Energy Storage Definition, Principle and Importance Explained

Energy storage is the act or process of storing energy for later use. This article discusses energy storage definition, principle and importance, as outlined below;


-Energy Storage Definition: 5 Ways to Define Energy Storage

-How Energy Storage Works

-Energy Storage Importance




Energy Storage Definition: 5 Ways to Define Energy Storage

Energy storage is the process by which energy is captured from its source, and conserved, using any of various devices or equipment, for later use [1].

The above outlines the basic mechanism of energy storage. Below is an alternative energy storage definition which mentions some of the sources from which energy is derived for storage;

Energy storage is the active conservation of energy from any of various materials and technologies like liquid hydrogen, gasoline, biofuel, electric generators, power plants, solar panels and wind turbines; and the storage of this energy in other systems or equipment, for later use.

Although the term ‘energy’ is used, energy storage is mostly concerned with electricity, which is derived from the electromagnetic or photoelectric conversion of energy [7], by some of the sources mentioned (like solar panels, wind turbines and electric generators).

An alternative energy storage definition is given below, which mentions some equipment used to store energy;

Energy storage is the capture of energy or electric charge, by deep cycle batteries, capacitors and other energy storage systems, for later use [3].

Energy Storage Definition: Capacitor as an Equipment for Energy Storage (Credit: USAID Pakistan 2012)
Energy Storage Definition: Capacitor as an Equipment for Energy Storage (Credit: USAID Pakistan 2012)


Below is another energy storage definition, which portrays the concept based on its link to sustainable development;

Energy storage is a process that aims to achieve sustainability in electricity generation and consumption, through improvements in energy conservation capacity, and energy efficiency of systems, by capturing and storing energy for later use.

As implied above, energy storage aims to protect the ecosystem from socioeconomic and environmental impacts of energy consumption, by reducing the rate at which waste energy is released and lost to the environment.

In the energy storage definition below, some types of energy storage are highlighted;

Energy storage is the process of capturing and storing energy by thermal dynamics, pumped hydro, batteries, compression, and flywheel mechanism, for later consumption [4].


How Energy Storage Works

Energy storage works by the active capture, conversion, and subsequent consumption, of energy. Each of these three stages is discussed briefly below;

1). Energy Capture (as part of the Energy Storage Working Principle)

Energy capture can be described using other terms like energy recovery, or energy diversion.

It is concerned with the active collection or diversion of energy from a source, into another system or unit.

Within the context of energy storage, this ‘other system’ is the energy storage system, which could be a battery or capacitor, among others.

Energy capture could occur through recovery of waste energy by cogeneration systems, or through the direct conduction of electric power (generated from energy) to a storage destination.

2). Energy Conversion

Conversion is often necessary in order to introduce energy into a storage system.

For batteries, this conversion is electrochemical, and usually involves the transformation of electricity to chemical energy through a series of reactions [2].

The need for conversion is based on differences in the compositions and working principles of energy sources and storage systems respectively.

3). Subsequent Consumption (as part of the Energy Storage Working Principle)

Stored energy is eventually retrieved from the storage system(s) and consumed.

For this to occur, it is usually necessary a second conversion to take place, which would result in a form of energy or power that can easily be used.

As stored energy in a system is being consumed, the system is said to be discharging. The effectiveness and efficiency of storage systems in releasing stored energy can both be evaluated using a quantity known as the Depth of Discharge (DoD) [5].


Energy Storage Importance

Energy storage is important because it improves the economy, society and environmental ecosystem, by reducing cost, mitigating environmental impacts, and preventing resource depletion.

The practice of energy storage is an effective way to electrify remote or rural areas. In such areas, energy storage systems can work alongside local power stations and microgrids, to supply power [6].

Energy storage promotes other innovative and sustainable solutions.

Renewable energy systems like wind farms and solar plants, benefit immensely from energy storage, which links these systems to the points of energy consumption through sustainable supply.

Others like smart grids, electric cars, and artificial intelligence networks, have benefited from energy storage technology for their advancement.

Energy storage can reduce the cost of energy itself, while mitigating energy-related hazards; by reducing the instantaneous strain which is placed on electric generators, power plants and utility grids, especially at times of peak demand.

This strain-reduction helps mitigate environmental pollution, climate change, and all other forms of degradation caused by the energy sector.

Lastly, the concept of energy storage is linked to, and supports, other sustainable concepts like recycling, waste-to-energy, sustainable production, and circular economy.



Energy storage is the capture, conversion, conservation, and subsequent use of energy, in order to minimize wastage and reduce environmental and socioeconomic impacts of the energy sector.

Its importance is based on the role of energy storage in environmental, economic, and social sustainability.

Energy storage works by;

1. Energy Capture

2. Energy Conversion

3. Subsequent Consumption



1). Chakraborty, M. R.; Dawn, S.; Saha, P. K.; Basu, J. B.; Ustun, T. S. (2022). “A Comparative Review on Energy Storage Systems and Their Application in Deregulated Systems.” Batteries 8(9):124. Available at: (Accessed 31 October 2022).

2). Dalverny, A.; Filhol, J.; Doublet, M. (2011). “Interface Electrochemistry in Conversion Reactions for Li-Ion Batteries.” Journal of Materials Chemistry. Available at: (Accessed 31 October 2022).

3). Drabek, D.; Streit, S., Blahnik, B. (2011). “Practical Application of Electrical Energy Storage System in Industry.” In (Ed.), Energy Storage in the Emerging Era of Smart Grids. IntechOpen. Available at: (Accessed 31 October 2022).

4). Janajreh, I.; Ghenai, C. (2015). “Comparison of energy storage options and detrmination of suitable technique for solar power systems.” SASEC2015, Third Southern African Solar Energy Conference, Kruger National Park, South AfricaVolume: 1, Page 205-210. Available at: (Accessed 31 October 2022).

5). Metz, D. (2017). “Economic Evaluation of Energy Storage Systems and their Impact on Electricity Markets in a Smart-grid Context.” Available at: (Accessed 31 October 2022).

6). Motjoadi, V.; Bokoro, P.; Onibonoje, M. O. (2020). “A Review of Microgrid-Based Approach to Rural Electrification in South Africa: Architecture and Policy Framework.” Energies 13(9):2193. Available at: (Accessed 31 October 2022).

7). Torres-Sánchez, E. (2019). “Energy Management through Electromagnetic Conversion.” Exergy and Its Application – Toward Green Energy Production and Sustainable Environment. Available at: (Accessed 31 October 2022).

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