Offer the ability to power your house from the vehicle.
Imagine using photovoltaic during daytime: charging your Tesla, supplying the household with electricity. In the evening your PV system doesn’t generate power anymore. But instead of buying electric power, it would be perfect to use some kW from your recently charged car.
Mitsubishi and other companies are supporting a system like this (keywords: smart grid, bidirectional charging). This system is even more interesting regarding a car with a huge battery.
Moderator: This is well beyond a software update, as a major redesign of the charging/battery electronics is required. That doesn’t mean Tesla couldn’t implement such a feature on future vehicles!
A new wall-charger connection would also need to be designed to flow the power in both directions and protect both the house electrical system as well as the vehicles.
(voting combined from a close duplicate that has been removed)