Reducing the Cost of Energy Storage Act of 2019 This bill requires the Department of Energy (DOE) to research and develop ways to reduce the cost of energy storage, including by (1) facilitating innovation in the manner in which energy storage systems are conceived, designed, manufactured, installed, and used for various energy services; and (2) identifying, addressing, and reducing market barriers that limit energy storage adoption. As part of its research and development, DOE must pay special attention to energy storage needs and opportunities that are relatively underdeveloped and potentially transformative for the electric grid. DOE must develop cost targets (e.g., technology costs, installation costs, balance of services costs, and soft costs) for energy storage across all types of energy storage technology.