This project demonstrates the use of a sodium-sulfur (NAS) battery system to shift
compressor peak load to off-peak capacity and provide emergency backup power at
a Long Island bus depot facility. The primary application will be to supply up to
1 MW of power to a natural gas compressor for six to eight hours per day, seven
days per week, especially during the summer peak period. The natural gas compressor
provides fuel for CNG buses that will replace diesel-powered buses.The system will power
the compressors during the day and recharge from the grid at night when utility rates
are lower.
Primary participants:
- ABB, Inc.
- New York Power Authority (NYPA)
- NGK Insulators, Ltd. (battery manufacturer)
- EnerNex Corporation (data acquisition and monitoring)
- Site Overview
- Energy Storage System
- System Connection and Operation
- Data Acquisition and Monitoring
Site Overview
The system is located at the Metropolitan Transportation Authority’s Long Island Bus maintenance
facility at Garden City, NJ. It powers the three 600 hp CNG compressors used to fuel 220 CNG busses,
shifting the load to off-peak, and providing back-up power for the rest of the facility. The system
is silent and emission-free.
Energy Storage System
The energy storage system consists of a NAS Battery System from NGK Insulators, Ltd. The battery cells
in the NAS battery system use Sodium anodes and Sulfur cathodes kept molten at approximately 300°C.
The system has a capacity of 1 MW and 7.2 MWh.
The Power Conditioning System (PCS) from ABB, Inc. acts as an interface between the AC grid and the DC batteries, automatically charging or drawing power from the NAS batteries and managing the system.
