Offer a version of the car to send power to a wall mounted DC to AC converter to power the house in the event of a grid power outage.
This requires new hardware external from the car, connected to the house’s electrical panel. Electrical code also requires the house power to be disconnected from the external line to prevent power company staff from being electrocuted. A split panel may be necessary depending on the power supplied. All this could require significant house electrical work, perhaps $5K or more not including Tesla’s equipment.
Costs would be reduced if it could somehow be wired into an existing Solar inverter and the proper switchover circuitry is in place. Most Solar installations do not have the necessary switchover circuitry (i.e. they don’t supply power in a blackout).
Tesla’s Powerwall might integrate in some way.
(rewritten by moderator)