Book excerpt: Energy Storage Basics closely covers the basics of energy storage in the form of a study guide. It is meant for energy professionals and a technical audience interested in understanding the concepts of electricity, renewables, and energystorage solutions. The important concepts will be covered and defined, and readers will have a chance to test themselves at the end of each chapter.The last decade has shown incredible progress in the world's transition towards a clean energy future. Today, the most competitive levelized costs of electricity, which refers to the cost of generating electricity and operating a power plant, is large scale grid-connected solar photovoltaics systems.As the world transitions towards clean energy, new challenges will emerge that need to be addressed. Renewable energy such as solar and wind energy are intermittent and non-continuous, which makes its output unpredictable and consequently makes managing energy loads a challenge.As intermittent renewable energy contributes to an ever larger proportion of our energy consumption, energy storage will play an important role in managing loads within the electricity grid. More specifically, energy storage will providegrid operators and utilities with the flexibility to deploy energy in response to their needs. Also, energy storage will allow residential and commercial industrial consumers to generate their own electricity and operate outside of the electric grid - what we often call 'behind the meter'.Energy storage systems, also referred to in this book as ESS, we believe is the holy grail for this clean energy transition.