POWER May 2016 - 46

DISTRIBUTED ENERGY RESOURCES
2. Central storage. If the goal is to better integrate renewable generation, large centralized
battery systems work better than smaller, distributed systems. AES Energy Storage's
10-MW system in Zeeland Province, Netherlands, supports the European grid via regional distribution
system operator DELTA Netwerkgroep and transmission system operator, TenneT. Courtesy:
AES Energy Storage
systems, and when you are seeking to maximize
the amount of batteries stored in each
container, cooling becomes even more important.
This can increase costs, as the heating
ventilation and air conditioning (HVAC)
systems in the containers can end up using a
significant amount of electricity. "
More powerful HVAC systems can also
increase the noise a BSS generates. Kokam
addressed this issue in its BSSs for KEPCO
by focusing the HVAC system so it cools the
battery racks directly rather than using ambient
cooling for the entire container. That uses
up to 70% less power (Figure 3).
High-density batteries are also a larger
3. Direct cooling. Kokam's high-density battery design generates a lot of heat. Rather that
cooling the entire container, the air conditioning system cools only the battery stacks directly,
reducing the parasitic power drain. Courtesy: Kokam
safety risk. " When you connect 5,000 75-Ah
batteries together in a 40-foot container, you
have a very high voltage and high power system
in a very small location, " Hong noted.
That means using more sophisticated controls
and battery management, which can
increase costs.
Finally, where you locate a battery determines
the environmental protections that are
necessary. While containerized BSSs are, for
the most part, sealed units that are less subject
to weather impacts than other infrastructure,
it's not a matter of just dropping the system
where you need it.
David Miller, director of business develgeneration
exists. " The capacity is specifically
in the LA basin where we have the interconnection
to provide peaking capacity. "
Good Neighbors
But location for a BSS matters for reasons
beyond its role on the grid. Unlike peaking
generation, batteries have very low
noise profiles and no emissions, Ash noted.
" Largely, it just sits there; it is automated, it
is quiet, so you can put it in adjacent neighborhoods
and similar areas, and you can
wrap it in whatever you want it to look like.
A lot of providers are incorporating them
into the local look and feel of the neighborhood "
in ways that aren't possible with a
substation or peaker plant.
What that means is an opportunity to bolster
resiliency and reliability in areas that
might resist more obvious infrastructure, and
to build community and customer support if
you do it right, Ash said.
" It has been our experience that communi46
ties
tend to be very supportive of this technology
because it is helping address constraints
where the utility would otherwise have to put
in some alternative transmission and distribution
infrastructure. You don't get the pushback
you would get with a new substation or
new overhead lines. "
Hong also noted that new, higher-density
batteries can pack a lot of capacity into a small
footprint. With its project for KEPCO, the
utility " wanted to limit the real estate used for
each project. " Kokam's new ultra-high-power
NMC battery technology allows it to put 2.4
MWh of energy storage in a 40-foot container,
compared to 1 MWh to 1.5 MWh of energy
storage for standard NMC batteries.
But with that smaller footprint and closer
proximity to the community comes other
concerns.
" One key consideration when packing a
lot of energy storage into a small footprint is
cooling of the batteries, " Hong said. " Most
large energy storage systems require cooling
www.powermag.com
opment for Greensmith Energy Management
Systems, which has deployed BSSs across
the U.S., noted that containerized enclosures
are usually rated NEMA 3R or NEMA 4,
depending on the local environmental conditions,
but they can be upgraded further. " The
range of weather-proofing options allows us
to configure the enclosure for a particular environment, "
he said. " Common packages that
might be included in an enclosure include salinity
protection if the system is located near
an ocean, or humidity control if the system is
located in a humid area. This range of enclosure
options allows us to site energy storage
in a tremendous range of geographies. "
McDowall explained that the Saft project
in Puerto Rico is being hardened against hurricanes,
a regular issue in the island territory.
That means the three 20-foot containers have
to be on solid ground.
" It's fairly well-established that the container
itself is hurricane-proof, " he said, " but
the foundations and ancillary equipment have
to be adequate. "
Saft has also delivered BSSs to far less
tropical environments. Last November, it
installed a 950-kWh system for an electrical
cooperative in Kotzebue, Alaska, above the
Arctic Circle. The battery is equipped with a
cold-weather package that allows it to operate
at ambient temperatures down to -58F. ■
-Thomas W. Overton, JD is a POWER
associate editor.
POWER | May 2016

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POWER May 2016

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