In Energy storage, there are devices or physical media that store energy to perform useful operation at a later time. A device that stores energy is sometimes called an accumulator.

Energy storage systems in commercial use today can be broadly categorized as mechanical, electrical, chemical, biological and thermal.

There are various forms of energy; they are potential energy such as chemical, gravitational, electrical energy, etc., kinetic energy such as thermal energy.

A wind-up clock stores potential energy in this case mechanical, in the spring tension, a battery stores readily convertible chemical energy to operate a mobile phone, and hydroelectric dam stores energy in a reservoir as gravitational potential energy. Ice storage tanks store ice thermal energy at night to meet peak demand for cooling

Energy storage is everywhere and is an important aspect in many commercial sectors, both in industrial and consumer goods. Battery mobile energy storage is a crucial component in both existing product types  such as mobile computing and telecoms, automotives, defence, space and healthcare , also in emerging new product types and markets such as wearable computing, e-medicine and medical devices.

Energy Storage Industry Current Trends

• As per the reports by Climate Change Business Journal i.e. CCBJ, the U.S. energy storage market was $3.06 billion in 2011 and is expected to exceed $5 billion in 2014.
• According to the Pike Research report, it forecasts that the Asia Pacific energy storage market will be worth $12 billion by 2022, with a capacity of 25 GW.
• The electric utility energy storage market is projected to top $2.5 billion by 2015 (Red Mountain Insights)

Major Energy Storage Industry Players

Major global player are  Alstom, Dresser-Rand, Ballard Power, Plug Power, Hydrogenics, Beacon Power, Active Power, Vycon, Maxwell, Johnson Controls, C&D Technologies, Panasonic, Hongkong Highpower, Xcel Energy, American Electric Powe, NGK Insulators,  ZBB, Sumitomo Electric Industries, Ener1, Valence Technology, Altair Nanotechnologies, Advanced Battery, Ultralife etc. Some of the battery manufacturers in India are Exide Industries Ltd, Amara Raja Batteries Ltd, Base Corporation Ltd, HBL Power Systems Ltd and Okaya Power Ltd and many more.