Simulated and Observed Mountain Waves and Their Implications on Wind Energy

The U.S. DOE Wind Forecast Improvement Project 2 (WFIP 2) is aimed at developing new understanding and improving the skill of weather forecast models, particularly NOAA’s High Resolution Rapid Refresh (HRRR) model. More specifically, this project focuses on weather phenomena and terrain effects that pose challenges for wind energy and wind power forecasting. An extensive field campaign in the complex terrain around the Columbia River Gorge has made available 18 months of data from many different instruments.

In this talk, we analyze a WFIP 2 case study of mountain waves that occurred in the Columbia River Gorge downwind from the Cascade Range. Simulated wind speeds with the HRRR show signals of mountain waves within the wind turbine operating region around 80 m agl. Simulated wavelengths of mountain waves are confirmed with observed waves measured from satellite retrieved cloud reflectance. We further confirm that simulations on a 750m grid are not influenced by Terra Incognita issues.

Furthermore, we assess the impact of mountain waves that reach down to the turbine layer on wind farms in terms of power output from a utility scale wind farm in the area.

This study leverages advances in simulation methods developed within the DOE Mesoscale-to-Microscale Coupling project which aims to increase the fidelity of wind plant aerodynamics simulation by including mesoscale flow physics into a microscale wind plant model. We present some of the challenges and intricacies of this coupled simulation strategy.