NREL and Great Lakes Wind target midsized turbine designers and manufacturers

The DOE and NREL have launched the Midsize Wind Turbine Development Project to help close a technology gap and facilitate development and commercialization of midsize wind turbines. The Laboratory is sponsoring workshops in Ohio and Oklahoma, facilitated by Cleveland-based Great Lakes Wind Network, to build awareness of the DOE-NREL Midsize Wind Turbine Development Project and encourage collaboration to assist U.S. manufacturers and wind turbine designers in producing near-term commercial value-engineered midsize turbine prototypes.

NREL worked with Northern Power Systems to redesign its 100-kW wind turbine.

The wind industry is growing fast in North America but the use of midsize wind turbines in the U.S. is hampered by a lack of options and market availability. This growth market provides a chance for designers, manufacturers, and component suppliers to join forces, close the technology gap, and at the same time build our nation’s midsize wind turbine supply chain.

Workshops will feature networking, panel presentations by turbine designers and manufacturers, information on NREL’s National Wind Technology Center, and existing and future manufacturing opportunities.

Cost for each full day event is $95. For sponsorship details contact Mari-Elen Sammon at (216) 588-1440 ext. 121. For more information, contact Ed Weston (GLWN) (216) 588-1440 ext. 125 or EWeston@glwn.org or Karin Sinclair (NREL) (303) 384-6946 Karin.Sinclair@nrel.gov .

Where and when:

In Ohio, Wednesday, March 24, 2010

Doors Open at 7:30 am

8:00 am to 5:00 pm – Networking Reception to Follow

University of Cincinnati – College of Applied Science

2220 Victory Parkway, Cincinnati, OH 45206

In Oklahoma, Thursday, April 8, 2010

Doors Open at 7:30 am

8:00 am to 5:00 pm – Networking Reception to Follow

Northeastern State University – Building A – Banquet Room

3100 East New Orleans, Broken Arrow, OK 74014

NREL and Great Lakes WIND target midsized turbine designers and manufacturers

The U.S. DOE and NREL have launched the Midsize Wind Turbine Development Project to help close the existing technology gap and facilitate development and commercialization of midsize wind turbines. The Laboratory is sponsoring workshops in Ohio and Oklahoma, facilitated by Cleveland-based Great Lakes Wind Network, to build awareness of the DOE-NREL Midsize Wind Turbine Development Project and encourage collaboration to assist U.S. manufacturers and wind turbine designers in producing near-term commercial value-engineered midsize turbine prototypes.
Wind is the fastest-growing industry in North America however the use of midsize wind turbines in the U.S. is hampered due to a lack of options and availability in the market. This growth market is a chance for or designers, manufacturers, and component suppliers to join forces to close the technology gap and at the same time build our nation’s midsize wind turbine supply chain.
Workshops will feature networking, panel presentations by turbine designers and manufacturers,
information on NREL’s National Wind Technology Center, and existing and future manufacturing
opportunities.
Cost for each full day event is $95. For sponsorship details contact Mari-Elen Sammon at 216.588.1440 ext. 121. For more information, contact Ed Weston (GLWN) 216.588.1440 ext. 125 or
EWeston@glwn.org or Karin Sinclair (NREL) 303.384.6946 Karin.Sinclair@nrel.gov .

WHEN:
In Ohio, Wednesday, March 24, 2010
Doors Open at 7:30 AM
8:00 AM to 5:00 PM – Networking Reception to Follow
University of Cincinnati -College of Applied Science
2220 Victory Parkway, Cincinnati, OH 45206

In Oklahoma, Thursday, April 8, 2010
Doors Open at 7:30 AM
8:00 AM to 5:00 PM – Networking Reception to Follow
Northeastern State University – Building A – Banquet Room
3100 East New Orleans, Broken Arrow, OK 74014

More about the sponsors:
A WIRE-Net initiative, Great Lakes WIND Network is an international advisory group and network of manufacturers and suppliers whose mission is to grow the wind industry supply chain and increase domestic content to meet the expansion needs of the global wind market.

