Low-Frequency Wind Energy Variability in the Continental Contiguous United States

Wind energy is characterized by exceptionally large power fluctuations at the single energy facility level, that remain significant also considering the average of the many different energy facilities connected to the same grid. A high-frequency statistic, 1 min or less sampling time, is needed to understand this variability and design the energy storage facilities needed to replace the combustion fuel power plants now used to stabilize a grid. While high-frequency data are unavailable for the United States, low-frequency data, collected monthly, allow assessing the month-to-month and year-to-year variability, and define a low-frequency variability “performance”. The manuscript analyzes the output of the onshore wind energy facilities of capacity more than 250 MW in the continental contiguous United States. The differences between wind energy facilities within the same macro-region, also in about the same location, are shown, for both the annual average capacity factor and the low-frequency variability parameters. Wind energy facilities with larger annual average capacity factors have reduced variability parameters, both seasonal and inter-annual, thus performing better. The facilities with a larger annual average capacity factor also feature smaller variations in between their monthly and annual outputs.