A recent report says improved forecasting is ‘low-hanging fruit’ for facilitating higher levels of variable generation capacity onto the grid.
The report, entitled ‘Recent Trends in Variable Generation Forecasting and Its Value to the Power System,’ published in the June issue of the Institute of Electrical and Electronics Engineer's Transactions on Sustainable Energy, says the greater the uncertainty between the forecasted and actual values, the less confident operators will be in relying on forecasts for maintaining system reliability, especially in high-penetration scenarios.
The variable nature of the atmosphere (e.g., wind, temperature and irradiance) impacts the power output from wind and solar power generators, and it is also a factor in determining the load, the report says. Together, these factors account for the variability that must be balanced by the power system.
According to the report, the power industry experiences much uncertainty around wind and solar power forecasts. The U.S. Department of Energy (DOE) sponsored two projects to advance wind and solar power forecasts. The National Oceanic and Atmospheric Administration and other public, private and academic organizations participated in the projects.
The Improving the Accuracy of Solar Forecasting project seeks to develop standardized metrics, baselines and target values to measure forecast accuracy improvement and enhance forecasting technologies. According to the report, the effort has resulted in a number of proposed new metrics for evaluating solar power forecasting, with an emphasis on capturing the economic value of improvements to power system operators.
These new forecasting metrics attempt to distinguish the most important improvements that would need to be made to the model, and make power output predictions. The end goal is to build a value chain that quantifies the value of the forecast to the end user, the report says.
The parallel Wind Forecasting Improvement Project is working on predicting winds within the atmospheric boundary layer.
The research is also exploring the use and benefit of variable generation forecasts for each utility, independent system operator and balancing authority. For example, integration studies have historically shown that day-ahead forecasts can provide significant cost savings to grid operators under high-penetration scenarios. On a system-by-system or intra-day basis, it is less clear what the benefits are, the report says.
For more information on the research, click here.