NREL's WIND Toolkit Provides the Data Needed to Conduct Power System Simulations
Researchers who conduct regional wind integration studies in the United States need to perform simulations of how the power system will operate under high-penetration scenarios. To do this they need detailed wind power output data from many locations. The wind data sets that are used in these studies must realistically reflect the ramping characteristics, spatial and temporal correlations, and capacity factors of the simulated wind plants, and must be time-synchronized with available load profiles.
The National Renewable Energy Laboratory (NREL) is providing a vehicle to meet these requirements: the Wind Integration National Dataset (WIND) Toolkit. The toolkit is a state-of-the-art national wind resource data set covering the contiguous United States from 2007 to 2013 and is available for free. It provides access to a wind speed and power data set that can be used for wind resource assessments, grid integration studies, grid planning studies, and a variety of next-generation wind integration analyses and wind power planning activities. It allows users to perform detailed simulations of how future power systems will operate under high-penetration scenarios and realistically reflects ramping characteristics, spatial and temporal correlations, and capacity factors of simulated wind plants. Furthermore, the data can be time synchronized with available load profiles.
There are three components to the WIND Toolkit:
- A wind resource data set
- A wind forecast data set
- A wind power production and forecast data set.
The wind resource data set and the wind forecast data set are derived from the Weather Research and Forecasting (WRF) numerical weather prediction model. WRF is a community weather model that was created through a collaborative partnership between the National Center for Atmospheric Research, the National Oceanic and Atmospheric Administration (represented by the National Centers for Environmental Prediction and the [then] Forecast Systems Laboratory), the Air Force Weather Agency, the Naval Research Laboratory, the University of Oklahoma, and the Federal Aviation Administration. WRF is used in the United States as the basis for the National Oceanic and Atmospheric Administration’s weather forecasts and by many other organizations worldwide for forecasts, research, and education. Using WRF ensures that the WIND Toolkit is based on sound meteorological simulations, and that the experience gained in this project can be leveraged by the WRF community.
The WIND Toolkit data were generated on a 2-kilometer (km) by 2-km grid with a 20-meter (m) resolution from the ground to 160 m above ground, and included meteorological and power data for every 5 minutes. A state-of-the-art forecast data set was also created on a 6-km grid at 1-hour, 4-hour, 6-hour, and day-ahead forecast horizons using industry best practices. During this process, a team of developers focused on mimicking state-of-the art forecast accuracy. The power data were created using data from actual and hypothetical wind farms for 126,000 land-based and offshore wind power production sites. Every site has its own characteristics and is represented differently by the numerical model. Barometric pressure, wind speed and direction (at 100 m above ground level), relative humidity, temperature, and air density data are available via an online interface.
The creation of the WIND Toolkit data is defined in a forthcoming report. Other reports describe the validation of the meteorological data against observations (forthcoming), and of the simulated power data. In the report describing the validation of simulated power data, the researchers explain the importance of developing this data set; the challenges associated with creating numerical weather prediction simulations for a large geographical area such as the continental United States; the numerical simulations themselves; how the simulated wind speeds are converted into power; and the initial validation results from the raw meteorological data set. In addition to this validation, the authors recommend that users carry out extra validation steps before using the data for their particular applications.
The WIND Toolkit data were created for NREL by Vaisala, leveraging the deep knowledge that each organization brings in meteorology, wind turbine performance, and grid integration of renewable energy. The WIND Toolkit will support the next generation of grid integration studies and serve as a benchmark for time-resolved wind resource simulations at national and regional scales in the United States and internationally.