creating a buffer that allows energy to be collected and used at different times.
Examples of different kinds of energy storage:
- Chemical (eg. fossil fuels, biofuels, hydrogen, food)
- Electrochemical (e.g. batteries)
- Kinetic (eg. flywheel)
- Thermal (eg. hot water, ice, molten salt, phase change materials)
- Gravitational (eg. hydroelectric dams, pumped hydro)
- Nuclear (eg. uranium, plutonium)
- Compressed air energy storage
Small-scale energy storage
Two examples of small-scale energy storage that are commonplace in an urban household are hot water tanks and rechargeable batteries. Batteries are used in many kinds of personal devices, from mobile phones to computers and music players.
Small scale energy storage is more useful when living with an unreliable power supply. For example, homes in some urban areas are subject to rotating power outages due to insufficient power generation capacity.
Off-grid living is even more likely to make use of small scale energy storage. Gasoline-fuelled generators, rechargeable batteries, and private water towers are all examples of approaches to energy storage with different sustainability characteristics.
In some areas, people with battery-electric vehicles may be able to share their car's energy storage with the power grid to assist with overall adaptability and possibly find an economic gain if Time Of Use pricing is offered by the local electricity provider.
Hikers and travellers might also be interested in energy storage so they can extend their activity or do more during their activity. Portable battery kits are one way to accomplish this.
Grid-scale energy storage
Energy storage is especially relevant when trying to incorporate renewables into an energy system. The best-known forms of renewable energy, wind and solar, are both available intermittently and do not necessarily align well with the usage and demand patterns of people in cities. Therefore, energy storage is very helpful when trying to incorporate these source of power generation.
Fuel-based power generation has implicit energy storage in the fuel that's being used to produce power; this allows power generation to be dispatched to meet demand exactly. A movement away from unsustainable fossil fuels therefore implies growing dependence on alternate forms of energy storage that is intentionally designed into the system.