May 25 - July 30
Evaluating High-Resolution NWP Forecasts of the Nocturnal Low Level Jet for Improving Wind Power Forecasts
Jeffrey Deppa, Richard Carpenter, and Brent Shaw
What is already known:
- Accurate wind and power forecasts that go out at least several hours are going to become increasingly more important as wind energy becomes more prominent.
- Unforeseen wind energy variability that occurs will lead to grid operators struggling to keep power loads balanced by needing to quickly fire up or shut down coal or natural gas generators.
- The WRF 3-km grid, although highly accurate, still needs improvements in order to make wind energy more reliable.
What this study adds:
- The study finds that errors in model forecasted boundary layer stability coupled with NLLJ terrain interactions could be the reason for wind forecast errors at Blue Canyon.
- The location of maximum winds during NLLJ events at turbine hub height tends to occur about 5 to 10 km downstream of where the wind farm is presently located.
Abstract:
The Nocturnal Low Level Jet (NLLJ) is a significant contributor to overnight wind power production in the Southern Great Plans. This region of the United States is expecting wind farm growth over the coming decades and therefore it is important to better understand how to forecast wind energy, and hence forecast the strength and location of the NLLJ. The Weather Research and Forecasting Model (WRF) is one tool that can be used for forecasting winds. This study investigates performance of a real-time, high-resolution (3-km grid spacing) configuration of the WRF for several NLLJ cases in southwest Oklahoma. Forecast location and intensity of the NLLJ and its interaction with moderate terrain features around the Blue Canyon Wind Farm, particularly the Wichita Mountains and Slick Hills, were evaluated. These model forecasts also provide insight into the relationship between NLLJ behavior as a function of wind magnitude and atmospheric stability. The study finds that errors in model forecasted boundary layer stability coupled with NLLJ terrain interactions could be the reason for wind forecast errors at Blue Canyon.