Smart Charging: parked EV batteries can save billions in grid balancing. 95% of a car’s time is spent parked. It’s why parked and plugged-in EVs could be the battery banks of the future, stabilising grids powered by wind and solar. More than 1bn EVs could be on the world’s road by 2050, their 14 TWh of EV batteries dwarfing the projected 9 TWh of stationary batteries, according to the IRENA report “Innovation Outlook: smart charging for electric vehicles”. Smart charging could therefore save billions of dollars in grid investments. Distribution system operator Stromnetz Hamburg is testing a smart charging system which, when fully implemented, could reduce grid investments by 90%. But there are specific challenges, including: slow charging (rather than fast) is better suited to grid balancing; “car sharing” reduces an EV’s grid availability; charging infrastructure at home and at the workplace is critical.