What is the bidirectional V2G technology being tested by auto manufacturers?

Renault is experimenting with bidirectional charging on a large scale, such as here in Utrecht, Netherlands. — Renault/VanDerVaartfotografie/Relaxnews

Audi is just the latest in a string of manufacturers to announce work on a bidirectional recharge system. Auto manufacturers are hoping to do their bit for the energy transition, and this technology could transform any electric vehicle into an energy supplier.

The idea behind bidirectional charging (the technology behind V2G, or 'vehicle to grid') is to use the energy held in the batteries of electric and rechargeable hybrid vehicles to feed power into a home or local grid via special charging docks. In this way, a car can be used as a way of storing energy and providing it according to need.