Energy storage describes a process/system which can be 1. filled with energy, 2. store the energy and 3. release energy.
- Fuel tank of a car: 1. refilling on fuel station, 2. store chemical energy as fuel if the car is not in use, 3. release fuel during driving.
- Rechargeable battery of MP3 Player: 1. refilling/charging with charger/USB port of computer, 2. store the electrical energy if MP3 Player is switched off and 3. release electrical power during the listening of music
- Massive stone walls of a building: 1. Warming up the walls during the day, 2. storing the heat energy during the afternoon and 3. releasing heat during the evening/night.
The examples show up different types of typical energy storage in different energy forms like chemical energy, electrical energy and heat.
Benefits from Energy Storage
In the case of the car the fuel is stored energy which helps to gain mobility with a car - net independent power supply. In the case of the MP3 player the stored energy of its battery allows to listen to music without access to the power grid.
Massive stone walls store heat during the day where enough heat is available and release the heat during the evening and the night where it is getting colder outside the building. In that case, the energy storage capabilities of the stone walls help to equalize the energy oversupply during the day and the energy deficit during the night with a simple structure.
Energy Storage and Renewable Energies
Energy storage is the logical counterpart for renewable energies like photovoltaics, solar thermal applications and wind energy. Solar irradiation and wind availability vary with seasons and diurnal cycles. Weather influences solar irradiation by clouds and wind speed.
To adapt the energy production variations to the energy demand variations energy storage will play an essential role in future renewable energy dominated energy supply.
A crucial point is the storage of energy for mobile applications with high energy demand: Mobility. Storage of electrical power is to expensive and relies on rare elements like lithium. More research for batteries with 1. low production costs, 2. high durability and 3. consisting of largely available raw materials might be helpful to realize a large fraction of electromobility.