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Significant Weather-Related U.S Electric Grid Disturbances
The number of incidents caused by extreme weather has increased tenfold since 1992. The portion of all events that are caused by weather-related phenomena has more than tripled from about 20 percent in the early 1990s to about 65 percent in recent years. The weather-related events are more severe, with an average of about 180,000 customers affected per event compared to about 100,000 for non-weather-related events (and 50,000 excluding the massive blackout of August 2003).1 The data shown include disturbances that occurred on the nation’s large-scale “bulk” electric transmission systems. Most outages occur in local distribution networks and are not included in the graph. Although the figure does not demonstrate a cause-effect relationship between climate change and grid disruption, it does suggest that weather and climate extremes often have important effects on grid disruptions. We do know that more frequent weather and climate extremes are likely in the future,2 which poses unknown new risks for the electric grid. Image Reference: EIA3
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- 2.  Gutowski, W. J., G. C. Hegerl, G. J. Holland, T. R. Knutson, L. Mearns, R. J. Stouffer, P. J. Webster, M. F. Wehner, and F. W. Zwiers. "Causes of Observed Changes in Extremes and Projections of Future Changes." In Weather and Climate Extremes in a Changing Climate: Regions of Focus: North America, Hawaii, Caribbean, and U.S. Pacific Islands, edited by T. R. Karl, G. A. Meehl, C. D. Miller, S. J. Hassol, A. M. Waple and W. L. Murray, 81-116. Vol. Synthesis and Assessment Product 3.3. Washington, D.C.: U.S. Climate Change Science Program, 2008.
- 3.  Administration, Energy Information U. S.. "[data]: assembled by Evan Mills, Lawrence Berkeley National Laboratory." (Submitted).