EPA says 12 environmental sites could be wind farms

The U.S. Environmental Protection Agency (EPA) and the U.S. Department of Energy’s National Renewable Energy Laboratory (NREL) are evaluating the feasibility of developing renewable energy production on Superfund, brownfields, and former landfill or mining sites.

Superfund sites are the most complex, uncontrolled, or abandoned hazardous waste sites identified by EPA for cleanup due to the risk they pose to human health or the environment. Brownfields are properties for which expansion, redevelopment, or reuse may be complicated by the presence of contaminants. EPA is investing more than $650,000 for the project that pairs EPA’s expertise on contaminated sites with the renewable energy expertise of NREL. The project is part of the RE-Powering America’s Land initiative, which aims to decrease the amount of green space used for development, reduce greenhouse gas emissions, and provide health and economic benefits to local communities, including job creation.

The project will analyze the potential development of wind, solar, or small hydro development at 12 sites. The analysis will include determining the best renewable energy technology for the site, the optimal location for placement of the renewable energy technology on the site, potential energy generating capacity, the return on the investment, and the economic feasibility of the renewable energy projects.

The 12 sites are located in California, Florida, Kansas, Massachusetts, Michigan, Minnesota, Pennsylvania, Puerto Rico, Rhode Island, West Virginia, and Wisconsin.

Some of the sites under consideration for renewable energy projects have completed cleanup activities, while others may be in various stages of assessment or cleanup. Renewable energy projects on these sites will be designed to accommodate the site conditions. For fact sheets on each location, and more information on the RE-Powering America’s Land initiative, visit the Web site, www.epa.gov/renewableenergyland/

National Labs and OEMs Have Lots of Ideas, Suggestions for Suppliers

The recent Wind Power Explained conference, presented at the Design and Manufacture Expo in Chicago, presented a full day of discussions to attendees on topics from the Department of Energy, NREL, Sandia Labs, GE Energy, Northern Wind, and Clipper Windpower. Here’s a sampling:

The presentation by Ron L. Harris included this list of DOE success metrics.

“The DOE recognizes the challenge in making wind energy a reliable and integrated source,” said Ron L. Harris, from the agency’s Office of Energy Efficiency. Harris told how the DOE wants to ensure that the supply chain for wind technology is sufficient to increase market demand and consistent with a goal of supplying 20% of the U.S. electricity needs by 2030. “The agency also wants to maximize opportunities for domestic manufactures of wind-energy equipment by facilitating supply chain development.” In the Q&A session, Harris mentioned that developers of small wind turbines should submit ideas and products to the U.S. Army because when deployed in remote regions, they would like to take power sources other than gas-powered generators, and small turbines might work well.

Sandy Butterfield, Chief Engineer, National Wind Technology Center, discussed his experience with gearboxes. “They were a source of reliability problems and maintenance costs in early designs,” he said. “Fatigue loads were the driving loads. Since then, development of standards, such as IEC 61400-22 have helped improve their design so they are more reliable. Focus now is shifted to bearings.” Regarding turbine size, Butterfield points to the problems of shipping, such as bridges too low for large turbine blades and nacelles, that will keep land based turbines to about the maximum where they are now. “Off shore, however, the designs would have no restrictions so turbines could grow to 10 MW and larger,” he said.

From Sandy Butterfield's presentation

Paul Veers, Technical Staff, Wind Energy Technology Department, Sandia National Labs, discussed how to get more power out of the wind. An early wind engineer Albert Betz observed that about 59% was a theoretical maximum. Recent designs have gotten bigger and taller. But a larger rotor increases in cost with the cube of the length increase, and taller towers cost go up with height to the fourth power. “Hence, the only way to win this cost battle is to build rotors that are smarter and components that are lighter,” said Veers. Then he showed several ideas for doing so.

