With Sandy, another hurricane and other violent events we've had our share of electricity interruptions. LBL has published an analysis of these events.
The researchers pinpointed what utilities and their regulators refer to as “major events,” or events generally related to severe weather, as the principal driver for this trend. “This finding suggests that increasingly severe weather events are linked to a 5-10% increase in the total number of minutes customers are without power each year,” said Berkeley Lab Research Scientist and Stanford PhD candidate, Peter Larsen, the lead author.
The full study is here (pdf)
Assessing Changes in the Reliability of the U.S. Electric Power System
Prepared for the Office of Electricity Delivery and Energy Reliability National Electricity Delivery Division U.S. Department of Energy
Peter H. Larsen Lawrence Berkeley National Laboratory and Stanford University Kristina H. LaCommare and Joseph H. Eto Lawrence Berkeley National Laboratory James L. Sweeney Stanford University
Recent catastrophic weather events, existing and prospective federal and state policies, and growing investments in smart grid technologies have drawn renewed attention to the reliability of the U.S. electric power system. Whether electricity reliability is getting better or worse as a result of these or other factors has become a material issue for public and private decisions affecting the U.S. electric power system. This study examines the statistical relationship between annual changes in electricity reliability reported by a large cross‐section of U.S. electricity distribution utilities over a period of 13 years, and a broad set of potential explanatory variables including various measures of weather and utility characteristics. We find statistically significant correlations between the average number of power interruptions experienced annually by a customer and a number of explanatory variables including wind speed, precipitation, lightning strikes, and the number of customers per line mile. We also find statistically significant correlations between the average total duration of power interruptions experienced annually by a customer and wind speed, precipitation, cooling degree‐days, the percentage share of underground transmission and distribution lines. In addition, we find a statistically significant trend in the duration of power interruptions over time—especially when major events are included. This finding suggests that increased severity of major events over time has been the principal contributor to the observed trend.