterwards. It is connected twice between two self-propelled units, which are then operated in loose coupling mode to lift the tower section on and off the trailer.
Faymonville has added to the list of wind power component transporters on the market. The G-Line Modulmax offers combinations of many modules comprising 2 to 6 lines of axles to carry payloads of 80 to more than 1,000 tonnes. Together with the existing S-Line, the series will benefit from rapidly growing demand, says the company. It offers 25 tonnes load per axle and its eight wheels per axle have 205/65 R17.5 tyres. Loading height is 1.020 m with a clearance of -250/+350 mm. Length is 3 m.
One of the biggest challenges for transport companies is the increase in length of wind turbine blades, which can measure some 60 m, says Roland Ter Linden, from Doetinchem, Germany-based wind turbine transport operator Ter Linden Transport. "This increase in length is so significant that the semi-trailers with turntable steering, which are currently still used to transport them, are no longer up to the job.
"It has become virtually impossible to carry blades that are longer than 45 m on semi-trailers with turntable steering. The manoeuvrability at roundabouts is too limited with this type of steering and the suspension offers too little ground clearance," continues Ter Linden. As a result, the company asked Nooteboom to develop a semi-trailer that was only limited by the length of the blade itself.
High and mighty
The TELE-PX Super Wing Carrier has pendular axles, which allows a wider steering angle and significantly more axle travel for extra ground clearance. The pendular axles also ensure the platform remains extremely stable, even at maximum steering angles, says the company.
"What makes the Super Wing Carrier so revolutionary is not just the use of pendular axles. Above all it is the possibility to extend and retract the axle assembly by more than 6 m. This means the wheelbase is variable adjustable and so is the rear overhang of the wind turbine blade, without the need to detach the blade from the load floor. Adjusting the axle assembly can be done en route, for instance when negotiating a roundabout, depending on the traffic situation," says Ter Linden.
This year Ter Linden Doetinchem also ordered six-axle trailers from Broshuis in the Netherlands. They are for carrying wind turbine tower sections weighing up to 100 tonnes. The sections can be transported at shorter overall length and height, making them more efficient, says the company.
Another solution for long blade transportation is the blade adapter from TII group. It is designed for travel on twisty roads to reach remote erection sites. The blade is attached to a pivot at the turbine end. It is then raised and lowered longitudinally to over sail tight bends as the transport turns around them. Previously, laborious manoeuvring or even unloading the sections and moving them by crane was required, says the manufacturer.
Goldhofer's SPZ-P 3AAA flatbed semi-trailer is designed for the transportation of extremely long blades over rough terrain. "For the first time we have succeeded in developing a transport vehicle with a maximum length of more than 62 m thanks to triple telescoping," says a company spokesman.
The pendular axles, with a 60 degree steering angle, provide good manoeuvrability and balancing of unevenness, both in height and in a lateral direction, adds the manufacturer. The vehicle can also be shortened while carrying its load to negotiate narrow passages and obstacles. The heavy loading capacity of the extension spines makes this possible, explains the company.
World Wind Energy Report 2010 breakdown: