Over the past decade, the wind fleet’s average capacity factor has increased substantially. Capacity factor is the ratio of actual generation to total possible generation, where total possible generation assumes a plant generated its maximum possible output across all hours of the year. Researchers have been debating how much of the improvement should be credited to technology (new plants show improved capacity factors) versus increasing wind speeds (surface wind speeds measurements trended upward during that period). Lawrence Berkeley National Laboratory (LBNL) took a detailed look at generation records and surface wind speed observations across the last decade. They found that technology change and plant design/siting increased capacity factors of newer plants by 25% compared to older plants, an order of magnitude larger than improvements due to increasing wind speed.
See more in the open-access paper in the journal Wind Energy.