This study addressed optimizing the integration of large-scale energy storage into microgrids for military installation’s energy security. This Phase 1 Project Team included the Electric Power Research Institute (EPRI), Southern Company, PowerSecure, and Lockheed Martin. The reliability performance targets and stacked grid services were investigated at five Department of Defense (DoD) installations, which were then incorporated into economically, viable energy storage enabled microgrids.

Evaluating two technologies, Li-ion, and Flow battery storage, is the distinguishing feature of this analysis for addressing energy security for military installations. Through the optimized integration of large-scale energy storage into microgrid designs, critical loads at five DoD installations: Fort Bliss, Naval Air Station Corpus Christi, Naval Base Ventura County, Holloman Air Force base, and March Air Reserve Base are considered that include each of the storage technologies with solar photovoltaics, diesel generators, and an uninterruptible power supply (UPS) within the microgrid configurations assessed.

As a baseline, analysis of a diesel generator-enabled microgrid provided reliability and economic operational fundamentals. Then, a four-step design procedure was followed to design an economically viable storage-enabled microgrid. In Step 1, an initial-storage enabled microgrid was designed by replacing one or more generators from the baseline configuration with energy storage. The storage system was sized to meet the reliability target of the baseline microgrid. For Step 2, each design was analyzed separately to understand the potential to provide secondary services without compromising the reliability target by reserving sufficient energy for potential outages. For each design during Step 3, a sensitivity analysis was performed to evaluate the economics of oversizing storage (both power and energy capacities) to increase the value of secondary services with an understanding of the increased system costs. And finally, in Step 4, the most feasible design with the best financial performance was selected through a cost-benefit analysis.

The project team executed its evaluation methodology and demonstrated the cost-effectiveness of storage-enabled microgrid solutions compared to diesel-based microgrids. The analysis methodology using a storage-enabled microgrid indicated the following benefits: 1) Microgrids enabled by storage are capable of meeting DoD performance objectives and reliability targets. Reliability performance of the storage-enabled microgrid demonstrated to have equal or higher reliability requirements for each DoD site; 2) Storage-enabled microgrids enhance reliability and energy security, lower cost of operations, allow power market participation, and provide a positive net present value compared to diesel-based microgrids; 3) Microgrids enabled by storage reduce the risk of loss of critical load during grid outages and reduce the cost of serving critical load; and 4) Incremental value of storage-enabled microgrids results from a) Avoided peak demand charge (except Fort Bliss), b) Avoided energy charge through self-generation and arbitrage, c) Avoided cost due to generation reduction and fuel savings, d) Avoided cost due to generator operations and maintenance (O&M), e) Avoided cost due to UPS reduction, f) Avoided cost due to UPS O&M, g) Demand response program participation value (except Fort Bliss), and h) Emissions reduction through increased renewable generation.