September 2010

Across the United States, the wind energy sector is primed for tremendous growth. More states have set renewable portfolio standards, and with the oil spill disaster in the Gulf of Mexico the federal government is poised to pass meaningful energy legislation that could include a tax on carbon dioxide emissions.

The move to a new energy economy offers a lot of positive outcomes such as lessened dependence on the grid, more sustainable business activities, and a host of new jobs. To meet these opportunities America’s workforce, like its energy economy, will need to be retooled to meet the growing demand for skilled labor in wind and other energy-producing sectors.

A January 2009 report delivered by the Council of Economic Advisers found that the clean energy investments of the American Recovery and Reinvestment Act (ARRA) are not only creating jobs today, but for the future. The clean energy provisions of ARRA alone have already saved or created 63,000 jobs and are expected to create more than 700,000 by 2012.

Clean energy jobs, according to the ARRA, are defined as new work for skilled laborers who can install efficient heating and cooling systems and windows, retrofit homes to save electricity, and can build and install solar panels, wind turbines, and other clean energy technologies. These investments are positioning the American workforce to remain competitive and keep our nation at the forefront of a new low-carbon global economy. At the same time, these initiatives are changing the way that we produce, distribute, and use energy to reduce green house gas emissions and cut our dependence on foreign oil [1].

To better understand where the wind industry is headed and how to meet the increasing job demand, Ecotech Institute spoke to three members of its board of advisors who specialize in the wind energy sector and helped develop the school’s curriculum. Those weighing in on the industry’s potential and the demand for talent include Abbas Ghassemi, Ph.D., director of the Institute for Energy and the Environment, WERC executive director, and professor of chemical engineering at New Mexico State University; Al Zeitz, director of North American Operations at the DeWind Co.; and Colin Coyne, managing principal of the Coyne Group, LEED 2.0 accredited professional and lecturer of sustainable enterprise at the Kellogg School of Management on “Sustainable Strategy.”

Setting the Stage
According to the American Council on Renewable Energy (ACORE), the anticipated increase in wind power energy by 2040 will be significant, as much as a tenfold increase when compared with today’s production and consumption. In addition, a study released in February 2010 by Navigant Consulting, Inc., found that the number of renewable energy jobs would more than double by 2025 if the nation adopted a plan to require 25 percent of its electricity from renewable sources. Several states currently have renewable portfolio standards, and the trend is continuing.

“As we approach global peak oil in the next 25 years, optimistically, we must be able to diversify into the many sources available in order to sustain energy production that will allow our economy to grow without intermittent shortages, security vulnerabilities, extreme costs, or environmental degradation,” says Ghassemi.

Sourcing United Nations data, an increasing population is a considerable factor when looking at alternative energy demand. “With projected population growth exceeding 9 billion people by 2050,” he continues, “global energy consumption worldwide, as well as the estimated domestic demand, increases the need for production, availability, and delivery of energy from all renewable sources [2].”

According to Zeitz there are a number of reasons to anticipate growth in the wind industry, including its benefits as a clean source of electrical power and a good investment. “The development of wind energy for electrical power is growing more popular in the private sector,” he says. “Many people would like to see more wind turbines installed to generate electrical power.”

“In the past three years, worldwide wind power capacity has more than doubled,” Coyne adds. “This is largely due to wind power becoming a cost competitive alternative, especially when one considers that a wind plant is far less expensive to construct than a conventional energy plant. Of course, one can’t ignore the general demand for clean power. Certainly this debate will heat up with recent events in the Gulf of Mexico. New clean air standards will also accelerate demand.”

Demand for Talent
As with growth in any industry, skilled workers are essential to meet the demand. In the case of wind power, people must be able to know how to build and sustain tools, equipment, and technology.
Ultimately, this means jobs—which is obviously positive in a tough economy—but what kind of jobs will they be? Our experts underscored the increasing need for educated, skilled workers across the industry, and what they could be doing.

“There are many different kinds of jobs needed to support the growth of the wind industry,” says Zeitz. “However, the greatest number of jobs needed in the wind industry will be technicians. Wind turbine technicians are the backbone of the wind industry, and these technicians will be required to keep the growing fleet of wind turbines maintained.”

“From green power brokers to wind turbine technicians, the demand for jobs will be substantial,” Coyne says. “At a very pragmatic level, the demand for technicians to serve these new facilities will be great, as will attorneys and paralegals who understand the unique nuances of green power and green power incentives, real estate leases, and project financing.”

“To address the ongoing and emerging needs for installers, operators, managers, field crew, and supervisors, we should train individuals in mechanical and electrical fields specific to wind power,” according to Ghassemi. “As the ramp-up takes place, there will be significant growth in the manufacturing area for wind blades, structures, gearboxes, and associated hardware, emerging software, and technologies. There will also be a tremendous growth for individuals to maintain and repair gearboxes, energy storage devices, and utility service/integration functions.”

Creating Skilled Workers
Ecotech Institute, which recently opened its doors in Aurora, Colorado, was created to help fill this demand. The first and only school in the United States entirely focused on renewable energy and sustainable design, it offers a path for people interested in entering the green economy with the right education. Ecotech Institute offers seven associate’s degrees and a certificate program.

When asked about Ecotech Institute’s role in training future workers in the wind industry, the experts were excited about applicable job training, especially for wind technicians. “The wind companies are obviously adept at what they do. However, graduates of Ecotech will bring much needed, on the ground, pragmatic knowledge,” Coyne says. “The issue for wind companies is taking what has largely been small-scale or theoretical models and turning them into full-scale operations. This requires well-trained technicians who understand the engineering behind the technology, available in sufficient numbers, and grounded in the mechanical realities of wind power conversion.”

Ghassemi believes that Ecotech can help companies find and place “trained individuals to participate in this growth. Ecotech graduates will be able to fill the niche in all of the sectors, including manufacturing in several positions.”

“With the number of turbines that are currently installed, and those that are scheduled to be installed,” Zeitz says, “the greatest demand is for skilled technicians to commission, troubleshoot, and maintain them.”