Lawrence D. Willey, GE Infrastructure, Wind, said the U.S. is likely to see a doubling of energy needs by 2030. Good news is that wind is now cost-competitive with other fuels. “The company has developed software for engineers to guide their design work with regard to cost. The software includes influence coefficients that determine costs.

What’s more, engineers have lots of ideas, and a value analysis is one way to weigh them. “It’s a way to tell we are working on the right thing for customers and ourselves,” he says.

The beginning is the sweet spot and when to put in all the options. “You can’t start early enough when it comes to designing to cost,” he added. Even for subcomponents, this makes sense. Money spent at a project’s start is money spent wisely. When manufacturing begins, its too late for cost savings.

Taylor Robinson, VP of Global Supply Chain for Northern Power Systems, discussed how the design of company turbines makes for an efficient supply chain. “We want a supply chain close to the company and working quickly. The concepts here go back to six sigma and lean.”

“Quality will be essential from suppliers, and they must deliver on time and at the agreed cost,” he said. Components for his firm’s 100 kW turbine come from Europe and U.S. suppliers. One turbine a day is their production target. “Another goal is to get suppliers delivering more complete subsystems rather than a few components. With the right partner, it is possible to have more control over a design from a supplier than if the component were made in your own factory,” he said. Robinson added that he will work on long-term agreements with suppliers, but the arrangements have to be win-win agreements.

Derek Ptech, Director of Engineering for the 2.5 MW turbines at Clipper Windpower, said value analyses come from designing to cost. One trend in the industry is certifying the technology by third parties, such as Germanischer Lloyd.

One industry driver is that energy consumption will be up by 50% in 2020 along with a population growth of 20%. “The more steady feed-in laws in Europe have resulted in steady growth there. Likewise, because Texas has an RES, it has a greater install capacity than other states, so a national RES would be a boost to the entire industry.”

Ptech added that increased reliability is one governing ideal for the company turbines because some components have no backup. “For instance, pitch mechanisms in the hub for each blade work independent of each other and so have batteries to run them in case conditions take the turbine off grid. Dramatic events define design conditions,” he said. Another example is that the Clipper has four generators so that one, two, or three of them can be removed and the turbine still produces power.

Simulating the Turbine-Simulating the Site

Designing the most efficient and effective wind turbine calls for modeling tools that provide accurate, reliable numerical predictions of wind-turbine rotor performance over a machine’s full range of operating conditions. Simulating real-world conditions using computational fluid dynamics (CFD) lets users understand flow phenomena and their effects on the system, better predict the system’s power output, and analyze the types of vibration, fatigue, and other wear-and-tear the wind turbine may experience for the conditions modeled.

Such complex analyses are necessary for complex machines. Wind turbines, for instance, typically include:

• A bladed rotor for converting wind energy into rotational shaft energy;
• A nacelle housing a drive train, which usually consists of a gearbox to increase the rotational shaft speed, a electrical generator that produces a medium voltage, and a transformer that later increases the voltage of the electric power to reach its distribution voltage
• A tower to support the rotor and drive train, and
• Electronic equipment such as controls, electrical cables, ground support and interconnection equipment.

CFD simulation provides valuable insight into all aspects of wind-turbine development, from optimizing advanced blade designs to simulating and comparing the behavior of competing wind-turbine configurations. Engineers can evaluate various tip devices, such as spoilers, deployable gurney flaps, and other control devices to assess the impact of different hub and tower heights, and test and explore alternative scenarios and “what if” questions related to optimizing wind turbine designs.

This is especially important because many innovative designs being considered cannot be reliably modeled using conventional tools. For example, the classical Blade Element Momentum (BEM) method has been the prevailing approach for modeling wind turbines. While it is sufficient for modeling many applications, it is not able to adequately account for the impact of large 3D effects on flow, nor the impact of new blade geometries. Recent experimental work shows that CFD modeling can effectively simulate the behavior of novel blade geometries, with better results than from the BEM approach.

