IEEE Electrification - December 2021 - 51

to lower the frequency when supply exceeds demand, or
to discharge when demand exceeds supply. Suitably
interfaced, it can be twice as effective in regulation compared
to conventional fossil fuel generators such as coal
units and combustion turbines.
The aforementioned services have often been used to
quantify the " payback " of USES installations, although in
many cases, the payback has been lower than the investment
cost. Perhaps the most lucrative service has been
that of frequency regulation. PJM Interconnect has been a
leading driver in this space, initially remunerating generous
amounts in capacity and performance payments.
However, other markets have been slow to follow, and the
payouts have declined as the proliferation has increased.
Yet it is perhaps unfair to judge the value of USES installations
based on payback alone. There are several other services
that are very beneficial to the system, but the impact
on payback is hard to determine.
Other Services and Benefits
USES can also be used for various other applications that
are crucial to the power grid in several ways, but they
might be difficult to demonstrate in terms of monetary
benefits. These applications can be classified according
to the customers being served, e.g., residential, commercial,
or industrial customers. The following are a few of
these applications:
x Voltage-flicker mitigation: Voltage flicker is often a problem
that needs to be addressed in power distribution
systems. It is harmful for customers of all load profiles.
Voltage flicker might damage electrical devices
ranging from the most common household appliances
household to industrial-scale equipment. It might
also lead to spoilage from semifinished industrial
products. Thankfully, USES can help stabilize the voltage
by charging or discharging within a very short
time, thus protecting the customer's equipment.
x Power-factor improvement: This problem is mostly
applicable to industrial customers that use a significant
amount of reactive power for their daily operation.
In most of the cases, they are charged with a
penalty from the utility serving them if the power factor
goes below a prespecified limit. These customers
can greatly benefit from the presence of USES, which
can act similarly to supercapacitors by providing reactive
power while also providing more general uses.
x T&D upgrade deferral: USES can also be used for the
deferral of T&D system upgrades. It can help in delaying
investments that would otherwise be necessary to
maintain the T&D capacity in accordance with the
load demand. For example, the purchase of a new
transformer with a high capacity may be avoided by
using a USES instead.
x Voltage-regulator lifetime extension: The addition of distributed
generation, e.g., PV or wind power to a feeder
in the distribution system, might decrease the lifetime
of a voltage regulator due to a rise in the number of tap
changes with an increase in voltage fluctuation. If USES
is suitably used to smooth variability, then it can reduce
the number of tap changes of the regulator by reducing
the voltage fluctuation, thus extending its lifetime.
x Emission reduction: Climate change and global warming
are matters of concern, especially with regards to emissions
from fossil fuel plants. Thermal power plants
across the world are among the largest consumers of
fossil fuels. The generation of renewable resources and
their integration into the grid reduces emissions and
the burning of conventional fuels. USES can accumulate
clean energy at off-peak hours, e.g., when wind
power generation is high at night, while load demand
is low, and then discharges it at peak hours, thus
improving its effectiveness at reducing emissions.
Business Models
USES systems have gained significant momentum to provide
opportunities for owners of RESs to lease portions of
their storage instead of buying individual ESSs. In this context,
new multiuse business models, which utilize battery
storage for different grid services and improve power supply
reliability and resilience for local communities, are needed
to increase economic benefits for USES owners (e.g., utilities)
and customers with BTM distributed energy resources
(DERs). In theory, USES can provide many benefits for individual
households and the community. For example, blackouts
and shortages due to extreme weather conditions can
be mitigated with an ESS. However, before this scheme can
be implemented, utilities, investors, and community members
need to know how to assess its costs and benefits. As
mentioned previously, developing and employing business
models for USES systems can be a challenge due to complicated
interactions between utilities, system operators, and
BTM participants. Also, USES can provide several benefits to
both utilities and investors (e.g., BTM participants) with different
perspectives, which can introduce conflicting objectives.
For utilities, the benefits can include increasing the
hosting capacities of distribution systems to electric vehicles
and high penetration of RESs, deferral of distribution system
expansion, and fewer communication requirements as
communicating with one point at the substation level
requires less communication than communicating with
many ESSs at homes or BTM devices.
Grid operators can utilize USES systems to provide grid
services at scale, including frequency regulation, voltage
control, and demand-side management. For investors,
USES systems can provide an affordable and safe energy
storage through leasing blocks of the shared energy storage;
this is extremely important for the occupants of multifamily
buildings and tenants. Such an offering would also
benefit property owners through a reduced maintenance
burden. This fee may be similar in nature to already-existing
renewable energy fees, wherein ratepayers who wish to
ensure that they are funding reliable technologies will pay
IEEE Electrification Magazine / DECEMBER 2021
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IEEE Electrification - December 2021

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