1. NREL is a national laboratory of the U.S. Department of Energy Office of Energy Efficiency and Renewable Energy operated by the Alliance for Sustainable Energy, LLC Bri-Mathias Hodge Debra Lew Greg Brinkman National Renewable Energy Laboratory Golden, Colorado USA Western Wind and Solar Integration Study: Forecast Data

2. NATIONAL RENEWABLE ENERGY LABORATORY Wind Forecasting Error Distributions 2 Using forecast errors taken from operational systems Aggregated at regions that are ISO-sized Map errors from WWSIS 1 through a model error distribution and tweak to generate more realistic error distributions

3. NATIONAL RENEWABLE ENERGY LABORATORY Mapping Forecast Errors 3 WWSIS Forecast Errors Model Production Forecast Errors 95% Normalized Forecast Error -1 0 1

4. NATIONAL RENEWABLE ENERGY LABORATORY 4 Total Capacity: 9,600 MW κ = 0.95 γ= -0.094 WWSIS I Day-Ahead Forecast Errors

5. NATIONAL RENEWABLE ENERGY LABORATORY WWSIS I Day-Ahead Forecast Errors 5 Total Capacity: 18,180 MW κ = 0.96 γ= 0.082

6. NATIONAL RENEWABLE ENERGY LABORATORY 6 WWSIS I Day-Ahead Forecast Errors Total Capacity: 26,760 MW κ = 0.92 γ= -0.103

7. NATIONAL RENEWABLE ENERGY LABORATORY WWSIS 2 Day-Ahead Forecast Errors 7 Total Capacity: 69,210 MW κ = -0.44 γ= -0.089

8. NATIONAL RENEWABLE ENERGY LABORATORY 8 ERCOT Day-Ahead Distribution κ = 1.0299 γ= -0.0616 Total Capacity: ~9000 MW

9. NATIONAL RENEWABLE ENERGY LABORATORY ERCOT Day-Ahead Distribution 9

10. NATIONAL RENEWABLE ENERGY LABORATORY ERCOT Day-Ahead Distribution 10

11. NATIONAL RENEWABLE ENERGY LABORATORY CAISO Day-Ahead Distribution 11 κ = 1.5025 γ= -0.393 Total Capacity: ~950 MW

12. NATIONAL RENEWABLE ENERGY LABORATORY CAISO Day-Ahead Distribution 12

13. NATIONAL RENEWABLE ENERGY LABORATORY CAISO Day-Ahead Distribution 13

14. NATIONAL RENEWABLE ENERGY LABORATORY Xcel Wind Plant 14 κ = 1.05 γ= -0.65 Total Capacity: ~300 MW

15. NATIONAL RENEWABLE ENERGY LABORATORY Solar Forecasting Data Working with SUNY – Albany Atmospheric Science Research Center to get data on solar forecasting errors Two different forecasting services: National Digital Forecast Database (NDFD) forecasts produced by the National Weather Service that are utilized as part of SolarAnywhere The Global Environmental Monitoring System (GEMS) forecast produced by the Canadian weather service One year of data for day-ahead forecasts Four sites: Desert Rock, NV Boulder, CO Fort Peck, MT Sioux Falls, SD 15

16. NATIONAL RENEWABLE ENERGY LABORATORY Questions? Bri-Mathias Hodge 303-384-6981 bri.mathias.hodge@nrel.gov Debbie Lew 303-384-7037 debra.lew@nrel.gov Greg Brinkman 303-384-7390 gregory.brinkman@nrel.gov 16