Skip to main content

The sky’s the limit

In close cooperation with Henkel, the German start-up company Timber Tower GmbH implemented a pilot project that could herald a new era for the wind power industry.

Reaching up to the heavens to a height of some 100 meters, a wind turbine tower of spruce – the first of its kind – has now been built near Hanover in Germany. Yet no dowels, no nails, and no screws or bolts are used to hold this timber construction together. Instead, the support tower has been adhesive-bonded using a special process – with various wood adhesives of the Purbond brand manufactured and marketed by Henkel Industrial Adhesives. The associated turbine-generator set is due to be hooked up to the grid in December of this year.

The project offers great promise for the future because switching to wood raises the prospect of increased tower heights. From the point of view of the operator, this aspect is particularly interesting because, at an onshore site, every additional meter gained means roughly one percent more in revenue. As tubular steel towers are made by assembling massive rings that have to be transported under highway bridges, however, with this technology the ring diameter is always going to be a limiting factor. Hence, the maximum height of construction currently lies at 110 meters. Wood is a potential problem-solver here as the components can be moved with relative ease to the site where they are then assembled to create the larger-sized parts required.

Close cooperation with Henkel
As a renewable resource, moreover, timber is in many respects superior to conventional materials such as steel and concrete. The service lifetime alone of the new system is likely to be double that of conventional solutions, according to the new German start-up company TimberTower GmbH, which implemented this project in close cooperation with Henkel.

In a direct comparison, steel and concrete are prone to much faster fatigue development. Particularly under heavy strain, both materials lose much of their already meager elasticity, causing them to embrittle. And that is why wind turbines tend to be disconnected from the grid after around 20 years. Wood does not have this handicap. The structure-strengthening effect of the glue also helps, with the result that the TimberTower generator with its capacity of around 1.5 megawatts should be able to supply electricity to around 150 households in Germany’s Lower Saxony for the next 40 years.

20 to 30 percent cheaper to make
“The way we see it, a timber tower offers nothing but advantages,” says TimberTower’s General Manager, Holger Giebel. “It has greater stress resistance, can be built significantly higher and is 20 to 30 percent cheaper to make. The Purbond adhesive joints had to prove their suitability right from the start of the construction project, with each one duly receiving a certificate of worthiness from the DIBt, Germany’s institute of building technology.

Now a white waterproofing membrane has been placed around the octagonal, wooden outer shell to protect the tower from the elements. The massive cross laminated timber located underneath are bonded with Purbond. Bolts were only used in the initial assembly phase in order to secure the structure. Once the tower was complete, all the mechanical fixtures were removed and the stabilizing inner construction was then adhesive-bonded from the inside using an especially developed application technique involving the 2-component casting resin, Purbond CR 421. The adhesive penetrates deep into the pores of the wood and interconnects the cross laminated timber panels with the perforated steel plates. The timber tower weighs more than 90 metric tons, with the top-mounted gondola and rotor blades adding another 100 t.

“One of the most innovative projects in the history of wood”
“This wind turbine is one of the most innovative projects in the history of wood,” says Walter Stampfli, General Manager of Purbond. It is already looking like it won’t be the last, because the expertise that Henkel particularly has gained from this project is gradually gaining renown in the relevant engineering communities. Back in 2008, the first eight-storey timber building was constructed in London with Purbond adhesives, while the first ten-storey high-rise was built in Melbourne. And in Canada a construction project involving a 30-storey building is also in the offing.

“We have the most advanced adhesives for the manufacture of load-bearing timber elements and constructions able to meet the standard specifications applicable in virtually all countries,” says Stampfli, alluding to the development results achieved over the last two years. “Moreover, we can offer technical support wherever this is required and have established ourselves as an internationally recognized source of expertise for public authorities, standards institutions and approval agencies almost everywhere in the world. As a consequence, we are ready to roll on all kinds of projects.”

Henkel acquired the Swiss company Purbond back in early 2011. Purbond is one of the world’s leading suppliers of polyurethane adhesives for load-bearing engineered wood applications and timber constructions. Since the takeover, the brand has continued to be managed as an independent business.


Popular posts from this blog

IDEC Releases New Line of High Efficiency Power Supplies

IDEC Corporation announces the PS5R-V line of DIN-rail power supplies, offering their customers high-efficiency in a compact form factor at competitive prices. These power supplies suit a wide range of needs in the industrial marketplace, and carry all of the required certifications necessary for use in these demanding applications. This next generation of the industry standard PS5R power supply family has updated features and specifications to meet current and future needs. The PS5R-V line of power supplies includes 10W, 15W, 30W, 60W and 120W versions, with additional versions coming soon. These power supplies have a very compact form factor with overall dimensions reduced by up to 25% from previous generations. The reduced form factors combine with DIN-rail mounting to free up valuable control panel space and reduce installation costs. Operating temperature ranges up to -25 to +75 degrees C offer more versatility. These extended operating temperature ranges often allow these p

Banner Engineering DF-G3 Discrete Fiber Amplifier Features World-Class Long Range Sensing Capability

Banner Engineering introduces its DF-G3 discrete long-range fiber amplifier with dual digital displays for use with plastic and glass fiber optic assemblies. Featuring increased sensing power, the DF-G3 can sense more than 3 meters (10 ft.) with opposed mode fibers or more than 1 meter (3 ft.) with diffuse mode fibers. The extra power provides increased detection reliability for dark targets at long range and enhanced detection sensitivity when using specialty fiber assemblies for large area and small part detection applications. The DF-G3 is available with a single discrete output or two dual discrete outputs. The dual discrete outputs can be independently taught to trigger at different intensity values, which is ideal for correct part-in-place or error-proofing, bottle down, and edge guiding applications. “We developed the DF-G3 fiber amplifier to meet our customers’ need to precisely detect smaller targets at longer ranges” said Dennis Smith, Senior Marketing Manager, Banner E


TURCK is now offering the option to completely shield M8 picofast ® cordsets by connecting a braided shield directly to the coupling nut. This provides a cost-effective and reliable connection with 100 percent cable and connector shielding, which protects against electromagnetic and radio frequency interference. The 3 and 4-pin cordsets are available with flexlife ® PVC or PUR jacketed cable. All connectors deliver IEC IP 67 protection. The M8 picofast line, like most TURCK cordsets, provides male or female, straight and right angle connectors, standard and custom lengths, and pigtails or extensions. Fully encapsulated mating receptacles are also offered, completing the system.