According to ISO 13600, an energy carrier is either a substance or a phenomenon that can be used to produce mechanical work or heat or to operate chemical or physical processes. It is any system or substance that contains energy for conversion as usable energy later or somewhere else. This could be converted for use in, for example, an appliance or vehicle. Such carriers include springs, electrical batteries, capacitors, pressurized air, dammed water, hydrogen, petroleum, coal, wood, and natural gas.
ISO 13600 series (ISO 13600, ISO 13601, and ISO 13602) are intended to be used as tools to define, describe, analyse and compare technical energy systems (TES) at micro and macro levels:
*ISO 13600 (Technical energy systems — Basic concepts) covers basic definitions and terms needed to define and describe TESs in general and TESs of energyware supply and demand sectors in particular.
*ISO 13601 (Technical energy systems — Structure for analysis — Energyware supply and demand sectors) covers structures that shall be used to describe and analyse sub-sectors at the macro level of energyware supply and demand
*ISO 13602 (all parts) facilitates the description and analysis of any technical energy systems.