The purpose of this report is to assist the U.S. Department of Energy (DOE) in 1) establishing a framework for understanding the role electricity storage resources (storage) can play in wholesale and retail electricity markets, 2) assessing the value of electricity storage in a variety of regions or markets, 3) analyzing current and potential issues that can affect the valuation of storage by investors at the wholesale and retail level, and 4) identifying areas for future research and development for electricity storage technologies and applications.