A Magnus effect windmill for generating electrical power is disclosed. A large nacelle-hub mounted pivotally (in Azimuth) atop a support tower carries, in the example disclosed, three elongated barrels arranged in a vertical plane and extending symmetrically radially outwardly from the nacelle. The system provides spin energy to the barrels by internal mechanical coupling in the proper sense to cause, in reaction to an incident wind, a rotational torque of a predetermined sense on the hub. The rotating hub carries a set of power take-off rollers which ride on a stationary circular track in the nacelle. Shafts carry the power, given to the rollers by the wind driven hub, to a central collector or accumulator gear assembly whose output is divided to drive the spin mechanism for the Magnus barrels and the main electric generator. A planetary gear assembly is interposed between the collector gears and the spin mechanism functioning as a differential which is also connected to an auxiliary electric motor whereby power to the spin mechanism may selectively be provided by the motor. Generally, the motor provides initial spin to the barrels for start-up after which the motor is braked and the spin mechanism is driven as though by a fixed ratio coupling from the rotor hub. During high wind or other unusual conditions, the auxiliary motor may be unbraked and excess spin power may be used to operate the motor as a generator of additional electrical output. Interposed between the collector gears of the rotating hub and the main electric generator is a novel variable speed drive-fly wheel system which is driven by the variable speed of the wind driven rotor and which, in turn, drives the main electric generator at constant angular speed. Reference is made to the complete specification for disclosure of other novel aspects of the system such as, for example, the aerodynamic and structural aspects of the novel Magnus barrels as well as novel gearing and other power coupling combination apparatus of the invention. A reading of the complete specification is recommended for a full understanding of the principles and features of the disclosed system.

A model was developed for wind fields over complex terrain. It was developed for use with a particle-in-cell (PIC) model for pollutant transport, dispersion, interaction, and removal. Terrain adjustment and adjustment weights are discussed. (JGB)

The objective of the Vertical Axis Wind Turbine (VAWT) Program at Sandia National Laboratories is to develop technology that results in economical, industry-produced, and commercially marketable wind energy systems. The purpose of the VAWT Design Technology Seminar for Industry was to provide for the exchange of the current state-of-the-art and predictions for future VAWT technology. Emphasis was placed on technology transfer of Sandia's technical developments and on defining the available analytic design tools.

A wind turbine of the type having an airfoil blade (15) mounted on a flexible beam (20) and a pitch governor (55) which selectively, torsionally twists the flexible beam in response to wind turbine speed thereby setting blade pitch, is provided with a limiter (85) which restricts unwanted pitch change at operating speeds due to torsional creep of the flexible beam. The limiter allows twisting of the beam by the governor under excessive wind velocity conditions to orient the blades in stall pitch positions, thereby preventing overspeed operation of the turbine. In the preferred embodiment, the pitch governor comprises a pendulum (65,70) which responds to changing rotor speed by pivotal movement, the limiter comprising a resilient member (90) which engages an end of the pendulum to restrict further movement thereof, and in turn restrict beam creep and unwanted blade pitch misadjustment.

This report documents the operating experience with two aluminum blades used on the DOE/NASA Mod-0A 200-kilowatt wind turbine located at Clayton, New Mexico. Each Mod-0A aluminum blade is 59.9 feet long and weighs 2360 pounds. The aluminum Mod-0A blade design requirements, the selected design, fabrication procedures, and the blade analyses are discussed. A detailed chronology is presented on the operating experience of the Mod-0A aluminum blades used at Clayton, New Mexico. Blade structural damage was experienced. Inspection and damage assessment were required. Structural modifications that were incorporated to the blades successfully extended the useful operating life of the blades. The aluminum blades completed the planned 2 years of operation of the Clayton wind turbine. The blades were removed from service in August 1980 to allow testing of advanced technology wood composite blades.

A preferred design and configuration approach is suggested for the DAWT innovative wind energy conversion system. A preliminary economic asessment is made for limited production rates of units between 5 and 150 kw rated output. Nine point designs are used to arrive at the conclusions regarding best construction material for the diffuser and busbar cost of electricity (COE). It is estimated that for farm and REA cooperative end users, the COE can range between 2 and 3.5 cents/kWh for sites with annual average wind speeds of 16 and 12 mph (25.7 and 19.3 km/h) respectively, and 150 kW rated units. No tax credits are included in these COE figures. For commercial end users of these 150 kW units the COE ranges between 4.0 and 6.5 cents/kWh for 16 and 12 mph sites. These estimates in 1979 dollars are lower than DOE goals set in 1978 for the rating size and end applications. Recommendations are made for future activities to maintain steady, systematic progress toward mature development of the DAWT.

A preferred design and configuration approach for the DAWT innovative wind energy conversion system is suggested. A preliminary economic assessment is made for limited production rates of units between 5 and 150 kW rated output. Nine point designs are used to arrive at the conclusions regarding best construction material for the diffuser and busbar cost of electricity (COE). It is estimated that for farm and REA cooperative end users, the COE can range between 2 and 3.5 cents/kWh for sites with annual average wind speeds of 16 and 12 mph (25.7 and 19.3 km/h) respectively, and 150 kW rated units. No tax credits are included in these COE figures. For commercial end users of these 150 kW units, the COE ranges between 4.0 and 6.5 cents/kWh for 16 and 12 mph sites. These estimates in 1971 dollars are lower than DOE goals set in 1978 for the rating size and end applications. Recommendations are made for future activities to maintain steady, systematic progress toward mature development of the DAWT.

The wind statistics summarized include monthly wind speed and spectrum analyzer summaries, diurnal wind speed tables, high wind summaries (greater than or equal to 50 mph), wind rose tables, and wind speed and direction frequency distributions. (LEW)

A study was made to estimate the impact tax credits (from Acts passed by Congress) would have on renewable energy investment and to estimate the net costs to the US Treasury of providing these tax credits. The appendices to this study are presented. Some investment and marketing penetration worksheets are presented on wind turbines, solar ponds, flat plates, evacuated tubes, and parabolic troughs. A market penetration and economic analysis program with test written for TI-59 programmable calculator with printer is presented. Data on the average $/kWh for each state are included for energy use (70 to 400/sup 0/F and electricity) and energy resource (total and direct solar and wind). Also included is an energy use processing program written for TI-59 programmable calculator with printer. (MCW)

This report proves that the characteristics of turbulence that are experienced by a rotating wind turbine rotor blade are in principle and in practice very different than those experienced by a nonrotating rotor blade. Thus conventional wind characteristics, which are formulated for the nonrotating frame of reference, are more inaccurate than generally supposed. The measurements and mathematical model that are presented for turbulence observed in the rotating frame of reference represent the third phase of the Pacific Northwest Laboratory work aimed at providing an accurate turbulence description for use in the design and evaluation of the performance of wind turbines. The first phase of work was the measurement of wind with a vertical plane array of anemometers. The second phase was the physical interpretation of the measurements in terms of implications for wind turbine rotors and initiation of development of a model of wind/wind turbine interaction. The third phase involved measurement of turbulence by rotating sensors and mathematical development of a physical model of this representation of turbulence as independent checks and expansions of the vertical plane array results. A fourth phase, to correlate real wind turbine response with rotationally measured turbulence and thereby understand the wind/wind turbine interaction, is in progress and preliminary results are quite promising.