An Enthusiastic Future
A look at the future is exciting for people inside and outside the field. With the potential to bring more sustainable choices to the marketplace and bolster new, diverse workforces, the wind industry offers promise. “We need to continue to be mindful of our energy availability, production, use, and delivery,” says Ghassemi. “While we need to have scientists and engineers doing their part in making this happen, job training is vitally important in completing the cycle and assists in providing the resources required for making renewable energy available.”

“So much of the alternative energy discussion has taken place at a global or strategic level,” says Coyne. “What has been ignored are the thousands of technical jobs that will turn these ideas into reality. To me, the opportunities of ‘green’ in 2010 are similar to those that surrounded the space program in 1969. Both were catalysts for a new generation of entrepreneurs.” 

References:
1) Executive Office of the President-Council of Economic Advisers. The Economic Impact of the American Recovery and Reinvestment Act of 2009. Second Quarterly Report, January 13, 2010.
2) United Nations, World Population Monitoring, ST/ESA/SER.A/228, United Nations, New York; Energy Information Administration, Electricity, www.eia.doe.gov/fuelelectric.html.G. Stix, Scientific American.

The technology used in manufacturing wind turbine blades has evolved over the past 20-plus years. Blade making has migrated toward processes that minimize cycle time and reduce both cost and the probability of defects. Early blade building techniques grew out of the boat building industry, using processes that were high in labor and prone to inconsistencies and defects. Vacuum infusion took blade manufacturing technology to a higher level, with improvements in consistency and performance of a blade. Prepreg—or “pre-impregnated”—technology further enhanced blade performance by combining resins and reinforcements in a more rigorously controlled manner before placement in the blade mold. Today the trend is toward Automated Tape Layup (ATL) or Automated Fiber Placement (AFP) to reduce labor and improve quality, whether one uses dry fiber or prepreg tape (Figure 1).

Input materials in blade production have not evolved as rapidly. Resin technology has expanded somewhat to include both polyester and epoxy on a broad scale. Wood or foam cores are still used in many cases. Skins are comprised of multiaxial fabrics with some use of unidirectional materials. The root end section of the blade is comprised of rovings and/or multiaxial fabrics. Spars have been manufactured with fiberglass rovings and a combination of unidirectional and multiaxial fabrics.

Throughout the early growth of the industry, basic fiberglass reinforcements have changed very little. The pace of that change, however, is now beginning to accelerate.

Performance of turbine blade composite materials has been documented by many agencies and universities, including Sandia National Laboratories and Montana State University in the U.S. and the Optidat database in the Netherlands. Figure 2 outlines these data sources and provides links to some excellent public Web sites. As part of an ongoing DOE project on Wind Blade Manufacturing Innovation (DE-EE0001373) we have collected and analyzed the performance of turbine blade materials and utilized these databases for input into an electronic database. We have also included PPG internal data and publicly available information from different material suppliers.

This data was aggregated and analyzed for performance characteristics based on material type. Detailed analysis of the data shows a basic split in material performance between prepreg and infusion based composites. The highest performance is obtained from unidirectional and biaxial prepreg materials. These materials are utilized on the latest generation of wind turbines. Material properties are more varied in infusion-based composites, particularly as a function of resin selection, reported fiber volume fraction, and material complexity. As fiber orientations shift from unidirectional to biaxial to triaxial, the dominant material characteristic changes as well.

The data contained in these public forums provide a rich body of work for all who take the initiative to explore them. Much credit must go to organizations like Sandia National Labs and their ongoing sponsorship spanning many years of Professor John Mandell and his group at Montana State University. The Wind Center in the Netherlands has also been a leading data provider, as has the Risoe DTU National Laboratory in Denmark. We are able to gain much insight as a result of this work.

The data based on prepreg composites allow us to compare various fiber types as well, including high performance fibers like carbon. The mechanical properties of unidirectional materials when loaded under tension are clearly fiber dominated, which means in the tensile and compressive direction the property of the fiber dominates the composite mechanical property. Specifically, the type of fiber and the amount of fiber determines the performance of the composite material as dictated by the “rule of mixtures” relationship. The advantage of a high performance fiber like carbon is most prevalent in the tensile properties. In the design of a wind blade the advantage of novel fibers like carbon is realized in the tensile direction, and hence is the reason that it is used in parts that undergo high tensile stresses such as a spar cap. In contrast, the compressive properties for carbon fiber reinforced laminates do not differ greatly from cost-effective alternatives like E glass based composites.

The properties of composites based on biaxial fabrics or fiber structures are dominated by the resin when loaded in the primary direction. The use of a high performance fiber does not provide a significant boost in mechanical property values. This is basically a result of moving the fiber orientation away from the load direction. So in using composites fabricated with biaxial fabrics, E glass continues to be a good cost-effective solution for this ply schedule.

The same trends are evident when comparing infusion-based uniaxial and biaxial fiber composites. Once again, higher performance fibers show benefits in uniaxial laminates but not in biaxial laminates. This trend continues in laminates based on triaxial fabrics. In the complex triaxial laminates the improvement in tensile properties is reduced such that there are negligible differences in laminate performance, even when fiber properties are substantially different.

Further reducing the value of high performance fibers in these complex fabric architectures is that other defects can take over. For example, the tensile strength of a fiber is a flaw-dominated property. Damage imparted to the fiber surface in the fabrication of these complex fabrics can reduce the value of the fiber. Since these fabrics are more complex, there is also a higher probability for basic defects (voids) that can compromise the properties. As we move further into more complex fabric architectures, the fiber property difference starts to blur in the performance data given the complexity of the load path, the loss of fiber alignment, and the reduction in effective fiber volume fraction.

Moving from historical data to future developments, the industry is clearly moving toward larger turbines with longer blades. Larger blades produce more energy, and this is a basic target for driving costs down. To grow the size of turbines there are two approaches one can take. Knowing that the deflection of a wind blade is inversely proportional to the moment of inertia of its cross section and the stiffness of the blade material, the goal is to increase moment of inertia or stiffness to reduce deflection. Changing the moment of inertia requires a change of the blade design or blade cross section. This is a design issue best tackled by wind turbine designers and builders, not by material suppliers.