Reading the CFD Output The CFD simulation of NREL’s unsteady aerodynamic experiment in a downwind two-blade rotor configuration shows isosurfaces of vorticity magnitude colored by the local air velocity. The simulation was performed by DR. Christopher P Stone of Computational Science & Engineering LLC and Georgia Tech Prof. Marilyn Smith. The physics were simulated using a NASA CFD solver, Overflow2, and resulting data post-processed with FieldView software from Intelligent Light. Isosurfaces highlight vortex wake structures generated by the wind turbine’s rotor blades, the tower and nacelle, and how they interact with one another. The interaction between the wake structures and the rotor blades affects the noise generated by the turbine and also affects the overall costs of the machine. The colored surface on the ground and near the rotor’s disc center indicate general turbulence that drifts down-wind. Also, the tower generates vortices that shed, adding to the rotor’s vibration. White outlines on the blue ground indicate pressure variations.

In the typical CFD workflow, the post-processing phase brings the simulation data to life. By breaking large data into smaller, more specific and manageable pieces, post-processing tools such as FieldView lets researchers easily and efficiently interrogate simulation results, identify the most relevant features of a design, and in so doing, create an iterative design optimization process in which the results of one simulation are incorporated into subsequent simulations. This process can be automated using tools such as FieldView FVX.

Post-processing also produces 3D color graphics, plots, and animations that display the simulation results in a meaningful and easy-to-understand format for presentation to various stakeholder groups, many of whom are usually not experts in engineering or the wind-energy domain.

In addition to providing a more rigorous and reliable modeling, CFD-based simulation can result in significant time and cost savings by reducing the need for scale models, wind-tunnel tests, and field testing. Small-scale test data can be effectively investigated and extrapolated to reliably predict system behavior at a larger scale.

Site selection, microsite considerations

Site selection is of paramount importance in wind-energy projects. Its goal is to identify locations with the strongest, most sustained overall wind patterns while avoiding wind shadows and highly turbulent areas. An emerging discipline called micrositing evaluates localized wind patterns and terrain effects, and helps engineers place the wind turbines in the most advantageous location within the selected site.

When evaluating competing sites for wind-based power generation, three factors are particularly important:

• High average wind velocities
• Optimal time distribution of high winds. For instance, does the wind tend to blow more in the afternoon when the grid needs the energy, or does it tend to blow after midnight, when demand for electric power is lower?
• Low turbulence levels.

Site selection is directly influenced not just by prevailing wind patterns such as speed, direction, and regularity, but by factors such as turbulence and altitude, which impact air density. Changes in air density come from temperature differences that occur because of heating by the sun, cooling from rain, or variations in the terrain, such as rocky areas adjacent to areas covered by vegetation. Nocturnal jets – streams of high-speed, turbulent flow that descend from the upper atmosphere in some clear-sky conditions – must also be considered because they generates large structural loads on a turbine.

The amount of energy that wind contains is a function of the cube of its speed. That is, when the wind speed doubles, the amount of energy it contains increases by a factor of eight. As a result, potential geographic locations are given a wind rating based, in part, on the average prevailing wind speeds at the site. In general, locations with a designation of Class 4, 5, 6, or 7 are considered commercially viable sites. Unfortunately, they are not that common.

Far more prevalent are the Class 3 sites, which are characterized by lower average wind speeds. To operate wind turbines at Class 3 sites, the engineering community is actively working to develop and commercialize various passive and active engineering advances in blade design and materials to maximize energy yield, reduce the cost per kilowatt-hour, and minimize wear-and-tear on the wind turbine blades, drivetrain, and other components.

Improving site-assessment techniques has become another goal. The complexity of the airflow at any potential location requires thorough quantitative and qualitative analysis, and the size of the data places special demands on the engineer and tools used to interpret and manage the data. Using computational fluid dynamics (CFD) to model and simulate the environmental conditions associated with a given terrain lets engineers identify, characterize, and predict wind patterns, atmospheric turbulence, nocturnal jets, and other relevant factors quickly and effectively. Micrositing is also significantly enhanced by CFD modeling.

