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found that undergrounding would not be economically
feasible and would negatively impact customer rates.
Additionally, although undergrounding lines can reduce
the frequency of outages, studies also showed that
restoration time can increase due to the complexities of
the systems and the inability to visually identify the
cause of the fault. However, while costs are currently
prohibitive for total system undergrounding, utilities and
regulators should review the metrics for selective
undergrounding as a potentially viable solution for
vulnerable areas and for locations serving critical
facilities such as police, fire, hospitals, water utilities,
and telecommunications. It’s also important to note that
LEARNING FROM EXPERIENCE undergrounding does not totally protect the system from
storm surges and flood damage.
In 2004, Hurricane Ivan devastated the nation of Other hardening measures for poles and lines can be
Grenada. Grenlec, the island’s sole utility, suffered incorporated as part of routine maintenance schedules
unprecedented damage to its distribution system. as new designs become available and older equipment
However, because of good planning and sound design in is retired and replaced.
prior years, the generation assets were largely untouched
by the storm and were made operational within 24 Overall, utilities need to weigh the size of the system,
hours of the “all-clear” status. Guided by its Disaster critical loads, relative costs, environmental factors,
Recovery Plan, Grenlec restored power rapidly to critical causes of outages, and weather-related risks to provide
locations for medical, water and public safety services. the appropriate level of resiliency.
Full restoration was completed within a year.
Distributed generation and microgrids. Solar photovoltaic
Resiliency and redundancy were designed into the (PV), wind, fuel cells, and fossil fuels, can provide
restoration plan and processes as Grenlec rebuilt the additional capacity to enhance resilience during major
electrical system in Grenada. The flexible nature of the outages. In some cases, systems can disconnect from the
generating assets allowed Grenlec to segment the main power system and serve as backup power.
system into multiple “islanded” power systems,
essentially creating ad hoc microgrids. The distribution
system was then rebuilt radiating from these “hubs.”
Assistance with this rebuilding effort was afforded by
several crews from neighboring islands’ utilities. A
disaster relief program, organized by the Caribbean
Electric Utility Services Corporation (CARILEC), ensures
that sister utilities are available to support each other in
recovery and restoration efforts. Lastly, and very
significantly, Grenlec also maintains a self-insurance
“Hurricane Fund” which allowed the utility to promptly
pay for restoration materials and efforts.
METHODS OF IMPROVING
RESILIENCY
Undergrounding transmission and distribution lines is
one of the most common measures proposed for
mitigating storm damage. However, in many cases, the
costs associated with converting overhead systems is
extremely high. According to a report by Edison Electric
Institute for U.S. utilities, Before and After the Storm,
not one study included in the report recommended a
complete conversion of overhead distribution
infrastructure to underground, given that the estimated
costs would be in the billions of dollars. The studies
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