A smart grid is a system that includes a wide range of operational and energy measures, such as renewable energy resources, smart metres, smart appliances, and energy efficiency resources. Lithium batteries, for example, are used in a wide range of mobile devices, including communication equipment, computers, entertainment devices, power tools, toys, games, lighting, and medical devices. Solar energy is derived from natural sources, which are not harmful to behavioural or environmental factors. The sun's energy is captured and converted into solar energy (thermal or electrical) for later use. Solar energy is also used to produce fuel, which is then heated to a high temperature. Energy storage captures energy that is produced at one time and stores it for future use.