ISO 15118 Turns Parked Vehicles Into Distributed Grid Storage

ISO 15118 enables electric vehicles to act as distributed energy storage for grid balancing, supporting demand response programmes, peak shaving and frequency regulation, and easing the integration of renewable generation and microgrids.

The appeal is a matter of arithmetic. A car is parked for the large majority of its life with a battery far larger than a house consumes in a day, and that capacity is otherwise idle. Aggregated across a city it is storage on a scale no utility would build deliberately, already paid for by someone else, sitting on the distribution network where it is most useful.

The obstacles are commercial and behavioural rather than technical, which is where most V2G discussion goes wrong. A driver will not accept arriving at a car with less charge than expected, so any dispatch has to respect a departure time and a floor the owner sets. Battery warranties have to account for cycles the manufacturer did not anticipate. And someone must settle payment for energy flowing backwards across a meter that was designed to measure one direction. The communication standard is the precondition, not the product — with it those problems become negotiable, and without it they cannot be addressed at all.