Environmental Engineering Reference
In-Depth Information
Case Study 1: American Electric Power NaS Battery Project
Introduction
Rechargeable batteries will play an important role in delivering clean, reli-
able electricity to businesses and consumers. As recent power outages have
demonstrated, battery technology is crucial for preventing the tremendous
losses associated with momentary or prolonged power failures. To this end
the sodium-sulfur battery has become one of the most promising candidates
for commercial-scale stationary energy storage. In this case study, we discuss
the installation of the first distributed energy storage system in the United
States, describe the basic features of the sodium-sulfur battery, and summa-
rize the rationale for its use.
Electrical energy comprises 12% of the total energy processed world-
wide. The production of electricity is highly centralized and production
usually takes place a long distance away from the end users. This delocal-
ized electricity production increases the difficulty of stabilizing the power
network, mainly due to a supply-and-demand imbalance. It is important to
note that because the production of electricity is centralized, a complex sys-
tem of energy production and transmission that makes little to no use of
energy storage has been developed. The traditional method of dealing with
increased electric demand has historically been to build more power plants
and transmission lines, but increasingly dense urban areas and environmen-
tal and legislative restrictions make this cost prohibitive and outright impos-
sible in some cases.
Storage capability is one of the main advantages of the NaS battery.
Although a battery storage facility costs as much as a coal power plant that
can supply the same amount of power, it has become impossible to build
power plants in cities—precisely where the power is needed most.
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From an
efficiency point of view, the ultimate goal would be to generate the energy,
transmit it, convert it, and then store it near the location where it is needed.
Past battery technologies lacked the ability to address the changing demands
for power back-up and storage and required bulky, costly equipment. Recent
strides in technology have now made it possible to implement the first gen-
eration of large-scale energy storage devices. To this end, American Electric
Power (AEP) decided to install the first commercial-sized NaS battery-based
energy storage system in the United States at a chemical station in North
Charleston, West Virginia.
Because the system was the first of its type, AEP received partial fund-
ing from the Energy Storage Program of the U.S. Department of Energy and
Sandia National Laboratories. Additional incentives came from the manu-
facturer, NGK Insulators Ltd., in the form of preferential prices for future
purchases of NaS batteries for a limited number of years. Installation of the
1.2-MW NaS-based, distributed energy storage system (DESS) was completed
in 9 months and entered commercial operation on June 26, 2006.
