Utility-scale energy storage is expected to continue breaking into the mainstream electricity industry in 2016. The market is projected to move away from RAndD projects and push toward full commercial deployments. While most new activity is concentrated in select regions and markets, grid operators around the world are beginning to recognize the value that large-scale energy storage systems (ESSs) can provide. Specific market dynamics and trends vary throughout the world, but there are overarching factors driving the market and technologies forward. Perhaps the most important driver of energy storage for the grid and ancillary services (ESGAS) is the substantial growth in the amount of renewable energy being deployed around the world. As the percentage of variable generation increases, energy storage can help grid operators maintain system stability and ensure the efficient integration of these new, clean resources. There are several other key macro trends driving ESGAS markets, including the rapidly falling prices of ESSs and the growing need for new electrical infrastructure around the world. According to Navigant Research, global installed ESGAS power capacity is expected to grow from 1.1 GW in 2016 to 21.6 GW in 2025. This Navigant Research report explores the growing opportunities for ESSs to provide numerous services to the grid and how these markets will evolve in the coming decade. All major technologies for utility-scale energy storage, including advanced batteries and electromechanical systems, are covered in this report for the six top services that energy storage can provide. Global market forecasts for power capacity, energy capacity, and revenue, segmented by region, technology, and application, extend through 2025. The report also examines the key business models related to ESGAS, as well as the competitive landscape.