The prototype five-legged closed lattice tower — clad in architectural fabric — has about 4,500 structural bolts, compared with 450 in a conventional tubular tower. GE bought the technology in 2011 from Utah-based Wind Tower Systems.
The tower will be unveiled at EWEA 2014 in Barcelona on 11 March.
More labour is needed for assembling the eight sections, acknowledged Keith Longtin, GE's general manager of wind products, while giving Windpower Monthly an exclusive tour of the prototype.
Field assembly costs will be offset by the lower weight and cost of steel, and the ease of transporting the parts in standard 40-foot containers, he said.
The number of bolts will be reduced somewhat on future models.
Tower maintenance is reduced because of the splined-pin and tension-control bolts, which do not need re-torquing throughout the product life, he said.
And servicing is easier, said GE, because of down-tower access to cabinets and transformers in the 12-metre base.
On-site assembly is no more vulnerable to weather delays than for a tubular tower, stressed GE.
Space frame towers of 139-metres for GE 2.75-120 turbines will go into production in 2015. They use 50% less steel.
The tower will initially be marketed for low-wind sites in northern Germany and Sweden, said Longtin.
