2.3 MW direct-drive turbine manufactured in Saginaw

The Northern Power 2.3 MW wind turbine is based on the company’s 100 kW unit and has, says the company, more than 50 years of cumulative field operating experience. Northern Power adds that the permanent-magnet generator and power electronics technology are state of the art. The company has installed and commissioned its first prototype Northern Power 2.3-MW wind turbine. The prototype is owned by Heritage Sustainable Energy and installed at the Stoney Corners wind farm in McBain, Michigan. This prototype turbine, shipped from the new Northern Power factory in Saginaw, Michigan, is the largest direct drive wind turbine in commercial operation in North America.

Using advances in permanent magnet (PM) generators and power electronics, the 2.3-MW unit  is said to represent the next generation in wind turbine technology. Its drivetrain eliminates need for a high-torque gearbox, thereby greatly simplifying the design while removing a frequent area of failure in competing wind turbines. The turbine rotor connect directly to a slow-speed PM generator rotor, without a separate gearbox, main shaft, bearing set, or couplings. This simple design transmits operating loads more directly to the tower, with a minimum number of parts in the load path.

The PM generator eliminates also need for rotor field windings, a field excitation system, and field-circuit slip rings. Eliminating field-circuit losses results in higher overall turbine efficiency, especially when operating at partial load. The proprietary low-speed PM generator is optimized for efficient energy capture with a higher power curve. Other advantage include 20% less weight of magnet materials, 75% fewer stator-coil assemblies, higher power density, and it’s easier to fabricate and assemble

The company adds that the FlexPhase power converter’s design offers high efficiency, high output-power quality, low generator stress, and advanced grid support and ride-through capabilities. The power converter, matched, and optimized for operation with the low speed generator, uses rack-out modules for fast and easy service.

The power converter, in combination with the PM generator, optimizes overall power train performance. This system results in more power delivered onto the grid than from competing designs. The software-enabled advanced topology has 40% fewer IGBTs, 50% fewer capacitors, and a higher power curve than similarly sized turbines.

In addition, the power converter and main transformer are located up-tower. Electricity is converted to medium voltage closer to the point of generation, minimizing long power cable losses between components. This layout results in increased efficiency and lower electrical losses, yielding more revenue-generating power.

Northern Power Systems

northernpower.com

DOE supports wind energy development with $5 million

U.S. Energy Secretary Steven Chu announced that the Department of Energy is awarding more than $5 million to support U.S. wind energy development. Two projects receiving a total of $3.4 million over two years will improve short-term wind forecasting, which will accelerate use of wind power in electricity transmission networks by allowing utilities and grid operators to more accurately forecast when and where electricity will be generated from wind power. Three additional projects are receiving a total of more than $1.8 million to boost the speed and scale of midsize wind turbine technology development and deployment. These grants will help reach the goal of doubling U.S. renewable energy generation capacity, and will promote energy security, environmental quality, and clean energy jobs.

“Wind power holds enormous potential to help reach our nation’s clean energy goals,” said Secretary Chu. “The awards will help better integrate wind energy into the electrical grid and will support the development of midsize wind turbines that can be used to provide renewable electricity in communities across the country.”

Electricity grid operators must accurately predict and plan for the energy output of wind power plants in their systems. With better forecasting, utilities can more reliably connect variable power sources, such as wind energy with electricity grids, and can decrease their need for back-up energy sources such as natural gas or hydropower. The two funding recipients announced today — AWS Truepower LLC in Albany, New York and WindLogics Inc. in Saint Paul, Minnesota — will lead teams of several partners and work with DOE and the National Oceanic and Atmospheric Administration (NOAA) to deploy advanced atmospheric measurement systems over a broad area, provide data that allow advanced weather prediction systems to improve short-term turbine-level wind forecasts, and demonstrate the value of these forecasting improvements for electric utility operations.

NOAA will provide project support in the areas of research instrument deployment and operation, data assimilation, advanced weather modeling, and meteorology expertise and analysis. A network of sophisticated atmospheric instrumentation will be deployed and operated in the regions identified and supported by the AWS Truepower and WindLogics teams. Data from these networks and other sources will be incorporated into an advanced weather forecast model by NOAA to provide more accurate wind forecasts.

