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Title: The WEI6K, a 6-kW 7-m Small Wind Turbine: Final Technical Report

Technical Report ·
DOI:https://doi.org/10.2172/887056· OSTI ID:887056

This project was selected by the U.S. Department of Energy under a DOE solicitation “Low Wind Speed Technology for Small Turbine Development.” The objective of this project has been to design a new small wind turbine with improved cost, reliability and performance in grid-connected residential and small business applications, in order to achieve the overall DOE goal of cost effectiveness in Class 3 wind resources that can now be achieved in Class 5 resources. The scope of work for this project has been to complete the preliminary design of an improved small wind turbine, including preliminary loads and strength analyses; analysis and design of all major components; systems integration and structural dynamic analysis; estimation of life-cycle cost of energy; and design documentation and review. The project did not entail hardware fabrication or testing. The WEI6K Turbine resulting from this project is an upwind horizontal-axis wind turbine rated at 6 kW. It features a 3-blade 7-m diameter rotor. The generator is a direct-drive permanent magnet synchronous machine generating 3-phase power at 240 VAC. The turbine is maintained oriented in to the wind via active yaw control using electromechanical servos. Power is regulated with active blade pitch control. The turbine is presently designed to be placed on a 100-foot (30m) tower. The turbine is predicted to generate electricity at a levelized cost of energy (COE) between 7.3 and 8.9 ¢/kWh at an IEC Class II site, with an average wind speed of 8.5 m/s at hub height, depending upon whether the customer uses a guyed truss tower (the lower figure) or a monopole tower. For the NREL Reference Site, with a mean wind speed of 5.35 m/s at 10 m height, the turbine would generate at a levelized cost of energy of between 9.7 and 11.9 ¢/kWh. The lowest of these numbers is presently competitive with retail electricity rates in most of the country. The 8.9 ¢/kWh is still competitive with retail rates in many regions of the country with high electricity costs. The study further concludes that several design changes could shave 10-14% from the cost of energy determined in the preliminary design. These changes include a new tower design that offers tilt-up capability without guy wires and takes better advantage of the lowered loads produced by pitch control; design a family of airfoils more appropriate for pitch regulation on a turbine of this size; tune the pitch controller properly to minimize shedding of power during turbulent operation in the transition from Region 2 to 3; value engineer the pitch system to shave costs, including consideration of a collective pitch system; and refine the design of the hub and main frame castings to minimize weight and cost. We are generally encouraged by the results. These preliminary numbers show that we can produce a turbine that is competitive with retail electric rates at relatively windy IEC Class II sites. With further improvements in the design, we believe the turbine could be competitive at sites with lesser wind resource.

Research Organization:
WETZEL ENGINEERING, INC.
Sponsoring Organization:
USDOE Office of Energy Efficiency and Renewable Energy (EERE)
DOE Contract Number:
FG36-03GO13136
OSTI ID:
887056
Report Number(s):
DOE/GO/13136-1; TRN: US200719%%366
Country of Publication:
United States
Language:
English