Acorn,The bank of under-utilised EV batteries has great...

Acorn,
The bank of under-utilised EV batteries has great potential as a grid back up. Particularly if EVs become dominant.

There are quite a few conceptual and engineering problems to overcome but none of these are impossible;

1) Given that the vehicle owner has invested in the battery, is having its life reduced by drawdown and is perhaps inconvenienced how is the owner compensated for the drawdown.
2) Can the EV owner choose to "opt out" if the financial incentive isn't attractive to them. Is participation truely optional.
3) Can the EV owner choose to reserve the battery capacity for their own home when the grid is in shortfall or does the need of the community reign.
4) The LV grid transformers, routing, monitoring and switching need to be able to cope with reverse flow.