In addition, the DOE identifies three projects will receive approximately $620,000 each to accelerate the first phase of development, testing, and commercialization of domestically manufactured midsize wind turbines with rated generating capacities between 200 and 500 kW. Midsize turbines are often used to generate renewable electricity at schools, farms, factories, private and public facilities, remote locations, and community and tribal wind energy plants. Their size allows installation at the site of electricity use, minimizing the need for new electricity transmission infrastructure.

DOE will provide funding over two years to strengthen the U.S. midsize turbine market and address factors that have contributed to slow growth in the midsize wind turbine market to date, including a small number of available midsize turbine models. These projects will leverage private sector investments to advance innovative technologies that lower the installed costs and improve the productivity of midsize turbines. Awardees will also support a variety of equipment manufacturers and supply chain vendors in the United States. Each of the grantees will be eligible to apply for a second phase of the projects, with up to $4 million available in additional funding.

To improve short-term wind forecasting:

• AWS Truepower LLC (www.awstruepower.com) $2.15 million
  This project will target a region of high wind energy use in Texas, and will assess utility system benefits with the Electric Reliability Council of Texas, which manages an electric power system with the largest amount of wind power capacity in the United States. The Truepower project team will also include Texas Technological University, the North Carolina State University, the University of Oklahoma, NREL, and consultants MESO, Inc., and ICF International.

• WindLogics, Inc. (www.windlogics.com) $1.25 million
  This project will span portions of several Upper-Midwest states with many active wind energy projects, and will assess utility benefits with the Midwest Independent System Operator. WindLogics is a wholly-owned subsidiary of NextEra Energy Resources, the largest operator of wind power plants in North America. NextEra will provide meteorological data from 14 wind plants totaling nearly two gigawatts of operating capacity. Other partners in the WindLogics project will include South Dakota State University and DOE’s National Renewable Energy Laboratory.

To develop midsize wind-turbines:

• Clean Green Energy LLC (www.cleangreenenergyllc.com)
  This project is working to bring a 200-kW vertical axis wind turbine design into cost-effective mass production. The vertical turbine design will allow for distributed onsite generation near buildings.
  

  Clean Green energy manufacturers vertical axis wind turbines.This project is working to bring a 200-kW vertical axis wind turbine design into cost-effective mass production. The vertical turbine design will allow for distributed onsite generation near buildings.

• Northern Power Systems (www.northernpower.com)
  This project is leveraging almost $10 million in private sector capital to develop a 450-kilowatt turbine, helping to complete the final turbine design, procurement, and prototype testing within 18 months. The project is expected to reduce the cost of energy from midsize turbines.

• Texas Tech University (www.ttu.edu)
  This project aims to adapt a turbine featuring two blades located downwind of the tower. This turbine design builds upon a commercially-produced architecture and scales it up to a 500-kW rated output. The tilt-down guyed tower (braced by guy wires and hinged near its base) allows installation without cranes. This project seeks to compete on cost with fossil fuel power generation.

Direct-drive generators find more followers

No gearbox will ever fail in our turbines, says Northern Power Systems VP James Stover. The reason for that is there are no gearboxes in the company’s turbines. Stover says his company’s Northwind 100 can still match the power needs of many local applications, whether municipalities, schools, farms, or business campuses. The turbine’s physical size is said to fit within constraints common to highly populated areas. The Barre, Vermont company says the unit was developed with a NASA grant, and designed for remote and isolated sites.

The company adds that its turbine works well in low winds, so users need not live in a high-wind area to benefit from wind power. The turbines can begin making power at wind speeds as low as 3 m/s. The gearless direct drive is said to maximize energy capture and it outperforms conventional gearbox designs. The turbine’s power converter provides smooth, clean power to local grids which simplifies grid interconnect. The company says its advanced fiberglass reinforced blades use an aerodynamic design shaped by its engineers.

The firm adds that one to three of the 100 kW units can meet all the energy needs for most municipalities, schools, and small industrial sites. Furthermore, the company says the turbine is without complicated approvals or expensive interconnection requirements.

The Northwind 100: By the numbers