The Global Wind Atlas: An EUDP project carried out by DTU Wind Energy

Abstract

Up until now, policy makers and energy planners tackling the challenges of climate change, and seeking approaches for climate change mitigation, have had no global wind resource dataset appropriate for their pressing needs. Use of coarse resolution reanalysis datasets has had the serious shortcoming that the wind energy resource is underestimated, as small scale variability of winds is missing. This missing variability means a large part of the wind resource is not captured. Crucially it is the windiest sites that suffer the largest wind resource errors at coarse resolution; in simple terrain one fifth of the wind resource may be missed, for complex terrain more than half of the wind resource may be missed. This project is built on a global methodology. It is the new and improved meteorological datasets and topographical datasets, in the public domain, that have made this project a possibility. The method employs large-scale global meteorological datasets (reanalysis), which are downscaled to high-resolution wind resource datasets via a so-called generalization step together with microscale modelling using the WAsP software developed at DTU Wind Energy. A new application of flow models in WAsP software allows calculation of high-resolution resource maps covering extensive areas. For the purpose of downscaling high-resolution datasets, appropriate surface elevation and roughness lengths have been derived from global surface elevation and land cover datasets. The application of geospatial information systems (GIS) and web-based tools help significantly to bring the Global Wind Atlas datasets alive to end-users; the end-users can analyse spatial and temporal distributions of wind resources in areas of interest determined by the end-user. Either by specifying ad-hoc areas or by selection of areas following administrative boundaries. Furthermore, through the IRENA Global Atlas the end-user is able to relate the wind resources to other factors, such as population centres, electrical transmission grids, terrain types, and protected land areas. The Global Wind Atlas does not provide a substitute for individual country-based wind atlases or wind resource assessment conducted commercially for wind farm developers. Those kinds of assessments require a higher precision, specific configuration for the region in question, and a more stringent validation phase. Importantly, the Global Wind Atlas data is the most appropriate wind resource dataset available for the needs of policy makers, energy planners, the Integrated Assessment Modelling (IAM) community and for Strategic Environmental Assessment (SEA). DTU Wind Energy has developed the methodology and carried out the work in the framework of the Clean Energy Ministerial Multilateral Working Group on Solar and Wind Technologies supported by the Danish Energy Agency. The DTU Wind Energy contribution has been made stronger by this international collaboration, because leading international institutions have shared valuable knowledge and liaised on the data specifications, applications, and dissemination of the data to a large and broad range of end-users.