LVXXU

Weather-Related and Other Reliability Vulnerabilities
Historically, weather-related disturbances are the leading source of grid outages. For a 5-year period from 2008
to 2012, estimated costs of weather-related power outages ranged from $107 million to $202 billion. 17 Weatherrelated
disturbances have a far greater impact on grid reliability—measured in terms of customer interruption
hours—than component failures, physical attacks, and cyber incidents combined (see Figure 2-3).
Figure 2-3. Left Figure: Electric Disturbance Events, January 2011–August 2014; Right Figure: Customer Hours
Affected by Electric Disturbance Events, 2011–August 2014 18
# of Events
400
350
300
250
200
150
100
50
# of Customer Hours (millions)
4,500
4,000
3,500
3,000
2,500
2,000
1,500
1,000
500
0
2011-2014
0
2011-2014
Weather
Component Failures and/or
Internal Causes
Weather
Component Failures and/or
Internal Causes
Physical Attack
Cyber Attack
Physical Attack
Cyber Attack
While weather was responsible for less than half of all reported incidents, weather accounted for the vast majority of customer interruption hours
from 2011 to 2014. Not all reported events (shown on the left), such as voltage reductions and public appeals, result in actual customer outages
(shown on the right).
The frequency and severity of certain types of extreme weather events have led to greater vulnerabilities for
electric transmission and distribution systems. 19 Recent Department of Energy (DOE) analysis 20 examining the
effects of climate change on infrastructure exposure to storm surge and sea-level rise found that vulnerabilities
are likely to increase for many energy sector assets, including electricity. Figure 2-4 illustrates that, under the
highest sea-level rise scenario from the National Climate Assessment, 21 by 2030 the number of electricity
substations in the Gulf of Mexico exposed to storm surge from Category 1 hurricanes could increase from 255
to 337. Projected sea-level rise by 2050 would increase the number to roughly 400. Any significant increase
in hurricane intensities in a warmer climate would greatly exacerbate exposure to storm surge and wind
damage. Another important factor is current and projected development patterns, which is expected to have a
larger effect on energy infrastructure vulnerability than rising sea levels, particularly in regions where energy
distribution infrastructure is being built to serve growing populations in exposed coastal areas. 22
QER Report: Energy Transmission, Storage, and Distribution Infrastructure | April 2015 2-9