WFIP2 Experiment: Wind Speed Ramp Events at 80 m above the Ground

The Wind Forecast Improvement Project 2 (WFIP 2) is a DOE and NOAA led multi-agency project that took place in the Columbia River Gorge and Basin in the Oregon and Washington states. The major goal of this project is to understand and to improve the forecast skill of numerical weather prediction (NWP) models in complex terrain. The WFIP2 study region is well-known for its excellent wind resource, and many wind farms are installed there. One of the biggest challenges for wind power production is the accurate forecast of wind ramp events, i. e. large changes of generated power over short periods of time. Ramps that are not forecast accurately (in terms of their sign, amplitude or timing) will cause large and sudden changes in generation that can ultimately increase the costs of power production.

A Ramp Tool and Metric (RT&M) was developed as part of the first WFIP experiment, to measure the skill of NWP models explicitly at forecasting ramp events. We apply this tool to 80 m winds (turbine hub-height) using sodar observations as well as operational and experimental forecasts from the Rapid Refresh (RAP) and High Resolution Rapid Refresh (HRRR) models. The statistics of ramp events in the observations and models are analyzed, as well as the model skill at forecasting ramps, including their diurnal and seasonal variability. Also, it will be shown that increasing model resolution in a complex terrain environment results in an increase in ramp forecast skill.