SpecsNGK’s NAS Energy Storage System is a proven large scale solution tothe integration of variable renewable energy forreplacement of fossil generation

Structure of NAS Energy Storage SystemThe Easiest Way to Achieve Megawatt-Hour Energy Storage SystemNAS Energy Storage System is designed to be easily able to expand the capacity as much as needed in one site or several separate sites. The scalability of NAS installation to many 10s or 100s of MW for durations of 6 to 7 hours is at a scale that can defer or elimi-nate some transmission, distribution and generation investments especially when used in association with variable renewables for a clean solution. (The current largest system at one site is 50MW, 300MWh.) The construction leadtime is significantly shorter than upgrading or building transmission/distribution lines or substations.

A NAS Energy Storage System consists of battery enclosures, battery modules and a PCS (AC/DC power conversion system) as the main components. The NGK scope is the battery enclosures and battery modules. NGK works with several PCS manufacturers to complete the battery system.It is also suitable to install in severe weather conditions, because the battery enclosure and insulated battery modules can resist awide range of environmental conditions and climate.

The NAS battery system is a “Plug and Play” design built around standard 20 foot ocean freight containers. The con-tainerized design expedites transporta-tion and installation and helps minimize installation costs.

New container type unit

Rated Output 800 kW and 4,800 kWh

Configuration

Dimension 6.1W x 5.6D x 5.5H (m)

Weight 86 tonnes

Four container subunits,series connected.A subunit includes six NAS modules, each rated at 33 kW and 200 kWh.

Dimension : m

2.4

5.2

0.8

2.4

6.1

0.3

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Battery Module Cell

NASBattery

PCS Sodium

Sulfur

BetaAlumina

The enclosure package and battery mod-ules are installed on site. This design achieves more compact system compar-ing with containerized design.

Package type unit

Rated Output 1.200 kW and 8,640 kWh

Configuration

Dimension 6.1W x 5.7D x 5.2H (m)

Weight 86 tonnes

40 NAS modules, each r a te d a t 3 0 k W a n d 216 kWh.

Dimension : m

4.4

10.24.8

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Features of NAS7

HOURS

1ms OK!

LONG DURATION COMPACT FAST RESPONSE RELIABILITY &SAFETY MAINTENANCE

Principle of NAS Battery

NAS battery cell consists of sulfur at positive electrode, sodium at negative electrode as active materials, and Beta alumina ceramic. Beta alumina ceramic is one of NGK's key technologies, which is mounted between sodium and sulfur as electrolyte.

This hermetically sealed battery cell is operated under the condition that the active materials at both electrodes are liquid and its electrolyte is solid.

Battery Cell

S

NaBetaAlumina tube

Sodium Na

Sulfur S

If a load is connected to terminals, electric power is discharged through the load. During the discharge, sodium ions converted from sodium in a negative electrode pass through solid electrolyte then reach to sulfur in positive electrode.The electrons finally flow to outside circuits. The electric power is generated by such current flow.With the progress of the discharge, sodium polysulfide is formed in positive elec-trode; on the contrary, sodium in negative electrode will decrease by consumption.

Operating Principle

Discharge

During the charge, the electric power supplied from outside form sodium in negative electrode and sulfur in positive electrode by following the reverse process of the discharge. Because of this, the energy is stored in the battery.

Charge-Pole(Na) +Pole(S)Beta Alumina

LoadDischarge

ChargeSource

Na S Na2SxNa+ e-

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