Seasonal-Scale Variability of Wind Energy and Its Relationship to ENSO and Other Teleconnections

The renewable energy industry is increasingly cognizant of seasonal scale fluctuations in wind and solar energy resource, particularly in light of the historically low wind anomaly that occurred across much of the southern Great Plains and western US in the first quarter of 2015.  This large anomaly caught many wind energy suppliers by surprise, and left them with many questions about the climatology of wind resource at their sites: How unusual was the anomaly? Could it have been anticipated? Is its cause understood? Does it represent a new normal for wind energy resource?  We have explored these questions by examining wind resource anomalies within global reanalysis datasets at the monthly and quarterly time scales, and relating them to known modes of climate variability.  While this does not lead directly to an ability to see the future (see companion abstract by Grimit et al. on the challenges of seasonal forecasting of renewable energy), understanding the seasonal and regional variability of wind resource and the climate patterns to which it is related is a first step to achieving a comfort level with the expected and actual variability of wind resource at an individual wind project, or across a portfolio of projects.  In our analysis, we examine the relationship of wind resource to ENSO, not only in terms of the amplitude of the ENSO signal, but the different spatial “flavors” of ENSO.  We also compare the strength of the relationship of US wind anomalies to ENSO versus the recently identified North Pacific Mode of sea-surface temperature variability (which might be expected to partially explain variations in the western US), and versus the North Atlantic Oscillation (which one might expect to more strongly explain variations over the eastern US).  We find that, not surprisingly, ENSO is the single strongest predictor of regional wind anomalies over the US, and that the “flavor” of ENSO is important to account for.