The Battery Energy Storage test (BEST) Facility is being constructed for the Department of Energy (DOE) and the Electric Power Research Institute (EPRI) by Public Service Electric and Gas (PSE&G) Company, The purpose of the facility, its general design philosophy, the proposed interactions of the facility with advanced batteries and AC/DC conversion equipment, and the layout of the facilty are described in this paper. The BEST Facility is one in a series of projects to encourage commercialization of battery energy storage systems. Through its particular design and implementation, advanced battery systems will be brought from the laboratory to application on a utility system. This step will provide significant information for both manufacturers and utilities on the characteristics of battery energy storage system. Copyright © 1979 by The Institute of Electrical and Electronics Engineers, Inc.