Power June 2023 - 35

RELIABILITY & RESILIENCY
more about the daily setting of the sun,
extended cloud cover, wind speeds,
cold snaps, and heat waves. "
Updating Considerations for Grid
Planning with Modern Power
Systems
Consequently, as resource adequacy and
planning procedures continue to evolve
amid decarbonization, it will still be
paramount to maintain the three pillars
of power system planning: affordability,
sustainability, and reliability. Today, affordability
is part of the evolving decarbonization
discussion and still includes
the traditional inputs, but now must also
account for a variety of newly injected
factors, some caused by IBRs, to determine
the ultimate cost to the consumer.
NERC defines reliability for the grid as:
■ Adequacy, or the ability of the electric
system to supply the aggregate
electrical demand and energy requirements
to the end-use customers at all
times, taking into account scheduled
and reasonably expected unscheduled
outages of system elements.
■ Operating reliability (formerly titled Security),
or the ability of the electric system
to withstand sudden disturbances
such as electric short circuits or unanticipated
loss of system components.
Because of the issues discussed
here, NERC and FERC are actively working
to address reliability and resilience.
Through its Reliability Issues Steering
Committee, NERC has developed a Resilience
Framework focused on robustness,
resourcefulness, rapid recovery,
and adaptability (Figure 4).
The risk of shortage of generation can
be offset by increasing the investment in
generation, that is, adding more megawatts
(MWs). However, the increased
investment translates to increased cost
to the consumer or simply affordability.
The acceptability of a reliance metric
depends not on the day-to-day demands
of the system but rather on the system's
5. Elements of grid reliability. Source: Energy Systems Integration Group
ability to maintain connectivity throughout
an extreme event such as the multi-day
events referenced above. An important
aspect of system reliability (Figure 5),
in addition to operating throughout an
extreme event, is the ability to rebound
from that event, and this is generally referred
to as resilience of the system.
An acceptable reliability outcome for
the BPS is the ability to bend but not
break-resilience is the capability of
the system to return to normal operations.
What became evident from Winter
Storm Uri was that the impact of system
performance in terms of temperature
was significantly magnified by the duration
of the event.
What Needs to Change to Improve
Energy Reliability and Resilience?
So, how do these issues factor into actual
reliability performance at the BPS
level and how is that reliability correctly
valued? Why would the current state of
technology and understanding of electrical
system behavior allow for a 20,000
MW load shed-one of the largest (if not
the largest) in U.S. history-that lasted
for days on end? How could it occur in a
state like Texas, which leads the nation
in total installed electrical generation capacity,
and leave more than 4.5 million
people without essential electrical service
during an extreme weather event?
The answer may lie in how system
reliability risk is established and what is
determined as acceptable. Regardless
of how ISOs and RTOs have historically
defined acceptable risk, an actual event
determines for us the current metric. For
Texas, a week of sub-freezing temperatures
inducing a multiple-day load shed
reaching a peak of 20,000 MW is the de
facto current risk level for reliability. But
is that still acceptable? Also, what has
changed and why has it changed?
Much has been learned from Winter
Storm Uri and similar force majeure
events. We learned that the BPS reliability
risks include a constellation of considerations
including unanticipated impacts
on fuel availability, the appropriateness
of the reliability timescale, and fuel diversity,
among many other variables. As we
saw with the effects on natural gas production,
the impacts related to fuel availability
for the local grid were multiplied.
Today, we need a dynamic planning approach
that changes to reflect the everchanging
inputs to the reliability matrix.
Finally, how does the energy transition's
potential impact on reliability affect
those services that manage risks associated
with the aftermath of a storm? Qualitatively,
those impacts are significant and
need to be part of the assessment on
reliability. How we define acceptable risk
when it comes to grid reliability needs to
transition at the same pace as the systems
themselves, and it will require a review
of both the metrics and how those
4. The North American Electric Reliability Corporation's (NERC's) Resilience Framework.
Source: NERC
June 2023 | POWER
www.powermag.com
metric results are priced in the market. ■
-John F. Peiserich is a senior vice president
in J.S. Held's Environmental, Health
& Safety - Risk & Compliance group; John
Dulude, PE is a senior vice president at
J.S. Held and leads the Energy Transition
& Impact Assessment and Permitting
service line within its Environmental,
Health & Safety Practice; Edo Macan is
an executive vice president in J.S. Held's
Energy Economics group; and Chris Norris
is a vice president at J.S. Held working in
Energy Transition - Special Projects within
its Technical Services Division and Environmental,
Health & Safety Practice.
35
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Power June 2023

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