Leading international renewable energy consultancy Natural Power are pleased to announce a new free web based service providing an estimation of wind flow complexity on potential wind farm sites. As potential development sites with simple, flat terrain become fewer and fewer, more and more projects are built in, or near, forests and complex terrain. It is these complex flow sites that are often associated with harsh wind conditions likely to affect wind turbine performance. For example, complex terrain can induce large values of turbulence and high loads on wind turbine blades.
As a result, there are increasing concerns about under-performing wind farms: maintenance costs are higher than expected, performance is reduced, and warranty claims are more common. Tools and methodologies for the designing of efficient wind farms in complex terrain are available but there is less awareness of them within the industry. For example CFD (Computational Fluid Dynamics) modelling, lidar measurements and well-planned measurement campaigns can help optimise wind turbine locations and provide manufacturers and investors the information they need to properly assess the site condition.
Whether to use such advanced tools rather than standard methodologies is not always obvious. Although the use of RIX (Ruggedness Index) values can help assessing complex terrain, it is not always readily available to investors or developers, and does not take in to account the effect of land cover on flow complexity. In response, Natural Power has developed a complexity assessment applet that is freely available on the company’s website. In order to provide an estimation of flow complexity, the applet simply requires turbine locations, which can be uploaded as Google earth place marks, and a simple estimation of forest coverage in the area of interest. Natural Power’s applet then automatically computes a complexity index, taking into account topographic features and approximate land cover. The results can be visualised in a report that also summarises findings, recommendations and next steps for development.
Director of Natural Power France, Oisin Brady commented ‘‘Our new complex site applet should help minimise the risk of underperforming wind farms by providing owners, investors and wind specialists with an easily accessible estimation of the risk at the early stages of a project and thereby informing about the need for tools and methodologies appropriate for the site conditions. Our experienced team can then suggest the best possible options for development of the site – from further CFD calculations which we perform with VENTOS, or a prescribed wind measurement campaign with traditional techniques such as met masts or more advances assessment tools such as our ZephIR 300 lidar.’’
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Source: naturalpower, December 02, 2010