High in the Tehachapi Mountains north of Los Angeles, GE has unveiled its space-frame turbine tower, a steel and architectural fabric concept seen as a breakthrough in the campaign to cut the capital cost of wind power.
The design, launched at
EWEA 2014 in Barcelona in a 139-metre version topped with a 2.75-120 GE turbine,
is build around an “Eiffel-tower-like” lattice structure clad with high-tensile
The technology could carve
“a large slice” out of the price of a conventional tubular tower by
streamlining fabrication and transportation, while opening up the possibility
of ultra-tall 150-metre turbines.
“When we started doing this
project, I and a lot of other people had reservations about how it would look.
Seeing it up, everyone is converted,” Keith Longtin, GE’s wind product-line
general manager, tells Recharge.
“It is a leap forward for
the industry. It... shows clearly there is great potential for cost-effective
scale-up of wind turbines with much taller towers.
“The industry is moving
toward taller towers, that’s no secret. And when you get up into the
130-150-metre-plus technologies, the material cost savings go from being 20-30%
lower [for a 100-120-metre tower] to closer to 40%.”
GE expects the tower to be
a “perfect fit” for the emerging markets of lower-wind and heavily forested
sites in Scandinavia and the rest of Northern Europe. “The next round of
permits going out in these regions, they are looking for 140 metres,” notes
Longtin. “And our design can be extended in 12-metre sections, so we can go
still higher, as required. The physics aren’t limiting.”
The 97-metre-tall prototype
was assembled with a 1.7MW 1.7-100 turbine at Tehachapi, where a three-month
testing programme begins this week.
The prototype took a month
to install, but GE expects to whittle that down to “around four days, like a
“Overall time of
construction will be the same, material usage much less,” Longtin adds. “Once
the panel material was decided on, that drove us toward the five-legged design
and overall architecture. The beauty of it is that you are not constrained by
Conventional steel tower
sections must be less than 4.3 metres wide to be manoeuvrable under
bridges and along most roads. The space-frame tower, designed with a
maintenance-free bolting system, can been packed up in a dozen freight
containers and trucked “pretty much anywhere in the world you want it”, says
“Shipping a 150-tonne steel
tower section to some of the more remote locations where there is little or no
road infrastructure is a real challenge. With the new tower, everything
changes,” he says.
Project leader Kathy Verna adds: “When you are transporting huge
tubular tower sections, you are talking fleet permits, weather delays,
restrictions on travelling through certain areas at certain times. With the
space-frame tower, all the parts [supplied by a ‘Midwest manufacturer’] were
onsite in California two days after our phone call.”
One of the hidden benefits
of the five-legged design, notes Longtin, is its stability in seismically
active zones. “In earthquake-prone areas you are going to have a big advantage
over tubular towers — our tower will be much more stable.”
The modular design also
means the component parts can be built on assembly lines, speeding up
fabrication and honing quality control.
“This project has required
an entirely different business model — from
how engineering interacts with project development and sourcing and
supply chains,” concludes Verna.