distribution-level power plant. The portable infrastructure consists of generators,
distribution equipment (stepped up to the
utility’s line voltage) and protective devices.
Switchgear and the protective measures
necessary to ensure synchronization with
required voltage and frequency ( 12 kV, 60
Hz) are included.
If there is a fault in the line, for example,
protective systems (relays, breakers, etc.)
ensure the temporary service remains
capable of disconnecting from the grid, if
necessary. In many cases, the lead time is
needed until the utility’s new assets (
transformers, etc.) are delivered and energized.
Other examples include sections of distribution lines that are at overcapacity and
that overcapacity can be alleviated with
temporary power until adequate resources
are available to upgrade the line.
Mobile power generation can be inter-connected to the grid at almost any
location to keep customers energized.
The time required to commission a temporary power project is largely dependent on factors such as project size,
terrain, proximity from a service center,
weather and available space. A typical 10
MW medium voltage power project, for
example, would take five to six days to
fully commission and test before being
ready for operation, and about half of
that time to fully decommission.
Whether in PG&E’s or some other utility’s service territory, most customers no
longer tolerate power outages. Best practices for minimizing outages and improving customer service through mobile
power solutions, therefore, should be
combined with utilities’ other quality
measuring metrics to ensure planned
outages are a thing of the past and
unplanned outages are short.
is industrial, commercial, residential, a combination of these, or a new
type of electrical consumer, such as an
urban medical center, any planned or
unplanned offline incident is unacceptable, even for short increments, no matter how much notification the utility
provides. For these constraints, PG&E
can now provide temporary power and
avoid interrupting customers’ services.
In addition, PG&E can use portable generation systems for both large and small
Because PG&E serves a large area
where unplanned events, such as earthquakes and large wildfires can’t be prevented, it also sees portable power as
a way to restore service faster during
“As we become better at deploying
these units, we’ll be able to respond
quicker to emergencies like earthquakes
and fires and restore power to customers
in a more rapid time frame than years
past where we had to wait for lines to be
restored,” said Branden Ezell, construction supervisor for PG&E.
Portable generation projects demonstrate the importance of optimizing strategies for staging crews and equipment
in heavily impacted areas. Whether the
requirement is for 1 MW or 100 MW,
these temporary power projects validate the mobile distributed power plant
concept’s ability to deliver repeatable
and scalable solutions. PG&E’s efforts to
modernize an aging grid sooner rather
than later is why the utility sought outside expertise to resolve this challenge.
Unplanned outages cannot be controlled,
but in the many instances where infrastruc-
ture needs to be upgraded or repaired, a
portable system can be built reflecting a
expertise to support grid challenges. Such
capability enables utilities to obtain tem-
porary power generation from outside
experts during scheduled maintenance
events, while also avoiding outages.
PG&E REDUCES OUTAGES
PG&E leverages robust portable generation systems by Aggreko for continuous power support while performing
improvements to power lines and substation equipment. One such project
recently took place when a 7 MW/12
kVA power generation solution energized more than 1,500 PG&E customers
in San Luis Obispo County for 13 hours
while upgrades were completed at the
Without the use of portable generators, customers in the San Luis Obispo
County area would have experienced a
“planned” outage for several hours while
this work was being performed.
“This is something that we are going
to be doing a lot more in the future so
customers don’t see interruptions. We
can deal with unplanned interruptions,
and we can respond to those, but it’s
really the planned work where we can
make a lot more headway in how we
take clearances and if we take clearances,” said Robert Cupp, superintendent
of transmission line maintenance for the
south region of PG&E’s service area.
In a typical scenario, medium voltage lines put up 60 years ago must be
upgraded because they are undersized
to meet current demand. The preferred
option is to perform the upgrade without
taking customers offline.
It has been typical during such
upgrades to take customers offline for
incremental periods until the project
is completed, increasing the utility’s
CAIDI. However, whether the end-user