Small Wind Turbines in Turbulent (Urban) Environments: a Predictable Wind Generation Resource
Document Type Article
Journal of Wind Engineering & Industrial Aerodynamics Vol. 0167-6105, p.1-18 submitted 2013.
The urban terrain and the associated topographical complexities, present significant challenges to the deployment of small wind turbines and in such a context, the viability of these technologies may be questionable. In particular, a considerable amount of uncertainty is attributable to the lack of understanding concerning how turbulence within urban environments affects turbine productivity. This paper considers two models that employ average wind speed and the industry standard metric, turbulence intensity (TI), in conjunction with the power characteristic of a 2.5kW wind turbine, to estimate said turbine‟s power performance. The first approach is an adaptation of a model originally derived to quantify the degradation of power performance of a wind turbine using the Gaussian distribution to simulate TI. An inherently detrimental characteristic of this approach however, is a potential for disproportionately high and asymptotic TI, associated, for example, with gusting within low mean wind speed observation windows. Furthermore, this approach requires an accurate turbine power characteristic. The second approach overcomes these limitations through the novel application of the Weibull Distribution, a widely accepted means to probabilistically describe wind speed. Both models are tested at an urban and suburban location in Dublin City, Ireland, where sonic anemometry, positioned at approximately 1.5 times the average height of buildings at the respective locations, record the three dimensional wind vectors at a temporal resolution of 10Hz.