The Department of Defense (DoD) operates over 500,000 buildings and structures with diverse inventory encompassing barracks, commissaries, data centers, office buildings, laboratories, and maintenance depots, among others. Most of these bases are largely dependent on a commercial power grid that is vulnerable to disruption from cyber-attacks, aging infrastructure, weather-related events and direct attack. To ensure mission assurance, DoD adopted an energy strategy focused on security and resiliency for fixed installations to reduce energy costs, increase security, and improve energy resilience. In line with this strategy, Environmental Security Technology Certification Program (ESTCP) has invested in a microgrid project, EW-201350 Portsmouth Naval Shipyard Microgrid and Ancillary Services, that demonstrated integration of a Microgrid Control System (MCS) capable of Fast Load Shed (FLS), and Battery Energy Storage Systems (BESS) for back-up power, to manage loads and distributed generation to meet economic, performance and security objectives while ensuring reliable operation.
The objective of this project was to demonstrate that a FLS capable MCS and BESS can be integrated with on-site generation at military bases to enhance the security and reliability of electric service to the base, provide ancillary services to the electric grid Independent System Operator (ISO), and generate cost savings. The demonstration was conducted at the Portsmouth Naval Shipyard (PNS) in Maine, where they typically experience two to three outages per year, resulting in disruption of Shipyard operations.
The demonstration included innovative technologies such as the BESS with a 580 kWh Li-ion battery, a 500kW bi-directional inverter and a MCS with FLS capability. The role of BESS was to provide on-demand power capacity during transitions from grid power to islanded microgrid power and ongoing voltage and frequency regulation to ISO-New England (ISO-NE). The MCS integrated the BESS and a variety of existing on-site generation assets to implement a fast load shed scheme and interfaced the PNS power system into the ISO-NE ancillary service power markets. The control system included new metering so the MCS can intelligently select the loads to shed to balance with available supply. The MCS used the metering data to adaptively calculate the steady-state generation load-balance for changing power system conditions and select the prioritized loads to shed to maintain this balance following the detection of a utility outage.
The project successfully demonstrated islanding the facility during both simulated and live loss-of-utility events. The MCS tripped sufficient load to maintain steady state generation and correctly dispatched the BESS output for the transition to islanded microgrid mode. The FLS took less than 80 milliseconds to shed non-critical loads once the loss-of-utility event was detected. The demonstration was well received by PNS and the Principal Investigator is actively pursuing technology transfer opportunities across DoD. Additional details on the demonstration results can be found in the Final Report and the Cost and Performance report available for download on the project webpage.