The second option is to change the materials properties to increase flexural stiffness of the composite. From the perspective of the materials supplier, there are a number of ways to accomplish this goal (Figure 3). The first is modification of the sizing chemistry on the surface of the glass fiber. The surface treatment drives wetting, composite tensile strength, and ultimately fatigue life. While these do not affect stiffness directly, they are critical to overall blade performance and durability. Secondly, we can make a stiffer structure by increasing the volume fraction of the fibers within the composite. Another approach is to change the fiber composition to provide a stiffer fiber. Lastly, providing composites with low probability for defects ensures fewer flaws that can become crack initiation sites in the event of large stresses.

Sizing chemistry effects can be illustrated by comparing two PPG products, HYBON 2002 and HYBON 2026. Both products are used in wind energy composites and are multi-compatible in that they perform well in many organic resin systems. HYBON 2002 is a workhorse product for the wind industry, and its performance is well established. An improved sizing chemistry using the same base fiberglass can be demonstrated by comparing properties with HYBON 2026. This product provides improvements in tensile strength, flexural strength, and interfacial shear strength. The value of these improvements is seen more dramatically in dynamic mechanical properties, specifically fatigue performance (Figure 4). In fatigue measurements the improvement of HYBON 2026 over HYBON 20002 translates to roughly 10 percent on a log scale (from ~5.5 to 6.0), and greater than double the absolute number of cycles to failure (320,000 cycles to 1,000,000 cycles). Benefits from sizing chemistry are especially meaningful when one considers that the chemistry is applied at the fiber level at a thickness on the order of 50-100 nanometers. In addition to fatigue performance, the latest generation sizing developments can provide property improvements that are controlled at the fiber level, which improve strength characteristics and strength retention of the composite. However, sizing chemistry does not have a direct effect on fiber stiffness.

The second option to increasing blade stiffness is to change the fiber volume fraction of the composite. Sizing chemistry can play a role here by providing improved wetting and lower resin demand. In general higher volume fraction laminates are more difficult to fabricate, as the permeability of a larger fiber array will be reduced as fiber volume fraction is increased. This can lead to a higher probability of defects. As the laminate approaches the maximum theoretical fiber volume fraction, the likelihood of dry spots and direct fiber-to-fiber contact leads to a higher incidence of flaw generation. Another negative is that the weight of the composite increases as the fiber volume fraction increases, which is something we want to manage when making larger wind blades.

To further explore the increased fiber volume fraction impact, we will consider the case of a hypothetical spar with a circular cross section (Figure 5). Assume for simplicity that it is produced with all the fibers aligned along the length of the spar. The physical dimensions are held constant, as well as the modulus of the fiber. Using a self weight deformation criterion for the analysis we can see that changing the volume fraction from 50-60 percent does provide tip deflection decrease (Figure 6). At the same time, however, there is a respective increase in the mass of our hypothetical spar. Additionally, more-complex fabric architectures are somewhat limited in their ability to achieve these high volume fraction levels. There is room to increase the fiber volume fraction and increase stiffness without incurring fiber-to-fiber contact. However, there is a weight penalty for increasing the fiber volume fraction on a composite laminate.

The third means of improving stiffness is through changes in the basic glass composition. Every glass manufacturer has a space in which they operate, so we must recognize that there are ranges for the resulting properties. E glasses are well known, and most widely used in the composites industry. However, there are other fiber types that offer higher modulus. These are commonly known as R and S type glasses. Carbon is the ultimate fiber based on very high mechanical properties. As modulus increase it must be recognized that this benefit generally comes at a higher cost.

Using the same equation for tip deflection and changing fiber modulus, we see that tip deflection decreases (Figure 7) as modulus increases. Further comparisons of fiber composition can be made when taking fiber volume fraction into account. In this figure the comparison is made between E and R type glasses. One can obtain the same deflection using 50 percent volume fraction of R glass compared to 59 percent for E glass (Figure 8). Furthermore, note that R glass has a 0.23 m tip deflection at 58 percent volume fraction. Volume fraction would need to exceed 60 percent to achieve this deflection with E glass, which is an unlikely scenario. These benefits are driven by fiber modulus, which is on the order of a 10-12 percent change. This can be coupled with an increased fiber volume fraction, which can result in further improvements in laminate stiffness.

The last point of improvement is defect reduction. A number of ongoing current developments are focused in this area. Automation is one means to reduce defects. Current material forms are not adequate for fiber placement and automated tape laying. On the chemistry front, resin specific sizing technology will provide better bonding to the resin and can reduce defects at the micro-scale. There is further value that can be obtained through higher tensile strength, interfacial shear and strength retention properties. This approach can also give greater fatigue performance. Faster processing can also be enhanced through sizing chemistry changes.

In conclusion, the focus has shifted from incremental improvements in performance to performance leaps. Interest in the reduction of defects and in cycle times by the introduction of high-end processes will drive this change. We are working on developing materials that are appropriate for the emerging technologies. Considerable research is ongoing in improving wet-out characteristics of rovings and fabrics and providing higher mechanical property retention over the life of a blade. New technology developments in fiber reinforcements, resin systems, and production concepts will continue to drive wind energy to lower cost of energy levels in the future.

Acknowledgment: This material is partly based upon work supported by the Department of Energy under Award Number(s) [DE-EE0001373)]. Disclaimer: Part of this presentation was prepared as an account of work sponsored by an agency of the United States Government. Neither the United States Government nor any agency thereof, nor any of their employees, makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. Reference herein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise does not necessarily constitute or imply its endorsement, recommendation, or favoring by the United States Government or any agency thereof. The views and opinions of authors expressed herein do not necessarily state or reflect those of the United States Government or any agency thereof. 

Atop Grouse Mountain—one of the North Shore Mountains in Vancouver, British Columbia, Canada—sits the Eye of the Wind, the world’s first wind turbine viewing tower with a public elevator. Built earlier this year, the Eye of the Wind viewing pod transforms the wind turbine from a passive element of the scenic landscape into an interactive, perspective-altering tourist attraction.

For the wind industry, it allows the public to personally experience the true power and potential of wind energy from the perspective of the turbines that harvest it (Figure 1). For the construction industry, the viewing pod is an example of how existing techniques can be used for new and unique projects; even those that pose tremendous challenges.

In this case, KONE lived up to the challenge to build a 20-story elevator for the public, all in a structure that is continuously moving, required protection from earthquakes, and offered one-third the amount of space for a normal elevator. While not every turbine requires a public elevator, the experience proves how teamwork and innovation can help meet even the most challenging obstacles in transporting people safely and efficiently.

