Resiliency and Off-Grid Capabilities for Military Bases: Vermont Air National Guard Case Study

Abstract

Grid level, and behind the meter, energy storage has grown at a rapid pace in recent years. Motivations for this growth include increasing energy resiliency and providing economic benefits through peak shaving and time shifting loads to off-peak hours. This work presents the results of an energy storage evaluation for a Vermont Air National Guard base. Presently, this base has 1.54 MW of solar photovoltaics installed with no off-grid capability. This work modeled the electric critical load demand, the existing photovoltaic array, and grid interconnection. The grid interconnection model includes photovoltaic interface with the utility and appropriate time-of-use pricing for demand and energy charges. With this baseline model, various energy storage options were examined to improve the economic operation of the base and provide resiliency. Initial research has shown lithium-ion batteries as a preferred energy storage option based on current market trends. Final results yield a range of resiliency recommendations based on percentage of load served and reliability of system. System sizing options are accompanied by an economic analysis, including complete off-grid capabilities for fourteen days. While complete off-grid capability may be impractical economically, a battery energy storage system is able to offset some of the cost of the system.