A typical CFD workflow begins with mesh generation and model development, and after specifying some of the prevailing flow conditions, such as wind speed and direction, a CFD solver runs to simulate and predict the density, velocity, and pressure of the airflow. The resulting large, unsteady datasets are then post-processed. Post-processing software such as FieldView from Intelligent Light, Rutherford, N.J. breaks the simulation data into smaller, specific, and more manageable bits, helping investigators more effectively interrogate the data to identify key flow features, characteristics, and visualize critical aspects of complex simulations. This improves overall data management and processing requirements, reduces the computational power needed, and increases the user’s speed and agility in analyzing and visualizing CFD results. Repetitive tasks can be automated with tools such as FieldView FVX, again speeding analysis and capturing a company’s knowledge and preferred calculations.

Wind Classifications at 10 M

Finally, post-processing produces high-resolution, 3D color graphics, plots, and animations that illuminate site aspects such as velocity vectors, pressure contours, and regions of constant flow-field properties. An ability to analyze and display the modeled results in a meaningful and easy-to-understand format is particularly important because these complex problems and modeled solutions must be shared with other stakeholder groups who are usually not experts in engineering or the wind-energy domain.

Today, CFD is being applied to a wide variety of issues in wind engineering. One major European wind turbine manufacturer, for instance, has successfully used STAR-CCM+ [CD-Adapco] and FieldView to develop design and siting tools. At the Sustainable Energy Solutions Group at Northern Arizona University in Flagstaff, researchers are working with the Navajo Tribal Utility Authority to study a wind site located in western Arizona. The location, Aubrey Cliffs, is a typical wind site in the southwestern U.S. It has numerous high elevations and ridge lines along the sides of mesa tops. These sites are thermally driven, with temperatures in nearby valleys (such as Phoenix) reaching more than 110F (43C). Researchers have been collecting wind data and predicting wind patterns in the area using flow solver codes such as Overflow from NASA and AcuSolve from Acusim Software, Mountain View, Calif. Post-processing with FieldView brings data sets from the solvers together and allows meaningful exploration of measured and simulated data.

Discuss ideas and comments at www.EngineeringExchange.com

::Windpower Engineering::

NREL adds two Multimegawatt Turbines

The clean wind energy industry must expand significantly in the next two decades to fulfill a strategy of generating 20 percent of the nation’s electricity. To provide the technological foundation for that dramatic growth, the National Renewable Energy Laboratory (NREL) is embarking on significant improvements at its National Wind Technology Center.

Engineers are installing the two largest turbines ever tested at the laboratory — a 1.5 MW turbine manufactured by General Electric and a 2.3 MW turbine from Siemens Power Generation.

Both turbines are being erected on the NWTC’s eastern perimeter for commissioning and operations in October. They will run for years under close observation and elaborate instrumentation. With data from these experiments, researchers will be working with the wind industry to increase turbine performance, improve durability and decrease loads.

The new turbines also allow NREL to take a significant step forward in generating its own clean electricity and meeting the Laboratory’s aggressive sustainability goals and reduce greenhouse gas emissions for its expanding research campus and support facilities. The new turbines are expected to generate twice as much energy as the NWTC uses. The U.S. Department of Energy (DOE), NREL and Xcel Energy are working to define an agreement that will allow surplus energy to be exported and sold to the local utility grid.

DOE purchase for NWTC

DOE purchased the 1.5 MW turbine for the NWTC. Crews using a crane assembled it over three days. The rotor was expected to fly — or be attached — on August 21.

The DOE turbine will operate atop a 262-foot steel tower. The diameter of its rotor will reach 253 feet.

“The DOE turbine is a national asset for the NWTC to operate as a test bed for wind energy research and development said NWTC assistant director for Testing and Operations, David Simms. “They would like us to offer it as a test bed for the best and brightest researchers from universities, laboratories and companies around the country.”

