Introduction to Energy Storage Technology

What are the Existing and developing energy storage technologies?

For short term storage, lithium-ion batteries are the dominant technology. They have the highest energy density and are capable of long lifetimes with high levels of discharge and ability to accept fast charging. Their development has been, and will continue to be driven by the EV industry. Related battery chemistries are under active development (such as sodium-ion, solid-state and aluminium-air), which may come to challenge or complement lithium-ion at some point. For many mobility applications, energy density is very important, but for stationary applications, and perhaps low speed transport such as shipping, it is less so. These different priorities are likely to drive a future divergence in battery types.

The most promising energy carrier for longer terms storage is hydrogen, either in its native form or chemically combined in a gas such as ammonia.

Other storage technologies such as flywheels, compressed air and gravity systems are under development and may come to occupy niches in the storage ecosystem needed for a smart gird.

What is a “Gigafactory”?

A “Gigafactory” is a term coined by Tesla’s Elon Musk in 2013 and refers to new-build, huge, highly automated, energy efficient factories dedicated to the manufacture of batteries or solar panels. The prefix “giga” is a reference to units such as gigawatts - giga denoting one billion. Gigafactories are at the heart of the mass production processes that are continually driving down the costs of batteries and solar panels. The first one was built in the USA by Tesla, but the concept is now spreading across the globe.

Electric vehicles and the stability of electrical girds

EVs are batteries on wheels, and like most vehicles, will be stationary for a high proportion of their lives. If they are connected to the electricity network with bi-directional connections, they can not only take power when needed for charging, but can also feed it back at times when the grid is under stress. This is achieved automatically with intelligent systems, ensuring no inconvenience to the EV user, whilst providing a source of distributed storage that supports the network and provides income for the owner, so incentivising this service.