The technical objective of this project was to demonstrate that the emerging technologies of Fast Load Shed (FLS)-capable microgrid controls and Battery Energy Storage Systems (BESSs) can be integrated with onsite generation at military bases to enhance the security and reliability of electric service to the base, provide valuable ancillary services to the electric grid Independent System Operator (ISO), and generate cost savings for the Government.
This project uniquely integrated several innovative technologies to provide cost-effective solutions for military energy security. These technologies included a 500-kilowatt (kW)/580-kilowatt-hour (kWh) BESS to provide on-demand power capacity during transitions from grid power to island power and to provide ongoing voltage and frequency control to the ISO. A new FLS system would integrate the BESS and a variety of existing onsite generation assets to implement a prioritizable shedding scheme and interface the facility’s power system into the Independent System Operator for New England (ISO-NE) ancillary service power markets. The control system included new metering so the FLS could intelligently select the loads to shed in order to balance with available supply. Combination of the FLS and BESS considerably enhanced the value of the Navy’s existing onsite generation assets. Currently:
- Existing generation assets include two 5.0 megawatt (MW) combustion turbines and two 1.5 MW emergency diesel generators. Yet, this 13 MW total of onsite generation capacity could not prevent a Shipyard-wide blackout when grid power is unexpectedly lost, because fast load shedding control did previously exist.
- Batteries can provide ancillary services to the ISO but are very expensive to install and operate. By combining a BESS with the onsite generation assets at the Shipyard, it is expected that frequency regulation can be provided at a lower cost per capacity when compared to systems solely dedicated to providing ancillary services.
The results of this project show that an investment in these technologies would significantly enhance the energy security of the Shipyard by maintaining power to all critical loads in the event of a loss of grid supply, avoiding otherwise lost production time and costs. The potential for reduction in net energy costs due to revenues from the provision of ancillary services to the ISO-NE grid is also demonstrated. The potential for broad implementation of this system across U.S. Government installations is promising.
Retrofitting new FLS-capable protective relaying into an existing electrical distribution system offers substantial challenges, specifically in obtaining accurate electrical drawings of existing equipment, which in some cases may be more than 30 years old, and understanding the flow of power when islanding. Also, implementation of grid-scale energy storage posed a challenge with lack of standardization between manufacturers, equipment reliability, and corporate stability, as can be expected when working with any nascent technology.