The late economist E F Schumacher (1911- 1977) became something of a hero to the early environmental and ecological movements, not least because of his oft-quoted maxim: small is beautiful. But if that was true back in the 1970s it is nevertheless a rule which is being ignored in the current wind generation industry. If small was beautiful back in those far-off days, it is now very much the case that B-I-G is the current watchword for the movers and shakers of the US wind business. But ‘big’ does not come without a series of attendant logistical problems, especially in the area of transporting these behemoths around the highways and byways of the North American landmass. PES investigates . . .
The University of Dayton Research Institute (UDRI), was recently granted $270,000 in order to research, design and test structures and materials for composite wind turbines of up to 100m in height. These composite towers will stand as much as 65ft taller than the steel towers currently used. In fact let’s not pussyfoot around here – they would be some of the largest composite structures ever built – so much for those Egyptian pyramids, then.
According to Brian Rice, Division Head for Multi-Scale Composites and Polymers at UDRI, wind turbine towers have to be strong enough to carry the weight of the turbine (which can be as much as 100 tons) but also resist buckling under the stress of the rotating machinery. Steel monopoles are pre-fabricated in sections as large as 14ft in diameter and 70ft long, then trucked individually to the wind site to be put together and installed on a concrete foundation.