In this work we describe the development of cost and performance projections for utility-scale lithium-ion battery systems, with a focus on 4-hour duration systems. The projections are developed from an analysis of recent publications that include utility-scale storage costs. The suite of. . DOE's Energy Storage Grand Challenge supports detailed cost and performance analysis for a variety of energy storage technologies to accelerate their development and deployment The U. Maintenance costs typically range from 2-5% of the initial system cost annually. The bottom-up BESS model accounts for major components,including the LIB pack,the inverter,and the balanc of system (BOS) needed for the in ange considerably more depending on duration. Looking at 100 MW systems,at a 2-hour duration,gravity-based. .