pwr_may-2024 - 14

O&M
Underground or Overhead:
Exploring Line Options to
Enhance Grid Resiliency
The power grid has been a topic that has
dominated headlines in the energy industry
and mainstream news over the past
few decades. Despite this increased focus,
with each passing year the problem
is only getting worse.
Contrary to the popular buzzword,
the problem is not actually power grid
reliability. Multiple studies have shown
that the grid is reliable more than
99.9% of the time. Homeowners are
not experiencing prolonged service interruptions
in most conditions, showcasing
that the grid is ultimately doing
what it was intended to do a majority of
the time: provide power.
However, what we are seeing now
is that the grid fails spectacularly in
extreme weather events, demonstrating
that resiliency is a much bigger
problem than reliability. According to
Climate Central, 83% of reported major
outages in the U.S. between 2000
and 2021 were attributed to weatherrelated
events. Furthermore, the average
annual number of weather-related
power outages increased by roughly
78% in the second half (2011-2021)
of that study compared to the first half
(2000-2011).
Complicating Factors
There are three major reasons why we
are seeing an increase in power outages
related to weather.
Weather Is More Extreme Now.
It is often hyperbole to claim that we
are living in the best or worst times,
but the facts clearly show that extreme
weather is worse than ever before. The
journal Nature Water published a study
in March 2023 that detailed how the
intensity of extreme drought and rainfall
has sharply increased over the past
20 years. The Environmental Defense
Fund reports that the proportion of major
hurricanes (Category 3 or above) in
the Atlantic Ocean has doubled since
1980. And the summer of 2023 was
the hottest ever recorded, according
to the National Aeronautics and Space
Administration (NASA).
People Are Flocking to the Coasts.
The National Oceanic and Atmospheric
Administration (NOAA) Office for
Coastal Management reported that
14
more than 128 million people, or about
40% of the U.S. population, lived in
coastal counties in 2023. That's despite
the fact that the U.S. coastline (excluding
Alaska) accounts for less than 10%
of the nation's land mass. It's hard to
argue the allure of the sun and the
sand, but heavily populated areas tax
existing grid infrastructure. Making
matters even worse is that these desirous
areas are also the most prone to
severe weather such as hurricanes and
extreme heat, and the increased population
density means that every one of
these events can impact a much larger
number of residents.
Overhead Lines Are Aging. At the
end of 2022, the White House acknowledged
that an estimated 70% of the
nation's lines are more than 25 years
old. This aging infrastructure leads to
vulnerabilities
in American communities
and economic interests. Those vulnerabilities
range from safety concerns
(including food spoilage, disrupted communication,
and lack of access to heating/cooling)
to financial impact attributed
to the loss of business revenues during
extended outages.
Extreme weather is a direct result of
climate change, and while we can certainly
take steps to reduce our impact
on global warming, this clearly isn't an
easy fix. Suggesting that people stop
moving to the coasts might get you
laughed out of some rooms. But there
are some immediate and cost-efficient
innovations and solutions to the transmission
line problems.
Solution No. 1:
Undergrounding Lines
One option to harden the grid would
be to bury power lines underground
(Figure 1), where they are much less
susceptible to the impact of extreme
weather. This is certainly not a new
concept, but reports estimate that only
between 18% and 25% of all power
lines in the U.S. are underground. The
biggest obstacle is cost, with many
utilities proving unable or unwilling to
take on the associated expenses of underground
lines.
We've seen multiple scenarios
where the fires on the West Coast
were exacerbated by a tree or branch
falling on overhead lines. In the Midwest,
high winds and tornadoes have
the same effect on overhead lines,
bringing them down, at times causing
fires or other dangerous situations. The
1. Burying power lines underground helps mitigate the impacts of extreme weather on the
grid. Utilities and grid operators recognize the additional cost of the undergrounding process,
which is why more lines have not been buried, but some utilities are taking steps to finance
undergrounding efforts. Source: POWER
www.powermag.com
POWER | May 2024

http://www.powermag.com

pwr_may-2024

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