Wind Energy's Manufacturing Crunch

In whathas to be one of the biggest ironies surrounding alternative energy, many ofthe objections to wind energy focus on its effect on nature. Yet while thecritics fret about the birds, the views and the noise, there's a much biggerbarrier to wind on the horizon, one that many of its biggest proponents haven'tyet taken into account. Wind energy, it seems, is starting to become a victimof its own success.

"Theworldwide demand for wind energy equipment is outstripping supply," says JohnDunlop, senior technical services engineer for the American Wind EnergyAssociation (AWEA). The manufacturing base that produces the huge structuralcomponents, blades, generators and gearboxes that make up today's high-techwindmills simply can't keep up with the number of planned and ongoinginstallations. 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.

Those leadtimes are confirmed by key components suppliers too. "It's more like 2012 inmost cases," says Parthiv Amin, president of Winergy Drive Systems, asubsidiary of Siemens Energy & Automation and maker of the gearboxes andpower transmission components used in wind machines.

A sizeablechunk of this demand is coming from the U.S. AWEA figures put the annualgrowth rate of wind energy capacity in the U.S. at 29 percent for thefive 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 to25,000 MW by the end of this year. Germany, the current world leader ininstalled capacity, had 22,000 MW on line at the end of 2007. "As earlyas next year, we'll have once again taken the lead, which we had until 1997,"Dunlop says.

And the growth taking place now is dwarfed by the growth thatcould take place in the coming decades. The U.S. Department of Energy this yearreleased a technical report about a future in which we rely much more heavilyon wind as a source for our electricity.Called 20%Wind Energy by 2030: Increasing Wind Energy's Contribution to U.S. Electricity Supply, the report forecast we'dneed 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 isalready on track to meet that capacity increase, judging from the growth in2007 and 2008.

Windenergy does have some adoption barriers unrelated to the supply chain forturbine components. For example, transporting and installing wind turbines thatnow routinely reach 100m and have rotor diameters ranging from 60m to 100m is one such barrier. So is power transmission over our existing gridinfrastructure. "The windiest locations tend not to be located near ourpopulation centers," says Dunlop. And with wind, whose available energy is afunction of wind-speed cubed, "location is everything," he says.

Yet thebarriers that may matter most to engineers can be found in design departmentsand factory floors. In particular, Dunlop mentions a lack of wind-friendlygearboxes, generators and bearings as a current bottleneck that could affectwind energy growth in the short term.

That's notsurprising. Wind turbine components have a lot more in common with aerospacecomponents than industrial ones. Consider gear boxes, for example. Amin says a 1.5 MW wind turbine would have a gearbox that weighs about 16 tonswith both planetary and helical stages. On a wind turbine, these gearboxes actto increase speed rather than reduce it. Amin says they typically take a 70 or80 rotor rpm up to 1,400 rpm or so to run the generator. In short, thesegearboxes have to be big and robust.

Yet theyalso have to be as lightweight as possible given the stresses they see,and they have to be more precise thanmany ordinary industrial gearboxes. "In the industrial world, you want agearbox 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 upto unacceptable weight penalty that could propagate through the turbine designin the form of heavier tower sections, foundations and bearings. "We have to designto razor-thin factor of safety because the weight issue," he says.

Thereduced safety factor obviously ups the ante on gearbox design and analysis asdoes the fact that these gearboxes sit in a nacelle that may be 100m offthe ground, have limited maintenance opportunities and operate under variableload conditions. "Mother Nature doesn't provide the same amount of wind everyday, and the location high up on a tower can produce all kinds of dynamic modaleffects," says Amin. "There's a lot of design expertise involved that doesn'tmatter as much at ground level."

Thesegearboxes are likewise more difficult to manufacture than many small, industrialmodels. Winergy measures the tolerances for some of the mating surfaces, holelocations and gear faces in the ten thousandths of an inch and uses gears madeto an AGMA Class 14 or 15. "Ours are very precise components, as precise asaerospace components, but much bigger," Amin says.

Many ofthe same design and manufacturing challenges likewise apply to bearings andgenerators, which also have to function in the same environment high off theground.

So what dothese supply chain issues for engineers and manufacturers mean? Dunlop believesthe very same issues that pose a bottleneck today will ultimately create opportunities.He says by NAICS codes, "there are currently 16,000 manufacturing firmsin the U.S. that could produce one or more of the 8,000-plus components that gointo a wind turbine."

Of course,not all of those companies will be able to make it in the wind energy business. "Manufacturing wind turbine components isn'tfor everyone," Amin says. In fact, it may be just for companies with the most capablemanufacturing systems. In the gear business, to take one example, profilegrinding machines in producing large precision components have improved by"leaps and bounds" over the past few years to the point where it would bedifficult to compete without a recent model, Amin says.

The same goes for composite blades. "You're starting to see somefailures in the field," says Bill McCormick, business development specialistfor composites at MAGCincinnati Automation & Test. He attributes them not to design but to lack of automationstill common in the production of the huge turbine blades. "There's still a lotof hand layup and eyeballing the placement of reinforcing layers," he says.

All that may change as more money flocks into wind energy. Aminsays he's starting to see "tremendous investments" in the kind of advancedmanufacturing capabilities needed to ease wind energy's supply chainbottleneck – perhaps as early as 2011 in his opinion. Winergy itself plans toinvest $30 million in its Elgin, IL facility this year and another $70 millionover the next four years. And Spain's Gamesa, a leading maker of wind turbines, has opened manufacturingplants in Pennsylvania to make blades, nacelles and towers.

Even asthe manufacturing issues work themselves, wind energy will likely create somejobs for design engineers. Dunlop estimates the 20-percent electricityscenario would result in about 500,000 direct and indirect jobs, "many of themtechnical jobs." And some of that hiring has started to happen. Amin points tothe hundreds or even thousands of engineering jobs currently available at theturbine OEM customers, other wind-energy component suppliers and theirsub-suppliers. For engineers with the right skill set, including the ability toanalyze precision power transmission and drive systems, wind energy promises to be more than a bunchof hot air.