has to be one of the biggest ironies surrounding alternative energy, many of
the objections to wind energy focus on its effect on nature. Yet while the
critics fret about the birds, the views and the noise, there's a much bigger
barrier to wind on the horizon, one that many of its biggest proponents haven't
yet taken into account. Wind energy, it seems, is starting to become a victim
of its own success.
worldwide demand for wind energy equipment is outstripping supply," says John
Dunlop, senior technical services engineer for the American Wind Energy
Association (AWEA). The manufacturing base that produces the huge structural
components, blades, generators and gearboxes that make up today's high-tech
windmills simply can't keep up with the number of planned and ongoing
installations. Dunlop points out wind turbines purchased today won't likely be delivered until 2011 or 2012.
"That's the lead time right now," he says.
times are confirmed by key components suppliers too. "It's more like 2012 in
most cases," says Parthiv Amin, president of Winergy Drive Systems, a
subsidiary of Siemens Energy & Automation and maker of the gearboxes and
power transmission components used in wind machines.
chunk of this demand is coming from the U.S. AWEA figures put the annual
growth rate of wind energy capacity in the U.S. at 29 percent for the
five years ending in 2007. The association's projections show the U.S.
installed capacity will increase from 17,000 MW at the end of 2007 to
25,000 MW by the end of this year. Germany, the current world leader in
installed capacity, had 22,000 MW on line at the end of 2007. "As early
as next year, we'll have once again taken the lead, which we had until 1997,"
And the growth taking place now is dwarfed by the growth that
could take place in the coming decades. The U.S. Department of Energy this year
released a technical report about a future in which we rely much more heavily
on wind as a source for our electricity.
Wind Energy by 2030: Increasing Wind Energy's Contribution to U.S. Electricity Supply, the report forecast we'd
need 300 gigawatts of wind-generated electricity to hit that 20 percent mark,
up from about 1.5 percent today. Dunlop says the wind energy industry is
already on track to meet that capacity increase, judging from the growth in
2007 and 2008.
energy does have some adoption barriers unrelated to the supply chain for
turbine components. For example, transporting and installing wind turbines that
now routinely reach 100m and have rotor diameters ranging from 60m to 100m is one such barrier. So is power transmission over our existing grid
infrastructure. "The windiest locations tend not to be located near our
population centers," says Dunlop. And with wind, whose available energy is a
function of wind-speed cubed, "location is everything," he says.
barriers that may matter most to engineers can be found in design departments
and factory floors. In particular, Dunlop mentions a lack of wind-friendly
gearboxes, generators and bearings as a current bottleneck that could affect
wind energy growth in the short term.
surprising. Wind turbine components have a lot more in common with aerospace
components than industrial ones. Consider gear boxes, for example. Amin says a 1.5 MW wind turbine would have a gearbox that weighs about 16 tons
with both planetary and helical stages. On a wind turbine, these gearboxes act
to increase speed rather than reduce it. Amin says they typically take a 70 or
80 rotor rpm up to 1,400 rpm or so to run the generator. In short, these
gearboxes have to be big and robust.
also have to be as lightweight as possible given the stresses they see,
and they have to be more precise than
many ordinary industrial gearboxes. "In the industrial world, you want a
gearbox to be as robust as possible. You might have a 1.5 to 2.5 safety factor,"
Amin says. On a wind turbine, though, such a big safety factor would add up
to unacceptable weight penalty that could propagate through the turbine design
in the form of heavier tower sections, foundations and bearings. "We have to design
to razor-thin factor of safety because the weight issue," he says.
reduced safety factor obviously ups the ante on gearbox design and analysis as
does the fact that these gearboxes sit in a nacelle that may be 100m off
the ground, have limited maintenance opportunities and operate under variable
load conditions. "Mother Nature doesn't provide the same amount of wind every
day, and the location high up on a tower can produce all kinds of dynamic modal
effects," says Amin. "There's a lot of design expertise involved that doesn't
matter as much at ground level."
gearboxes are likewise more difficult to manufacture than many small, industrial
models. Winergy measures the tolerances for some of the mating surfaces, hole
locations and gear faces in the ten thousandths of an inch and uses gears made
to an AGMA Class 14 or 15. "Ours are very precise components, as precise as
aerospace components, but much bigger," Amin says.
the same design and manufacturing challenges likewise apply to bearings and
generators, which also have to function in the same environment high off the
So what do
these supply chain issues for engineers and manufacturers mean? Dunlop believes
the very same issues that pose a bottleneck today will ultimately create opportunities.
He says by NAICS codes, "there are currently 16,000 manufacturing firms
in the U.S. that could produce one or more of the 8,000-plus components that go
into a wind turbine."
not all of those companies will be able to make it in the wind energy business. "Manufacturing wind turbine components isn't
for everyone," Amin says. In fact, it may be just for companies with the most capable
manufacturing systems. In the gear business, to take one example, profile
grinding machines in producing large precision components have improved by
"leaps and bounds" over the past few years to the point where it would be
difficult to compete without a recent model, Amin says.
The same goes for composite blades. "You're starting to see some
failures in the field," says Bill McCormick, business development specialist
for composites at MAG
Cincinnati Automation & Test. He attributes them not to design but to lack of automation
still common in the production of the huge turbine blades. "There's still a lot
of hand layup and eyeballing the placement of reinforcing layers," he says.
All that may change as more money flocks into wind energy. Amin
says he's starting to see "tremendous investments" in the kind of advanced
manufacturing capabilities needed to ease wind energy's supply chain
bottleneck – perhaps as early as 2011 in his opinion. Winergy itself plans to
invest $30 million in its Elgin, IL facility this year and another $70 million
over the next four years. And Spain's Gamesa, a leading maker of wind turbines, has opened manufacturing
plants in Pennsylvania to make blades, nacelles and towers.
the manufacturing issues work themselves, wind energy will likely create some
jobs for design engineers. Dunlop estimates the 20-percent electricity
scenario would result in about 500,000 direct and indirect jobs, "many of them
technical jobs." And some of that hiring has started to happen. Amin points to
the hundreds or even thousands of engineering jobs currently available at the
turbine OEM customers, other wind-energy component suppliers and their
sub-suppliers. For engineers with the right skill set, including the ability to
analyze precision power transmission and drive systems, wind energy promises to be more than a bunch
of hot air.