A method is presented for estimating the root mean square (rms) value of the wind direction change, ..delta..theta(tau) = theta(tau + tau) - theta(tau), that occurs over the swept area of wind turbine rotor systems. An equation is also given for the rms value of the wind direction change that occurs at a single point in space, i.e., a direcion change that a wind vane would measure. Assuming a normal probability density function for the lateral wind velocity change and relating this to angular changes, equations are given for calculating the expected number of wind direction changes, larger than an arbitrary value, that will occur in 1 hr as well as the expected number that will occur during the design life of a wind turbine. The equations presented are developed using a small angle approximation and are, therefore, considered appropriate for wind direction changes of less than 30/sup 0/. The equations presented are based upon neutral atmospheric boundary-layer conditions and do not include information regarding events such as tornados, hurricanes, etc.

Separate abstract are included for each of the papers presented concerning the use of wind turbines in agriculture.

The first objective of the WCPE's regional assessment was to develop and test prototype techniques for the analysis of wind-energy potential and distribution over a large area. These techniques involved the utilization of a much larger data set, the application of meteorological and topographic factors in the analysis, and the use of indirect methods of wind power estimation in areas where no wind measurements existed. Five states in the Pacific Northwest were selected as a test of these techniques.

Information is presented concerning wind characteristics for design and performance evaluations; mesoscale wind characteristics; siting methodologies; and wind characteristics for WECS operations.

FY78 results of the Wind Resource Analyses task of the ERAB are described. Initial steps were taken to acquire modern atmosphere models of near-surface wind flow and primary data sets used in previous studies of national and regional wind resources. Because numerous assumptions are necessary to interpret available data in terms of wind energy potential, conclusions of previous studies differ considerably. These data analyses may be improved by future SERI research. State-of-the-art atmosphere models are a necessary component of the SERI wind resource analyses capacity. However, these methods also need to be tested and verified in diverse applications. The primary data sets and principal features of the models are discussed.

This evaluation of wind turbines is part of a series of Technology Evaluations of possible components and subsystems of community energy systems. Wind turbines, ranging in size from 200 W to 10 MW, are discussed as candidates for prime movers in community systems. Estimates of performance characteristics and cost as a function of rated capacity and rated wind speed are presented. Data concerning material requirements, environmental effects, and operating procedures also are given and are represented empirically to aid computer simulation.

A survey of small municipal and rural electric cooperative (REC) utilities was accomplished. The relationship between these small utilities and the mean wind power at their locations was found by locating them on appropriate maps of mean wind power density. Some of the safety, systems and economic implications of WECS deployment by these utilities were discussed. It is concluded that certain financing advantages and geographical considerations make the Great Plains region a strong candidate for the early commercialization of WECS.

Information is presented concerning the Rocky Flats wind turbine test site; the philosophy of testing at Rocky Flats; test procedure development; atmospheric SWECS testing; SWECS component testing; data collection, handling, and analysis; reporting procedures; and future plans.

Volume II of the First Semiannual Report of the Rocky Flats Small Wind Systems Test Center (WSTC) describes the nine (9) small wind energy conversion systems (SWECS) tested as of June 30, 1978 and provides the significant quantitative and qualitative data collected to that date. Meteorological data collected at Rocky Flats are also provided and described.