The need for energy emerged as soon as human beings learned to cook food, although people were unknowingly benefitting from solar energy to protect their bodies from coldness and drying clothes in the sun etc. The first planned utilization of energy was from wood and fire. However, increasing awareness of nature for taking advantage of energy, various sources of energy were identified and put to versatile uses. People also acquainted to change forms of energy and storing it for the times when sources were not available, for example, solar energy at night, though the ways of conserving energy were very basic like storing wood under shelter and other safe places. However, increased populations and energy usage versatility added other sources like coal, steam, water, wind, and petroleum. The invention of electricity changed the whole scenario of energy. The olden sources of energy were replaced partially by the production and consumption of electricity. Some modern sources of energy like nuclear and renewable resources have been identified in the twentieth century. Presently, an energy mix is prevailing and being used in different parts of the globe. The demands for energy are increasing rapidly due to an increase in populations, economic development in developing countries, enhancement in per capita consumption, change in lifestyle, and supply at more remote places as stored energy. The world’s primary energy consumption was 149,634 and 157,064 Terawatt-hours (TWh) in 2015 and 2018 respectively (Ritchie and Roser, 2019). According to their estimate, the regional consumptions were 69,615, 32,936, 23,859, 10,822, 10,494, 8164, and 5367 TWh for Asia Pacific, North America, Europe, CIS, Middle East, South and Central America, and Africa respectively. Thus, the biggest consumers of energy were Asia Pacific and North America while Africa used the least quantum of energy in 2018. The Gulf Cooperation Council (GCC) countries are although low populated, but are high consumer of energy, even in comparison to some of the developed countries (Al-Badi and AlMubarak, 2019). The consumption of electricity in the GCC region has grown from just 51 TWh in 1990 to almost 536 TWh in 2015 whereas the per capita use has been recorded as one of the highest rates. It is estimated that the GCC countries will be consuming 1094 TWh by 2025 (Almulla, 2014). Such a pattern is mostly due to rapid economic development and significant change in the lifestyle. The household energy storage system necessarily require smooth, balanced, reliable and quality supply (maintaining constant voltage and frequency) to the customers without any breaks and potential damage to electrical appliances. The strong variations always exist in demand of electricity at different times. Hence, there could be certain times when the energy production will be more than demand and vice versa. Just to quote an instance, the peak demand of GCC countries in summer is twice the off-peak summertime requirement due to the running of air conditioners and is thrice of winter peak times (Al-Badi and AlMubarak, 2019). For balancing and matching the demand and supply, the storage of energy is a necessity. The present trends indicate that the need for energy storage will increase with high production and demand, necessitating the energy storage for many days or weeks or even months in the future. According to estimates, requirements for storing energy will become triple of the present values by 2030 while the stationary energy could dominate in quantities of electricity supply through grids (IRENA, 2017). The energy storage techniques and devices have been changed and modernized simultaneously along with increasing production and demand. The devices conventionally were magnets, batteries, dry cells, and capacitors. However, besides changes in the olden devices, some recent energy storage technologies and systems like flow batteries, super capacitors, Flywheel Energy Storage (FES), Superconducting magnetic energy storage (SMES), Pumped hydro storage (PHS), Compressed Air Energy Storage (CAES), Thermal Energy Storage (TES), and Hybrid electrical energy storage (HES) were developed for sustainable and renewable usage (Frackowiak and Béguin, 2001, Doetsch, 2014; Haisheng et al. 2009; Luo et al., 2015; Silva & Hendrick. 2016; Stanley, 2012; UCS, 2006). However, energy storage mechanisms also face many challenges as well (Mohd et al., 2008) because none is complete in all respects due to one or more limitations like storage capacity and form, string time, special structural or implementation requirements, energy releasing efficiency, and operation time (Yae, et al., 2016). In addition, there are cost, and environmental aspects like CO emissions (IEA, 2019) associated with the energy storage technologies, which must be identified and considered when planning and deciding the selection of technologies for installation in the grid systems of an area. The aspects identified above need to be elaborated through a systematic study from the literature so that valuable research work of earlier authors is gathered, understood well, and arranged in a good array to clarify the study areas, which can contribute to support and ease the decision makers and practitioners for selection of best energy storage devices and mechanisms for their particular grid systems. Considering the high importance and problems of electric energy storage, some aspects of this subject are being discussed and highlighted with support from the literature review.