Grouse Mountain
Grouse Mountain is known for its sustainability platforms, and harvesting energy from the wind was a natural for the developers. But in this case they wanted more than just an industrial use for the tower. They wanted to promote the new technology, and to increase demand from consumers for clean energy. “The Eye of the Wind is an iconic symbol of sustainable wind energy that encourages visitors from around the globe to demand alternative energy solutions in their own hometowns,” says Chris Dagenais, director of communications for Grouse Mountain.

The Eye of the Wind tower stands 223 feet (65 meters) high and provides a breathtaking scenic view 4,176 feet (1,273 meters) above sea level of Grouse Mountain, recently highlighted during the Vancouver Winter Games.

Each year over 1.2 million people visit Grouse Mountain from around the globe, including Canada, the United States, Japan, Korea, Germany, and the United Kingdom. For these visitors the revolutionary viewing pod represents one of the most recent innovations in eco-tourism, allowing tourists a breathtaking view and the chance to learn about the next generation of energy technology.

Construction
Getting from idea to completion posed many challenges including the turbine’s mountaintop location, the size and weight of its components, and the points of origin around the world. The turbine’s 122 foot (37.3 meters) blades were airlifted to the peak of the mountain after arriving in Vancouver via barge. Each weighing more than 50 tons, the tower sections arrived at the construction site after a tediously slow trek up Grouse Mountain’s eight miles of winding back roads. Even the large, pre-assembled viewPOD™ traveled across Canada on train before arriving in Vancouver.

On top of that engineers had to decide how to house not just the observation pod, but also the elevator that provides access for the public to the Eye of the Wind. KONE was selected for this project, working closely with a number of different contractors to finish the job on time and successfully. Figure 2

Elevator Planning
The first challenge for the elevator planning was the timing for the entire project. Construction of the entire project required assembling the tower as it arrived in pieces. For engineers this meant that installation of the access elevator could proceed only after the tower was fully erected. For the elevator planning KONE engineers had to take into account the limited space inside the tower, the seismic requirements of Grouse Mountain, and the tower’s continuously swinging structure.

Consider these space issues: While the base of the tower measured a standard 13 feet (3.96 meters) in diameter, the tower tapers to just over 6 ½ feet (2 meters) at the top. That space on the top allows for only one-third of the space of an average elevator shaft. To meet those tight requirements, the tower was fitted with KONE’s MonoSpace© solution, which doesn’t require a machine room and is powered by KONE’s EcoDisc hoisting technology, allowing engineers to maximize use of the restricted space while ensuring a safe, energy efficient, and comfortable trip to the top.

KONE has pioneered the “machine-room-less” (MRL) technology, allowing more and more commercial, residential, and industrial buildings the advantage of greater design flexibility. With this technique there is no need for the bulky elevator room above the top floor. Such a design would have been impossible at the Eye of the Wind, and it is increasingly falling out of favor in more-traditional structures. In addition, KONE’s solution is more energy efficient than traditional technology, another benefit for all structures. This approach is up to 70 percent more efficient than a hydraulic device, and 50 percent more efficient than a traditional traction unit.

After the size of the elevator was determined, engineers turned their attention to Grouse Mountain’s location in an active fault region. KONE’s Marine Department was called in to help design and implement the structure, as that department has experience with moving structures. In this case, the land on Grouse Mountain is part of an active fault line, so it is literally moving. At the same time, the pressure from the wind and design of the structure itself—which pivots to capture the best winds—means that the structure is constantly moving. The unique solution combines KONE’s elevator technology with a seismic installation and an emergency brake release system. All of these features working together provide a safe and efficient manner to visit the Eye of the Wind.

“This project was unique in that it drew on existing technologies but applied them in an innovative way,” according to John Hemgard, coordinator of the project at KONE Marine & Major Projects. “So many people worked together to make this happen, from the turbine builder to Grouse Mountain to the local KONE installation team. This was a clear example of how existing KONE technologies were used by the teams, which collaborated and drove the completion of the project.” Figure 3

The Visitor Experience
The Eye of the Wind gives visitors the chance to experience wind power from a revolutionary perspective. The vast majority of the population is familiar with wind turbines simply through magazine articles, documentaries, or by witnessing them churning away in the distance, but very few people have the opportunity to see them in person. Until now, almost no one has been able to experience the harvesting potential from The Eye of the Wind. Overlooking Greater Vancouver’s bustling harbor, the pristine Coastal Mountain Range, and the vast, green wilderness of the Canadian countryside, The Eye of the Wind provides visitors with unprecedented 360-degree views from the sky. Visitors begin the ascent to the top with a 35 second elevator ride.

After exiting the elevator, visitors step into the viewPod™, a glass-encased room suspended directly below the hub of the turbine’s blades. The room also features a glass segment on the floor, allowing visitors to look down at the ground and fully appreciate the tower’s height and magnitude. The experience is described as similar to flying in the clear plexiglas nose bubble of a helicopter, only the viewPod is approximately 30 times larger. Once they have entered it, visitors can literally feel the movement of the giant turbine blades. On a clear day they can see southeast to snow-capped Mount Baker and Mount Rainier, and to the north their sister mountain, Mount Garibaldi. All three are part of the still-volcanic Cascade Range of western North America. Directly to the west and southwest lie Vancouver Island, the Gulf Islands, the San Juan Islands, and the Olympic Mountains. Depending on the time and day, views from The Eye of the Wind may include sunsets, sunrises, and the silver-gray storms that blow in off the Pacific Ocean.

“Days with clear, sunny weather tend to be the most popular,” Dagenais says. “However, the public is beginning to realize that days with inclement weather provide the opportunity to see the tower in action, when it is generating electricity.”

The Benefits of Tourism
The viewPod presents the public with an opportunity to experience the true power of wind energy, making The Eye of the Wind an important educational vehicle for the wind industry. For many years wind turbines have been perceived as the massive, sometimes imposing structures read about in magazines or driven by on the highway, not structures known and enjoyed personally. By providing a face-to-face, intimate glimpse into the wind industry, The Eye of the Wind introduces the concept of wind power to tourists and allows them to get comfortable with the industry as it expands.

