Prospecting for Wind: Windmills and Wind Characteristics

Past experience with power generation by windmills indicates that the most important factor controlling success or failure is site wind characteristics. Incorrect placement on a site sheltered by buildings, terrain or agricultural growth may drop performance to one-third of the original expectations. Conversely, the appropriate hill or ridge shape may amplify power available. Site selection procedures, which are the pick and shovel of the modern wind prospector, include statistical climatology, numerical simulation, and physical simulation in meteorological wind tunnels. Laboratory measurements of wind overspeed, streamline patterns, and turbulence changes over idealized topography are compared with frozen vorticity numerical models. Field measurement of wind velocity and direction over the Rakaia Gorge region, Southern Alps, New Zealand, compare favorably with wind tunnel measurement over a 1/5000 scale model.