Wind resource estimates with an analog ensemble approach

•An analog ensemble method is demonstrated for use in wind farm development process.•This method provides an accurate long-term wind resource estimate at target sites.•It outperforms the Measure-Correlate-Predict method especially for complex terrain.•It reliably quantifies the uncertainty allowing for cost-effective decision making.•The analog ensemble method is a computationally efficient method.

The wind resource and energy assessment is key to a wind farm development project. It allows for establishing the feasibility and economic viability of the project over the typical 10- to 30-year lifetime of a wind farm. Recent studies show that the accuracy of assessments has substantial room for improvement. Estimating and reducing uncertainty is important to secure financing and ensure the confidence of investors. A new method is proposed and demonstrated for the long-term estimation of the wind speeds at a target site, a key step in assessments. The method is based on ensembles made of analogs between a short-term observational record from the target site and a long-term historical record from a nearby site or an atmospheric model. It provides a high-quality long-term wind resource estimate, characterized by an accurate wind speed time series and frequency distribution. It also provides a reliable estimate of the uncertainty based on the actual physical processes determining the current atmospheric flow rather than the climatological wind distribution.

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