Individuals take away the grace of the turbine blades circling in the air and the majestic views from the top of the tower. The whole experience dispels the myths and rumors about noise pollution from the blades and amends the public perception of the towers’ unsightly nature.

To make that access a reality, the public elevator was necessary to safely and quickly move visitors to the top of the structure. The Eye of the Wind is at the cutting edge of a trend to turn wind turbines into tourist attractions and create additional sources of revenue for wind farm owners. Turbines can now be seen as part of the environments in which they stand, becoming tourist attractions rather than simply accessories to scenic landscapes. Figure 4

Future Opportunities
Throughout the world turbine owners are taking steps to attract curious visitors and educate tourists on the value of wind energy. For example, wind farms are building visitor centers to attract and educate tourists on the value of wind energy. Companies are developing boat tours to take tourists out to sea and visit offshore wind farms in Michigan. Even tourist destinations at remote offshore farms are being conceptualized: one Norwegian design firm’s concept, “Turbine City,” places a hotel, spa, and cultural museum at the base of an offshore wind turbine.

Already people are paying to visit wind turbines and be photographed with them. At Whitelee, Europe’s largest wind farm, over 25,000 people toured the visitor center in its first nine weeks of operation. The center is located in a fairly remote area of Scotland that has not previously attracted much tourist attention, suggesting that the lure of wind power to tourists is strong.

Conclusion
From the project’s start to its meticulous finish, The Eye of the Wind has truly become more powerful as a whole than the sum of its parts. The project’s turbine, its revolutionary viewing tower, and the access elevator that makes the experience possible symbolize the kind of creativity, innovation, and collaboration taking place in the sustainable energy industry. It is the most recent marketable wind energy advancement and a leading example of eco-tourism to advance the wind energy cause, and KONE is proud of its participation in this project. 

The cornfields around Yorktown, Indiana—about 40 miles from Indianapolis—are among the most fertile found anywhere in the United States. It’s also the perfect environment for cultivating another kind of business, so it’s here that Brevini Wind USA has set down deep roots with a $50-million, 100,000 square-foot ultramodern facility featuring North America’s only 6.4 MW test bench for the production of main gearboxes for 0.9 to 3.5 MW wind turbines. This, of course, is the size range typically found in most of today’s land-based applications in the region. If you think that Brevini Wind is “betting the farm” on the U.S. wind power market, you’d be right. After all, wind turbine deployments in North America are expected to exceed 40,000 units between 2010 and 2015. While Europe dominated the world market for wind turbines five years ago with 70 percent of new capacity, today the U.S. and China account for 62 percent of new capacity, with Europe following at 27 percent.

Beginning in November of this year the new facility will offer many advantages to wind turbine customers seeking to penetrate the booming North American marketplace, according to Managing Director Dr. Jacopo Tozzi. “Most of the major wind turbine manufacturers are based in Europe, so the logistical benefits of sourcing gearboxes ‘locally’ through Brevini Wind USA will be significant for them going forward,” he says. “We are already seeing evidence of this, in fact, with a large order from Finnish wind turbine manufacturer WinWinD for their 3MW wind turbines.”

The gears for WinWinD’s gearboxes, and Brevini Wind’s other customers, will all be produced by Gleason machines employing new technologies that simply didn’t exist a year or two ago. Tozzi believes that his company’s investment in these new Gleason technologies and processes will help the company to quickly become a major player in the production of a new generation of highly reliable, lightweight, and efficient wind power main gearboxes, giving the company a decided competitive advantage going forward. “Brevini Group, and the Brevini Power Transmission division in particular, is no stranger to wind power, having produced some 60,000 pitch and yaw systems for wind turbines over the years,” Tozzi explains. “Our division, Brevini Wind, was established two years ago in order to concentrate on the design, development, testing, and manufacture of main gearboxes for wind turbine applications. This, of course, is one of the most challenging applications for gears, given the high and dynamic loads and the need for extreme reliability. In order to better understand how our competition was meeting these challenges I had the opportunity to tour many of their plants in Europe, China, and India. Almost without exception, the machines they were using for gear production were made by Gleason.”

By November two new Gleason profile grinding machines—models P1600G and P2400G—and two Gleason hobbing machines, models P1600 and P2400, will be up and running at the Brevini Wind USA facility, producing all of the gears found in a series of new generation two-stage planetary gearboxes. These include ring gears with diameters as large as 2.2 meters and accuracy requirements as high as ISO Grade 6 or better, and smaller gears of ISO Grade 5 or better. These classifications are typical of gears for wind turbine applications, although the Gleason profile grinders can actually deliver even ISO Grade 3 or better, if required.

These new planetary gearboxes can produce reduction ratios of up to 37:1 with up to 98 percent efficiency, while at the same time reducing overall size and weight by 25 percent as compared to competitive models. But perhaps most importantly, Brevini Wind will gain an enormous competitive advantage by producing these gears much faster, more accurately, and using fewer machines thanks to a revolutionary new Gleason hard finish grinding process called OPTI-GRIND™. Available only on the latest generation of Gleason profile grinding machines, OPTI-GRIND will enable Brevini Wind to cut precious minutes and even hours out of the time typically needed to profile grind one of its large gears, since productivity gains of up to 40 percent are possible as compared to grinding conventionally. In addition, OPTI-GRIND also can be used to deliver surface finishes better than 0.2 microns; a finish two to three times the level that is generally achievable with profile grinding alone, and so accurate that no additional processes are required after grinding.

According to Gleason Director of Product Management, Grinding Solutions, Dr. Antoine Türich, for the first time OPTI-GRIND solves the dilemma that every gear manufacturer faces: how to achieve, with optimum efficiency, both highly desirable productivity gains and exceptional accuracies. “Wind power gear manufacturers can of course achieve high productivity by using a coarse-grit grinding wheel that will remove a sufficient amount of material when roughing, but these won’t deliver the required fine surface finishes,” Türich explains. “Conversely, a fine-grit wheel can be used to produce an excellent surface finish, but at the expense of productivity. As a result, grinding wheels are generally used that are a compromise solution, delivering reasonable levels of productivity and accuracy, but well below optimum levels. But with OPTI-GRIND we can achieve both optimum productivity and surface finishes by simultaneously using multiple dressable grinding wheels for profile grinding rather than just the single ‘compromise’ grinding wheel typically used.”

