This tutorial will cover the basics of electrical energy storage (primarily for the grid), including the factors driving the need for electrical energy storage, the various energy storage applications, various present and potential future battery energy storage technologies (BESS), e.g. Li-based, advanced lead-acid, flow batteries, sodium-based batteries, metal-air batteries and zinc-based rechargeable batteries commissioning of energy storage systems interconnection with the grid (e.g. IEEE 1547) and code compliance and safety for energy storage systems.