Electrical Energy Storage
The EES technologies around the world:
- Early 1800s – batteries were essentially zinc and copper electrodes in sulphuric acid.
- In 1859, lead acid battery emerged as a power source for automobiles.
- In 1888 alkaline batteries were invented.
- in 1970s with nickel- cadmium cells that set off the electronic boom, walkman’s and power tools became popular inventions
- The next major turning point was 1991 with the commercialization of Lithium batteries (LIB) which actually revolutionized the portable electronic gadgets industry
- Nickel-Metal Hydride (Ni-MH) batteries emerged in 1997
- 2000s: mass production of LiBs
NaS – by far sodium sulphur batteries are considered the most matured technology. Closer to home, at Mitsui House in Delhi they have recently completed a microgrid with NaS battery.
LIB – rechargeable Lithium Bromide has changed our daily life. This technology has products for all the four industry segments- electronics, EVs, home applications and grid connected applications. Li is a comparatively light metal and is very active. Without prejudice to the great leaps made by LIBs the recent Dream Liners troubles have put doubts on LIBs scalability to megawatt levels. Heat dissipation might warrant active cooling. That is a whole lot expensive as temperature sensors and cooling systems are going to be expensive.
Lead Acid – Lead acid batteries are the world’s most widely used battery type and have been commercially deployed since about 1890. Their usability decreases when high power is discharged and this makes them unviable as MW scale solutions.
Vanadium redox – this technology is a flow type battery that is emerging as a dark horse. Flow batteries use PEM fuel cell technology. UTC is ready for commercialisation of this technology and intends to manufacture it in India considering the huge market potential here.
Electric Double layer capacitors –
Super conducting magnetic energy storage – very much in its infancy stage, it has a superconducting coil and a cryogenically cooled refrigeration system that once charged stores the energy in the magnetic field created in the coil for an indefinite period of time. 1MWh systems used for grid applications, 20 MWh systems than can provide 40MW for 30 mins or 10MW for 2 hrs are under development.
Thermal storage – systems use cold water, hot water or ice storage to store the heat and use for later. The efficiencies vary with the material.