The new process offers end users like Brevini Wind a number of variations to choose from to meet their specific applications. When optimum productivity is desirable, for example, an assembly of three dressable wheels is used to rough grind four tooth flanks simultaneously, as compared to the typical process of a single wheel roughing only two tooth flanks at once (Figure 1). OPTI-GRIND then is used to finish grind conventionally using just the single center wheel, which has been dressed to produce the desired surface finish and flank modifications.

For planetary gears and pinions, an OPTI-GRIND variation using the two outer wheels alone is available, with each grinding a flank on separate gear teeth simultaneously (Figure 2). This variation reduces the radial infeed required as compared to grinding conventionally with a single wheel. OPTI-GRIND provides a wheel orientation that optimizes the contact angles between the grinding wheel and workpiece flank. This variation offers the largest benefit for pinion type gears because of their substantial profile angle variation from tooth tip to the tooth root.

In applications requiring maximum surface finish quality, a third variation is available. As shown in Figure 3, OPTI-GRIND uses two outer wheels with an aggressive grit size to each rough grind a flank on separate gear teeth, before a middle wheel with extremely fine grit size finishes the left and right flanks.

“It’s important to note that OPTI-GRIND uses dressable wheels for fine finishing rather than the non-dressable CBN wheels used in previous multiple-wheel profile grinding techniques. With OPTI-GRIND we give users the flexibility to produce a variety of highly desirable tooth modifications, including grinding of the root without burning,” Türich says, noting that on the Gleason profile grinders the dressing unit is actually integral to the grinding head, a unique design that helps to reduce dressing times and improve accuracy and repeatability. Figure 4

Brevini Wind also hopes to gain yet another edge on its competition by optimizing its “soft” cutting operations as well, with a new Gleason hob design called OPTI-CUT®. Unlike the solid HHS cutters normally used for large gear hobbing, the OPTI-CUT family of roughing and finishing hobs, as well as gear gashers and shaper cutters, are very high quality assemblies consisting of either five or six cutter body segments and utilizing the latest replaceable, indexable carbide insert technology. Figure 5 By using a cutter with the latest carbide materials, coatings, and cutting geometries, Brevini Wind will be able to run its two new Gleason hobbers at significantly higher feeds and speeds—for both external and internal gears—and even cut dry, helping to make significant reductions in total cost per workpiece.Other benefits include more-consistent tool life and surface finishes, while at the same time eliminating the time and expense needed for resharpening and recoating a conventional solid cutter.

“Launching a company to produce main gearboxes for today’s wind turbines is not something that can be done easily or quickly,” according to Tozzi (Figure 6). “We have spent a number of years laying the groundwork with the right team of people, and a significant investment in new technologies and processes, with the new Gleason machines being among the most important of these. Now we are poised to help customers take advantage of the enormous potential that exists today and tomorrow in wind power throughout North America.” 

From determining optimum wind conditions in a large general region to micrositing turbines in more localized areas, the proper location of wind power facilities is imperative. Precise elevation data can be used to develop viewshed analysis, project siting plans, visualization and preconstruction presentations, and other critical aspects of wind power project planning. In short, high-resolution elevation data can improve many physical and environmental suitability aspects of wind power analysis, all while helping to control a project’s final cost.

Data Quality and Cost
Elevation data can be gathered from a variety of optical and microwave sensor sources, each with its own set of benefits and drawbacks. For instance, the lowest-cost (or even freely distributed) elevation data has been gathered by satellites. However, most satellite-sourced elevation data has vertical accuracy ranging from 3 to 10 meters. Shuttle Radar Topography Mission (SRTM) elevation data, collected onboard the U.S. space shuttle Endeavour in 1990, provides coverage for much of the world at 10- to 15-meter vertical accuracy. At the other end of the precision spectrum is data collected with Light Detection and Ranging (LiDAR) technology, which offers 20-centimeter vertical accuracy, and at a much higher price than other options. Aircraft-mounted interferometric synthetic aperture radar (IFSAR) data, which has an average vertical accuracy of 1 meter, lies in the middle of that precision and pricing range. Figure 1

Each digital elevation dataset has a different posting, or the size of the grid on which individual elevation measurements are taken. For instance, a RADARSAT-derived elevation dataset has a 30-meter posting, meaning that elevation values are available every 30 meters in the dataset, with vertical elevation values accurate within 10 meters. Intermap Technologies’ IFSAR-derived NEXTMap dataset has a 5-meter posting specification with a predominantly consistent 1-meter or better vertical accuracy.

The range in vertical accuracy and posting specifications of digital elevation data lends itself to the different types of applications in the wind energy market. Reconnaissance mapping, for example, is generally conducted on a 1:50,000 scale and thus requires a less-accurate dataset, whereas micrositing a series of turbines would require significantly more precision since a turbine in a location with prime wind conditions can be almost twice as productive as another located only 30 meters away, the horizontal and vertical accuracy of data used in the micrositing process is critical.

Intermap’s NEXTMap USA and NEXTMap Europe datasets provide complete uniform coverage of the contiguous United States and Hawaii, as well as all of Western Europe, respectively. NEXTMap Europe was made commercially available in May 2009, and NEXTMap USA was made fully available in June 2010. The programs mark the first time in history that a private company has remapped, processed, and edited digital elevation data for the United States and Western Europe.

Elevation Data Crucial
Digital elevation data provides information for planning new infrastructure, assists in the prediction of wind condition calculations, and can help project planners make more cost-efficient business decisions about existing infrastructure and accessibility. Wind project planners know that it’s important to identify the various factors that can affect a project’s cost structure, such as:

• Local policies, including restrictions that govern turbine height, noise levels, and protected environmental areas;
• Product standards and certifications required by local authorities;
• The potential of extreme weather and natural disasters;
• The planned site’s infrastructure and accessibility.

