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AEP Commissions First U.S. Demonstration of the NAS Battery
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AEP and a world-class team of partners are conducting the
first U.S. demonstration of the sodium sulphur (NAS)
battery at an AEP facility in Gahanna, Ohio. Through
the 2-year demonstration, AEP is testing the combined
power quality and peak shaving capabilities of this
advanced electrical energy storage technology that
promises vast improvements over conventional batteries,
including:
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Small | Large
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- High energy density
- Ease of maintenance
- High efficiency
- 15-year life
Jointly developed over a number of years by the
Tokyo
Electric Power Company (TEPCO) and
NGK Insulators, Ltd.,
(NGK), the NAS battery was originally created for large
users in the domestic Japanese market. In April, the two
companies launched the commercialization of this energy
storage system in Japan, after an extensive development
and testing program that included nearly 50 demonstration
and pre-commercial projects throughout the country.
Over the past two years, AEP has guided a team effort to
introduce the NAS battery system to the U.S. market. Our
U.S. team includes ABB for power electronics and
integration, as well as NGK and TEPCO. In addition, we
are pleased that the Department of Energy, Sandia National
Laboratories and EPRI have added their support.
The need for electrical energy storage technology
Demand for electric power constantly increases as
technological advancements improve industrial automation,
expand consumer appliance use and provide continual overall
lifestyle enhancements. Electric energy storage technology,
such as the NAS battery, can help to improve reliability
and quality of electrical service by storing electricity
in a battery overnight when demand is low and then using
this energy during the day when peak times are higher.
How it works
The NAS battery stores and releases electrical energy by a
reversible electro-chemical reaction. When a cell is
discharged, sodium at the negative electrode separates
into a sodium ion and an electron, and the sodium ion
migrates through the solid electrolyte to the positive
electrode. The electron moves from the negative electrode
through the external circuit to the positive electrode.
When the cell is recharged, these reactions are reversed.
Building on NGK's history of producing the highest quality
ceramics, NAS battery cells use a beta-alumina ceramic tube
as the electrolyte, ensuring both performance and
reliability.
The NAS battery is designed to ensure safety.
Cells are constructed with a stainless steel cartridge at
the cell's center to hold the sodium. It's surrounded by a
safety tube that limits the amount of active material in
contact with the beta alumina tube (the electrolyte to a
very thin annulus. The sulfur electrode is outside of the
beta alumina tube. It is made of sulfur impregnated
high-density graphite felt. Each cell assembly is
enclosed within an outer aluminum shell.
Individual cells are connected and encased
within a thermally insulated, stainless steel enclosure to
form a NAS battery module. A battery energy storage system
includes a sufficient number of battery modules connected
to supply the voltage, power and energy required by a
user's load.
The electrical interface between NAS batteries and utility
grid is accomplished with a conventional AC-DC power
conversion system.
History
The basic principle of the NAS battery was
discovered by Ford Motor Company in the 1960s. Since then,
developments toward practical use have been carried out in
countries all over the world. NGK, in cooperation with
Tokyo Electric Power Company, has developed and
demonstrated the NAS battery in almost 20 demonstration
projects over the last two decades.
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Strategic
Focus