The DOE turbine was manufactured by GE and is a workhorse of the domestic wind power industry. More than 10,000 now operate at commercial wind farms around the nation, accounting for about 50 percent of the U.S. market. Because of its market share, NREL researchers say it is important to more fully understand the turbine’s performance in the field and look for ways to help advance its design.

Among the questions researchers will address are the microclimate in which the turbine operates, the aerodynamics of the turbine design and the effects of turbulence on its load and performance — and how all these factors may combine in potentially unforeseen ways. The NWTC was located at the base of the Rocky Mountains to take advantage of particularly gusty, challenging winds in order to challenge turbine designs in conditions not typically seen at commercial locations.

“If we could improve performance, thousands of turbines could remain in operation for years beyond the industry’s original expectations,” said NREL senior project leader Jim Green.

Additional trucks will be delivering the Siemens wind turbine, the cranes, and other installation equipment in August and September. The Siemens turbine will use a second tower of the same height, but its rotor diameter is 331 feet, or more than 30 percent bigger than the DOE turbine. The Siemens turbine employs an advanced new rotor design that needs field testing in the NWTC’s gusty and challenging conditions. Siemens has opened a research office in Boulder to provide engineering support and maintenance.

Siemens turbine among the largest in the U.S.

“It’s as large as any turbine in North America,” said project leader Lee Jay Fingersh. “The final design is different than most turbines with a different blade shape. Land-based turbines are getting larger to meet the demand for wind energy. This is the direction of the wind industry and we want to understand the aerodynamics of these new, larger machines.”

DOE/GE 1.5 MW Vital Statistics

* Hub height – 80 meters (262.5 feet)
* Radius – 38.5 meters (126.3 feet)
* Total ground to tip = 118.5 meters (388.8 feet)

Siemens 2.3 MW vital statistics

* Hub Height – 80 meters (262.5 feet)
* Radius – 50.5m (165.7 feet)
* Total ground to tip = 130.5 meters (428.2 feet)

Power Generation:

* Average US home monthly electricity consumption in 2007 = 936kWh
* DOE/GE estimated production from DOE/GE turbine at the NWTC* = 1,600,000kWh/year (enough to serve 142 homes)
* Siemens 2.3 MW estimated production at the NWTC* = 2,800,000 kWh/year (enough to serve 249 homes)

*The NWTC is a testing site. Production at more typical commercial wind farm would be higher.*

The Siemens turbine was selected for testing by the DOE after a national competition.

More than meets the eye

As considerable as the new turbines are, NREL researchers are equally interested in what is required beneath the ground in order to support such imposing machines, which can weigh more than 300 tons.

NREL engineers worked with Renewable Energy Systems Americas, Inc., to pour the large customized concrete foundations for the turbines. The concrete was delivered in July in an impressive convoy of more than 80 trucks.

NREL and RES Americas have signed a cooperative research and development agreement to study the design and performance of turbine foundations to increase the reliability of non-turbine components and lower the cost of wind-generated power. RES Americas recently established its U.S. headquarters in Broomfield, Colo., near the NWTS.

Research questions include structural loads on foundations of operating wind turbines, thermal performance of underground collection system electrical cables, and side-by-side comparisons of alternative wind speed measurement systems.

“This CRADA will result in some of the first-ever measurements of loads inside and under the foundation of an operating wind turbine,” Green said.

After the two new turbines are operating, NWTC engineers will erect two new meteorological towers to the west of the turbines. Each tower will stand 440 feet high and feature more than 60 instruments to collect the most advanced information on the wind, temperature, dew point, precipitation and other weather features that can influence the performance and lifespan of a wind turbine.

NREL and the wind energy industry are turning to taller towers to characterize the wind resources and conditions higher up where new, larger turbines operate.

The new towers also will feature LED lights that require virtually no maintenance and use a fraction of the energy of conventional lights.

After the towers are completed this fall, crews will remove the red flashing warning lights atop the new wind turbines and three of the existing meteorological towers, too, leaving the NWTC with a total of three lighted towers.

NREL