High-resolution digital elevation models (DEMs) and aerial images that have been orthorectified using those DEMs allow planning to proceed based on the exact geospatial locations of existing infrastructure such as access roads and transmission lines, and therefore more accurately predict the cost of extending transmission lines or building new facilities. Because wind farms are predominantly located in rural open areas or on mountainous terrain, far removed from urban centers where the greatest power demand exists, efficiently locating the best placement of the transmission line corridor is critical to a project’s success. Digital elevation and image data provide planners with the ability to take a number of key factors including terrain, land acquisition, and cost into account while optimizing the route of a transmission corridor, all while reducing the costs, time, and risk involved with the project. Figure 2

For instance, an orthorectified radar image (ORI)—a grayscale image of the earth based on a DEM—accentuates topographic features on the earth’s surface far more than what is possible with a standard aerial photograph. An ORI of an existing wind farm allows planners to be aware of the precise location of all current infrastructure including wind turbines, transmission lines, power stations, and highways when considering a possible expansion of the farm.

DEMs Provide Planning Information
Digital elevation models (DEMs)—which include digital surface models (DSMs), digital terrain models (DTMs), and orthorectified radar images—provide a wealth of information about many different aspects of a wind farm development project, and they can help definitively determine whether a proposed site can accommodate wind turbines and supporting infrastructure such as roads and transmission lines. Further, the information can be used to determine the efficiency of turbines in a proposed location compared to those in another location. Figure 3

Both DSMs and DTMs provide critical information including elevation analysis, slope gradients, and ridgeline locations. DSMs present a wide array of accurate, three-dimensional information about potential site locations, including the crucial viewshed analysis. Adherence to local setback regulations, critical to the local approval of any wind farm planning project, can be achieved with the information conveyed by DSMs.

DTMs, derived from DSMs, are topographic models of the bare earth from which vegetation, buildings, and other cultural features have been digitally removed. DTMs are ideal solutions for planning construction of wind power facilities, from micrositing turbines to placing access roads and transmission lines.

DTMs are also used to develop landslide hazard maps for areas with significant slopes such as ridgelines. For instance, DTMs could be used to classify the terrain in a proposed development area into slope grade categories of less than 20 percent, between 20 and 30 percent, and more than 30 percent, and those categories would then be superimposed with local soil survey maps that provide soil type information such as whether the soil is predominantly silt, clay, or bedrock. The resulting map would provide a planner with information about whether a proposed site meets a local government authority’s criteria for landslide hazards. Figure 4

To help minimize contact between birds and wind turbines, DEMs have been used in studies that combined wind velocity and direction, tower height, and bird behavior such as elevation of their flight, among other factors, with the slope, aspect, elevation, and orientation to wind direction of the terrain.

Still in the planning phase, aerial photography is coupled with digital elevation data to produce three-dimensional visualizations, panoramic views, and line-of-sight viewshed perspectives, allowing planners to see the possible impact of a proposed wind farm development. The perspectives allow planners to realistically see what a proposed wind farm would look like from a particular point on the ground, or to accurately determine how much, if any, of a wind farm could be seen from a particular point.

For instance, a viewshed perspective can show exactly how many turbines would be visible from a farmer’s house. Using only an aerial photograph of the house and surrounding terrain, it’s difficult to determine the extent to which a series of turbines could be seen from the house. Using digital elevation data together with the aerial photograph, a viewshed perspective will illustrate exactly which, if any, of the turbines can be seen from that house. Viewshed perspectives can be developed with varying factors, such as the radius of the viewshed; a three- or five-mile radius from the farmhouse, for instance.

To help demonstrate the visual effect of a planned wind farm, ORIs provide up to date and accurate information that helps interested parties see the potential impact of a project in relation to existing infrastructure, and to a precision that’s unavailable with standard aerial images. Because ORIs are generally derived from DEMs, their horizontal accuracy is dependent on the accuracy of the original digital elevation model. An Intermap ORI derived from a NEXTMap DEM, for instance, has a 1.25-meter pixel resolution—each pixel in the image covers 1.25 meters, or about 49 inches, on the ground—and an average horizontal accuracy of 2 meters. Since they are images rather than digital elevation data, ORIs have no vertical accuracy specification.

Terrain Analysis and Wind Modeling
The software packages that extrapolate wind climate statistics and create wind flow models—information used to predict wind farm production and efficiency, calculate power production, and microsite turbines—use terrain data as one of their primary inputs. In the case of wind modeling the “roughness,” or level of terrain detail, of the elevation data used is critical in order to accurately predict wind currents. Forest canopy height data from Intermap’s NEXTMap program was recently used in a study conducted by Meteodyn to show the effects of high-level disturbances and strong wind shears in forested areas. DTMs are also used to create contour lines. Together with the land use digital map and meteorological data, contour lines can help determine the potential wind energy that could be obtained at a particular site.

On a regional level, digital elevation data and orthorectified images can help a wind project planner determine the optimum areas in a very large region in order to further refine the search for a project site. By combining various factors such as terrain elevation, slope, land use, access to existing infrastructure and the power grid, federally and locally protected areas, and models of wind power potential provided by software, a planner can localize a search to only those areas that meet each of the optimum conditions. For instance, a planner can restrict site searches to only those areas that are at a certain vertical elevation and within a certain number of miles of the power grid, while excluding those areas that are a certain number of miles within any airports, national parks, urban areas, and many other variables. This approach, generally undertaken with a geographic information system (GIS), saves considerable time and resources while reducing unnecessary risks and costs.

The wind energy applications enabled by digital elevation datasets are wide and varied, and as the industry continues to grow the list of uses for precision elevation datasets will undoubtedly expand as well. 

In recent years the world has witnessed continuous and rapid development of wind power in China. By the end of 2009 more than 20,000 wind turbines had been erected across the country from north to south, and from inland to the coast. As time passes turbines are coming out of warranty, and their maintenance begins coming at the operator’s own cost. Therefore, besides the productivity of a wind turbine, wind farm operators are more and more interested in reducing their lifecycle costs; i.e. reducing maintenance costs during the lifetime of wind turbines.

