IEEE Electrification - December 2021 - 50

externalities. USES systems do have
them, and they are worth noting. The
two main forms of battery storage are
Li-ion and lead acid. Lead-acid batteries
have very clear disadvantages as
they are from one of the most hazardous
metals known to humanity. Li-ion
batteries, on the other hand, do not
have the same health drawbacks that
come from lead-acid batteries, or from
their disposal. Their difficulties lie on
the other end of the supply chain.
Li-ion batteries, the main form of
An ESS can be
utilized to store
energy during offpeak
hours and then
discharges at peak
demand periods for
peak shaving or load
following.
battery storage for USES, can create
significant environmental damage
during the procurement and extraction
of lithium. Current lithium mining techniques involve
both strip and brine mining. Strip mining involves the
stripping of a mountain or landscape to find the minerals
underneath. This can be very difficult for plants and animals,
especially the endangered species that may rely on
elements in the area. Brine mining can have just as significant
an impact as strip mining, although not in the same
way. It is a system wherein aquifers are deliberately
drained and allowed to evaporate so that the minerals
within it can be extracted. Brine mining can be damaging
to water-scarce areas, such as the American Southwest,
which may need that water for agriculture, conservation,
or domestic uses.
This is seen especially in the Thacker Pass project, which
has faced heavy backlash from environmentalists over concerns
for local species, which live on top of what is one of
the largest proven reserves of lithium in the United States.
This can cause cognitive dissonance for environmentally
minded utilities, which may rightly see the benefits that
USES can give to improving the viability of renewables, but
also do not wish to see more immediate harm come to ecologically
significant areas or to endangered species.
None of this is to say that large-scale batteries would
do more harm than good. There are clear and observable
benefits to using more storage, which has helped make
things such as solar and wind generation far more viable
components of the grid. It is only to say that policy should
be directed in a considered manner for the pros and cons
of each energy storage method.
Services From USES Systems and Value
Proposition
USES systems can provide grid services and various
forms of support at the distribution level. These include
energy services (energy time shift and supply capacity),
ancillary services (regulation, voltage support, and so on),
transmission and distribution (T&D) infrastructure services
(T&D upgrade deferral, transmission congestion relief,
and so forth), and customer energy-management services
(power quality, demand charge management, and so on).
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IEEE Electrification Magazine / DECEMBER 2021
We discuss some of these services in
the following sections.
Reliability Services: Outage
Mitigation
Service interruptions can be caused by
many events, such as failures of generating
units, or T&D components such
as transformers, lines, and feeders. In
such situations, a USES can effectively
support customer loads when a partial
or complete loss of power from the
source utility takes place. Sometimes,
due to the capacity constraint, it might
not be possible for a USES to mitigate
the outage completely. However, for
such an event, it can shorten the interruption duration or
reduce the number of interrupted customers. Blocks can
also be appropriately allocated to customers based on load
criticality to provide a framework that supports reliabilitydifferentiated
services. USES also creates a better opportunity
to recover from said outages, as unlike traditional turbine
systems, they are able to come back online very rapidly,
allowing for local microgrid creation, which can supply critical
loads while the grid at-large comes back online.
Energy Arbitrage
An ESS can be utilized to store energy during off-peak hours
and then discharges at peak demand periods for peak shaving
or load following. This helps to reduce the generation
cost and postpone the need for peaking units. It is also profitable
for the energy storage owners as they can take advantage
of the energy price difference. In competitive markets,
locational marginal prices (LMPs) indicate the value of energy
at different locations and points of time. To benefit from
this application, the USES can be charged at off-peak hours
or with less-expensive energy, and discharged during peak
hours or when LMPs are high. The locations with large variability
in LMPs will generally provide higher margins.
Frequency Regulation
Energy storage is also well suited for frequency regulation.
Frequency regulation helps to maintain grid frequency
within specified limits and comply with the Real
Power Balancing Control Performance (BAL001) and Disturbance
Control Performance (BAL002) Standards of the
North American Electric Reliability Corporation (NERC) or
any other relevant governing agency. The system's frequency
tends to deviate from the specified value as generation
and load imbalances occur during normal
operation. Traditionally, several generator actions are
taken to restore and maintain frequency within the normal
operating range. These include primary, secondary,
and tertiary frequency control and response times, which
range from a few seconds to several minutes. A USES can
help in such a situation, either by acting as an extra load
IEEE Electrification - December 2021

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