In this context, Condition Based Maintenance (CBM) is recognized as the most practical approach to tackling this market demand. It allows timely maintenance before failure occurs so as to avoid consequential failure escalation and prepare necessary resources, e.g. spare parts, cranes, time slot, etc. At the same time this means increased availability and reduced lifecycle costs. Due to this it is necessary to monitor the conditions of wind turbines and their components in an overall approach based on real-time data on the wind turbine, providing information and automatic diagnosis in advance in cases of potential failure. Figure 1

With years of experience in condition diagnosis for electromechanical systems Siemens Ltd., China-Corporate Technology—SLC CT, for short—works hand in hand with Winergy to foster the application of condition-based maintenance in China, to ensure a sustainable future for its ever-growing wind power market. The lessons learned and technologies developed for this particular application will benefit newer, evolving markets around the world, such as that found throughout North America.

Resolution: Winergy CDS
The new Winergy Condition Diagnostics System (CDS) supports wind farm operators and wind turbine manufacturers with comprehensive health information of their wind turbines. The Winergy CDS goes far beyond a conventional condition monitoring system. It delivers advanced signal processing and automated machinery health diagnostics values on vibration levels, load, and oil properties, therefore permitting more-reliable diagnostics and forecasts about future availability once the operating abnormalities of the wind turbine are detected. You receive recommendations for the necessary corrective action so that your workflow is optimized. Fault messages, diagnostics, localization, forecast, recommended solutions—all of the relevant information is provided in an automated format to the Operations and Maintenance center. All of this happens at once, without any experts being involved, and the information is delivered to the appropriate parties in real time. As a consequence, the all-decisive time advantage is being created in order to secure increased system availability and to minimize the lifecycle costs. It could hardly go any faster.

The following example may demonstrate how an automatic diagnostics system like Winergy CDS can help wind turbine owners keep their turbines in good shape. When a defect is detected on a wind turbine gearbox—e.g. flaking on rolling element bearing or on gears—alarm information will be displayed on the monitoring screen of Winergy CDS which is located, for example, in the central monitoring room of the power generation company (Figure 2). Here the health conditions of all turbines owned by this company are monitored. Operators can identify where the problematic wind turbine stands on a map screen, on which a status overview of all wind turbines is organized as wind farms (Figure 3). The defective wind turbines will be categorized according to different criticality levels. A yellow-colored number indicates how many turbines have detected defects, but can still continuously operate. A red number shows turbines with defects that have reached critical level and need timely maintenance actions. In this example, it reports that a wind turbine has a critical defect and needs to be dealt with immediately (Figure 2).

This information is then automatically sent to the maintenance department, and the maintenance technicians can look at detailed diagnostic results provided by Winergy CDS to arrange their repair work. It shows that the critical-level defect is located in the gearbox with a red color (Figure 4). And when the gearbox icon is clicked, possible defective bearings or gears are displayed in red (Figure 5). When needed, a text message alarm window can point out the defect location, type, criticality level, and recommended actions (Figure 6). Here the defect is diagnosed as a rolling element defect on gearbox’s high-speed shaft bearing #542. There are 94 days remaining for continuously normal operation in worst case. Such a clear diagnosis will save plenty of time on manually analyzing signals and possible defect locations, guiding maintenance technicians in conducting inspection and repairs.

On the other hand, experienced users can still use the state of the art signal analysis tools provided by Winergy CDS, e.g. spectrum, order tracking, trend analysis, etc., to conduct their own diagnosis (Figure 7). The system is based on standard products that are proving themselves in daily operation worldwide. It records, processes, visualizes, and stores signals (analog and binary) and numerical data. Based on the latest industrial PC technology (Microbox PC) and hardware I/O nodes, the modular structure is flexible and grows with the requirements of customers (Figure 8). Moreover, the system can be integrated into existing and new wind turbine systems interference-free and for use with multiple devices. Standardized interfaces ensure reliable, simple connection of the most varied signals sources.

Synergy: Service Package
As the only supplier offering a complete drivetrain of wind turbines to customers, Winergy has the privilege of integrating its CDS system with its after-sales service for its gearboxes and generators. When such a monitoring system issues a warning, wind farm operators must determine what they should do about it. Based on the comprehensive health data from CDS, Winergy provides on-site inspection, professional advice on reaction, repair service, and even long term service agreement for wind farms (Figure 9) so that a real predictive maintenance scenario can be implemented together with wind farms to keep their turbines in good operating order. In the case of wind turbines equipped with non-Winergy drivetrain components, Winergy CDS can also be applied without difficulties or reduction of diagnostic functions. Certain service consultancy can be provided to wind farm operators in such instances.

Fostering Acceptance
The sustainable development of the China wind market relies on the profitable operation of wind farms. If not, large-scale application of wind power will become a money-burning game. The condition monitoring and condition-based maintenance for wind turbines seem to be a hopeful solution.

Unlike the European market, however, where insurance companies mandate the application of condition monitoring systems on wind turbines, in the China market wind farms decide whether or not to install such a system on their turbines. Suspicions about the effects of condition monitoring systems always arise when it is introduced to China wind farms, with concerns including: how automatic conclusions are made, and conclusions can be verified; and what should be done when defects are reported by the system­—replace the part, or allow the turbine to continue to operate?

This is when SLC CT comes onto the stage. With years of experience on condition diagnosis for electromechanical systems, we help wind farms in China adapt condition-based maintenance with the Winergy CDS system to improve maintenance efficiency and reduce related costs. Capabilities include:

• Conducting onsite inspection and system specification for applying the Winergy CDS at the wind farm;
• Helping integrate Winergy CDS into the wind farm’s maintenance workflow;
• Providing consultancy on the automatic diagnosis result by Winergy CDS, thereby increasing user confidence.

Since September of 2009 we have been involved in executing four projects in China, including local wind farms at Gansu, Hebei, Jiangsu, and Fujian provinces, and from the northwestern inland region to the southeastern coast, helping them use Winergy CDS in their daily maintenance work to improve efficiency. Early defects have been reported on generator bearings, and a clear development trend of these defects can be drawn automatically by the system, allowing maintenance technicians to plan their future work in advance.

Perspectives
No matter where it is located, the world wind industry is beginning to realize that they should not concentrate on new turbine installations alone, but also how to operate existing turbines in a profitable way. Today big wind power owners have begun to think about this maintenance challenge, and a resolution will be required soon. SLC CT will use its experience to continuously help foster the application of condition-based maintenance at wind farms located in China, ensuring the sustainable growth of the wind power industry while contributing to the development of a global green economy.